Can you Fiberglass over expanding foam?

Question

Can you Fiberglass over expanding foam?

Answer 1

Have to test it first as some foams melt with the resin>

Answer 2

You can fiberglass over everything that doesn't run away. As long as your glassing job is ok it will keep the shape. Epoxy resin does not particularly like polyurethane, it might not adhere well and vibrations or mechanical stress will get the foam disconnected, at least partly. But it may take a while.

Answer 3

yes, as long as the foam has gone of(cured), if you using the foam as a release mould you will need a release agent on it, and as long as its a cold cure wet lay up you are doing, it will be fine.

the foam will not stand up to a vacuum cure or an autoclave.otherwise crack on.

Answer 4

a warning, reddish foams are un-suitable to use with fibre glass, that's the general rule in the industry, green foams are not apt for salt water, as it degrades, in no time. i repaired my boat and used yellowish foam call hard as rock, worked well easy to shape sets like rock after 4 hours, then fibre glassed over it, primed and sprayed, perfect

Answer 5

If you are referring to polyurethane foam ( 1 part ), polyester resin will erode the foam underneath, unless you wax the surface first, and then you will not get a bond.  You need to use a 2 part foam system, available from many manufacturers.  Here is a link to ClarkFoam, they probably have some good info for you.

http://www.clarkfoam.net/

Answer 6

I was warned that sometimes curing resin heats up enough to melt or ignite some foams.  And you know it does get really really hot.  Tried it anyway without a problem -- with a polyester boater's resin.  

Just proceed with caution.

Answer 7

if it melts with resin,then you need to use cling film that works ok

Answer 8

do you mean that the foam will collapse? You may need to coat the foam with filler to make it impervious to the gelcoat.

Answer 9

As long as the foam has cured you should not have any problems.