I am curious, what is a good process to clean some of the prep damage to aluminum up, lets say catch cans or end tanks. That are being fabricated from a 8x4 sheet of aluminum?

 

what do you mean post weld cleanup. usually alum comes out pretty damn clean after weld

 

I believe he is referring to wire brush or scotch brite scratches on the AL surface.

A buffing wheel and polishing compound is your most thorough bet. But of course it means polishing the whole assembly to have it match correctly, if you are going for aesthetics.

 

if you choose to wire brush it, only use stainless one. if you you a mild steel brush, you will end up with rust over time.

aaron

 

Precisely, there is always a surface area done after you've prepped for the initial welding, and it looks like ***. I want all of it to look clean, and not "thrown" together.

 

you shouldnt need to wire brush it if its being made from a new sheet of aluminum. more importantly you should be concerned with not contaminating the material when cutting

 

winner winner chicken dinner!

 

^^^^Buzzer, wrong.

Even with a heavy cleaning action set up on the welder, always brush aluminum. Some level of oxide will always be present. Use a stainless brush which is used only for AL as stated above. Or, you can use a scotchbrite successfully. Try not to use a rotary stainless brush as they can trap impurities in the metal. If you do use one, use low speed.



Also, use a degreaser before welding like acetone. Let dry before welding of course.



Cut with carbide (Bits, skill saw blade etc), although I have used cutoff wheels before they are not optimum.

100% Ar for tig, and good luck.

Perhaps you are cleaning an area way larger than the weld takes place in?

Chay

 

wait do you actually do this lol. I weld all types of alum from basically pop can sheet metal to 2in thick military stuff and have never in my life every cleaned aluminum. Even if it sat in our shop for months. Unless its got oil or paint on it it welds perfect

 

Generally speaking, you should prep your aluminum shortly before welding it. For some people that means using a stainless steel brush in a back and forth motion, followed by cleaning well with acetone. This helps to remove some of the aluminum oxide build up on the surface which will leave less impurities in the weld.

That said, you will never completely get rid of the aluminum oxide. Aluminum in its pure form is extremely unstable and will react with any oxygen is contacts to form that protective layer. It's all about decreasing the thickness of that layer to something more manageable.

That said, the best technique is to completely surface prep your entire piece of aluminum, wipe it down with acetone and a clean cloth, and then weld it. Use the settings on your welder to minimize the rest of the cleaning action (the white haze around your welds). Takes a lot of time to dial this in, but once you get it together it will come out very nice.

 

To each their own.

I think if you do any research you will find that what I do, and what I have recommended are very common practice.

I have no idea, unless you are making crappy MIG welds, how one would tig a decent bead on dirty aluminum.

Perhaps you'd like to share a video of you doing your process, machine, amps, etc? Until then I'll believe it when I see it.


Chay

 

here machine set at 80% freq is all over the place but when I really want to **** people off I run max like 400hz and pulsed at like 5000 pps lol
some fairly clean alum. welded about 1000 of these

some 2" thick military Stuff I welded a few weeks back

I just welded a few dozen alum pieces saturday that was pretty damn dirty. Never once though about cleaning with a brush, I dont even own a brush, to me its a waste of time. I weld stainless fuel tanks without a cleaning them. If you weld 10 hours a day you find almost nothing needs to be cleaned unless its coated in something or just really thin

 

Gotta say, the top ones look pretty clean.

My machine (Transformer based) would not like that dirty stuff.

The bottom one looks cold and seems to have inclusions (dark dots through the weld), but it's tough to really tell not being there in person. How many amps were you running for the 2"?

Also can't tell how much pen you got, but agree, overall they seem not too bad.

I still think that this is not the best practice, and that cleaning first would produce a superior weld.

Chay

 

2" run max amps on 350 machine. obviously had to preheat every block of alum for a good 10 minutes before welding. btw that bottom piece was welded pulsed. most of those welds are ground/machined flat so it doesn't matter if they look good.

 

Look at the size of your cleaning action though, compared to something like this.



Obviously this is a bit of an extreme example, but I believe it truly goes to show the potential regarding what is possible when you take the time to truly prep your parts.

 

Like I said if I wanted to make pretty welds I would but I dont get paid to make pretty welds I get paid to make welds that just work. marcello gets paid for pretty welds so he can take his time polishing every single piece of alum he welds. If I made something like that I would be out of a job lol

 

This was my first time welding aluminum, well I mean after doing some initial lines to get the concept down. Stainless brush, acetone and weld.