fuel tanks

[DRDEATH]

i am looking for beer kegs for fuel tanks for some gensets. I would like to use 8 gal beer kegs but would use 16 gal.  These things have become almost as hard to find as chickens teeth. I would prefer aluminium. I guess these haven't been used for quite a few years. New kegs are 200 dollars. Liquor stores charge 50 deposit but if you do not send back the word is put out so if I took it to a welder in town i would get to spend a few days free complements of the county probably or pay the 200 dollars. Thanks Mike

[Stan]

Go to any respectable tool distributor and buy a portable air tank.  It's steel, but can be welded easily.  Get a hole saw and cut a hole in the top the appropriate size input that fits a standard automotive (used) fuel cap, and then drill  a small hole in one end near the bottom to braze in a brass fitting for the fuel tap out.

You then have a nice looking, "legal" fuel tank.
Stan

[Tijean]

Go to any respectable tool distributor and buy a portable air tank.  It's steel, but can be welded easily.  Get a hole saw and cut a hole in the top the appropriate size input that fits a standard automotive (used) fuel cap, and then drill  a small hole in one end near the bottom to braze in a brass fitting for the fuel tap out.

You then have a nice looking, "legal" fuel tank.
Stan

I do have a stainless beer keg but have other designs upon it.

I have used a number of expired 20 pound propane tanks which give something around 5 or 6 imperial gallons. I think somewhat larger ones are available too. Our landfill attendant finds the $5 found money.

[bschwartz]

I sometimes come across the stainless ones at yardsales.  I used one for part of my exhaust.  If I see another one, I'll snag it for you.

[DRDEATH]

Tijean I thought about the propane. In fact the guy who has bought the 16/2 owns a large scrap yard and is going to make 2 tanks. One for his engine and one for mine. I checked into that today and a guy told me that was a bomb waiting to happen. He claims the two fuels could react and that propane absorbs into the aluminium. Any truth to that??? I was worried creating a WMD in peoples back yard. Mike  PS the air tank is just a little plain. I wanted something that has a little class.

[Tijean]

I have welded on quite a few over the road truck aluminum diesel fuel tanks. Pretty much standard. No problem with compatibility there. I have never seen aluminum propane tanks but that is not the direction you are wanting to go anyways.

There certainly are precautions necessary in dealing with welding or using a vessel that has contained any volatile. The fellow in the scrap yard likely has the right mindset for his safety. Err on the safe side. I have worked in refineries and been exposed to a lot of sessions on safety procedures so I guess I am taking some of this for granted. There are recognized safe procedures for doing this and lots that are not. Stans suggestion of using a new uncontaminated air receiver tank has its merits but I would treat any tank like it might have fuel in it before I cut into it or welded on it.

Tanks or fittings with galvanized metal or copper fittings or line should not be used for diesel. Not sure of the exact reason but suspect it is to do with self plating metal onto the extremely close fitted parts of injection pumps and injectors. If you are fabricating a tank it is a good notion to push the fuel exit  nipple up an inch or so inside the tank to avoid drawing off any water. A water drain then on the very bottom is a good partner. Otherwise you depend on your filter system to keep any stray water from galling up your injection system.

[listeroidsusa1]

He's right about welding on any tank that has held propane. When I built my used motor oil still I removed the valve, filled the 100 lb propane tank with water, let it sit two weeks, emptied it out and let it air out for 3 months, filled it with CO2 before welding on it and the thing still had an explosion. I had already cut a 3" hole in it with a holesaw for a pipe connection before welding on the tank. The stem and the 3" hole in the side made the tank spin and fly around like crazy, not to mention deafening me for half an hour. Imagine a 100 lb tank spinning around like fireworks! In other words, DON'T DO IT!!! It is not safe!!!! I was lucky it didn't hit me.

[DRDEATH]

Well i guess the propane tank is out for me to do. The guy in Huston feels that his welders can do it so I suppose I will get his. THANK YOU FOR THE ADVICE.

[Tijean]

He's right about welding on any tank that has held propane. When I built my used motor oil still I removed the valve, filled the 100 lb propane tank with water, let it sit two weeks, emptied it out and let it air out for 3 months, filled it with CO2 before welding on it and the thing still had an explosion. I had already cut a 3" hole in it with a holesaw for a pipe connection before welding on the tank. The stem and the 3" hole in the side made the tank spin and fly around like crazy, not to mention deafening me for half an hour. Imagine a 100 lb tank spinning around like fireworks! In other words, DON'T DO IT!!! It is not safe!!!! I was lucky it didn't hit me.

