What would be the best type of pipe fitting to weld onto a propane tank? I was thinking of using pipe couplings in black steel if I can find them. I'm assuming I should stay away from cast iron or mallable iron couplings. I have welded cast iron couplings before on my log splitter hydraulic tank but it took a few tries before it passed a pressure test.
what kind of fittings to weld on propane tank?
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I think you're on the right track - I'd go with plain steel couplings like you said. You definitely don't want any cast iron. If you had to, you could probably use a galvanized steel fitting - just grind the zinc off where you need to weld and don't breathe any of the fumes. If this is going back in general water storage service, you should be fine. If you actually plan to store propane back in the thing or pressurize it, then the quality of your weld will be crucial.
Couderay80
Member
What would be even better is what they call a Thread-O-Let. It has a curveature unlike a coupling. Order the size of the piping you need by the size of the pipe or vessule in your case. Like 2" (threaded) for a 36" pipe.
Chris S
New Member
Dune
Minister of Fire
The couplings that come with black pipe are straight thread, not tapered like regular pipe thread. Welding them to a tank and then trying to get a good seal is difficult. As mentioned above, weld-u-lets are your best bet. The weld is far enough away from the threads that you don't need to worry about distortion.
sgschwend
New Member
Just did that today. Now I have two 1 1/2 and one 1" npt holes.
Black pipe fittings work well, the 1 1/2 bushing fit in the original level indicator hole. Be sure and grind both surfaces, I ran a water line into the tank while I welded it.
Stay away from the galvanized fittings since burning the galvanize plating will result in a poisonous gas.
I also added 16" long legs to raise the tank high enough to allow for the insulation.
Black pipe fittings work well, the 1 1/2 bushing fit in the original level indicator hole. Be sure and grind both surfaces, I ran a water line into the tank while I welded it.
Stay away from the galvanized fittings since burning the galvanize plating will result in a poisonous gas.
I also added 16" long legs to raise the tank high enough to allow for the insulation.
Just go to any plumbing supply and ask for weld couplings.
You'll get the right steel heavy pipe couplings you need. Then get the right size hole saw, and your in business. You don't need thread-0-lets.
You'll get the right steel heavy pipe couplings you need. Then get the right size hole saw, and your in business. You don't need thread-0-lets.
jebatty
Minister of Fire
Although I haven't thought it through to the point of doing it, this is where I would be headed for fittings on an LP hot water storage tank, 500 gal or larger, installed horizontally.
1) Near the top at each end, I would cut a hole and extend a 2" black steel pipe about 3 feet into the tank, parallel with the top, and about 8" down from the top. The pipe would have a series of holes drilled into it, probably 1/2" each, in a straight line, with the holes aligned on the "up" side of the pipe once it is welded in place. The end of the pipe exiting the tank would be threaded, of course, to take 2" or with an adapter smaller pipe connections. One of these would be used for hot water supply to the tank and the other for hot water draw from the tank. I think this would pretty well insure that supply or draw would result in minimal mixing, even at very high flow rates.
2) Better alternative: extend the pipe all the way through the tank, end to end, with the drilled holes, etc. This would be even better and may allow hot water draw actually to pull from hot water supply, if the supply was active at the time of draw.
3) Do the same at the bottom of the tank, about 8" off the bottom, holes aligned on the "down" side, for return to boiler and return from system.
4) Other fittings, as desired, for monitoring, etc. The normal fittings on the tank might be sufficient for this.
5) If the tank does not have a drain at the bottom, or only a 1/2" drain, I would replace that with a larger drain fitting. A 1/2" fitting takes a long time to drain a large tank.
There is a good chance I will be building a new shop, and if so, I will me moving the Tarm and 1000 gal LP storage tank next summer. If so, this is where I may be headed on fittings.
1) Near the top at each end, I would cut a hole and extend a 2" black steel pipe about 3 feet into the tank, parallel with the top, and about 8" down from the top. The pipe would have a series of holes drilled into it, probably 1/2" each, in a straight line, with the holes aligned on the "up" side of the pipe once it is welded in place. The end of the pipe exiting the tank would be threaded, of course, to take 2" or with an adapter smaller pipe connections. One of these would be used for hot water supply to the tank and the other for hot water draw from the tank. I think this would pretty well insure that supply or draw would result in minimal mixing, even at very high flow rates.
