Fiberglass Tank Questions

[JerseyRat]

I've recently started carving a tank from a thick piece of insulation. I was hoping to make a "mold" out of it and fiberglass over it. After some research, (youtube has a bunch of info), I found out the fiberglass will melt the foam insulation. I've never worked with fiberglass before and am wondering if any of you had any helpful (and cheap) hints on how I should go about this. Here is what its looking like....never mind the mess and the crappy cell phone pic.

 

[frameteam2003]

Try a small piece of the foam--I don't think the Rosin will melt the foam.You can leave it in for a solid core tank or use acetone to melt the foam .

 

[schwinnless]

Maybe you could wrap the foam in plastic and then glass it?

Just a thought.

 

[B607]

That's a good idea. If you can work out the details and make an acceptable tank, you could make a bunch of money casting Schwinn straight bar tanks. Good luck, I hope you succeed! Gary

 

[LukeTheJoker]

Check out the "Genesis 32 ratiziation" build thread, he is doing one there that I think he painted in a latex paint to stop it melting...

Luke.

 

[petesponies]

I have done lots of fiberglass work. I have made a few molds. If you have any specific questions, ask.

 

[two spot]

It depends on both the foam you used and the resin. Polyester resin will melt expanded polystyrene (EPS) foam but not urethane foam. Epoxy resin is safe on any type of foam. That's why guys who make surf board often use epoxy. EPS foam can usually be identified by the small expanded "beads" that make it up-- similar to a styrofoam cup. Urethane foam has no beads. Most pink, yellow, or blue insulation panels are a form of urethane foam, so is "oasis" foam, the stuff that florists use. If you are using polyester resin and EPS foam you will need to seal the foam so the resin won't attack it. A couple coats of latex paint, as was suggested, would probably suffice. You could also brush on some white glue or wood glue or even wrap it in saran wrap.

Regards,

 

[LukeTheJoker]

Here is the thread I was talking about, appears the name got changed...
viewtopic.php?f=21&t=69024

Luke.

 

[JerseyRat]

@ Luke, thanks, I had already checked that out...waiting to see how he's gonna go about it. His is definitely more involved than mine. I just need two halves and don't really care if the foam stays inside.
@ two spot I hope your right, as I keep getting different answers about the foam melting.
@ Petesponies One specific question I have is whether to glass right over the foam and call it a day, or glass over the foam to make a fiberglass mold to glass from. Which would turn out better results?
My plan was to either wrap foam in plastic or painters tape then fiberglass over it...

 

[dragnusa]

you could wrap the foam in foil and make a plaster mold that you can cast your parts from

 

[petesponies]

Well to make more than one, you need to make a mold. But a mold should come from a finished piece. I don't see how you "finish" one in foam. You could make a wood tank, or use a steel tank to make a mold from. Starting with foam and building fiberglass on it is more what you would do for a one off item.
As was stated earlier, there are different resins. The epoxy resin is more expensive and not something you will find in an auto parts store though, just want to point that out. But different foams as was pointed out too.
If you see your self selling fiberglass tanks, I think I would spend my time crafting one from wood. That way you can get all the details you want into the tank, then make a mold from it. A second option for media, would be clay. But again you make a finished looking "model" ( not a prototype as this will not actually work like a tank does ) that will look like a real tank, with all details etc.
What do you think? Which way do you want to go?

 

[dragnusa]

when you mold something out of plaster once you pull the foam out you can fix any imperfections by either sanding the area done or adding a bit of plaster then sanding down smooth, and if your wanting any raised details you can carve them into the mold.

 

[Road Master]

All I want to know is when are you going to start making Cleveland Welding 3 Gill Tanks because I want to be FIRST on THAT List to receive one? Good Luck!! Robert

 

[petesponies]

when you mold something out of plaster once you pull the foam out you can fix any imperfections

huh??? This isn't how you do it.

 

[Rizzoguy]

HMMM.Try making a "shell" that will stick to that nice cheap insulation you want to use.
I would spray 3 coats of appliance epoxy (greatest stuff Eva) onto it, sand it down lightly,
And maybe then your New "barrier" will hold fiberglass. Any leftover pieces
To experiment with??

 

[The Renaissance Man]

Well to make more than one, you need to make a mold. But a mold should come from a finished piece.

I agree with petesponies 100%. Your plug needs to be as finished as it's going to be. You would also have to consider how the piece will be removed from the mold, meaning the sides need to fall away slightly so that it doesn't get stuck. You will also have to consider where your edges will be trimmed and plan for that ahead of making the mold. Also, there should be a good layer of gel coat before you lay down any glass so that you can season it with wax before making parts.

However, if you only intend on making a one-off piece then all you need to do is seal the foam to prevent a chemical reaction to the resin. You should be fine with any cheap latex paint as stated by Luke earlier as long as you apply several coats. Just lay the glass over the foam and then finish it with automotive body filler. The plaster idea could also work for a rough one use mold. Whatever you do, try a test piece before you commit to anything!

Good Luck.