Welding On 100 lb Propane Tank Questions

[excelagator]

Ok I called my propane supplier for my home. We recently switched to a local propane company and I helped get the new tank installed.

"This is totally unproven process and unfounded"

Unofficial propane report......... He said once you purge with water and let it overflow the propane vapor is out. The wild card is the odorant because it is an oily substance and can trap some propane and can flame up, explode and etc when welding or cutting. He said once this is removed it is "safe". Of course he wants me to be safe and continue to be a customer. He also said most weld them up with water.

I "think" the best way to clean it is to purge with water twice, fill a bit and dump a bottle of dawn it there and sit and roll it around or Egon's way because it will loosen up the substance too.

Dan

 

[Renze]

Why not get a cardboard Sona tube from the big box store and put a PVC piece of pipe through the center of it and fill it full of concrete. That way you live to use it.

My idea was to just fill that steel tank with concrete, but this will work as well...
However a steel running surface would be more durable than bare concrete, which might erode. Also, more dirt would stick to concrete than to steel.

 

[sandman2234]

Something I have done, so I guess this makes me a Darwin candidate...
I had a 350 gallon horizontal tank left over on a piece of rental property after I switched to a heat pump. I thought it might make a good "something" so I removed the valve which left a 2.5" hole in the top. I also opened the valve at the bottom of the tank. Fast forward three years, when I got ready to sell the property and needed to remove the tank. I stuck a hose in the top and filled it up with water, and let it drain while I was filling it. (couldn't get bottom valve to close). Refilled it several times over the next week, and then grabbed a torch and carefully ran the torch above the open top. Nothing, so I took a nervous cut and as I made a circle of the tank, I would get small pops of propane as I went around it, but nothing too bad. Remember the tank still had a hose running into it, pretty much keeping it full. I probably would do it again, but I would do a lot of reseach to find out the proper way.
I took a class by a large welding supply company on how to cut acetylene tanks for disposal. Three of us were bidding on disposal preperation for acetylene tanks and the course was required. After I learned the right way, the acetylene tanks weren't that hard to take a torch to. When I was approached about cutting them up, I told the guy he was crazy, despite me knowing that there must a safe way or he wouldn't be involved.
David from jax

 

[escavader]

AFTER FLUSHING IT WITH WATER ID STAND IT UP FILL IT 3/4 FULL AND CUT THE TOP OFF WITH A SAWZ ALL. I would make up two round plates out of heavy stock and weld on the end[do a good job so it dont leak]Use your tractor flip it over do the same on bottom.In one of the ends install a fill/drain plug,something threaded like in a rear end of a pickup,so you can fill with water to the desired weight you want.Thus hole rotated to high side to fill,low side to drain
Then i would weld to stub axles on them end plates,add bearings, then build your hitch.
when you weld your spikes or fins on simply have it full of water.
This would be how id do it ,i see no reason for cement unless you think the tank wont hold its shape on rocks etc.Isee no reason for a solid shaft all the way through either if the ends are built correctly.
GOOD LUCK AND SAFETY FIRST.
ALAN

 

[Egon]

Just curious; how many people that have replied to to this thread have had experience in preparing hydrocarbon vessels or piping for hot work?

 

[gemini5362]

I have not had any experience at cutting or welding a propane tank. I also sleep very well at night without having had that experience. For a dirt roller I did make one out of a 55 gallon drum. cut a hole in the botton exactly center then cut a hole in the lid exactly center. Put a piece of 2 inch pipe throu the center of the hole. hold the pipe in the center of the drum and then fill it with concrete. Put the lid back on with the pipe through the center of that then let it set. I did put the drum up on cement blocks so that the pipe could go all the way through and stick out a bit. After the cement dried I had an old piece of stainless steel rod about 1.5 inch thick. I ran that through the pipe in the center of the drum and then made a hitch that fitted to the two ends of the rod. It is not the best roller I have ever seen I am sure but it was easy and cheap to make. I made it while I was pouring the slab for my garage and just had them put the remaining concrete in from the last truck.

 

[Reg]

To find the centers on the ends;
There is a device called a "round square" for finding the center of round objects.
Imagine a Tee square, but instead of the short bar being a straight edge it is a Vee - typically 90 degrees. The long bar bisects the Vee. Push it up against the round edge and draw a line across center, move around the circle 90 degrees and do it again, the center is at the intersection. Do it in a third place to check if you want/need that much accuracy.

Since this is a domed tank end you might try this;
Cut a stick to approx half the diameter, something like an old yard stick.
Lay the tank down on a smooth hard surface. Use the stick to make a mark from the ground up as close to the center line as you can. Rotate and repeat several times. You should get a small area that is easy to estimate the center of, it won't matter if your stick is slightly longer than the radius or slightly shorter.

 

[SPYDERLK]

AFTER FLUSHING IT WITH WATER ID STAND IT UP FILL IT 3/4 FULL AND CUT THE TOP OFF WITH A SAWZ ALL. I would make up two round plates out of heavy stock and weld on the end[do a good job so it dont leak]Use your tractor flip it over do the same on bottom.In one of the ends install a fill/drain plug,something threaded like in a rear end of a pickup,so you can fill with water to the desired weight you want.Thus hole rotated to high side to fill,low side to drain
Then i would weld to stub axles on them end plates,add bearings, then build your hitch.
when you weld your spikes or fins on simply have it full of water.
This would be how id do it ,i see no reason for cement unless you think the tank wont hold its shape on rocks etc.Isee no reason for a solid shaft all the way through either if the ends are built correctly.
GOOD LUCK AND SAFETY FIRST.
ALAN

LOT of use of water in this thread. Liquid water is a good rinse/wash, but not good to have in contact with the welding surface. Hard to heat, violent change to the steam state, isolation of the surface providing the possibility of forming an inflammable/explosive bubble with massive incompressible material around it -- a small shaped charge right under your torch. All problems are solved by continuous turbulent flushing with a non-flammable gas. This prevents buildup of a volume of ignitable gas-the difference between at most a little flame, and an explosion. The turbulent mixing inherent in forced gas flow is the key. Steam, as Egon suggests, would be great - perhaps best, but who has it. Air does the job and is readily available. Use it liberally.
larry

 

[SPYDERLK]

Just curious; how many people that have replied to to this thread have had experience in preparing hydrocarbon vessels or piping for hot work?

I would guess 3 or 4. I have done it several times. No indication of a problem. Mine didnt even flame up. I guess I was too careful. But not so careful as to forgo the task.
larry

 

[FreakDaddy]

Having done this I will offer my advice. Rinse it several times and then fill it with water entirely then weld it. I'll have to admit that I really don't believe that steel is capable of absorbing propane as some have said. Nonetheless it is not something to play with. If you have to weld where there is a hole just position the tank so the hole is on top and the water is filled withing 1/8 inch of the hole. If you've purged it with rinses you will be ok.

As a side note... Crazy as it may sound... One day I took the gas tank out of a car that I was preparing for the demo derby. I had a fire burning so I naturally wanted to put the tank in the fire to see if it would explode. The tank had about 5 gallons of gas in it so I figured it would be a cool explosion. I had removed the pump from the tank so there was about a 3 inch hole open to the atmosphere. I pushed the tank onto the fire with a long board (not expecting an immediate explosion) and waited. After a few minutes I heard the gas boiling and then a large gush of flame shot out of the hole about four feet high but no explosion. So my point is... for something to explode it needs to be fairly well confined.

...but please be careful. I know my mom prays daily for my safety and I credit her largely to my survival thus far. You may not have such a mom.