[pgmelton]

I need to encapsulate some foam with polyester resin, in the past I have used styrene to thin out the resin for better absorption into the foam. I saw a product called xylene at Home Depot and I wonder if it can be used for the same purpose?

Thanks in advance.

 

[Brett]

I've never thinned polyester resin. Always used it straight from the drum it came in.
After mixing with MEKP I'd work a prime coat of resin on/into the surface to be glassed over,
then place the first layer of fiberglass. That way there was never an area of glass starved of resin.
As a result I ended up with a solid lamination.
I have thinned gelcoat, but used a small amount of acetone to thin with.
Never with styrene or xylene, both of which are now  suspected to be carcinogens.

 

[Frank_Sebastian]

What kind of foam? Poly resins don't do well with most foams.

Frank_S

 

[firecat1981]

If it is typical styrofoam, or a variation of polystyrene the polyester resin will eat through it and break it down from my experience. Epoxy resin is safe to use on it though.

As far as thinning I know most people I've talked to use acetone to thin it. Maybe because styrene is hard to get, I don't know?

 

[pgmelton]

Hello,

I ended up buying the styrene because it is a known factor. The styrene is easy to get, they have gallons of it at my local fiberglass shop.

I am using a polyester 5lb dnsity foam design for this purpose, great stuff. very easy to work with, forgiving and LIGHT.

I saw John Greviskis (as well as several glass people I spoke to) from Ship Shape T.V. "priming" the foam prior to glassing. The styrene is used to thin the resin so that it has time to soak into the prepping for fiberglass. I don't think you should ever use styrene for glassing.

I coated all the foam pieces for the skiff this afternoon. They do flex up a bit during the drying process but it is still very flexible.