Topic: Is this possible??

[leaderbean]

So I have an idea but need feedback from those that have gone before me. 

Would it be possible to fiberglass a new tank for a CB550 by first carving a model out of blue insulation foam (polystyrene), then coating the foam in some kind of release (so the fiberglass doesn't stick to it), then fiberglassing the entire thing on all sides, then pouring in gasoline to melt away the blue foam so you can just pour out the goop that it is reduced to?

[kghost]

Try a small piece first and let us know how it goes.

Be the guinea pig 

[KB02]

Fiberglass tanks often need to be coated with something in order for the gas not to eat the fiberglass. Might not work the way you are thinking, but like KGHOST says, try a small piece and let us know how it goes.

[gregk]

you might want to try the gasoline desolving trick before you glass the tank.  If gas doesn't work, try acetone.  It might.

greg

[BeSeeingYou]

Yes this is possible.  Use epoxy resin instead of polyester resin.  I have used epoxy, fiberglass cloth, and plywood to make diesel tanks for sailboats with no problems.  I have also heard of it being done the way you describe.  A fine finish is not required on these and the biggest problem is what to do with the nasty gas mixture you have left.  Your biggest problem will be getting a nice smooth finish on the exterior of the tank.  It will take a fair bit of filling, fairing, and sanding.

[masonryman]

After you make the foam blank cover it with melted block wax, this will let the fiberglass seal and be smooth. Acetone does a better job dissolving the foam, put the whole tank in the oven or some other method of heating the tank to melt the wax.

As far as the exterior finish use ultra lite-weight body filler to achieve your finial shape and finish, it has a very good adhesion and it is very easy to work

Mark

[masonryman]

Make sur the tank is empty and dry between the Acetone and heat stage

[754]

Why not use a small inflatable pillow or balloons, the wax over that, for a mold.

Then you can melt it out & pop the inflatable.. and not have to mess with gas or acetone..

[leaderbean]

Hmmm, I guess the balloon would have to be the exact shape of the tank I want, which would be hard to find.

Dissolving the foam would be relatively easy, I think.  But the harder part would be removing 100% of the wax left still stuck to the inside of the fiberglass.  Doesn't hexane dissolve wax?  There are different kinds of wax.  It looks like carnauba wax is sold as a mold release.  Would this be right?

[HavocTurbo]

sure you could use caranuba wax. but you'd still have the same cleaning problem.

use your polystyrene foam as a base and make yourself a larger gas cap hole.

Coat the foam in saran wrap around the neck. (for sturdiness)

Then glass... pour in acetone or gas and as it kills the foam remove the  saran wrap.

The larger filler hole makes it easier to spray hot water in when rinsing the goop out.

[gregk]

 Somewhere on this forum is a very detailed explanation of how to build a tank using the methods you have suggested but, the tank was cut in half and the "plug " was removed and then the two halves fastened back together.  He also detailed the construction of the filler and the outlets.  unfortunately, I can't find it.  It is worth while searching this article out as it was very well done with lots of pictures.

Greg