Fiberglass resins come in at least three formulations, polyester, vinylester and epoxy. Polyester is the least expensive, but also has the least amount of adhesion and can delaminate easily. Both vinylester, used in a lot of kit airplanes, and epoxy (used in boat building) can be used as resins for fiberglass cloth to coat the foam.
I always wanted to build one of those 3 wheeled cars like in that link.. now build it with a 125cc scooter rear end and you got a 100mpg car.. so so tempting..
I was misinformed and mis nformed you .. sorry hiope you get this.. fiberglass resin works on the yellowish white foam.. the pink stuff gets eaten..
I was told the pink was fine but never tried it till yesterday.. tride it and yep the pink stuff melts with fiberglass resin.. spray paint too..
The white/yellowish foam in the foil backed sheets doesn't melt also spray foam doesn't either..
Some one talked about blue foam and i cant test that becuase here i cant find it anywhere..
THe white yellowingt foam in the foil sheets if you peal the foil off is very nice and flexable.. even 1" gets semi flexible with the foil removed.. been working with the stuff all day today .. great stuff to work with but its not reall strong enough unless you coat it with resin with some other fiber like fiberglass or cloth.. something to add some fixed strength.. fleece works great but end up being really thick when done..if you need a nice thin coating use fiber glass or t-shirt material from the fabric store.. many options play around and see what you come up with.
many people have had great success with just cardboard and fiberglass.
I always wanted to build one of those 3 wheeled cars like in that link.. now build it with a 125cc scooter rear end and you got a 100mpg car.. so so tempting..
I'd love to do that. But I'm also attracted to Riley's idea of using a small diesel engine in front and an electric motor in back, and just using a manual switch over when you run out of electrons. Running the diesel on biodiesel would be ideal. The only problem is that he is looking at a Kubota tractor engine, which I'm sure doesn't pass California emission standards.
As far as top-coating polystyrene foam, epoxy resin does not melt it, but the polyester resin does (I'm not sure about vinylester). You could try epoxy resin over the blue foam; it may work well.
I'd love to do that. But I'm also attracted to Riley's idea of using a small diesel engine in front and an electric motor in back, and just using a manual switch over when you run out of electrons. Running the diesel on biodiesel would be ideal. The only problem is that he is looking at a Kubota tractor engine, which I'm sure doesn't pass California emission standards.
As far as top-coating polystyrene foam, epoxy resin does not melt it, but the polyester resin does (I'm not sure about vinylester). You could try epoxy resin over the blue foam; it may work well.
Quote:
Originally Posted by fshagan
I'd love to do that. But I'm also attracted to Riley's idea of using a small diesel engine in front and an electric motor in back, and just using a manual switch over when you run out of electrons. Running the diesel on biodiesel would be ideal. The only problem is that he is looking at a Kubota tractor engine, which I'm sure doesn't pass California emission standards.
As far as top-coating polystyrene foam, epoxy resin does not melt it, but the polyester resin does (I'm not sure about vinylester). You could try epoxy resin over the blue foam; it may work well.
Well, we must be talking about something slightly different then because I have been spray painting the pink stuff for the last 2 or so days with white spray paint to make the grill blocks for my bumper (works rather well actually, fits like a glove when molded properly) and if I spray on a REALLY heavey coat, it doesn't melt, but the air in the foam comes through and causes some bubbling, so you just have to make sure you put really thin coats on, lots of times. I ended up doing about 10 really thin coats per piece I think and it came out really great (just wish I had a camera to take pictures with).
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Quote:
Originally Posted by NoCO2
otherwise I'll just move to plan B which was this plastic sheet stuff I found at home depot that's used to cover overhead florescent lights.
That stuff has next to no integrity - just installing them in light fixtures is a crapshoot. Sure it's light, but it's really brittle. A little too much flexure or one pebble, and there goes your wheelskirt. If that takes place on the road and a fragment causes damage to another car, you're liable.
I've been wondering about foamboard myself. Coroplast requires I find a sign shop, but foamboard is at every Staples and Office Max. It's a little pricier, but I have experience working foamboard. Break out the X-Acto!
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Lead or follow. Either is fine.
Skim coat it with bondo, then put fiberglass/resin on top of the bondo.
Of course, by that point you might as well just do a few more coats of fiberglass cloth, then remove the foam/bondo (which was now just a mold). I've helped make some molds for carbon fiber parts that way. Male foam form, bondo, smooth it all out, add release agent, spray fiberglass chop to make a female mold.
Great call there adam728 on the making a mold for a fiberglass piece...I might just do that and make fiberglass molds out of bondo. I'll let you guys know how that goes!!!
We built an entire car body out of foam and then covered both sides with fiberglass and polyester resin. EXTREAMLY strong. I weigh 175 lbs and can stand on the front end with no cracking etc. The reason for the strength is due to covering both sides. Think about a steel I-Beam. The reason that is so strong is because steel is hard to stretch or compress. It bends easily but not so easy to stretch/compress. The I-Beam forces the outside lays to stretch and compress in order to bend the beam in two. Having foam covered in fiberglass (both sides) is like making a continuous I-Beam through out your body. Want to have some fun? Make a sample and see how hard it is to break.
Here is our car body. Don't laugh, we are not autobody engineers and autobody technicians Just an electrical engineer looking for something different to do.
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Just an electrical engineer looking for something different to do.
