Welding Tips and Tricks

Ok guys working on a project for the shop. Fabricating a motor mount for the Portable Line bore Machine I'm building. A lot of the aluminum I have came from my cousins shop when he passed away. I have some 3/8" plate that welds very nice but the 3/4 x 1 1/2 bar stock welds like crud when the puddle starts to form it is full of black spots and will not flow no matter what you do to it I have cleaned it, wire brushed it and pre heated it but it is still giving me fits. Are some aluminum's just prone to trouble. It machines nice looks clean is not cast but I am at a loss. I know it's a thick piece but most of it has been machined off. and I have been able to weld heavier pieces before. Any advice would be appreciated before I have less hair left than what I do now.

Some aluminum won't weld (7075 comes to mind). Depending upon its age, scuff it heavily, preheat it with propane (or other suitable) and wipe down with acetone. See if the preheat helps drive out impurities before you weld. You can also adjust the AC balance on your machine closer to 50% to see if that helps with that material.

Thank you I will try that next The shop is starting to smell really foul from all the hair on the floor getting burnt by sparks.lol
I hope I can get it to weld because I already have a lot of time machining it.

Well success or well good enough lol Definitely a Gorilla weld not very pretty but stout as hell.
I cleaned it and pre heated it again and then passed over the seam a few times with just enough pedal to keep the arc going and cleaning then went to the start point and it started to flow better. If this was for a customer I would mill out the joint and redo it but it's for my machine so it stays ugly. Someday I hope to be half the Tig welder Jody and some others are.
Thanks Again for the help

If you got it to weld, and the bead looks crappy but is strong, you can adjust your balance back to about 65%, and wash over the bead with no filler. This will allow you to at least dress up the weld so it doesn't look like Frosty the Snowman blew his nose on your material (I've done this LOTS of times when the material I am welding is so dang thick I can barely get the heat into it.)

Dr,
You said you cleaned the line with low amps then welded it. I know from my chemistry that AL oxidizes like instantaneously in air, not deep but every atom made buddies with a couple oxygens.
I was wondering if a 2 steps forward, 1 step back approach would be the same or better...
Also that's thick stuff. What kind of amps? I weld 3/4 6061 with my max 160 amps when 1/4 is the stated maximum.

That's basically What I did a little forward of the puddle then back to weld that spot. And Amps well I could use a few more I was maxed out on my Squarewave 175 when I can afford to do so my next investment will be a welder with more leg room and horsepower.

Thank. I'll try that. I've gotten great with steel...not pretty but I can build up small worn out things and keep production going instead of milling new parts.
That said, aluminum is tough. I recently had to weld a small 1/4 X 1/2 piece onto a thick 3/4 part...I did it but it's about half melted and marginally strong... Then I realized I welded it to the wrong part. Steel would've been easy. Even the rework.

DrDogwood wrote:That's basically What I did a little forward of the puddle then back to weld that spot. And Amps well I could use a few more I was maxed out on my Squarewave 175 when I can afford to do so my next investment will be a welder with more leg room and horsepower.

If you have only 175 amps you're gonna need more heat than what your welder can offer. Try preheat, not just where you want the weld, but the whole piece.

Setting up for helium is a big step, but it is incredible what it does for you.

Willie

Bill Beauregard wrote:[quote="DrDogwood"And Amps well I could use a few more I was maxed out on my Squarewave 175 when I can afford to do so my next investment will be a welder with more leg room and horsepower.

If you have only 175 amps you're gonna need more heat than what your welder can offer. Try preheat, not just where you want the weld, but the whole piece.

Setting up for helium is a big step, but it is incredible what it does for you.

Not that big a step really. Either get a bottle of 75%Ar/25%He, or 50%/50%, or a second bottle of 100% He. Use a Western Wye between the 2 bottles and a single input to machine. Allows any ratio of mixing on the fly. Also, you can with this setup run 100% He TIG on DC to aluminum. Lay your root, then switch back to Argon and cover it up pretty since the part will have all the needed heat in it to weld at lower amps.

I ran out of 100% Argon this weekend and finished up a steel frame in 75%Ar/25%He and had zero issues with puddle or heat control or contamination. Gotta learn to be flexible and make the most of a single machine