Check the expiry date of your expanding foam...
Yes, that is an deliberately obscure title as clickbait... but bear with me.
I have an old three legged tubular metal equipment rack in the shed, and had an idea to employ it by filling the voids in the tubes with expanding foam to deaden the ringing and perhaps make it usable.
It did not go to plan... Having spent 2 hours cleaning hardened foam out of the applicator gun, I squished the foam liquid in only to have it eventually dribble out of the tubes, partially expanded in places, in others just smeary fluid, making a horrific mess of the kitchen table, the floor and me. Now have a headache from the solvent fumes.:doh:
Expiry date of the tin of foam was 2015!:rolleyes: