Veneer Repairs - A few simple questions [Archive]

Wakefield Turntables

11-05-2014, 19:23

I'm in the middle of refurbing some JR149's and need a little help. Forgive the basic nature of the questions.

1. Can you apply a new veneer over an old veneer?

2. I have many scratches on the top of my speakers. Is it better to apply fresh veneer or try and somehow polish them out?

http://i98.photobucket.com/albums/l247/WAKEFIELDAUDIO/DSCN1297_zpsa8ba1145.jpg (http://s98.photobucket.com/user/WAKEFIELDAUDIO/media/DSCN1297_zpsa8ba1145.jpg.html)

3. How the heck do you repair chips in the chipboard? Is it a case of wood filler and then sanding this down and applying new veneer over the top?

http://i98.photobucket.com/albums/l247/WAKEFIELDAUDIO/DSCN1296_zpsd49fc54f.jpg (http://s98.photobucket.com/user/WAKEFIELDAUDIO/media/DSCN1296_zpsd49fc54f.jpg.html)

http://i98.photobucket.com/albums/l247/WAKEFIELDAUDIO/DSCN1295_zpsdb18bff9.jpg (http://s98.photobucket.com/user/WAKEFIELDAUDIO/media/DSCN1295_zpsdb18bff9.jpg.html)

http://i98.photobucket.com/albums/l247/WAKEFIELDAUDIO/DSCN1293_zpsf3a2b628.jpg (http://s98.photobucket.com/user/WAKEFIELDAUDIO/media/DSCN1293_zpsf3a2b628.jpg.html)

Thanks in advance.

Gordon Steadman

11-05-2014, 19:40

Provided the old veneer is rubbed down properly and the surface is dead flat, there is no problem veneering over the existing or trying to sand out the scratches. However, given the other damage to the edges, I would be making those good first and then you will find it difficult to avoid having to reveneer. I fill small dents with superglue and wood dust. Once the edges are good then some new veneer would finish it off. I would do the edges too so that the colour is a good match. If the other end is OK, a small difference in colour shouldn't show. I use contact adhesive for veneer these days but you can get iron on which is quite effective.

Of course, if you want to be adventurous, you could redo all four sections in some really nice veneer, rosewood or burr elm perhaps. Might not be original but who cares about that other than collectors? Would look great.

Wakefield Turntables

11-05-2014, 19:43

Thanks Gordon, what grade sandpaper would you use, I only ask cos I'm off on a shopping trip tomorrow and can purchase some.

Gordon Steadman

11-05-2014, 20:00

Thanks Gordon, what grade sandpaper would you use, I only ask cos I'm off on a shopping trip tomorrow and can purchase some.

To rub down for reveneering, I'd probably use 120 or 180. That would cut reasonably quickly and still leave a good surface. If you are just rubbing down, then 240. It might be wise to remove any wax first with some acetone to avoid clogging the paper too quickly. Wrap the paper around a piece of flat wood to ensure the surface remains flat.

Of course, if the veneering troubles you at all, you could just fill the whole thing and then spray the caps. Maybe pink or green or something!

Wakefield Turntables

11-05-2014, 20:06

YNWaN

11-05-2014, 20:55

I've not seen that product before but I have used iron on veneer (where the already applied glue is activated by the heat of the iron) and real veneer - not cut to shape at all and you have to clamp and glue it all by hand. The iron on stuff is less exotic but is very easy to use (you can even get it pre-cut for banding edges)). No, you don't have to remove the old veneer but I would sand it first with quite a coarse glass paper. I generally use car body filler to fill in chips etc - or just make new tops and bottoms from scratch.

The Barbarian

11-05-2014, 21:16

The problem is the original board has the edge slighty rounded off. It really needs to be perfectly square to re-veneer, it would be much easier with a fresh board to veneer tbh...

Audioflyer

11-05-2014, 22:52

You may be able to lift the scratches out of the veneer, by placing a damp cloth over them and use the tip of a hot clothes iron and follow the path of the scratches.
The secret is not to press to hard and let the moisture expand the wood fibre.

If this doesn’t work you will need to sand them down I find wet & dry works best and can be bought form any car accessory shop.
I would also recommend that you get eight sheets of the following 320,480,600 grit and 2 sheet of 1000 grit this should be enough do for all four panels.

For the exposed chipboard damage you will need to cut it away and make sure it parallel to the main surface.

I prefer iron on veneer if you have a look on evil-bay you can find veneer strips from 10mm to 50mm wide, look at you panel the finish look like Teak veneer.

If the damage to the chipboard is not very deep you can pack it out with strips of veneer cut to shape.

I hope it make sense it late.

Sharif.

Barry

12-05-2014, 00:44

The following might be of some interest/help: http://theartofsound.net/forum/showthread.php?7659-On-the-cosmetic-refurbishment-of-used-classic-or-vintage-audio-equipment

Gordon Steadman

12-05-2014, 05:23

My plans are to do the following.

1. Fill all holes in, sand these down to make flat surface to apply a new veneer.
2. I found this product. http://www.thewoodveneerhub.co.uk/Peel-n%27-Stick/c20/index.html which I think would mean that I wouldn't need to remove any old wax. It looks like it just sticks over the old veneer.

3. Was re-veneered, oil an oil to fetch the grain up.

Does this seem a sensible plan?
Sounds fine..... Andre has a point about the rounded over edges but as you are reveneering, just sand until its square. This means that any wax will have gone anyway but nothing will stick properly over wax. As I said, the paper will clog up but it will remove the wax and old finish eventually.

The originals were not overfinished and still look like wood. I only use anything over 240 grade paper if I'm looking for a glasslike finish. Obviously, sand the new veneer WITH the grain only and sand very lightly between coats of oil. Let each one dry properly before applying the next.

