Tig welding with magnets around and aluminum cleaner

[Steve]

Here are a few things I've discovered lately.

I often use those arrow magnets to hold steel parts together and on my tig table to position aluminum parts. What I have noticed is that you cannot have magnets around the weld area especially when tigging aluminum with pulse. It just will not allow the torch to strike an arc with any magnets near the weld area. I have not had much of a problem with DC and magnets.

Now as far as aluminum cleaners go, I recommend not getting them. I have tried several aluminum oxide removers and all have not worked nearly as well as a good stainless brush and acetone. I have had problems with aluminum cleaners with residue left. When using these cleaners, you really have to make sure that you get every bit of them off the aluminum or you will get contamination. Plus that stuff is really expensive. Like $25 for a small bottle. Best bet is a gallon of Acetone for $17 and a good stainless steel brush or wheel. I have found that acetone really is the best oxide remover and will also remove most any other contamination present.

[Rambozo]

Acetone will not really remove any oxides, it does degrease and carries away most residues. The stainless brushing is what removes the oxides. There are chemical oxide removers but as you noticed, most leave behind something that will still require a wipe down with acetone before welding. Aluminum will oxide instantly upon contact with air, so what you are doing is making the oxide layer as thin as possible. A lot depends on the size of the part and access. Sometimes chemical cleaning is an acceptable choice, and other times mechanical removal is prefered. Here is a cheap source of a great oxide remover, that is water rinsable and leaves minimal residue. An acetone wipedown is nice, but you can weld fine with just a rinse and dry, as well. Of course there are downsides like anything else. In this case it is that this is acid based (Hydrofluoric & Phosphoric) and produces some fumes, also while it will remove some grease and oil, since it is water based, really dirty parts should be degreased first for best results. At $20 a gallon it lasts a long time as you tend to dilute it quite a bit. I find about 10 to 1 in a spray bottle works great for aluminum that has been outside. Up to full strength for marine stuff like old boat props. The good thing about chemical cleaning is that it will penetrate porous castings and other places where a brush won't reach. It really makes a big difference in what boils out from something during the welding process.

http://www.grainger.com/Grainger/COM...-Cleaner-4PDA3

You can also get this at most any HVAC warehouse. There are a lot of brands, but they are always pink. There are also blue alkaline versions and soap versions, but they do not work as well, for this application.

[Steve]

Acetone will not really remove any oxides, it does degrease and carries away most residues. The stainless brushing is what removes the oxides. There are chemical oxide removers but as you noticed, most leave behind something that will still require a wipe down with acetone before welding. Aluminum will oxide instantly upon contact with air, so what you are doing is making the oxide layer as thin as possible. A lot depends on the size of the part and access. Sometimes chemical cleaning is an acceptable choice, and other times mechanical removal is prefered. Here is a cheap source of a great oxide remover, that is water rinsable and leaves minimal residue. An acetone wipedown is nice, but you can weld fine with just a rinse and dry, as well. Of course there are downsides like anything else. In this case it is that this is acid based (Hydrofluoric & Phosphoric) and produces some fumes, also while it will remove some grease and oil, since it is water based, really dirty parts should be degreased first for best results. At $20 a gallon it lasts a long time as you tend to dilute it quite a bit. I find about 10 to 1 in a spray bottle works great for aluminum that has been outside. Up to full strength for marine stuff like old boat props. The good thing about chemical cleaning is that it will penetrate porous castings and other places where a brush won't reach. It really makes a big difference in what boils out from something during the welding process.

http://www.grainger.com/Grainger/COM...-Cleaner-4PDA3

You can also get this at most any HVAC warehouse. There are a lot of brands, but they are always pink. There are also blue alkaline versions and soap versions, but they do not work as well, for this application.

Yes, I agree Acetone does not remove aluminum oxide but it does "wet" the aluminum which makes oxide removal easier with a wipe down after I brush them. All I know is that whenever I brush, then wipe aluminum with acetone, plus I wipe the rods, I get a much cleaner weld. Far better than the more expensive oxide removers that I have tried. It is amazing how much residue is on the aluminum welding rods. I keep mine is the tube until use but they still are pretty dirty.

I always run a wire brush over whatever I weld. I've noticed that the combination of brushing and then acetone seems to work best for me. I will try what you have recommended. I've been doing some aluminum diesel tank repairs lately and found that tigging is not the best way to go there. I've been using my Cobra 2000 torch with flux and I think I could weld aluminum with mud and grease on it with that set up! Those diesel tanks are so oily that it is almost impossible to clean them enough to tig weld.

[Tritium]

Beware that hydrofluoric acid is one of the worst, particularly in its dilute forms since it has already caused damage by the time it begins to be felt. It will penetrate skin and go straight for the calcium in your bones killing the skin and tissue along the way. This usually requires shots of calcium gluconate and or surgeries / amputations in severe cases. I worked with this stuff in the semiconductor industry and it DEMANDS CAUTION and respect. As a side note the brown recluse spider has fluoride ions in its venom and can cause similar necrosis of skin and bone damage.

Thurmond

[sportbike]

We have hydrofluoric acid in out metallurgy lab for etching aluminum. We also have tubes of calcium rich cream that is intended to be applied immediately should skin contact occur.

[DaveO]

Beware that hydrofluoric acid is one of the worst, particularly in its dilute forms since it has already caused damage by the time it begins to be felt. It will penetrate skin and go straight for the calcium in your bones killing the skin and tissue along the way.

Just when I was thinking, maybe I'll get some of this stuff. It does sound like exactly the right thing for castings or aluminum that's been outdoors; the MSDS talks about not breathing fumes or vapors, using a respirator, etc. It doesn't mention heavy rubber gloves, I guess even OSHA figures that's a given.

Steve, what kind of repairs are you making on aluminum diesel tanks? I was at a rail yard one time, a guy was using a tap to re-thread some kind of fixture on an engine's diesel tank. The weight of the fuel in the tank was causing fuel to jet out in a big arc about 10 feet high. I'm guessing he did it that way so thread cuttings wouldn't get into the fuel system.

[johnnymg]

Has anyone tried cleaners that have sodium hydroxide? I've seen mention of 'greased lighting' cleaner to remove oxides/anodizing.

?????

regards
JohnG

[Ron66]

Was welding up some patch panels on a steel hood ths weekend, DC with pulse, and experienced the magnet issue. It was a 100lb pull magnet and even 2 inches away it was erratic. Ended up using 4 small refrigerator magnets to hold the panel while I tacked it. That seemed to be ok.

[youngnstudly]

Has anyone tried cleaners that have sodium hydroxide? I've seen mention of 'greased lighting' cleaner to remove oxides/anodizing.

?????

regards
JohnG

I don't know anything about welding over any type of cleaners that remove anodizing, but easy off oven cleaner will remove anodizing well. I don't know how well that stuff removes oxides as compared to other methods. I used some Easy Off to remove the factory anodizing on one of my fuchs a few years back. I would a$$-u-me that you'd want to get the basic stuff with the least amount of ingredients in it (odorless for example). The question is whether or not the other ingredients in oven cleaner can be safely heated to welding temps without causing some reaction that will rot your brain and make your eyeballs spin counterclockwise.