Balsa and Fiberglass Fuel Tank

Discussion in 'General Questions' started by nweiner, Aug 12, 2007.

  1. nweiner

    nweiner Guest

    Is it possible to build a tank out of balsa and seal it with fiberglass and resin?
    Will gasoline react with the resin??
    Any Tips?


  2. azbill

    azbill Active Member

    you could seal the ouside with resin and cloth ...
    and use a tank sealer like "KREEM" for the inside
    just an idea :p
  3. HoughMade

    HoughMade Guest

    I've seen gas built from fiberglass before...and actually, I've been thinking of doing this exact thing. For some reason, I feel like I would want fiberglass cloth inside....but it may not be necessary.
  4. machiasmort

    machiasmort Active Member

    For what it’s worth, I won’t be a stuck up crybaby like a few others around here and will share some knowledge.

    Great idea with the sealer, I wouldn’t have thought of that.

    I would however stay away from fiberglass cloth as the structural material and instead opt for mat. The fibers in mat go different ways, making it more porous but the positive trade off to porosity is strength.

    One consideration is to make sure it’s vented real good with a cork and copper winding like the old school.
  5. HoughMade

    HoughMade Guest

    Saw an article in Cycle World this month that talked about a fiberglass gas tank that started to dissolve enough to leak and clog carb parts. Seems like the Kreem or similar product would take care of that.
  6. machiasmort

    machiasmort Active Member

    I know that there are alot different products out there (tank linners). Oil and petrolium type products are of the same base that mat and resin is, believe it or not! It's very likely that if the linner failed there would be rather swift consequence.

    The linner itself is a serious consideration that I will have to look into and report my findings. Of more serious detriment to the idea is that it would have to be cast in 1 piece. I think trying to join numerous pieces together would pose structural risk given the vibration we experience. I've applied linners before, to steel tanks tho!!! Big difference! I didn't pay attention to the name of the stuff but know it was a pretty penny!
  7. Parah_Salin

    Parah_Salin Member

    Probaably more artsy, but what are people thoughts on a glass bottle with some sort of additional resin liner (something more structural than the Kreem) on the inside, and a resinn+cheesecloth wrap on the outside?
  8. machiasmort

    machiasmort Active Member

    Ehhh! I'd stay away from glass on a MB. Just my opinion. Some may argue but I seen what happend to a friend durring a pedal bike crash when younger. Had a beer bottle in his hand and one in his drinkholder. When he wipped out, he came up looking like a rag doll that encountered a pitbull. Not a good seen, 100's of stitches.
  9. HoughMade

    HoughMade Guest

    I would agree with that.
  10. Chris Crew

    Chris Crew Member

    fiberglass tanks

    Fiberglass tanks seem to be pretty common in the boatbuilding industry.

    Epoxy is a much tougher resin, and I imagine that it is, or could be rendered fuel proof with an appropriated addative or coating.

    Instead of balsa, you could make up a plug mold out of expanded polystyrene (styrofoam) and lay up your tank with successive layers of cloth or matting and resin. While another poster suggests that mat roving is stronger (he is right) the woven polyester cloth is easier to form into compound curves because you can stretch it along the bias (diagonal to the weave) much farther than you can stretch it in either direction along the warp or woof of the fabric. The roving is sprayed out of a chopper gun and has no "grain."

    There are also boat repair shops that use chopped matting---that's a deal where chopped up fibers and resin are sprayed out of a special tool similar to a paint sprayer to build up successive layers.

    The beauty of the styrofoam is that once your get your tank all laid up and nice and smooth like you want it, pour a little gasoline in it and the foam will turn to liquid and you can pour it out. CAREFUL, you now have what amounts to napalm---nasty gooey stuff that burns and sticks.

    I thought about punting and just building a decorative shell or case around a metal tank.
  11. HoughMade

    HoughMade Guest

    One things I do know- napalm sticks to kids.
  12. machiasmort

    machiasmort Active Member


    Your obviously into boats and sounds like you definately know your stuff! With regard to polystyrene, wouldn't it react to regular mat and resin that you would fix a Corvete with? The stuff you'd use w/ a paint brush....

    I know I ain't got money for a fancy chop gun!!! Looks like I'll be sanding alot!

    On second thought, within the next few days, I'll give a small piece a try and let you know what I come up with. I've got alot of ambition toward this project.

    For greater clarity on your advanced terminology, I can assume that roving is fiberglass shavings mixed with catalized resin... I've got experience working on VET's and stuff but the application of materials is different
    Last edited: Jul 27, 2009
  13. sjackson

    sjackson Member

    This is correct, and I've posted this a couple times in response to some other threads too. Fiberglass tanks are not new, and are used in boats and airplanes all the time. Nortons used to use glass tanks back in the day. As long as you use epoxy resin and not polyester, you will be fine. Kreem could be used, but it's not necessary IMO.