I have no experience with peel off or iron on veneer so can't comment on the stuff in your link. Hot glue or contact for me. Old school stuff.

PS. If you feel confident enough and have a very sharp chisel, you could just remove the old veneer completely. This is what I would do but it would take a bit more work.

Naughty Nigel

12-05-2014, 19:15

If you are planning to use an 'oil' on your timber I would recommend something like Rustin's Danish Oil, which is a proper drying oil, and will dry to a hard film after a week or two. For best results apply multiple coats with a clean cotton cloth.

Danish Oil penetrates well, and once fully dried it may be overcoated with a conventional varnish if you want a glossy finish.

Avoid the so called 'yacht varnishes' sold by DIY outlets such as B&Q, as most are no more than low-cost commercial marine varnishes repackaged for the DIY market. If you want a rally good varnish I can thoroughly recommend Epifanes, a Dutch manufactured varnish sold by most good yacht chandlers. It isn't cheap but it is very good.

Epifanes varnish is available in both gloss and 'rubbed effect' (satin) finishes. However, for the best possible satin finish wait for the varnish to become fully hard and dry (usually two or three weeks), and then gently rub the surface with fine wire wool dipped in beeswax. That is how the best yacht builders do it. :)

Edit: One final thing, drying oils and varnishes are quite reactive as they dry (cure) by absorbing atmospheric oxygen from the air. Open up any rags after use to minimise heat build up, and ideally keep them outside to minimise fire risk. Don't leave them crumpled up on your wooden bench in the garage!

Nigel.

Wakefield Turntables

12-05-2014, 19:32

Thanks for the info. I will probably take some photo's of how the guys who designed the 149's actually veneered them, It's not pretty. :doh:

awkwardbydesign

12-05-2014, 21:54

I have no experience with peel off or iron on veneer so can't comment on the stuff in your link. Hot glue or contact for me. Old school stuff.

PS. If you feel confident enough and have a very sharp chisel, you could just remove the old veneer completely. This is what I would do but it would take a bit more work.

I use contact adhesive and raw veneer for large areas, and iron-on edging. If the tops are ready veneered ply or chip, you won't be able to remove the veneer with a chisel, IME. Polyester body filler should work to square up the edges before re-veneering, but make sure there is no wax left; solvent or sanding (or both!).
And if you varnish the veneer, beware of water based varnish; it can make the veneer swell. I speak from bitter experience!

PaulStewart

12-05-2014, 23:34

As I said, the paper will clog up but it will remove the wax and old finish eventually.

When I was a nipper, my grandfather, who was apprenticed as a cabinet maker and French polisher in 1913, taught me to use fine wire wool to rub down anything with a wax or varnish as unlike sandpaper, it won't clog. I have used it ever since when restoring vintage kit, especially on veneers. I'm starting the restoration of an A&R A60 at the weekend and will use this method.

nat8808

13-05-2014, 01:37

When I was a nipper, my grandfather, who was apprenticed as a cabinet maker and French polisher in 1913, taught me to use fine wire wool to rub down anything with a wax or varnish as unlike sandpaper, it won't clog. I have used it ever since when restoring vintage kit, especially on veneers. I'm starting the restoration of an A&R A60 at the weekend and will use this method.

My mum has told/shown me the same thing - wire wool rather than sandpaper.

nat8808

13-05-2014, 01:53

Winding back to the OP..

I find Rustin's Scratch Remover is almost miraculous. Basically it is just a wax/oil mixture which fills in the grooves of a scratch but which allows the colour beneath to come through so well that the scratch disappears, at least after a few goes of rubbing it in well.

I always clean off the surface with a surface cleaner for the purpose beforehand - again Rustins does one. Think it's basically some kind of meths-like mixture although I've a vague recollection of a home-made substance of something like meths and white vinegar too - although that might be for removing water marks? My mum once helped with a pair of speakers, got the really bad water mark/green stuff (might have been a copper plant pot?) out completely and after oiling could have been new. Wire wool with the mixture she'd made.

As Andre says, you need a really sharp edge to get the veneer on the sides meeting the top properly - MUCH easier to therefore have some circles cut out by some local work shop fresh. Then you can practice restoring what you have and practice the veneering the new pieces too - then choose between the two/sell on the others as spares if you wish. Why not get some hardwood circles cut out? No veneering, no sanding, no filling - just some rubbing with wax or oil.

Veneering over veneer - or papering over the cracks - sounds like an unneccesary complication and recipe for a bad result to me.

Gordon Steadman

13-05-2014, 07:16

If the tops are ready veneered ply or chip, you won't be able to remove the veneer with a chisel

Sorry, this is nonesense. I said if you have a sharp chisel - I do it all the time.

Gordon Steadman

13-05-2014, 08:03

My mum has told/shown me the same thing - wire wool rather than sandpaper.

Yup, I use wire wool all the time but....... make very sure that there is no trace of the stuff left on the surface. It can rust. Even just a spot can turn red and stain the wood. If using oak, avoid altogether unless the grain is completely filled beforehand.

Kember

13-05-2014, 08:14

Just a thought, and very slightly OT, but would it not be perfectly feasible (and possibly better from an audio pov) to replace the tops with a proper hardwood disc? More expensive possibly, but given the size it is probable that you could find an offcut of a kitchen worktop or somesuch.

You have the template, after all!

Peter

Naughty Nigel

13-05-2014, 08:53

Yup, I use wire wool all the time but....... make very sure that there is no trace of the stuff left on the surface. It can rust. Even just a spot can turn red and stain the wood. If using oak, avoid altogether unless the grain is completely filled beforehand.

Oak is very acidic, and encourages rapid corrosion of iron and steel. Ask any boat builder! (The effect is known as 'Nail Sickness' because it destroys iron fastenings.)

