Think you know FG?

k.. this is a long shot, but it reminds me of like 1st grade school.

get a balloon, blow it up to your desired size, then paper mache it, and wrap it in a layer of tin foil, then do your fiberglass work.

you can make it any size you want while keeping a realtively good shape (the paper mache also allows you to mold it a bit)

my really f*cked up 2 cents :)

FYI: the walmart ball mentioned earlier is not a regular beach ball.  They are extra heavy so that children can jump on them and stuff.  The plastic is about 3/16"-1/4" thick, and they will work perfect for what ever it is you're trying to achieve, provided you can match the correct size. 

PS. don't ask how I know that lol.

you wanna know how to do it? I'll tell you how I do it. get your self a big bouncie ball at walmart. get some two part expanding foam. Let all the air out of the ball cut a hole pure the mix in it. LOTS of mix. work the ball out as it expands press it down so the foam mix fills every curve. fill it to the top let it dry wrap it with tape and glass it. the foam keeps the rubber ball from deforming.good luck,have fun and don't get to excited over your big ball. oh yeah if you want the foam out cut it in half and patch it back together when your done.

Actually, the ball idea is a great idea, get yourself 2 balls one small one thats cheap and expendable the other one the correct size, test your resin on the small ball to see what happens, use small amounts, mix it cold, mix it hot and mix it normal to see which works better, the thing you really are wanting to avoid is well 2 things, 1 a chemical reaction with the rubber, and 2 a reaction from the heat of the resin setting, both of these will be very bad and cause horrid end results, mixing your resin so it sets faster will produce more heat which may eat thru the ball that much faster, another thing is that fiberglass most likely wont stick to the ball anyway so the actual chemical reaction with the rubber probably wont happen and the ball will come out rather easy as i've seen resin stick to plastic like crazy but never stick to a trailer tire or anything of that nature if your really smart you'll make a 2 peice mold from this pull as the inside will be just about perfect, make a few little repairs a new coat of resin on the inside to seal the mold and it should be great, then you can make as many of these as you want ;).

J~

branvw wrote:

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it will not work very well! the FG chemical will warp the plastic ball, you will have to tape it all up or wrap it in foil. you might find a ball that has a thick enouh plastic you might get lucky and the FG hardens before the ball warps.....but i doubt it. good luck!

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OK, this wil sound weird, but go to Michaels or Jo Anns Fabrics and get yourself a polystyrene ball, commonly used in crafts.  Coat the thing in foil or other heat resistant tape.  Cut and lay your fleece over it, coat with resin and let harden overnight.  Then cut a small hole in the fleece resin shell and then dissolve the polystyrene with Limonene. What is Limonene? Well it is a biodegradable alternative to degreasers, and is an effective grafitti remover as well.  Search Google for Florida Chemicals or got www.floridachemicals.com. If you are curious about the chemcla, lok for the MSDS sheet for d-limonene.  Limonene is a chemical derived from citrus rinds. Basically, pour the Limonene into the sheel containing the polystyrene foam ball and in a few minutes (or more) if will be dissolved to liquid which can be poured out.

One benefit to this type of polystyrene ball is you can cut it and form it to whatever you want using a "hot wire cutter".  There are ways to make them with a soldering iron and some copper wire.

Good luck.  Also, I think you are making a Sphere for custom sub woofer. The volume of a 20 inch sphere is almost 2 cuft. Nice size for a 12"

OK, Polystyrene comes in various forms. You can buy it retail or you can buy it whole sale in sheets or blocks.  (really big blocks).  There are various weights classes (I.E. 1 lb,  2lb, 3 lb, 5 lb, up to 18 lb which is pretty much indestructable without heat.) Yes all polystyrene can be cut by a hot wire and there are some hot wire cutters outthere which are custom made and ver yexpensive (>$500,000).  The average John Q can make one out of Soldering Iron, copper wire, and a Hook (note hook will get hot too).

Personally, I would not try very complicated molds, your basic sphere, square, ect. are easy, when you get into complex concave and convex curves it gets really tricky.

well i just want to use it to make some simple dash forms or something (like rear deck form or center counsil) so it's nothing but a few curves really, i'm not doin anything crazy,, how well does this stuff take to the FG, does it melt at all from the FG resin or no? will it warp a lot?     i would think you would oviously have to make sure you didn't mix a really hot resin mixture to ensure that you didn't melt it, but i didn't know if they reacted chemically,

i just think this would be a lot easier then framing everything out of mdf all the time, i HATE working with wood and a jig saw, haha

Ive sanded it with an air sander, and small disk, to form a hand to fill a glove to fiberglass for a craft project for my mom.

But I never thought I could apply it to MY hobby (car Audio.)  Awesome.

Kevin