Grinding Aluminum

[rockable]

I learned two important lessons today while practicing my TIG welding of aluminum. Everyone needs to recognize the symptoms of a contaminated electrode. As I was welding along in a nice shiny puddle, apparently I touched the filler rod to the electrode and everything went to crap. I'm a little slow on the uptake sometime but I finally figured out that I had contaminated my electrode. After two or three attempts, trying it on a piece of scrap, I finally got a good electrode again. Lesson 1 - When the puddle is no longer shiny and the filler material no longer flows into the puddle, you have contaminated your weld! Stop now!

Lesson number 2 was don't try to weld over the contaminated weld. Further, you should stop immediately upon recognizing that your weld is contaminated. You will only make it worse if you continue. The contaminants will not float off or burn off!

Here is my question. How is the best way to remove the contaminated weld from the workpiece after you've fouled it? I tried a sanding disc but it gets clogged and I know what will happen with my Dremel burrs if I try them. Also, how do you grind down the welds and finish the area when you don't want the weld bead showing, like when you butt weld two panels?

Thanks,
Rock

[no999gr]

Rotary file. You will add more contamination by grinding or sanding.

[Overkill]

I use WD40 from preventing it getting clogged up. You have to watch your speed as well.

[nosire]

we used to use bees wax on a burr also you need a sharp burr

bob erison
cleveland ohio

[rockable]

Ok. Use a rotary file treated with something slick to keep the aluminum from sticking for cleaning ups fouled up welds. What about smoothing a weld on butt welded panels? Sander with something slick?

[Cal D]

Check out you local weld supply shop. They should stock 4 inch grinding wheels specifically for aluminum and stainless steel. They do not load up and do not contaminate the parent material. Kind of expensive - $10 each.

[welderboy]

I use this, it's my "Taz" saw. The aluminum boat industry here in Southern Oregon uses this tool, but you won't see it till it's needed as OSHA doesn't like them. I use it to bevel thick aluminum, and to grind out a bad weld or even do a nice clean plunge cut. When you use a grinder with a wheel or flap disk to cut or bevel or even grind out a bad weld.....you have a very contaminated area loaded with contaminates and oxides. The air motor is low torque so when it binds it doesn't decapitate you...it stops pretty easy.

[Pete's Metalshaping]

Originally Posted by nosire

we used to use bees wax on a burr also you need a sharp burr

bob erison
cleveland ohio

You can also use bees wax with a grinding disc. Either way would work.

[welderboy]

The saw I have show and a burr for aluminum are the tools that remove the bad metal...it actually cuts it away. A grinder gets the metal hot and smears the metal you are removing into the surfaces around that area. thats not to say you can't "wash over" contaminated surfaces. The integrity of that area will be compromized by grinding the metal though. my .02

[frank luten]

I use a diegrinder with a carbide cutter for aluminum. Getting WD40 or whatever into the weld area seems counterproductive to me.
Frank