Wrinkled Celotex - indicative of an issue?

been left out in the cold thats all.

delta expansion coefficients

Yes, so it does correlate with potential shrinkage of that face (or the material closer to it than the other side.

Maybe so, although I was going to fit them on Friday so don't have long to wait! I think I was more wondering if I should be raising it with the supplier (which I have just done, but more as an enquiry than threatening a rejection or anything).

Okay, that's reassuring.

I thought the first response was going to be an straight up "Shocking. I wouldn't even accept them as seconds!" or something along those lines!

I thought you were talking about /cellulite/ until I re-read the subject line (a female preoccupation that appears to have been invented in the late 60s).

Not at all IMHO.

My only concern would be damage to the wrinkles, which of course would make the foil face porous.

Well, if that's so, they will flatten out spontaneously as they equalise.

I have had lots of this insulation and never seen this sort of thing. I have never seen visible expansion. I have seen concave edges but not enough to matter.

It's closed cell structure so shouldn't absorb water either.

It may not matter, depending on application and how small you are cutting it up.

Think about it. They are intended to go where it's hot on one side and cold on the other.

They seem to have a lot of seconds judging by the market. Usually they have voids in the foam or mechanical damage.

And leaned against a wall probably, if they are bowed. I often wonder though, if these insulation panels are supposed to insulate, how come they can show this sort of effect if cold on one side, rather makes you wonder about their long term integrity. I cannot see the picture, but have heard of this before and it jogged my mind.

Brian

slight wrinkling like that is immaterial

NT

The supplier said similar and they also offered to replace any bowed boards should they be a problem for my application but the bowing is only slight (<10mm over the full length) and so I don't think that'll be necessary.

Are the wrinkles on the "inside" of the bow iyswim?

I wonder if they'll come right after temps have stabilised across /through them?

Well, after all once they're in & doing their job they'll be trying to do the same thing...