Expansion

Of the order of 10^-4/deg C

MBQ

i.e. virtually nothing in the temperature range my back garden goes through. Thanks.

Correct, that's why it is used in some building applications despite being flammable and giving off toxic fumes. Guy

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Polystyrene does not support a fire. The building authorities regulate that polystyrene is not to burn on its own. Polystyrene used in construction is treated with a fire retardant to sufficient levels so that once the heat source is removed the polystyrene cannot continue burning and self extinguishs.

The toxicity of gases produced by heating polystyrene is lower as compared to say wool, wood or even cooking oil.

In a room filled with heated wool you's last about 7 to 8 mins', wood about 14, Polyurethane Foam ( you're suite ) about 20 and polystyrene almost 30.

What are you thinking of using it for Jane ?

I've got a load of Peco platform edging that I want to stick to 7ft of

18mm plywood to make a station platform. So I don't want the platform and the edging expanding at wildly different rates.

A good idea, I have a long platform to make (over 10ft) so will shamelessly nick this idea. Guy

Howevre, the killer will be UV, which makes PS brittle, and reduces the surface to dust. You can reduce/delay UV damage by painting the PS.

Another major enemy will be humidity. Unless the wood is _completely_ sealed before you glue on the PS, it will expand and contract with the weather/seasons. You'll be using some type of waterbased contact (impact) glue, which will allow some relative movement between PS and wood, but in the long run the PS will work loose. BTW, some PS formulations will warp over time because the fillers in it react with oxygen etc in the atmosphere.

Mind you, the deleterious effects are fairly slow to show up, so the above effects may not reach the objectionable stage for several years.

cheers, wolf k.

Also known as weathering. Yes, it will be painted, as will the wood.

Actually I was going to use decorators' caulk as glue; this stuff is supposed to be flexible.

As long as "several" equates to "more than five and preferably ten" then I'm happy.

Thanks for the advice, Wolf.