Board logo

Which foam and where to buy?
beppesignori - 6/9/08 at 09:13 AM

I need to make up a slightly modified bonnet bulge to accomodate the secondary injector fuel rail on my CBR engine. Idea is to make a positive mold ind just lay the glass over it. Working with foam is probaly the easiest, but which foam should I use, and where do I get it?

Cheers, c

tegwin - 6/9/08 at 09:15 AM

I have used building insulation foam before....Comes in 6" thick sheets...

BUT....The resin will desolve the foam...

So once you have made up your shape....cover it in packing/duct tape and then lay your resin over it....

Once its cured, pour petrol over the foam to desolve it....or peel it out etc..

iank - 6/9/08 at 09:35 AM

The 'proper' stuff is polyurathane foam which doesn't react with the resin - but still needs a shiny coat to stop the it sticking.

CFS stock it, but it's a lot more cash than B&Q building foams.

http://www.cfsnet.co.uk/acatalog/CFS_Catalogue__FOAMS___CORE_MATERIALS_129.html

Benzine - 6/9/08 at 09:45 AM

quote:
Originally posted by tegwin
BUT....The resin will desolve the foam...

So once you have made up your shape....cover it in packing/duct tape and then lay your resin over it....

Once its cured, pour petrol over the foam to desolve it....or peel it out etc..


Yeah it eats away at it. I took mr whippy's advice and put a couple of layers of PVA over it, made a good seal and then it wouldn't dissolve

twybrow - 6/9/08 at 12:56 PM

Buy a can of expanding foam from B&Q etc. It is normally PU and should be good with most resin systems you try. Shape it, then spray with automtive paints, then coat with wax and or PVA. Done.

BenB - 6/9/08 at 01:24 PM

Floral foam (otherwise known as Oasis foam) is compatible with most polyester resins.... It's also compatible with car body filler (bondo).