[watermelon]

Hi All,

Just looking for tips on how to prep metal and aluminum prior to welding.

What I do is just grind the area to be welded with my angle grind and a 120 grit wheel. I will probably start wiping down grinded area with isoprop alcohol. Not sure if this is good enough.

I have not welded aluminum but will give it a try sometime. I am thinking I just grind and wipe like above.


What do you do?


thanks,

watermelon

[noddybrian]

I have used IPA because I had some free & asked a similar question previously on the forum - I found it works on some but not all contaminants - if the material is new / clean it works OK, but for second hand material or used / broken parts then it's not strong enough unless left to soak for some time - I find brake cleaner is good & cellulose paint thinners - but have purchased some acetone ( as generally recommended ) for some sheet I had problems with & this has improved my results .

I also found that using a grinder made maters worse - firstly if you grind prior to solvent cleaning you will spread & imbed into the surface whatever was on the material - you uncover a fresh surface so to the eye it's clean - but still contains unwanted residues - this is made worse if you have used the grinder for anything else - I now keep 1 grinder for ally exlusively to help prevent this - also the ally has an oxide layer which has protected it to a degree - the AC punches through this when welding & exposes clean material just around the weld pool - even anodised parts seem to work - I now try solvent first & only abrade if necessary - & then with a " Scotchbrite " mop - as the relatively coarse surface left by grinding seems to promote arc wander & other undesirable traits.

Exceptions to this would be things like corroded parts off boats / oil impregnated stuff like gearbox casings - with these I'd bake the cr-p out of them first - then solvent clean - then remove surface material where feasible untill clean solid base is found.
Hope this helps - good luck !

[TamJeff]

I weld aluminum all day, every day. The most I use on visibly contaminated aluminum is a stainless wire brush if it's solids or oxidation, soap and water for just about everything else. Seems that aluminum that is stored outside for any length of time will have an organic contaminant and distillate solvents don't phase many of these. I keep a spray bottle of diluted dawn dish detergent and a roll of paper towels. The other thing I have is a squirt bottle with naptha to get china marker off and things like that. Acetone works well too but I never have it around for very long.

[Otto Nobedder]

Jeff, this probably won't surprise you, but,

I welded 6061 pipe, 100% x-ray, for about four months. 5683 rod. (Never used it before.)

My best results were a simple wire-wheeling of the joint, and a wipe of the rod with a dry SS dish-scrubber.

This was clean material, no grease or machine oils, so all the wire wheel, etc. did was break the oxide layer enough for a clean arc.

Steve S

[TamJeff]

Doesn't surprise me at all. I often forget to change my ac balance and HF from anodized and the extra cleaning is enough to take care of even gray colored 6061. I mean, I see it cook away to the edge of the wash zone but the weld puddle is clean and shiny with no pepper. Sometimes 'we' get import material that looks like it was stored in a pigeon coop, and smells like it too when you put the heat on it. That, I clean outdoors with soap and water so I don't end up wearing any of that mess. Every once in awhile I will get some funky aluminum that has mud/dust and such on it and that's basically what I use the spray bottle of soapy water for.

I don't like the look of joints that have been ground and it creates a grain that distorts the edges of the weld. The capillary nature of aluminum wants to sweat with the grain, if that makes any sense. I also notice it when welding brushed anodized. If the grain goes in a different direction than the weld, I have to work harder to get that fine edge.

[racingparts]

new aluminum , i never clean it, dont see why i should waste the time, and it comes perfect

i clean the dirty one with wire brush and brake cleaner. seems to do the job quite nice, welds perfect as on new aluminum