    The lost foam plug method you describe is ideal for one-off production. There's no need for balsa wood. Just get some of the pink or blue foam insulation sheets, tack them together with a couple dabs of wood glue, carve them into the shape you want and then cover it with glass. I've never heard of using gas to melt the foam. I usually see people using acetone. But hey, whatever works.

    The only thing that has ever stopped me from doing this (aside from having recently sold my motor and mounting kit) is that I couldn't think of a good way to mount the tank.
  14. Parah_Salin

    Parah_Salin Member

    You mentioned earlier that fiberglass matting wasn't necessary, and that some regular fabrics would work. What regular fabrics do you think would work well? Denim, cheesecloth, burlap, something clear or translucent?, Fishnets even? Trying to be creative...

    I'm liking this idea because I could make a plaster mold of my wine bottle, pour some spray isolation foam in, and then use that form to have a fiberglass wine bottle.

    Also, as far as mounting goes, could you embed some mounting hardware in the fiberglass? Like some steel brackets or something? Or possibly use some mold release spray on the top of the frame after the tanks is mostly done, and then make two ridges with your original material to partially cover the frame, and then epoxy that? Then build some mounting hardware to bolt to the flanges?
  15. fasteddy

    fasteddy Member

    My idea for an Indian style tank was to use a piece of steel tubing or have a sheet metal shop roll one out to size and cap the ends as was mentioned.
    Glue a coloured foam[not styrofoam] to the ends and shape it. You can buy the foam at a builders supply or check the dumpsters at a constuction site.

    I have heard both fleece cloth and spandex cloth work to cover the metal and foam. Just soak the material with resin and sand smooth when it is dry.

    For the filler tube I plan to use a car, gas filling tube. The first part from the cap down to the rubber hose that goes into the tank. Look under your car and you will see what I mean.Drill a hole in your tank with a hole saw and weld in the cut off tube and wrap the tank.

    For a square tank, I'd cut the side panels to shape and cut a strip of metal long enough and wide enough to wrap around the full length of the tank. Just one seam where you join the ends. Recess the side panels in an 1/8in and solder the tank together. Check for leaks. I don't plan on using really heavy body metal for this. Thin and bendable so it's easy to work. Probably galvanized to protect against the new gasoline.

    Wrap the tank in a thin layer of foam glued to the tank and shape the foam to what you want. Round edges ect. Wrap the tank as above.

    Hope this all makes sense.

    Last edited: Jul 28, 2009
  16. machiasmort

    machiasmort Active Member

    Fiberglass is a better material because if for some reason the resin gets a break in it, other materials will attract fluid!
  17. fasteddy

    fasteddy Member

    machiasmort, I agree with you. My thought is it's just a gas tank,not a boat. If it is damaged it will be repaired quickly. Just as soon as the crashee heals. I spent a few years in the fiberglass industry making every thing from septic tanks [the low] to Everitt-Morison's Cobra kit car bodys[the high]. In between there was work for Disney World and a couple of drag car bodys, race cars,boat shops, hot tubs, ect. Mostly job shop stuff.
    Never did a Corvette repair though.

    Thinking that spandex/fleece would be easier to use and would be nicer to use than glass. Do you remember the itch or did you have a good vent system where you worked?

  18. machiasmort

    machiasmort Active Member

    I'm sure you know more than me then! LOL

    Promised I'd post my findings. Here they are.

    Used thin styrofoam 1/4 thick and placed small ammount of BONDO (polyester) catalized resin onto it. It ate through in less than a minute!

    On the possitive side Caswell makes a sealer that will seal polyester resin against gas, or so they claim.

    In conversation here, I'm having trouble understanding the difference between epoxy and poyester resin. What is a good local source of epoxy fiberglass resin fitting this application? I've read a few other posts which also agree that a sealer is not required with epoxy. My main issue is that these morons get on the internet and blab about stuff they have no clue. I've read alot of conflicting information regarding resins and the process of application, sanding ect.
  19. machiasmort

    machiasmort Active Member

    Alternative mats, I'll be honest, I never thought of... Brilliant idea! Afterall it is only the resin that seals! Just wouldn't do it to a tank tho. Just my opinion. On a cracked ferring, all day long! I get that itch worse than most, It's a serious drag!
  20. Fiberglass tank

    Hi all
    Here is a tank I made about 6 years ago from tap plastic epoxy and fine fiberglass. It was a lot of work I made a plug or male mold in two haves after about 6 layers aprox 3/16 in I trimmed and joined the two haves with thickened epoxy. I first glued small tabs made from epoxy and glass to each half so that when the two haves were brought together the
    tabs forced the edges into alingment, half of the tabs were on one half and half on the other. the bead of thickened glue along each edge flowed together over the joint.
    Brent Merkley

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