Simple idea for 55 gal fuel tank w/ sight glass

[bschwartz]

When I made my propane tank muffler/expansion chamber, I made two holes with a 2" hole saw before washing the inside and welding.  Would the two large holes make it 'less explosive' and more likely to just 'WOOSH' a pop of fire?  I didn't have any problems, but would you consider having large openings safe?

[mobile_bob]

the larger openings help, however
there is really no opening large enough for the very violent explosion that is possible with the use of oxy/acetylene welding.

don't even ask me how i know so much about the risks involved.

just don't wanna hear of anyone here getting hurt, i have grown rather found of you fellars, and would really feel horrible to
hear of something bad happening.

the 125 dollar kit seems like a pretty good deal when you consider the risks involved with welding on tanks/drums.

i have a long history of welding and repairing leaks and tears on fuel tanks and the like, and as crofter, cognos and others have stated
there are serious risks involved, you can be lucky or you can be unlucky.

large fuel tanker trailers that have baffles have to be repair welded because of leaks between the baffles from one compartment to the other,  this requires the welder to be down inside the tank, those tanks are steam cleaned for 24hours by law before anyone is allowed to drop down in and strike an arc, often times the baffles are double which means there is airspace between them, and of course if there has been a leak then there is gasoline, diesel, condensate or god knows what in there..

an explosion while inside that cell means being crushed!

diesel fuel saddle tanks, and gas tanks are another matter, when these blow up they often will cut you seriously when the shards of metal flower petal outward. of course you get seriously burned as well, and it happens so fast it is unbelievable.

i use CO2 although as Crofter states nitrogen would be as effective, i like CO2 because i have it around and because it is heavier than air and will force all the air up and out of the tank, usually up out of where you are going to weld anyway. this assures there is no possibility of ignition, explosion or even a poof which can burn you.

personally i am not at all comfortable with the direction of this thread, i fear there might be someone that chooses to take a shortcut
and have a very rude surprise.

bob g

[bschwartz]

I ran wire feed.  If that any safer than gas welding in this case?

[mobile_bob]

its safer than having the added issues of admitting acetylene, however
the other issues still apply

i know of a shop, steel frame building 6200 sq/ft with two drive through bays
inside were two tanker trailers, one having some welding done on it after being prepped properly
and another that just pulled in for a brake job.

while they were starting on the brake job the guy doing the welding with a mig spool gun noticed
the vent pipe support broken lose on the rear of the frame,  he turned the ball valve off, dropped his hood
and in an instant the trailer was gone, the building was gone, all that remained was the concrete and the main I beam
supports to the building, the trailer with the broken vent pipe had been hauling condensate from a well head, was empty but
full of fumes, the ball valve was later found to not turn off completely,

that little spark from the mig set off the fumes in the vent pipe, traveled into the tanker and split it in half, sending the front half out the end of the building about 200 ft and the dual axle end out the other end by about 100 ft.

it blew the tanker trailer sitting in the next bay off its jack stands.

5 men were in the building at the time including the welder, one man was outside having just driven up with his truck to plug in the blockheater.

no one was killed, or injured

i figure that their  guardian angels were due a vacation after that event.

there was sheet metal from that building over a mile away in nearly all directions from ground zero.

that is but one incident that i have direct knowledge of... and no i was not in the building and no i was not the welder.

however i do learn from others mistakes if i can.

oxy acetylene explosions are very violent, without going into details i had such an occasion many years ago, it involved very little
gas and a very small enclosure...
one guy nearly lost an eye, we both nearly lost our ear drums and it felt as though i was hit in the chest by babe ruth trying for a grand slam.

to answer the question, mig is safer than oxy acetylene, only because mig gas is inert, but you still have the possible problems caused by residual oils and/or gasses inside the tank to deal with.

bob g

[BioHazard]

I've used electric heaters to drive out whatever may be left in a propane tank...4x 1500w space heaters placed all around it, the metal will get quite hot, but not enough to combust. Most anything volitile should come out.

As a side note, my favorite use for old propane tanks are targets for my .44 magnum...haven't had one blow up yet! 

[vdubnut62]

I agree with Bob in the respect that this IS an uncomfortable subject. However, I feel it better to at least try to impart proper safety procedures. (besides I have a vested interest!)
Ron

[mbryner]

OK, no welding on the oil drum for me, just maybe drilling a hole or two.   Glad the propane tank is already welded, too.   Besides all I have is my FIL's buzz box welder and I wouldn't know what to do w/ it anyway.

