Here you go non welders. I have been welding for about 25 years (not as a living). I have been titrating my oil prior to running it into the processor. Well to keep it short I was not getting what I believed to be an extremely accurate result. So I decided to weld a nipple and a valve to the side of the reactor to allow me to circulate the oil, get it heated and then do the titration. Knowing I can't weld a barrel with remnants of methanol I filled it with water. Fellas I am on the verge of the going downhill in this story. Barrels aint made to be welded when full of water. Can you say blow a hole in the side of the processor? A hole that refused to be welded shut. It was impossible to get it closed off. Slag inclusions were the worst, I could go on and on but lets just say I went to bed and let the water drain out.

Day 2- Filled the reactor with water again all the way to the top. Ran the pump for 15 minutes and drained again. Filled again and ran the pump 15 minutes. I did this until the water ran clear and I was sure the methanol was gone. Then I had to grind off the mud dobber nest I created the day before. Then continue to weld ove rthe entire mud dobber area to get the barrel closed. Filled with water again for a final check. Finally done.

It is pretty kewl to take the oil right out of the barrel for titration. Not kewl to weld a barrel full of water. So any newbies on here-yall are welcome to learn from my newbie mistake-Don't weld on a barrel full of water. More importantly don't weld on a barrel with any signs of methanol in it.

safest way to do this is to use nitrogen, or co2 to purge the barrel of oxygen you will need to get a co2 or nitrogen supply to do this

1. rinse the tank a few times with water empty, then and cover all but the hole to be welded, and one other (ideally at the top of the tank), 2. clamp the new fitting fixture to the tank in some manner, and run a hose into the tank, run the inert gas it at a few pounds for 10 or so minutes, checking for air flow out from around the hose, those with a methanol meter should check the tank for vapors. when clear but leaving the inert gas running, weld the new fitting

you should cover "all" of your hair with a welders hat, and use a full face welding hood and full welding leathers when you do this, (as a last ditch protection, should the worst happen.)

safety wise, just water washing is not enough on a contaminated tank (especially if it held gasoline, diesel, biodiezel) but robbing any remaining fuel of oxygen cuts the ignition process short .

to make fire you need the "un-holy" trinity, that is, fuel (any flammable substance in the right concentration) sufficient heat above flash point of the fuel (the welding) and oxygen. the oxygen is the easiest to purge from the tank.

I used to work with a guy who welded gas tanks by attaching the exhaust pipe of his truck to them. Once the CO saturated the tank he commenced welding... No oxygen = no boom
Jon

If you have a fitting that is leaking water and you try to weld on it the leaking water will contaminate the weld, it will be just blind luck if you are able to seal it up, just rinse with water once or twice and drain it out and then weld, the remaining material in the tank will be no where close to ignitable.

Hey Fab that is what I had to do. I had to do it the rigth way the second time around. Even though I am in my 40s I still need a reminder to do it the right way the first time around so I don't have to spend two days undoing what I did.

Hi Jon

quote:

I used to work with a guy who welded gas tanks by attaching the exhaust pipe of his truck to them. Once the CO saturated the tank he commenced welding... No oxygen = no boom Smile

But us guys all drive diesels, right? A diesel's exhaust is mainly fresh air and a little CO and CO2 and other stuff - very lean, with the intake always WIDE open - no throttle.

Don't use a diesel exhaust to try and purge a tank!

thinking about it, i think a great way to purge a tank, would be to drop large chunk of dry ice in the tank, the cold co2 would tend to settle in the tank and push the air out the top of the tank.

I am not sure I understand, are you using a closed top 55 gallon barrel for a reactor? I make reactors using a removeable top and it is easy to get a sample.

When ever I weld a gas tank (car or motorcycle) I drain the tank, rinse it with soapy water 3 times and then flush it with water until the soap is gone. Then it no longer smells of fuel and at that point I consider it safe to weld. I've done this many times.

I've also welded many fittings into the bottom of 55 gallon drums. I always use flux core wire (.035" I think). I have a MIG (Lincoln Electrig Pro-Mig 175) but I just can't ever seem to get it to weld as nice on gas. I crank up the amps and blow a hole the size of a steel plumbing bushing into the drum... clean up the hole with a die grinder and weld it in.

To weld it, I always start the bead on the bushing and run it out onto the drum. After I go 360 degrees, I weld over it once more. Then put some water in it and check for leaks. There's usually a few pin holes that need touching up... fill them in and then clean the weld and paint. I've done several of these and after several years, no leaks...