I think what you want is normally called a 33 pound motor fuel tank. It holds about 7 1/2 gallons of fuel The other common forklift fuel tank is a 44 pound tank. It holds about 10 gallons. You may be able to rent or buy one from your LP supplier. As mentioned McMaster-Carr has them. But so does Amazon and Ebay. Another source is ProTank (that is where the fitting photos below come from). I've not dealt with ProTank personally, but experience has taught me it may be worth a little more talking to someone with experience at stuff like this. There is getting to be a demand for propane motor fuel tanks for off-road 4wd vehicles, because it is a better fuel choice for that use than gasoline. The system is sealed and works at awkward angles 
Tanks are made of steel or aluminum. Steel weighs more but is usually cheaper. Here is a new steel one listed on Amazon right now  A new Worthington steel cylinder is usually $150 - $220, depending on supplier and shipping. One of the little things to watch for is the fittings. The gotcha to watch for is fittings. If it does not include the motor fuel adapter  you just spent another $15-$25
The tank listed on Amazon includes the motor fuel fitting (the one your hose adapter screws on to) and a fill fitting (the big fitting an LP truck can fill). Those 2 little items are worth $30-$50 depending on where you buy them. Speaking as a guy who fills forklift cylinders for folks once in a while, that fill fitting  is nice to have.
You can buy tanks on ebay as well. There is a current listing on ebay for new tanks for $150 shipped. BUT it does not show and does not state what fittings are included. And like anything else on ebay you have to really pay attention. I bought a used aluminum tank through ebay with the fittings at a very good price. When it got here I found it did not have a gauge. It works fine, we fill it by weight or spit gauge, but it is a bit unhandy. Shipping is a big thing. There is a listing for new 33# tanks with all the desired fittings for $120. BUT the fine print is they will not ship, local pick up in El Monte. California only. Of course, that does make the trip to California in January a business trip ... Used tanks are sometimes a lot cheaper, but I don't think they are supposed to be shipped with any hint of fuel in them. Even, maybe especially, the smell.There is a listing on ebay right now of two 33# tanks with $60 Buy It Now price. BUT you have to pick them up in Gray, Georgia. And the gotcha with used tanks is the date. The tank and the relief valve both have the mfg. date stamped in them. After ... I think it is 10 years but I'm not certain off the top of my head ... the relief valve needs replaced. After 12 years the tank needs requalified. Not a big deal, but just another hassle and possible expense. OH! And a big thing with a new tank is it MUST be purged before filling. Blow the air off, pressure it up with propane vapor, blow it off, and repeat 2-3 times. This is where the ASME fill fitting is nice. I can use an adapter to do it through that valve quickly. The supply valve has a restriction in it so if there is a leak it doesn't leak as quickly. It also makes purging the tank a real pain.
Edited by Mike SE IL 1/24/2013 05:10
| 
Forklift Propane Tanks ?
