Does Styrofoam expand?
Does Styrofoam expand?
(OP)
Hi
I hope this is not a stupid question. I am looking to cover a shaped piece of styrofoam, (Dow Cornings 'Foamular'), with epoxy and am wondering if it will crack the epoxy with changes in temp. of about 30degreesF. From about 40F to 70F. Foam is approx. bathtub size and similar shape.
Thanks for any help.
I hope this is not a stupid question. I am looking to cover a shaped piece of styrofoam, (Dow Cornings 'Foamular'), with epoxy and am wondering if it will crack the epoxy with changes in temp. of about 30degreesF. From about 40F to 70F. Foam is approx. bathtub size and similar shape.
Thanks for any help.





RE: Does Styrofoam expand?
So a 30 degree diff would yield:
.01167" expansion for an inch long part double that for two inches triple it for three... i think you can take it from there. This assumes the foam was formed at 40deg F.
Your epoxy shell will also expand (but at a different rate). The shell may be strong enough or flexible enough to accomodate this difference in expansion.
You will likley be ok but i would do a quick prototype.
Hope this helped.
RE: Does Styrofoam expand?
RE: Does Styrofoam expand?
I also suppose that you will use fibre reinforced epoxy.
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RE: Does Styrofoam expand?
The foam is a plug to make a mold from. I was hoping to simply cover with epoxy and paint so it can be finished to a very smooth, high quality surface similar to a boat hull.
The temp. problem is simply the range of temps I am expecting over the process of finishing the mold. There will be other products eg. 'Awl Fair' by US paint that will be used to help the fairing process but no reinforcement in this piece.
RE: Does Styrofoam expand?
Don't worry about it this sounds like no problem. The epoxy is sticky yes? No problem, as long as what you make off of the mold has an overall tolerance of +/- 1/6". It sounds like you'll have a tougher time controlling the thickness of the epoxy!
GO FOR IT, its a good idea and a cheap way of making the mold.
I'm really curious now. what is the final product? a personnal watercraft?
RE: Does Styrofoam expand?
RE: Does Styrofoam expand?