A Glis Glis ate my DHW Cylinder !

As it was in all likelihood polyurethane foam covering the cylinder why do you think that any new foam would corrode the copper? Have a look at this:

If you're still concerned, just stick some thin polythene (bin bag, etc) on the copper before you put the expanding foam over it.

Because I don't know about something that others on here might.

Have a look at

Looks pretty safe. Thanks, Jeff.

Actually, I've just looked at the cans of foam which were sold to me in December - and their expiry dates are all 02/2024.

What? Is the stuff that unstable? Looks like a rip-off - unless everyone but me knows that it'll go off in the can within 3 months of purchase. Says not to use it above 50°C, too.

I've Gas Tape that's been used to wrap an outside copper pipe 22 years ago and both tape and pipe look stable so maybe a wrap-round of that tape will retain a pad of fibreglass - bit like a false beard.

As for the gliss gliss - you're not even allowed to trap them - let alone zap them. Crazy.

PA

See my response to Jeff re: the junk I've been passed off with !!!

PA

Fairly sure expanding foam is safe on everything: I cant recall it ever having any stories or warnings of corrosion associated with it.

That's true - but in three months? We've all got a "flat" aerosol of WD40 somewhere - but after about 5-10 years, I reckon. ;-}

The can can lose pressure over time - especially if they have been used. Only way to find out is try and see. (or try your luck taking them back to the shop).

It is really not safe on some soft PVC like plastics - say for example a sealing sleeve on a WC pan connection. DAMHIK!