Anyone familiar with the dense foam used for body building and prototype work?...I'm looking for something that can be sculpted, and hold up, (not melt), when fiberglass resin is applied...am I looking for something that doesn't exist?
Use blue insulation foam the stuff that comes in sheets it is sandable and you can cover it with resin or bondo... your home depot should have it. Mario
Not sure if you are near a marina, but my father - model maker - use to us the blue float foam used for floating docks. You could cut it with a hacksaw blade, sand it, do what ever and it will stand up to resin. Feel free to PM me if you want more detail. ~ Carl
Another option depending on your application is to use Epoxy Resin instead of Polyester resin. It doesn't eat foam.
Good 'ol Ed Roth used Plaster over a wooden structure. The Factories use clay for full scale prototypes, or at least they used to. I have used Fiberglass over foam before with limited success, it all depends on how hot you mix the resin. Too much hardener will burn up any type of foam. The best way I found was to coat the foam in unhardened resin as a base and then lay it up as normal. Then knock out the foam and brush on some hot resin to cure the gooey layer.
If you get stuck using regular foam(less $$$$), you can seal it so it doesn't melt from the resin. Some people use PVA, aka White Glue or Carpenters Glue. Ed Roth recommended a couple coats Latex Paint.
I think Aircraft suppliers will be your best bet. Try these http://www.aircraftspruce.com/ http://www.wicksaircraft.com/ Also look on the EAA web site for more tips http://eaavideo.org/video.aspx?v=1445041265 Hope this helps you out. Good luck
I used polyurethane foam. Check you local yellow pages to see if you have any plastic and foam supply houses near you. I bought mine from a supplier in Houston that would cut it to any size and thickness you needed. It sands real well and won't 'melt' under polyester resins.
Blue or Pink insulation foam will melt from both polyester and epoxy resin, i did both in college (industrial design) with varying results. The heat release from the chemical reaction will melt the foam and leave you with a huge mess. Polyester resin will definitely do it, epoxy you can get better results. How are you planning on doing this? Do you want to use the fiberglass as a mold? Or build up the material then finish the surface? If you want it for a mold using any kind of release such as plastic or aluminum foil will ruin your surface quality. If you're building it up these can be acceptable but the underside surface appearance will suffer. Expanding foam is ok for certain things problem is you end up cutting off more than you use, its hard to control where it goes unless you have a mold in which case you don't need it. Also you end up with air bubbles which leave pockets and need to be filled. It is also quite flimsy and flakes easily throughout the sanding/sculpting process. HDU is the best option but very pricey. We called it yellow foam b/c of its color. Its also hard to get in the private sector but not impossible. It's not carried at any local home depot or lowes. Personally i'd suggest building a undersized wood or mdf buck like you would with a metal panel. you can glue in some bases to attach the foam or whatever else you choose to use. Then layer the material on top of it. Another option is clay but it's also pricey. Just like the big 3 use for their prototypes. Build the buck then layer clay over top, it's a hot messy process but your surface quality is easily achieved and alterations are a snap.
I do believe what you are referring to is Perfect plank, available at Russ Simpson Co. in warren....You are from detroit I take it???The other option for a one off body or part would be to clay model the part, pull a plaster mold , & then lay -up the part in the plaster, and it does not matter if it is polyester, of epoxy. The plaster is the cheap part, the clay is a little pricey tho...How big a part are you thinking about???I would personally try to stay away from laying a part up on the blue/pink foam You will have A-LOT of cleanup to get the part presentable..Oh the perfect plank , or as they refer to it at work, 30lb. foam, or renboard is available in several densitys, but is also pricey....but you will be able to seal it up, and pull parts off it...it also machines, sands, & carves better than wood....and you can patch it with bondo/tuf carve...PM me if you have any other questions, dad was a pattern maker for AMT(models) & a clay modler for GM and has done plenty of side jobs at home , so if you ask a question I can't ansewer , I can talk to Dad...Shawn
I have been through this nightmare before. Since you live in Detroit, you should be able to find HDU somewhere. I got on a surfboard building site and after testing with pink and blue insulating board (that failed big time using polyester resin),leaned that some Lowes stores stock a yellow board that is backed with a foil that worked good for me. The foil peels off pretty easy and the stuff is easy to work with. Good luck,Man!
I'm looking at modifying/customizing a late '50's-early '60's fiberglass boat...was thinking I could attach the foam, shape it, then lay the 'glass over it...?
Be careful if you're planning on keeping the foam inside. But if you're going to glass over then finish the outside i'd recommend the blue or pink insulation foam with an epoxy resin. Any boat supply store sells it for repairs and refinishing. It's expensive about $80/90 a gallon with hardener and doesn't go as far as you might think. You will also have some trouble with bubbling without being able to vacuum everything.
Ifyou are intending on leaving the foam in place , and get the poly to bite to the old stuff & seal the foam in,it may work....but I would be afraid of the stuff next to the foam staying soft...you could also try coating the foam W/ bondo in a cold mix, sand, add another layer, and seal with shellac, and then do the lay-up...the bondo works best with the open cell foam like they use for flower arrangements, (to stick artifical flowers in) is is some dusty, slipery stuff to work with tho....The other stuff was mentioned above...spray foam...we use it to fix armatures at work...(clay) but I am not too sure how it would handle poly...it would be pretty cheap to find out , at 5 bucks a can.....Shawn
The plan was to leave the foam in, because it will be completely enclosed by the resin...and, the boat won't ever see the water...
yeah, i used this stuff when i took some industrial design classes. It's super expensive, but shapes great. It's pretty dense though, so if you leave it in, it might add unwanted weight to the boat. if you end up using the blue or pink house foam, i think this would be your best bet. I've done this method A LOT, and it works great. You should be able to get it from just about any marine/boat supply or repair shop. I'd pull the foam out if you can, after you glass over the shape, and then glass it onto the boat. But if you're sure it's sealed properly, then you probably could leave it in. just my 2 cents
I used the pink foam when I did my trike body, i skimmed it with a thin layer of drywall mud and painted it with latex paint to keep the resin from eating it
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