Tim Mitchell wrote in message ...
That sounds like B&Q (or other brand) cheapo. It will say "silicone" if
it really is, Dow Corning make the stuff but you can get other brands.
The cheap stuff is acrylic and that will crack and pull away. When the
silicone stuff sets you can stretch it like a rubber band.
The Unibond acrylic substitute for silicone is pretty good. It's certainly
as flexible, doesn't crack, and is a lot easier to use. Some blurb on the
pack about "technology beyond silicone" which might even turn out to be
true.