Just a thought, and very slightly OT, but would it not be perfectly feasible (and possibly better from an audio pov) to replace the tops with a proper hardwood disc? More expensive possibly, but given the size it is probable that you could find an offcut of a kitchen worktop or somesuch.

You have the template, after all!

Peter

Chipboard and MDF are chosen not so much for their price but because they are acoustically dead; which is what is needed in a loudspeaker cabinet. Hardwoods and plywoods tend to resonate, which is why they are used in musical instruments such as pianos and violins. A violin made from MDF would sound 'orrible! :)

Nigel.

Kember

13-05-2014, 09:01

Gordon Steadman

13-05-2014, 09:17

Nigel,

I'm sure you are generally right, but does that apply even to ebony, iroko or some of those other naughty African/S Asian woods we should not really be buying any more? They might be a bugger to work, however...

Best

P
I used to use such woods for musical instruments before they were overharvested. You are right about the working though. Some of them were a right pain.

I might just try an MDF violin or guitar. Might be an interesting challenge!!

Naughty Nigel

13-05-2014, 09:22

Nigel,

I'm sure you are generally right, but does that apply even to ebony, iroko or some of those other naughty African/S Asian woods we should not really be buying any more? They might be a bugger to work, however...

Best

P

I have never had the pleasure of trying them, but their density is no guarantee of their acoustic behaviour. In fact, soft woods tend to resonate less than hardwoods. I bet they would smell nice when cut though!

Of course chipboards and MDF also have the advantage of dimensional stability, which tends to be a problem in proper tree woods.

If anyone is interested, John Boddy timber at Boroughbridge in North Yorkshire has a fascinating shop selling everything from exotic timbers to veneers and word working machinery. Well worth a visit.

Nigel.

Reffc

13-05-2014, 10:32

Oak is very acidic, and encourages rapid corrosion of iron and steel. Ask any boat builder! (The effect is known as 'Nail Sickness' because it destroys iron fastenings.)

Chipboard and MDF are chosen not so much for their price but because they are acoustically dead; which is what is needed in a loudspeaker cabinet. Hardwoods and plywoods tend to resonate, which is why they are used in musical instruments such as pianos and violins. A violin made from MDF would sound 'orrible! :)

Nigel.

I don't think MDF is acoustically dead at all...in fact it rings like a bell! I've tested various timbers using an accelerometer and applying vibration to measure amplitude and decay times in various panels. MDF didn't do well at all. Chipboard (more accurately particle board) was much better as it has better self damping and many well made speakers of yesteryear used particleboard for that reason. Ply wasn't bad at all either (short decay time due to stiffness). The main reason that MDF is used is 1) because it's cheap and easy to machine and 2) because it can be strengthened by bracing to shift resonance up out of the midrange area. The fashion towards slim floor standers is partly, I'm convinced, due as much to cheapness of manufacture as it is for fashion reasons.

All materials have a natural resonance point (or points) and whilst for musical instruments, specific resonance characteristics help voice the instrument, loudspeakers don't want it! There are designs (Harbeth and AN speakers for example) where thin wall design or panel resonance is used to help boost bass output (think of the cabinet panels as passive radiator drivers) but personally, I always find them a little too coloured sounding for my tastes in the bass compared with thicker walled stiffer cabinet designs.

Hardwoods are not suited for loudspeakers partly due to resonance but partly because some tend to twist or move with age and changes in relative humidity and getting cabinet consistency isn't easy. Furniture board doesn't warp or twist as much but a good slow grown laminated Baltic Birch Ply remains for me the best of the timber laminates due to stiffness, predictability, consistency and strength. You can work out panel resonance accurately for any given panel size and thickness in order to determine internal bracing requirements. You can do this with MDF as well, but having built several test cabinets, ply was by far the better material.

Just my tuppenceworth.

Naughty Nigel

13-05-2014, 11:01

I don't think MDF is acoustically dead at all...in fact it rings like a bell! I've tested various timbers using an accelerometer and applying vibration to measure amplitude and decay times in various panels. MDF didn't do well at all. Chipboard (more accurately particle board) was much better as it has better self damping and many well made speakers of yesteryear used particleboard for that reason. Ply wasn't bad at all either (short decay time due to stiffness). The main reason that MDF is used is 1) because it's cheap and easy to machine and 2) because it can be strengthened by bracing to shift resonance up out of the midrange area. The fashion towards slim floor standers is partly, I'm convinced, due as much to cheapness of manufacture as it is for fashion reasons.

All materials have a natural resonance point (or points) and whilst for musical instruments, specific resonance characteristics help voice the instrument, loudspeakers don't want it! There are designs (Harbeth and AN speakers for example) where thin wall design or panel resonance is used to help boost bass output (think of the cabinet panels as passive radiator drivers) but personally, I always find them a little too coloured sounding for my tastes in the bass compared with thicker walled stiffer cabinet designs.

Hardwoods are not suited for loudspeakers partly due to resonance but partly because some tend to twist or move with age and changes in relative humidity and getting cabinet consistency isn't easy. Furniture board doesn't warp or twist as much but a good slow grown laminated Baltic Birch Ply remains for me the best of the timber laminates due to stiffness, predictability, consistency and strength. You can work out panel resonance accurately for any given panel size and thickness in order to determine internal bracing requirements. You can do this with MDF as well, but having built several test cabinets, ply was by far the better material.

Just my tuppenceworth.

Thanks for your comments Paul.

I suspect your experience with MDF will depend on the resin to particle ratio. A resin rich board will indeed ring like a bell; as will any other resin rich composite, but a particle rich composite should be fairly dead.

I personally like concrete, but it isn't always practical, or popular with SWMBO!

