fiberglass gas tank?

I guess im posting this in the right forum. But Ive been shaving wieght on my 1000 after a total rebuild, cut the frame and much, much more. Anyways, I've been looking around and cant find to much info on a complete gas tank made of fiberglass. I will shave alot of wieght doing so and will be able to replace old tank!
Any idea if fiberglass is resistant to gas,(over a long period of time)? If not what could I line the inside of the tank with?
thanks

I have a friend that has a fiberglass gas tank made by "Tracy". It is on a 750 Honda. It is the only one i've seen in the last 30 years. Tracy made these tanks for about every brand bike made.
A complete Tracy Body only weighs 14 lbs.
I have two.One for a triunph+honda.One for a Z1/KZ 900.
They come up for sale on eBay every once in a blue moon. Roy

Try Beasley Composites -www.beasleycomposites.com.They are now located in Painesville Ohio and used to be Custom FRP.Used a 1 gal tank/shell on dragbikes for years and no problems.

www.airtech-streamlining.com/vintage/vintagetanks.htm

nothing stock looking; but hell what fun is stock neways?

I am in the midst of making one for my 550. I want greater capacity. I have started by making a paper mache mold of the tank. I also made a mold of a 5 Gallon (eagle brand) gas can.

Next, I am going to wax the inside of the makeshift molds (or use some other release agent), and then use expanding foam to make a positive form. I will work these together, cutting the gas can foam in 1/2 and mounting these rough extensions on the tank form. I plan to shave it down using a "cheese cutter" (surfoam tool) and when I am all done, I will layup a thin layer of paper mache to keep the foam safe from the resin.

I plan to use fiberglass and carbon and possibly epoxy resin rather than plain polyester resin.(see below) I have a friend who builds his own kayaks, and will ask for help with the materials when I am ready. I would not use fiberglass alone - too brittle and weak! The carbon will ad strength and stiffness without a lot of weight. If I really want it strong and light, I can vaccuum bag it to squeeze out all the excess resin.

I plan to cut out the tunnel from a junk tank I have to incorporate in the tank and to make mounting a snap. The metal/fiberglass interface is my only concern right now, but I have no doubt that my friend knows a way around any difficulties.

I looked into the resins, and found this:

Fiberglass resin, acrylic resin, polymers and monomers. Cyanoacrylate ester (methyl and ethyl) , caulking, bondo, contact cement , etc. Be careful.. you can get HIGH just by breathing it.

Epoxy resin is a chemical that is part of an epoxy resin system. Epoxy resin systems are used widely in industry because of their strong adhesive properties, chemical resistance and toughness

They are not different that much.. both have very good bonding aspects. The Fiberglass resin is cheaper though.

I can post photos as I go along, but I think I should create my own thread rather than hijacking yours!

Yea there were some glass tanks made for the 900-1000's. The one that I have laying around looks just like an old z1 tank except it has a twist on gas cap.It holds the same amount of fuel as a stocker. Mine was made in Indiana a long time ago. All you'll get from beasley is a shell which is okay if you want to make your own bottom. Just remember that they don't dent, they crack.

outlawz1 wrote:

Yea there were some glass tanks made for the 900-1000's. The one that I have laying around looks just like an old z1 tank except it has a twist on gas cap.It holds the same amount of fuel as a stocker. Mine was made in Indiana a long time ago. All you'll get from beasley is a shell which is okay if you want to make your own bottom. Just remember that they don't dent, they crack.

most of them were used on bikes with backbone tanks in frame ,so the fiberglass was just a shell to make it look origional.

Fiberglass tanks do stand up to gasoline, it's the additives such as alcohol that will dissolve the resin. POR 15 or similar products have been used by the vintage race guys to protect the resin inside the tanks.

Regarding making the mold, try using plaster over the foam rather than paper mache, it's easier to sand smooth, add to if necessary and can be waxed.

Careful using epoxy resins. Some people can have allergic reactions, anywhere from mild to severe dermological problems, to respiratory difficulty. In my case, I developed a sensitivity to it over the years using it in paleo work, missed a lot of work and ended up in the hospital twice. Had to leave the paleo field because of epoxy.

Thanks for the help!!!

Thanks for the info. The paper mache I refer to is not the grey stuff one buys, but rather a homemade paste that strips of newspaper are dipped in. The mold cane out very well; it is stiff enough to accept wax easily.

The recipe for the paste is:
1/2 cup flour dissolved in 2 cups cold water.
bring another 2 cups water to a boil, then add the flour/water mixture. Return to boil, then remove from heat. Add two tablespoons sugar and mix in well. Allow to cool and thicken.

Now take strips of newspaper and coat with paste. place on master (form) in multiple layers, alternating the direction the strips are applied to improve strength. Using hand / fingers, squeegie out as much excess paste as possible. Continue / repeat until you have several (I did about 6) layers. Allow to dry (mine took 36 hours.)
Remove from form and allow to dry the rest of the way. You now have a light, strong mold.

Try it! It worked great for me.