Oompa wrote:Easiest way is toset the tank up so it's very stable and fill it with water to just below your cut line. Cut it with a sawzall or something that doesn't make sparks. Remember that water and electricity don't play well together. Once you have cut the top or bottom off either salvage the top or bottom or make a new top or bottom and weld it on with the water once again just below your joint. Leave the cap off the top if welding on a new top or the drain bung off if it's a bottom. It's the vapour that explodes so by minimizing the possible air gap you minimize the chance of an explosion. You can also flood the remaining air space with Argon to be extra sure just leave it running a little while before you start and whilst you are welding.
I do not recommend leaving the water inside while cutting. But I do agree with leaving the cap off during cutting and purging during welding.
I have done these before also and agree with the others about filling with water to just below the cut/weld line, and purging the rest with argon or Co2 and venting. Biggest Thing, approach this with caution, especially if you have never done this before, if you even think it will explode it probably will, maybe have someone that does this on a regular basis do it for you, safest way.
On a side note, I have never been a big fan of mounting tabs on aluminum tanks, to prone to cracking even in a truck bed, I would suggest over the tank straps, just my opinion.
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Tank is apart & cut to size. Since I'm not an expert alum. welder, would it be better to use a a strip 1" to 1 1/2" wide & do lap welds instead of a butt weld? Might be less prone to cracking too?
As far as the tabs for mounting, I don't have them bolted tight, but have a spring on the bolt to allow a bit of movement.
Personally, I am more of a hobby welder, but not bad quality...However, I have been in oil & gas refining most of my life. Your problem is not so big. If the diesel is gone..no liquid? Your concern is not flashing. Diesel in America can be full of goofiness, flash being 125F. to around 200F, but so what? If nothing is left, nothing to flash.
Like any aluminum welding, you MUST have clean metal with proper purging. I have welded some outside joints with no inside purge and done OK...If you have doubts, purge the inside too! Combustion cannot happen. Again, your metal needs to be clean, so your puddle is too.
If really worried, let it sit in the sun for a while...open of course. Open with a low point and a high point. (Heat rises) Natural vaporization happens. The porous aluminum will gas off quite easily. Wipe all surfaces with acetone or isopropyl alcohol.
Looks really nice, you must have done a good job cutting it to get a nice tight joint. When you first posted I looked up Frostbite Falls, I thought you were being a wise guy. I never knew it was a real place but was one of my favorite imaginary places as a kid.
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77cruiser wrote:No BOOM, didn't come out too bad for first time welding aluminum. Made some straps for it, instead of the tabs being bolted to the box.
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Nice Job, especially for your first aluminum, I do like the straps!
Yesterday is History, Tomorrow is a Mystery, Do it Right Today!