I also wonder about advanced composites, such as sandwich structures. Most sandwich structures are lightweight yet incredibly stiff, and can be acoustically dead if the right core material is chosen (end-grain balsa or foam). However, I guess that apart from cost there wouldn't be much interest in loudspeakers that weighted only a kilogram or two each.

I should add that I have effectively damped loudspeaker cabinets and equipment housings by applying the sound deadening material sold for use in motor vehicle bodies. The material is only about two millimetres thick, but is strongly self-adhesive and will damp unwanted resonance in most substrates.

Nigel.

Reffc

13-05-2014, 11:23

I agree entirely Nigel. The sort of MDF boards bought at your local DIY store tend to use very fine (dust) particles and are fairly resin rich. It was a typical DIY store MDF I tested and I suspect its this cheaper and more readily available grade which is used by many manufacturers.

RE concrete, I was having a conversation recently with someone who wanted to build a set of speakers in concrete and I suggested using the method of building the ply formers and using glass reinforced concrete which is easy to form and which can be used with small aggregate particles (10mm) but the SWMBO factor is a hard one to get over! It is an ideal material in many ways. I think there have been a few European manufacturers of concrete speakers although I suspect they ultimately have limited WAF plus weigh a ton (almost literally in the case of large floor standers). They can take a finish though with multi-layers of sealing coat and paint over-lacquered.

I think that there's a lot yet to come from composites as technically, laminated composite construction using kevlar, polyester fibres, carbon fibre etc has loads of merit. You can design the stiffness into a relatively thin structure and the damping layer too.

Bamboo is also another sustainable material and it has excellent natural properties but does need careful heat processing to get the best from a bamboo laminate. To my knowledge, only one UK company is manufacturing such bamboo laminates but the cost is a little prohibitive.

I guess that there would be major advantages commerically too. For me, using sustainable timbers seems more eco-friendly long term and timber is such a lovely material to work.

awkwardbydesign

13-05-2014, 11:40

I don't think MDF is acoustically dead at all...in fact it rings like a bell! I've tested various timbers using an accelerometer and applying vibration to measure amplitude and decay times in various panels. MDF didn't do well at all. Chipboard (more accurately particle board) was much better as it has better self damping and many well made speakers of yesteryear used particleboard for that reason. Ply wasn't bad at all either (short decay time due to stiffness). The main reason that MDF is used is 1) because it's cheap and easy to machine and 2) because it can be strengthened by bracing to shift resonance up out of the midrange area. The fashion towards slim floor standers is partly, I'm convinced, due as much to cheapness of manufacture as it is for fashion reasons.

All materials have a natural resonance point (or points) and whilst for musical instruments, specific resonance characteristics help voice the instrument, loudspeakers don't want it! There are designs (Harbeth and AN speakers for example) where thin wall design or panel resonance is used to help boost bass output (think of the cabinet panels as passive radiator drivers) but personally, I always find them a little too coloured sounding for my tastes in the bass compared with thicker walled stiffer cabinet designs.

Hardwoods are not suited for loudspeakers partly due to resonance but partly because some tend to twist or move with age and changes in relative humidity and getting cabinet consistency isn't easy. Furniture board doesn't warp or twist as much but a good slow grown laminated Baltic Birch Ply remains for me the best of the timber laminates due to stiffness, predictability, consistency and strength. You can work out panel resonance accurately for any given panel size and thickness in order to determine internal bracing requirements. You can do this with MDF as well, but having built several test cabinets, ply was by far the better material.

Just my tuppenceworth.
I tend to agree with most of this post.
I built 2 pairs of otherwise identical speaker cabinets in the '70s, one from 18mm MDF (Medite) and one from 700kg/m3 chipboard. The chipboard pair sounded less coloured; not scientific, I know, but good enough for me.
Manufacturers like MDF for a number of reasons; the edges are smooth and take a profile, and can be stained to look like wood, and they know how long their tools will last, making production runs easier to plan.
MDF may be dimensionally stable in length and width, but NOT in thickness; it changes with humidity, so if corners are butt jointed, lines appear as it shrinks.
I use it for ease and cost, but much prefer birch ply, although there are different qualities there also. Many years ago Finnish was the densest, but oily, and Russian was the prettiest, but lighter and cheaper. Now there is Chinese and Baltic, but I don't know details.
Laminating ply and MDF is my usual method of construction these days.
700kg/m flooring chipboard doesn't seem to be the same; it used to have 5 distinct layers with good self damping.

Naughty Nigel

13-05-2014, 12:09

Reffc

13-05-2014, 12:48

Thinking on, I bought a cabinet kit from Wilmslow Audio some years ago, and their MDF board was quite dead. The material also seemed to crumble or powder fairly readily at the edges, and did not have the knife-sharp edges of some other MDF boards that I have come across. Presumably Wilmslow will have bought their board for its acoustic properties?

Regarding composite materials, there indeed considerable scope for using sandwich materials in loudspeaker enclosures. However, such composites are expensive, and (unlike MDF) require skilled fabrication.

There is another avenue to explore, and that is of shape. Modern structures make extensive use of 'shape stiffness' to achieve optimum mechanical strength and stiffness. Just look at modern car bodies, where curves are pressed into the thin metal to provide stiffness.

Similar techniques could be used in loudspeaker enclosures to reduce panel resonance. An ideal enclosure would be spherical in shape, but even a cylindrical enclosure would provide significant reductions in cabinet colouration.

In short, the ubiquitous loudspeaker 'box' is probably the worst shape of all! :)

Nigel.

You mean like this Nigel? ;)

http://referencefidelitycomponents.co.uk/wp-content/uploads/2013/04/MG_6736-200x300.jpg

6 layers of 4mm slow grown Latvian Birch Ply laminated in a custom built vacuum former using "lossy" (and expensive!) specialist PVA glues.

This is an expensive way to create a panel, but yes, it does add considerable stiffness and is also good in respect of controlling internal standing waves.