Sorry; I should have made the disclaimer on my original post that you should not do this at home unless you have been trained on welding fuel handling pressure vessels and use an approved safety procedure. Dont accept your uncle Joe's method as gospel. There are many more ways of doing it wrong than right. Many have gotten away with things on pure luck, not knowing how close they were to disaster. They will claim it was perfectly safe and they are the living proof of that.

Nothing special about propane compared to almost any other mineral based hydrocarbon. Since mineral based  compounds are not water soluble the water filling and rinse is not effective. Propane is a dogs breakfast of different compounds and some oil often collects over the life of a tank. Airing it out will not remove this and welding heat can vaporize it to an explosive state. Many tanks used to incorporate lapped seams that can also trap material that is not easily exposed and removed.

The CO 2 is an adequate purge but once you cut a large hole in the tank you can lose it. Purge must continue to flow in air excluding volume. Some people have got into trouble on a clean tank when using oxy acetylene because they have introduced an explosive mixture to a clean tank. Heat volatized paint can do you in also. That is why I suggest treating any closed vessel as potentially explosive. I saw a picture of a drive shaft that someone had blow up on them when welding on it. It was likely one that used the internal cardboard sound deadener material.

[DRDEATH]

So Tijean would the exhaust pipe method work I posted earlierwork like it does in regular gas and diesel tanks?? I have done this many times without even a burp from the tank. Mike

[Tijean]

So Tijean would the exhaust pipe method work I posted earlierwork like it does in regular gas and diesel tanks?? I have done this many times without even a burp from the tank. Mike

Mike, PM sent.

It is hard to get purge into and vented from available tank 3/4 pipe thread opening on a propane tank. Whatever is being vented out can ignite as it mixes with outside air and of course it is an asphyxiant itself. An approved method will almost always involve high pressure steaming to a tank temperature of around 450 F then a sniffing with an approved combustible detector device, then continuous non combustible purge while welding. This gives a redundant safety factor and cancels any combustibles that may be re introduced from the welding process. Perhaps a bit of both belt and suspenders but no engineer would pen his name to anything less. It is not that propane has any especially different properties from other fuels but its single small opening creates some special circumstances.

[DRDEATH]

I think the idea of me doing anything with a propane tank is OUT. I just spoke to the owner and he said the engine should be to my place tomorrow. He also got a lead on a scrap yard in Huston where he is from that takes in beer kegs for destruction. I guess he knows the guy and was told to come over to see if there were any still intact and he could have them. So if the beer keg thing will not work out he feels he can build the tanks out of the propane tanks without a problem. So I will look to the south to see if there is an explosion. Thanks to everyone for there advice. I know now that if I get the urge to weld on propane tanks to just not do it. I learned much from this post. Mike

[bschwartz]

FYI I was able to use a flux wire feed welder to attach a steel pipe to a SS keg with no problem.  I didn't know if welding to SS would work or not, but for an exhaust it has held well.

[DRDEATH]

OK so I found out how the fuel tank hunt was solved. Norman the guy in Huston has friend who imports beer kegs from Mexico. Norman found an 8 gal tank intact and is going to cut a slot in the top and put an copper coil in it an attach to the outside so hot water can circulate through it then through the radiator to heat the fuel. I plan on using WMO and WVO after the engine has warmed up the fuel. He got an extra tank to cut a flap which will attach to some bolts that will be welded inside the tank. This should never have to be used unless a leak forms. He is giving me the 8 gal tank.

His friend said he will have some more in a week or so and he is going to get a 16 gal tank for himself.  He will do the same thing in his tank to increase the efficiency of the engine. He plans on flying up to Dodge to meet me and bring my tank in the next week or so. I will post a picture of it when I get it. Mike

[Tom]

My strategy for welding fuel tanks is to use a high volume air purge. If the atmosphere in the tank can kept to lean to ignite no boom or I've just been lucky . If the tank was used recently I will let purge for a few hours before welding/brazing.

The oil/residue in the bottom of a used propane tank is probably what got Mike. Fortunately the tank I used for my propane muffler was clean and dry on the inside.