I want to use a piece of EPS foam I have laying around, but I don’t have the epoxy skills or materials to use it in a conventional way. Is there a material that I might coat or apply a “cheater” layer with so that I can use my Polyester resins to finish this polystyrene foam with? Maybe a latex, acrylic or some other cross-compatible paint or surfacing agent that would allow the resin/cloth matrix to bond to the coated foam? Any thoughts on this. Tom S.
i’ll take a wild stab at this (especially since you’ll do test pieces, right Tom?). how about nice THICK brushed on coat(s) of a water based bonding agent…like elmers glue, dried hard and then abraded??? is this loco??>>> I want to use a piece of EPS foam I have laying around, but I don’t have > the epoxy skills or materials to use it in a conventional way. Is there a > material that I might coat or apply a “cheater” layer with so > that I can use my Polyester resins to finish this polystyrene foam with? > Maybe a latex, acrylic or some other cross-compatible paint or surfacing > agent that would allow the resin/cloth matrix to bond to the coated foam? > Any thoughts on this.>>> Tom S.
I want to use a piece of EPS foam I have laying around, but I don’t have > the epoxy skills or materials to use it in a conventional way. Is there a > material that I might coat or apply a “cheater” layer with so > that I can use my Polyester resins to finish this polystyrene foam with? > Maybe a latex, acrylic or some other cross-compatible paint or surfacing > agent that would allow the resin/cloth matrix to bond to the coated foam? > Any thoughts on this.>>> Tom S. Tom, I
ve had passable, temporary results with multiple coats of acrylic-based spackle. Two or three thin, (squeeged) coats seemed to work the best. Light sanding between coats is helpful. Do a small test panel first. Using this simple technique, Ive never been satisfied with the long-term bonding strength (particularly under excessive heat) and impact characteristics of EPS foam, even under several layers of fiberglass. There definitely are better laminating agents than polyester resin over EPS foam and whatever intermediate layer. Epoxy resin is the way to go. Dale
Spackle your foam, and clean it up with a foam pad and some sand paper. Pull a tight layer of epoxy resin over it. As long as you don’t get sloppy with the cheater layer, you can glass right to the cheater layer with little to no prep, the sooner you glass to it the better (no need to skip sand). As you know, If you are using poly resin over the eps you have to make sure the foam is sealed, you don’t want your project to melt away. This is why I would only use epoxy resin. I just met a guy that is a engineer at Boston Whaler (Boat Man. in FL). He was telling me that they use eps foam to construct their scaled models of the new boat models, so the big wigs can have a model to hang in the office. Anyway, he said after much experimentation they have found that the best & easiest thing to use to coat/seal these models is simple Elmers Glue applied with squeege and brush. This might be an option for you if your project is a sculpture/model where strength is not an issue. Your fins look great. Very nice.
Tom, I’ve gotta go with the guys who say “use epoxy anyway”. The EPS/epoxy formula seems like a natural combination because, unlike polyester resin, epoxy resin doesn’t melt EPS. But that’s not the reason to use epoxy over EPS. You should use epoxy over EPS because EPS is weak and springy, like sponge. Because epoxy makes such a hard glass surface, epoxy glass doesn’t deflect as much when knocked or pressed. When you deflect epoxy glass, it springs back. Only a springy foam, like EPS, will spring back with the the epoxy glass when it is depressed. Idealy, you wouldn’t laminate epoxy glass over poly foam. Poly foam crushes when deflected. Epoxy glass will spring back out of the crushed poly foam and delaminate. You don’t use polyester resin over poly foam because polyester resin is cheaper and easier to use. You laminate polyester resin over poly foam because polyester glass is weak. It stays depressed in the poly foam depressions when you make them. As my wife says, “a place for everything, and everythiong in its place”. -Noodle>>> I want to use a piece of EPS foam I have laying around, but I don’t have > the epoxy skills or materials to use it in a conventional way. Is there a > material that I might coat or apply a “cheater” layer with so > that I can use my Polyester resins to finish this polystyrene foam with? > Maybe a latex, acrylic or some other cross-compatible paint or surfacing > agent that would allow the resin/cloth matrix to bond to the coated foam? > Any thoughts on this.>>> Tom S.
I want to use a piece of EPS foam I have laying around, but I don’t have > the epoxy skills or materials to use it in a conventional way. Is there a > material that I might coat or apply a “cheater” layer with so > that I can use my Polyester resins to finish this polystyrene foam with? > Maybe a latex, acrylic or some other cross-compatible paint or surfacing > agent that would allow the resin/cloth matrix to bond to the coated foam? > Any thoughts on this.>>> Tom S. what is the weight of the EPS, i use 40Kilo/sq. meter i also made boards from 30kilo, epoxy resin have too be the ride temp. (18°celcius min.)and dry air. go for the epoxy, also use epoxy speed coat.