2) Better alternative: extend the pipe all the way through the tank, end to end, with the drilled holes, etc. This would be even better and may allow hot water draw actually to pull from hot water supply, if the supply was active at the time of draw.
3) Do the same at the bottom of the tank, about 8" off the bottom, holes aligned on the "down" side, for return to boiler and return from system.
4) Other fittings, as desired, for monitoring, etc. The normal fittings on the tank might be sufficient for this.
5) If the tank does not have a drain at the bottom, or only a 1/2" drain, I would replace that with a larger drain fitting. A 1/2" fitting takes a long time to drain a large tank.
There is a good chance I will be building a new shop, and if so, I will me moving the Tarm and 1000 gal LP storage tank next summer. If so, this is where I may be headed on fittings.
RobC
Minister of Fire
Just did this myself.
Ckuck 172 said "Just go to any plumbing supply and ask for weld couplings" This does work well.
I got a 90, comes as a long sweep, used for sprinkler systems. I think I went with a 2" and took a 1.5" schedule 80 nipple cut it in 1/2, stuck it inside the sweep and your good to go.
You can also go with a schedule 80 nipple and stick it out of the tank and weld it that way.
Schedule 80 nipples are not that much more expensive and you will be less apt to burn out the sidewall of the nipple while welding to tank.
I think I'm a OK to good welder, and have been told so by welders. Welding these tanks tight is not easy.
Air pressure checking has been addressed before and you must fully understand the safety factors involved. Once I had already hydraulically checked my tanks before welding to 70 PSI so I knew that the tanks were sound. Once the tanks were welded together I was told that they really need to be checked with air to at least operating pressure, 30psi and sprayed with Windex window cleaner to find leaks. I started at 10 psi and applied Windex. Leaks. Fixed them and retested and went to 20psi, Leaks. fixed then and did some extra work in areas that looked suspect. When I went to 30, you guessed it, three more tiny, tiny leaks. All of the leaks, except the first 3 leaks at 10 psi, water never would have come out of. In fact the size of these are so small that after being filled with air all night there was no pressure drop in the tanks and from a pressure check alone you never would have known about them. In fact you have to be really through and patient to find them with Windex.
Fact air molecules are much smaller than water molecules and will allow you to find the leaks.
Fact, the amount of compressed air it takes to fill 1000G even to 10psi is frightening. Don't even think of doing this if you are not 100% sure of your equipment. Do not think of staying in the area while filling the tanks. Do not think of working on the tanks when there is any psi in the tanks.
Things to do, keep welding to absolute minimum. Where tanks have curved surfaces make sure you can get to all sides comfortably. Set air regulator coming off air compressor to the psi you want in tanks and go do something else. Seriously if you have any questions about your welding ability hire it out. I found this to be a very humbling experience.
Messing around with these tanks with air pressure is most likely more dangerous than when that had just been emptied with propane inside.
Neither situation you would want to be around for the results.
Rob
Ckuck 172 said "Just go to any plumbing supply and ask for weld couplings" This does work well.
I got a 90, comes as a long sweep, used for sprinkler systems. I think I went with a 2" and took a 1.5" schedule 80 nipple cut it in 1/2, stuck it inside the sweep and your good to go.
You can also go with a schedule 80 nipple and stick it out of the tank and weld it that way.
Schedule 80 nipples are not that much more expensive and you will be less apt to burn out the sidewall of the nipple while welding to tank.
I think I'm a OK to good welder, and have been told so by welders. Welding these tanks tight is not easy.
Air pressure checking has been addressed before and you must fully understand the safety factors involved. Once I had already hydraulically checked my tanks before welding to 70 PSI so I knew that the tanks were sound. Once the tanks were welded together I was told that they really need to be checked with air to at least operating pressure, 30psi and sprayed with Windex window cleaner to find leaks. I started at 10 psi and applied Windex. Leaks. Fixed them and retested and went to 20psi, Leaks. fixed then and did some extra work in areas that looked suspect. When I went to 30, you guessed it, three more tiny, tiny leaks. All of the leaks, except the first 3 leaks at 10 psi, water never would have come out of. In fact the size of these are so small that after being filled with air all night there was no pressure drop in the tanks and from a pressure check alone you never would have known about them. In fact you have to be really through and patient to find them with Windex.