Boxs are fine providing that their stiffness requirements can be accurately met through thickness of panels and number of internal braces (plus spacing). Important also to understand that equal spacing of internal braces is a big "no-no". Front baffle width/shape is an important part of speaker design.

Cylindrical is a good shape as long as the drivers are located on the curved plane. Place on the end (flat) profile results in the very worst edge diffraction possible with a perfect square being the next worst. Spherical is the best shape but expensive in laminated timber as each sphere is made up of multiple cut cylinders laminated, shaped and smoothed. I'm a big fan of the Cabasse spherical speakers...very low colouration indeed.

Naughty Nigel

13-05-2014, 13:54

You mean like this Nigel? ;)

http://referencefidelitycomponents.co.uk/wp-content/uploads/2013/04/MG_6736-200x300.jpg

Yep, that's the idea. :)

I spotted some large concrete pipe sections beside the new A1M the other day, and wondered whether they would work as loudspeaker enclosures if capped properly?

Somehow I think I would have a lot of explaining to do, even if I did manage to get them home! :lol:

As an aside, I was talking to an organist friend recently about a new electronic instrument installed at the church where he plays. The loudspeaker systems attached to these instruments tend to be the weakest link in the chain, as they need to deliver very high sound pressures at very low frequencies (CCCC = 16 Hz), so loudspeaker enclosures need to be large but stiff to avoid colouration. Several hundred watts of amplification is needed, and is usually Class D for efficiency.

Anyhow, the crux of the matter is that the organ builders installed a concrete column of about 20' (six metres) height, and fitted the bass speakers in the bottom of the column. The column is neatly hidden inside a timber enclosure. Higher frequencies are handled by a total of thirty-six smaller speakers (driven by 18 amplifiers) higher above the console so the sound comes from where you would expect to hear it. This little lot cost about £65,000!

Nigel.

Gordon Steadman

13-05-2014, 13:59

As an aside, I was talking to an organist friend recently about a new electronic instrument installed at the church where he plays. The loudspeaker systems attached to these instruments tend to be the weakest link in the chain, as they need to deliver very high sound pressures at very low frequencies (CCCC = 16 Hz), so loudspeaker enclosures need to be large but stiff to avoid colouration. Several hundred watts of amplification is needed, and is usually Class D for efficiency.

Anyhow, the crux of the matter is that the organ builders installed a concrete column of about 20' (six metres) height, and fitted the bass speakers in the bottom of the column. The column is neatly hidden inside a timber enclosure. Higher frequencies are handled by a total of thirty-six smaller speakers (driven by 18 amplifiers) higher above the console so the sound comes from where you would expect to hear it. This little lot cost about £65,000!

Nigel.

A shame that so many pipe organs are either thrown out or just deteriorate beyond economic repair. It would be interesting to hear how close the sound is. How does your friend feel about it.

The building and repair of organs was part of my studies and I used to love clambering around inside the things. I still have the little hand pumped organ I built at college, must get around to repairing the bellows.

Barry

13-05-2014, 14:33

Yep, that's the idea. :)

I spotted some large concrete pipe sections beside the new A1M the other day, and wondered whether they would work as loudspeaker enclosures if capped properly?

Somehow I think I would have a lot of explaining to do, even if I did manage to get them home! :lol:

Many years ago, Wharfedale published a DIY design for a speaker using a 10" spun concrete sewer pipe (please - no jokes about it sounding crap!).

PaulStewart

13-05-2014, 14:52

Many years ago, Wharfedale published a DIY design for a speaker using a 10" spun concrete sewer pipe (please - no jokes about it sounding crap!).

They most certainly didn't sound crap, I built a pair in about 68/69 when I saw the design in the Gilbert Briggs book and a near neighbour was having some drain work done and there were a couple of pipes left over, which he gave me. Mine had Wharfedale Bronze 8s pointing upwards to a conical reflector made of lead and sand filled. Inside was a resistive panel that was moved up and down, till optimum tuning was found. Eventually a pair of EMI tweeters were added per side. They sounded awesome especially with acoustic bass and pipe organ. Got taken apart and the drivers moved to wooden cabs when I went to college :(

Barry

13-05-2014, 15:03

They most certainly didn't sound crap, I built a pair in about 68/69 when I saw the design in the Gilbert Briggs book and a near neighbour was having some drain work done and there were a couple of pipes left over, which he gave me. Mine had Wharfedale Bronze 8s pointing upwards to a conical reflector made of lead and sand filled. Inside was a resistive panel that was moved up and down, till optimum tuning was found. Eventually a pair of EMI tweeters were added per side. They sounded awesome especially with acoustic bass and pipe organ. Got taken apart and the drivers moved to wooden cabs when I went to college :(

Nice! My first speakers were DIY, made following one of the Gilbert Briggs's designs. They used Wharfedale RS 8DD drivers in an 18" x 10" x 8" distributed-port enclosure. (It was a long time ago, so the dimensions may not be quite correct.) I used them for about four years, then replaced them with Quad electrostatics.

nat8808

13-05-2014, 15:27

Chipboard and MDF are chosen not so much for their price but because they are acoustically dead; which is what is needed in a loudspeaker cabinet. Hardwoods and plywoods tend to resonate, which is why they are used in musical instruments such as pianos and violins. A violin made from MDF would sound 'orrible! :)

Nigel.

I don't think any of this applies much to the JR149 which Andy wants to restore.

I'm not even certain the circular ends even make up a functional part of the cabinet!

