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tig welding super rusty steel

Posted: Fri Jan 14, 2011 9:15 pm
by waynebergman
I have found some cool odds and ends out in the bush that are very rusty. I kind of like the rusty look for this project as it will be kind of an arty thing. I have brushed off most of the crud and used a combo of lemon juice with baking soda and lots of wire brushing, after welding while its still hot I brass brush and hit it with a tung oil at the end.
Flap disc sanding the areas that will be welded. The welds are looking ok but I am looking for an easier way to clean up the rusty old components. My question is how would sand blasting work for steel as an easy prep before welding. The pieces I am welding are big threaded pieces and irregular shapes so its hard to get in there with a sanding disc.
If sand blasting is ok before tig welding steel, is sand ok or what should I use for sand blasting material?

Re: tig welding super rusty steel

Posted: Fri Jan 14, 2011 11:15 pm
by admin
for what you are doing, sandblasting with sand is probably a good option.
sand wont hurt the welds and is probably better than aluminum oxide blast media for welding over. it wont weld as clean as if it was ground to shiny bright metal but that seems kinda impractical from your description.

good luck,

jody

Re: tig welding super rusty steel

Posted: Sat Jan 15, 2011 12:36 am
by Otto Nobedder
Sandblasting is probably your BEST option for this, and Admin is right, silica sand is the right choice. Any residue left by plain 'ol silica sand will float to the top like slag in a stick weld.

For structural welds where I work, this is often the only prep we do, unless the material rusts heavily before we get to it. I sometimes TIG right over light rusting in non-critical applications with no ill effects.