Fact air molecules are much smaller than water molecules and will allow you to find the leaks.
Fact, the amount of compressed air it takes to fill 1000G even to 10psi is frightening. Don't even think of doing this if you are not 100% sure of your equipment. Do not think of staying in the area while filling the tanks. Do not think of working on the tanks when there is any psi in the tanks.
Things to do, keep welding to absolute minimum. Where tanks have curved surfaces make sure you can get to all sides comfortably. Set air regulator coming off air compressor to the psi you want in tanks and go do something else. Seriously if you have any questions about your welding ability hire it out. I found this to be a very humbling experience.
Messing around with these tanks with air pressure is most likely more dangerous than when that had just been emptied with propane inside.
Neither situation you would want to be around for the results.
Rob
After the welding is completed, look out for those made in china bushings, very prone to sand holes. Absolutely pressure test with soapy water.
sgschwend
New Member
I am not sure if folks want to install permanent discharge and suction lines. I would rather have these lines so that they can be removed. It is difficult to install such a part on a pipe thread hole (since pipe thread are tapered). That is why the two methods used in the propane tank is to have a marriage (as in the infill) or a flat flange (as in the fuel gage).
I believe I will go with the marriage idea. Here it is:
Installing a 1 1/2 X 1" bushing with a 1" nipple or pex adapter into the tank. The bushing will have a 1" pipe nipple welded to the underside, 36" long, where the other end will be setup to deliver the return water through a series of drilled holes with an area that will be twice that of the 1" pipe (the end of the nipple will be closed).
My particular flow requirements is low, if I needed more flow I would consider a horizontal connection.
I believe I will go with the marriage idea. Here it is:
Installing a 1 1/2 X 1" bushing with a 1" nipple or pex adapter into the tank. The bushing will have a 1" pipe nipple welded to the underside, 36" long, where the other end will be setup to deliver the return water through a series of drilled holes with an area that will be twice that of the 1" pipe (the end of the nipple will be closed).
My particular flow requirements is low, if I needed more flow I would consider a horizontal connection.
Chris S
New Member
I put mine together today. My thread o lets are 1.5"
I had planned on 1 1/2 x 1" reducing couplins with 1 " cxm adaptors, but the 1" cxm could not be filed out. The 1 1/4" adaptors I had only had a small shoulder on them which I was able to easily remove with a die grinder & sanding wheel
I then slid the fittings down onto the pipe & soldered them so that the dip tubes would be 3" off the bottom of my tanks.
I'm not a good welder, so this was easier than welding to a fitting - for me anyway
I had planned on 1 1/2 x 1" reducing couplins with 1 " cxm adaptors, but the 1" cxm could not be filed out. The 1 1/4" adaptors I had only had a small shoulder on them which I was able to easily remove with a die grinder & sanding wheel
I then slid the fittings down onto the pipe & soldered them so that the dip tubes would be 3" off the bottom of my tanks.
I'm not a good welder, so this was easier than welding to a fitting - for me anyway
Dune
Minister of Fire
sgschwend said:
Actualy it is easy. Say you want a one inch pipe to extend into the tank. Weld in an 1 1/2" coupling to the tank, slide a one inch pipe inside an 1 1/2" sched 80 nipple cut weld around one end, screw into coupling.
sgschwend
New Member
Yes, that would be a marriage, sounds like your setup would work pretty good for a horizontal connection.
I am doing the same but utilizing the tanks previous threaded holes.
I am doing the same but utilizing the tanks previous threaded holes.
heaterman
Minister of Fire
chuck172 said:
I avoid bushings as a matter of standard practice. They are illegal for gas and I've had too many failures with the China/Thailand variety encountered these days. Give me some good old made in the USA Ward or Anvil brand fittings............please?
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