This photo might suggest that the cabinet ends are made from some kind of hardboard and the veneered ends just adding mass and there to look nice.. therefore go for some real hardwood ends!

http://farm9.staticflickr.com/8112/8605552129_2aa67a9a85_o.jpg

This photo also suggests that the circular ends aren't the cabinet walls, else that hole would be sealed in some way:

http://farm9.staticflickr.com/8234/8584619239_ee7a6c1406_o.jpg

Reffc

13-05-2014, 15:30

Briggs book "Loudspeakers: The why and how of good reproduction" Still stands as a great reference piece today. It was the first book I picked up a couple of decades back when first learning about loudspeaker design. Given that this book was first published in 1948, it's testament to how very little has really changed bar materials science and production techniques improving driver quality. Also pre-T-S parameters, so not as much to help the budding designer back then!

Naughty Nigel

13-05-2014, 15:49

A shame that so many pipe organs are either thrown out or just deteriorate beyond economic repair. It would be interesting to hear how close the sound is. How does your friend feel about it.

The building and repair of organs was part of my studies and I used to love clambering around inside the things. I still have the little hand pumped organ I built at college, must get around to repairing the bellows.

I think 'mixed feelings' would sum it up well.

The instrument has a fantastic specification and stop list (3 manuals and 64 stops, including two 32' stops on the pedal) which most parish organists could only dream of. Better still they all work every Sunday, whatever the weather, and are always in tune!

In addition to the 64 'native' English/German stops it also has a French voice setting which provides a passable imitation of a Cavaillé-Coll instrument (with 48 stops IIRC), plus Harpsichord, bells and one or two others.

As such it is a very impressive instrument and the sound is very good; but it just isn't the real thing. Interestingly, non-organ buffs believe it is a pipe organ until they notice there are no pipes, and are told that the sound is coming from loudspeakers. Meanwhile, the 'Anoraks' amongst us can tell instantly that it is a 'toaster'.

There is another down side in that there is a ¼" Jack socket hidden under the console, which will accept the output from a CD player. Wedding parties in particular tend to turn up bearing CD's from Comfort FM or whatever, and insist on playing awful recordings of excerpts that are heard on the hour every hour on such stations - presumably to make their day 'unique'? :confused:

Sadly the cost of maintaining real pipe organs is becoming increasingly prohibitive, especially when major overhauls are required every thirty or forty years. It is a craftsman's job involving joinery, lead working, leathering and so forth, so time and cost quickly escalate. To put this into perspective, Newcastle City Hall has a wonderful 1928 Harrison which is a real gem, but has fallen into disrepair owing to almost constant central heating and lack of use. (Only a very selected few were allowed to play it.) The cost of overhaul is currently estimated at around £1,000,000, which I doubt will ever be found. :(

Nigel.

Gordon Steadman

13-05-2014, 16:01

I think 'mixed feelings' would sum it up well.

Newcastle City Hall has a wonderful 1928 Harrison which is a real gem, but has fallen into disrepair owing to almost constant central heating and lack of use. (Only a very selected few were allowed to play it.) The cost of overhaul is currently estimated at around £1,000,000, which I doubt will ever be found. :(

Nigel.

This is indeed a problem. My tutor was teaching because his income was drying up on the repair and maintenance side and that was twenty years ago. I hate central heating with a vengeance. Quite apart from preferring open fires for the kind of heat they put out, working almost exclusively in solid timber and now mostly antiques restoration, I spend my life repairing the ravages of dry heat. Drying out, surfaces crazing, bloody great splits, you name it. Lots of it down the CH:steam:

Its tragic that funds can't be found to save this part of our heritage. If I did the lottery and if the unlikely were to happen, a fund for fixing musical instruments would be one of the things I would put money into.

Wakefield Turntables

13-05-2014, 17:35

I will post some pics of my cabinets tonight and my thoughts on how to veneer them.

Gordon Steadman

13-05-2014, 17:47

I will post some pics of my cabinets tonight and my thoughts on how to veneer them.

Oh, is this a thread about your speakers?:eyebrows:

Naughty Nigel

13-05-2014, 19:27

For what it's worth I veneered a pair of Celestion DL8 Series II speaker cabinets about twenty-five years ago, having first stripped off the horrible black PVC veneer that they came in.

The veneering operation was slightly tricky as the font of the cabinets is chamfered rather than square, and there is a narrow margin of veneer around the font baffle. (Those who know the DL8's will know what I mean.)

I used Mahogany veneer from John Boddy at Boroughbridge, with sheets of iron on adhesive.

The trick with edges is to leave just enough excess veneer to sand off once the glue has set. Any sanding dust can be kept to make a filler!

The iron on adhesive should be fool proof enough, but I found that the heat required to melt it tended to split the veneer. If I did the job again I would probably choose a two-part epoxy adhesive. PVA glues can be used, but I don't like using water borne solutions on bare timber for the risk of staining. I wouldn't have the courage to use contact adhesives as veneer is delicate stuff, and once contact is made it is difficult to reposition the veneer. Epoxy of PVA would be much easier.

Finally I varnished then with several coats of two-part polyurethane yacht varnish (International Blue Peter Crystal) for a near piano gloss finish. Twenty five years on they still look good, although they have faded a little from the sun.

Nigel.

Wakefield Turntables

13-05-2014, 20:01

OK, i need to start thinking about how i'm going to cut the veneer. The worst bit for me is going to be the circular inside bits, I need a piece for the base and the upper inner of the speaker unit. I think I have come up with a method of cutting these which is a little hard to describe. But the bits I'm talking about are in the following picture

http://i98.photobucket.com/albums/l247/WAKEFIELDAUDIO/DSCN1319_zpse77235a5.jpg (http://s98.photobucket.com/user/WAKEFIELDAUDIO/media/DSCN1319_zpse77235a5.jpg.html)

I'll probably do these bit first, sanding the edges down so that they merge with the speaker's edge. The edge should be the easiest bit. The chaps at Jim Rogers simple finished off the veneer at the rear of the speaker where no-one looks, see the vertical join on the bottom pic

http://i98.photobucket.com/albums/l247/WAKEFIELDAUDIO/DSCN1317_zps7ea7610d.jpg (http://s98.photobucket.com/user/WAKEFIELDAUDIO/media/DSCN1317_zps7ea7610d.jpg.html)

So the edge is something I'm not that worried about I can buy stick on 22mm edge veneer pretty cheaply. I'll probably do the edges secondly and then concentrate on the top and bootom sections. The top and bottom veneer should simply be a case of applying the veneer on the top and bottom, applying even pressure for an even finish and then using a scalpal to neatly cut around the edge. I'll probably do these last.

