Question on drilling holes in propane tank ..

[taxidermist]

Do you need to put copper heat exchange tubes in the propane tank? Or is it just to store the hot water coming from the boiler?? I want to buy a propane tank and make my own storage but dont know where to begin. If anyone has taken pictures during their process of building there storage tanks and could send them to me it would be greatly appreciated.

No exchangers just the tanks to store the hot water. You can see some pics of mine in my blog.

 

[patch53]

I just talked to my buddy down the road and he said he has a tool that can measure the curvature on the side of the tank, and then he'll take the coulpings to work and cut them at the same angle/curve so they'll butt up flush to the side of the tank horizontally. Should make it nice for welding I would think .

Pat

 

[boatboy63]

On the other hand, a fellow near here repairs propane tanks for one of the local propane dealers when they have a pinhole leak. He says he has them top them off with propane before he welds them. Talk about the courage of your convictions.! I guess if it's full of liquid propane it doesn't have room for air, huh? The arc is only running for a couple seconds and he knows where the leak is by the little yellow flame. Says he's repaired 5 tanks that way.

Better be telling your friend goodbye before it happens. First of all, a propane tank isn't filled totally so it doesn't have any air. The most they fill them to is 80%. The other 20% is for expansion when the tank heats from the sun. His time is coming if he keeps doing it that way. I have seen local propane companies "burning off" tanks when they are trying to empty tanks. When they try to pump them down, it won't all come out so they hook a long pipe to it and light the end of the pipe. One of their techs told me that it will sometimes burn for several hours that way.

 

[leaddog]

On the other hand, a fellow near here repairs propane tanks for one of the local propane dealers when they have a pinhole leak. He says he has them top them off with propane before he welds them. Talk about the courage of your convictions.! I guess if it's full of liquid propane it doesn't have room for air, huh? The arc is only running for a couple seconds and he knows where the leak is by the little yellow flame. Says he's repaired 5 tanks that way.

Better be telling your friend goodbye before it happens. First of all, a propane tank isn't filled totally so it doesn't have any air. The most they fill them to is 80%. The other 20% is for expansion when the tank heats from the sun. His time is coming if he keeps doing it that way. I have seen local propane companies "burning off" tanks when they are trying to empty tanks. When they try to pump them down, it won't all come out so they hook a long pipe to it and light the end of the pipe. One of their techs told me that it will sometimes burn for several hours that way.

He gets away with that because there isn't any air in the tank. just liquid propane and gas propane. with the tank full there isn't much room for the gas and there isn't enough air to suport combustion. Now with the tank empty and open to the air it has very little propane but lots of o2 and it takes very little propane gas mixed with o2 to cause a BIG bang.
When they flare off the tanks the propane is mixing with the air at the end of the pipe and burns there. If they put air in the tank it might just swell up very fast and move to the other side of the country.
leaddog

 

[DaveBP]

He gets away with that because there isn’t any air in the tank. just liquid propane and gas propane. with the tank full there isn’t much room for the gas and there isn’t enough air to suport combustion. Now with the tank empty and open to the air it has very little propane but lots of o2 and it takes very little propane gas mixed with o2 to cause a BIG bang.
When they flare off the tanks the propane is mixing with the air at the end of the pipe and burns there. If they put air in the tank it might just swell up very fast and move to the other side of the country.
leaddog

I don't buy his explanation, either. I just thought it was a startling technique.

The fact that we're still alive doesn't mean we understood every dumb thing we got away with.

 

[ewdudley]

He gets away with that because there isn’t any air in the tank. just liquid propane and gas propane. with the tank full there isn’t much room for the gas and there isn’t enough air to suport combustion. Now with the tank empty and open to the air it has very little propane but lots of o2 and it takes very little propane gas mixed with o2 to cause a BIG bang.
When they flare off the tanks the propane is mixing with the air at the end of the pipe and burns there. If they put air in the tank it might just swell up very fast and move to the other side of the country.
leaddog

I don't buy his explanation, either. I just thought it was a startling technique.

The fact that we're still alive doesn't mean we understood every dumb thing we got away with.

No really, there's no death-defying stunt here. Without oxygen you're golden. After all, lighting an LP gas burner doesn't lead to a chain reaction back down the supply piping through the regulator and into the tank, kaboom. As long as the area is ventilated enough to be sure that heavier than air LP hasn't pooled nearby, and as long as you're sure there's no oxygen inside the tank, how could you ignite an explosive mixture of fuel and oxygen?

Welding on an open empty tank is a different matter of course, especially with tanks that have had petroleum products in them because fuel can be present for years. Filling with water can work if the tank is truly full. Another technique is to put a dip tube to the bottom for exit flow and then pipe engine exhaust into the top so the warm exhaust displaces the cooler oxygen laden gases. Calculate RPM of the motor times four-stroke displacement divided by two, convert to gallons per minute assuming exhaust volume is larger than displacement volume, and run the motor for a couple times longer than should be necessary, and have at.

 

[DaveBP]

I got my tanks from a propane dealer. They "retire" tanks by filling them with water through one of the big fittings on the top (they're out back on a level lot) and pull all the fittings and hardware out of them and continue the water until it's squirting out all the holes. He was careful to give me these details to reassure me, I guess. Then they pump all the water out that will come out with their suction tube. They still smell pretty strongly. He said he couldn't trust some kids (with a death wish, maybe) from messing around with them.

I put a 1" PVC pipe into them and ran air through them for a month or two sitting in the hot sun. No more stink.