>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

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>>> Does anyone know the coefficient of expansion of polystyrene?
>>>
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> 18mm plywood to make a station platform. So I don't want the platform
> and the edging expanding at wildly different rates.
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.
Jane Sullivan - 05 Feb 2010 12:01 GMT
>>>> Does anyone know the coefficient of expansion of polystyrene?
>>>>
[quoted text clipped - 10 lines]
> the surface to dust. You can reduce/delay UV damage by painting the
> PS.
Also known as weathering. Yes, it will be painted, as will the wood.
> 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
[quoted text clipped - 3 lines]
> formulations will warp over time because the fillers in it react with
> oxygen etc in the atmosphere.
Actually I was going to use decorators' caulk as glue; this stuff is
supposed to be flexible.
> Mind you, the deleterious effects are fairly slow to show up, so the
> above effects may not reach the objectionable stage for several years.
As long as "several" equates to "more than five and preferably ten" then
I'm happy.
> cheers,
> wolf k.
Thanks for the advice, Wolf.

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Jane