Any thoughts, comments, does any one this make sense, is it logical?

The Barbarian

13-05-2014, 20:19

Naughty Nigel

13-05-2014, 20:20

I cut mine with a large pair of sharp scissors. I would think that any other method is asking for trouble but others may know better.

Nigel.

Gordon Steadman

13-05-2014, 20:25

I wouldn't have the courage to use contact adhesives as veneer is delicate stuff, and once contact is made it is difficult to reposition the veneer.

What's all this reposition stuff?? That suggests that a mistake might have been made!! Don't be silly:lol:

Gordon Steadman

13-05-2014, 20:29

I cut mine with a large pair of sharp scissors. I would think that any other method is asking for trouble but others may know better.

Nigel.

I have a veneer saw. However, I'm quite happy using scissors, Stanley knife or scalpel depending on the thickness of the wood.

(By the way, an earlier comment about using a sharp chisel.......if you think a Stanley knife is sharp, you haven't used a sharp chisel. The steel used in a good chisel is far superior to that of a Stanley blade and will take a far better edge. Stripping veneer is just a matter of a light push.)

Gordon Steadman

13-05-2014, 20:34

I'll probably do these bit first, sanding the edges down so that they merge with the speaker's edge. The edge should be the easiest bit. The chaps at Jim Rogers simple finished off the veneer at the rear of the speaker where no-one looks, see the vertical join on the bottom pic

So the edge is something I'm not that worried about I can buy stick on 22mm edge veneer pretty cheaply. I'll probably do the edges secondly and then concentrate on the top and bootom sections. The top and bottom veneer should simply be a case of applying the veneer on the top and bottom, applying even pressure for an even finish and then using a scalpal to neatly cut around the edge. I'll probably do these last.

Any thoughts, comments, does any one this make sense, is it logical?

Sounds OK. The edges should obviously be done last as, if there is an imperfection in the join (unlikely I know!!) its the edges which will show - at least underneath.

The Barbarian

13-05-2014, 20:47

I never re-did mine in Veneer the edge veneer is bad practice imho where they meet around the back. I made four brand new ones out of English oak..

:sofa:

Wakefield Turntables

13-05-2014, 20:49

Thanks Gordon, its advice like yours that helps a complete novice like me. I'll be going with American Walnut veneer as this is as near to original as I can find.

Gordon Steadman

13-05-2014, 22:17

Thanks Gordon, its advice like yours that helps a complete novice like me. I'll be going with American Walnut veneer as this is as near to original as I can find.

Great pleasure.

I need to have a practice myself. I have a speaker project coming up and some of the veneer work is going to be 'interesting'. There are eight drive units in each box so I'm going to having fun with the rebates!!

nat8808

14-05-2014, 00:14

Looks like the original construction is just that of the whole disc being veneered a then glued on top of the hardboard cabinet tops/bases.

If there's veneer between the chipboard and the hardboard then you can just chisel the top/base discs off the rest of the speaker by getting in between the veneer and the chipboard. Hopefully that makes sense. i.e. you pull off the discs in their entirety but allowing the veneer to stay stuck to the hardboard, just to prevent damage to the hardboard. Might not need too much effort, just something to start it and a few knocks with a block and hammer.

You can then veneer the whole disc once it's off.

I bet you that will be LESS effort and frustration than trying to veneer that inner edge! Have to break eggs to make the perfect omelette.

In all honesty though, the funny thing is that someone with the right tools and materials to hand could knock a better pair of these cabinets off in an afternoon! 2 x hardwood circles, 2x hardboard circles with a 4mm lip cut in, 2mm aluminium sheet bent into a cylinder with a flat front and holes drilled in the front + plus some deadening material and glue to stick it all together. Oh a black strip to hide the join around the back.

Yet someone without the tools and workshop will spend a week re-veneering..

Gordon Steadman

14-05-2014, 06:07

Yet someone without the tools and workshop will spend a week re-veneering..

Yes indeed.

Wakefield Turntables

14-05-2014, 07:37

Yes indeed.

True but it's my little escape and I enjoy learning new skills.

Gordon Steadman

14-05-2014, 07:56

True but it's my little escape and I enjoy learning new skills.

I think its easy for us 'professionals' to be slightly superior sometimes. As in all things, having the right tools for the job makes so many things fairly easy.

I started out by making a guitar on my mum's dining table. I'd never made anything in wood before. It laid the foundations and some of the skills learned have seen me through 50 years of pleasure (and income!!)

Some of the work I see here by amateurs is stunning. I sometimes think the only real difference between amateur and professional is that one of them does it for money - only sometimes though:).

So good to see you enjoy yourself, it is, after all, what its supposed to be about. I await the finished job with interest.

Wakefield Turntables

15-05-2014, 18:58

Naughty Nigel

15-05-2014, 19:12

It depends on the veneer, but basically keep oiling it with Danish Oil until the veneer is filled with oil and allow to dry for at least two weeks. Some people are happy to leave it at that. (You can achieve a glossy finish by flooding with oil or satin by rubbing off the excess.)

If you want to varnish it Epifanes is without doubt THE BEST varnish is in my opinion. Buy it from any good yacht chandlery.

Nigel.