Marcus

[cognos]

Yes - all very good points on the safety of welding/cutting/drilling on enclosed containers. This is called "Hot Work" in many industrial settings - using any tool, around anything, that could cause any sort of ignition source.

In some refinery settings, all the hand tools we use - pipe wrenches, box ends, hammers, wheel wrenches, etc - are made of brass to limit the spark hazard. (The tools are quite expensive, and beautiful when new. As you can imagine, they look pretty beat up in short order...)

Be aware, that drilling is "Hot Work"... the arcs at the commutator of the motor, or even if the tool is air driven... there are sources of ignition even here.

In hot work, one controls one or more of these things, without which there can be no fire/explosion - Ignition source, Oxygen, and Fuel supply.

Your tool will be the ignition source. You have to eliminate the source of oxygen, or the fuel source.

Steaming, purging with inert gas, maintaining a constant flow of steam/gas/air while welding are all examples of techniques used in industrial settings to control the risk of fire/explosion. Careful monitoring procedures with meters that measure the "Explosive Limit" of the atmospheere in the vessel.

Common sense approaches need to be well thought out. Logical puzzles are sometimes best handled by pros. Always err on the side of safety.

If I was going to drill a hole in a drum that had *ever* contained a fuel - I'd clean it as best I could, then fill it with water, then drill into the full vessel. Messy, but safer than not... 

[squarebob]

There are a lot of nice parts listed in this thread. It would be nice to have these parts listed in the "Parts Source" Board also. How does that get done???

Bob

[NevadaBlue]

Yes be safe. Water fill is a good thing.

Many years ago, I had an old Norton motorcycle and the gas tank leaked. I didn't have any way to fix it, so I took it to a radiator shop to get him to braze the leak. He wouldn't touch it... "gas fumes". I took it outside his shop and dropped a lit match into it... WHOOOOT! end of problem. Took it back inside and he brazed it. 

Wouldn't recommend that with a propane tank however. 

[AdeV]

Many years ago, I had an old Norton motorcycle and the gas tank leaked. I didn't have any way to fix it, so I took it to a radiator shop to get him to braze the leak. He wouldn't touch it... "gas fumes". I took it outside his shop and dropped a lit match into it... WHOOOOT! end of problem. Took it back inside and he brazed it. 

You were lucky.... I did that to a car petrol tank (well, sort of). The "whooot" deformed the tank to the point of being useless, as well as blowing a million tiny holes in it where the metal was a bit thin...

[vdubnut62]

I made a 5 gallon bucket out of a 1 gallon lacquer thinner can with fumes, an O2 jet & a match once
Hey ya'll watch this...wait, here, hold my beer.
It was a pretty thin bucket 'tho.
Ron

[rcavictim]

I have always filled tanks that contained fuel or propane with water before cutting or welding on them.  Never had a problem.  In the case of small propane tanks like 20 lb I'll use a vacuum pump to pull the air out and then let the vacuum pull water in.  This way they can be completely filled.

[Crofter]

RCA, I guess I am a bit of a contrarian but your suggestion of putting the vacuum pump to work on the tank, might lead someone to use a vacuum cleaner to the same effect. I know a fellow who decided to suck accumulated oil out of one of the old float controlled oil burner stoves that had flooded. Unfortunately the fumes out the other end of his hoover were going into his shack and eventually something ignited it. It melted off all the plastic storm windows and also a good portion of his moustache and eyebrows but it could have been worse. That sucker had some design flaws!

[rcavictim]

RCA, I guess I am a bit of a contrarian but your suggestion of putting the vacuum pump to work on the tank, might lead someone to use a vacuum cleaner to the same effect. I know a fellow who decided to suck accumulated oil out of one of the old float controlled oil burner stoves that had flooded. Unfortunately the fumes out the other end of his hoover were going into his shack and eventually something ignited it. It melted off all the plastic storm windows and also a good portion of his moustache and eyebrows but it could have been worse. That sucker had some design flaws!

It is pretty much impossible to make anything, even instructions or advice idiot proof.  This is because idiots can be so creative.  In the end, we all have to take responsibility for our own actions.