Polycarb sheet & silicone

May 02, 2007 4 Replies

Went to B&Q to price up replacing some twinwall placard sheeting and noticed a large sign stating that you had to use 'special' silicone to seal polycarb. Apparently 'ordinary' silicone would cause staining, discolouration, splitting & cracking of the polycarb.



Further noticed that the 'special' silicone is £7:50 a tube!



Is this right or just a marketing rip off?



Haven't bought the sheet yet, B&Q prices seem well OTT.



Polycarb!! Bloody spell checker!

I used bath sealant silicone to build a clean room c 1990, which has polycarbonate sheet vision panels. There is no sign of any adverse reaction yet, but the vision panels are indoors and I don't know what extra effect sunlight might have.

Colin Bignell

They mean neutral cure silicone, as opposed to the more common acid cure variety which liberates acetic acid when curing (and smells of vinegar).

The reason is the acetic acid can attack polycarb (in theory at any rate

- I've never actually see it happen).

You can get neutral cure here:

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Awesome - I had just seen your post and thought must Google and see what this "twinwall placard sheeting" is as I had never heard of it ;-)

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