Gordon Steadman

15-05-2014, 19:16

Right now I've got over my initial worry of applying a veneer I like a little info on how to finish it off. I presume I would do the following steps.

1. Clean the veneer down.

2. Oil the veneer with ?Danish oil?

3. Varnish

OK, so a three more questions

1. Whats the best thing to clean veneer with?

2. How many applications of Danish oil would I need?

3. What's the best varnish to use and how many coats am I going to need?

Thanks

A

I reckon there are a few ways of doing this!! In the first place, why does the veneer need cleaning? Has it got glue on it? If not, the rubbing down should clean it well enough

In all the years I have been doing this job, I have never used Danish oil so someone else will no doubt tell you about it. Because most of my work involves furniture that has been French polished, I use that or a modern water based polyurethane which I rag on. It gives a perfectly hard wearing surface, more than good enough for speakers too and needs very little maintenance. If the veneer has been rubbed down properly, a couple of coats seals it (ragged on, its dry enough for another coat after about half an hour) and I would normally put six to eight coats on thereafter. I don't see why you need both Danish oil AND varnish although I do see it suggested on here.

If I want gloss, I use acid catalised lacquer which can be rubbed to a glasslike finish.

Wakefield Turntables

15-05-2014, 20:03

Gordon,

Thanks, seems like I need to rub the veneer down and then simply wipe down/clean with damp rag, allow to dry and then apply the water based polyurethane finish. I'll get the thing fully veneered first!

Andy

nat8808

15-05-2014, 20:45

I wonder if Gordon was thinking about the veneer you're coving up or the new stuff you'll be applying.

I'd have thought the old stuff will just need a rub down to be flat and clean and probably to take the glue from the new veneer better.

Naughty Nigel

15-05-2014, 20:45

I reckon there are a few ways of doing this!! In the first place, why does the veneer need cleaning? Has it got glue on it? If not, the rubbing down should clean it well enough

In all the years I have been doing this job, I have never used Danish oil so someone else will no doubt tell you about it. Because most of my work involves furniture that has been French polished, I use that or a modern water based polyurethane which I rag on. It gives a perfectly hard wearing surface, more than good enough for speakers too and needs very little maintenance. If the veneer has been rubbed down properly, a couple of coats seals it (ragged on, its dry enough for another coat after about half an hour) and I would normally put six to eight coats on thereafter. I don't see why you need both Danish oil AND varnish although I do see it suggested on here.

If I want gloss, I use acid catalised lacquer which can be rubbed to a glasslike finish.

I am used to working with yacht finishes so that is how I would protect my loudspeakers.

I have to say I'm not a great fan of most water borne coatings. The polyurethanes that you are using are probably urethane oils or possibly urethane modified alkyds (where the oil or alkyd resin has been partially cross-linked (reinforced) with an isocyanate monomer), so you are effectively applying a pre-dried paint film; which is why flow and wetting is rarely a strong point. Such materials may be the future; just like integrated circuits and Class D amplification, but it's not what I like to use myself.

True polyurethanes are a different kettle of fish, being comprised of a polyol (polyester) base component, mixed and cross linked with an aliphatic isocyanate curing agent. These can provide phenomenal gloss (better than 90 GU at 60 °), hardness and durability, and also provide good film build if you want a 'piano gloss' type finish. That, however, is usually achieved commercially with polyester gelcoat type materials, as these can be applied in a single coat, and form an exceptionally hard, but brittle film. Thickness is about 500 µm (half a millimetre) before polishing.

The acid catalysed lacquers (using paratoluene sulphonic acid) can indeed provide hard-wearing high gloss finishes, but their volume solids and film build properties are much lower than the alternatives discussed above, so whilst you might achieve a good visual gloss the coating will only be 100 µm or so thick.

Regarding cleaning the veneer, I would avoid water or solvents. Thorough vacuum cleaning and a Tak Rag after sanding should be more than enough. The only timbers that I would recommend solvent wiping are very oily teak and some mahogany, but sadly you won't come across much of that today.

Nigel.

Wakefield Turntables

15-05-2014, 20:59

Thanks guys, any product recommendations, remember your talking to a complete newbie so be gentle.

Gordon Steadman

15-05-2014, 21:10

I am used to working with yacht finishes so that is how I would protect my loudspeakers.

I have to say I'm not a great fan of most water borne coatings. The polyurethanes that you are using are probably urethane oils or possibly urethane modified alkyds (where the oil or alkyd resin has been partially cross-linked (reinforced) with an isocyanate monomer), so you are effectively applying a pre-dried paint film; which is why flow and wetting is rarely a strong point. Such materials may be the future; just like integrated circuits and Class D amplification, but it's not what I like to use myself.

True polyurethanes are a different kettle of fish, being comprised of a polyol (polyester) base component, mixed and cross linked with an aliphatic isocyanate curing agent. These can provide phenomenal gloss (better than 90 GU at 60 °), hardness and durability, and also provide good film build if you want a 'piano gloss' type finish. That, however, is usually achieved commercially with polyester gelcoat type materials, as these can be applied in a single coat, and form an exceptionally hard, but brittle film. Thickness is about 500 µm (half a millimetre) before polishing.

The acid catalysed lacquers (using paratoluene sulphonic acid) can indeed provide hard-wearing high gloss finishes, but their volume solids and film build properties are much lower than the alternatives discussed above, so whilst you might achieve a good visual gloss the coating will only be 100 µm or so thick.

Regarding cleaning the veneer, I would avoid water or solvents. Thorough vacuum cleaning and a Tak Rag after sanding should be more than enough. The only timbers that I would recommend solvent wiping are very oily teak and some mahogany, but sadly you won't come across much of that today.

Nigel.

I understand at least 10% of that. I just use what works for me. I think you are being a little overcomplex for what is a simple job.