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Methods for pre-heating aluminum?

Posted: Tue Apr 19, 2011 4:20 pm
by 98 SNAKE EATER
First off, I'm a newb when it comes to welding aluminum :oops:

I picked up my first tig rig a few weeks back (Lincoln PT225) and I've just been goofing around with it for the most part....no real work yet.

From what I've gathered by watching the tips and tricks videos, I figured the best way to learn is to get all my aluminum scraps together and just get as much seat time as possible 8-)

After messing around with all the settings, I pretty much have 1/16" dialed in to where I can strike an arc and get a proper puddle going in an instant :)

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However, for thicker stuff like these 3/4" x 1-1/4" pieces of raw stock, I had to crank up the heat quite a bit and wait until it heated up before I saw a puddle :|

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As you can see, the beads are quite shallow as I ran them as quickly as I could to avoid melting my torch :oops:

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However, after a few minutes of letting my torch cool, I flipped the pieces over and was able to get a lot more penetration with far less power because they were still hot, so I ran a bunch of random beads just to get the feel of it and the pieces were still hot to the touch even after 20 minutes :o

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I guess that's how I learned that it's easier to weld thick aluminum when it's hot ;)

Thing is, I'm a little lost on how to go about pre-heating the material :?

Do I just keep loading up the tig torch until I see a puddle or hit it with a blowtorch beforehand?

I figure sticking them in the kitchen oven would be my best bet, but my house is over 20 miles from my shop :|

Re: Methods for pre-heating aluminum?

Posted: Tue Apr 19, 2011 4:27 pm
by Lexi
Maybe just put it in boiling water for a few minutes. Maybe this temperature will be enough to make the piece 'workable'.

Re: Methods for pre-heating aluminum?

Posted: Tue Apr 19, 2011 11:52 pm
by jakeru
300k BTU "weed burner", operating off a barbeque size propane tank will get it up to temp in a hurry. Harbor freight sells a nice one with a push-button ignition for < $40.

Also, raise your AC balance setting to "max penetration" (highest possible EN%).

Re: Methods for pre-heating aluminum?

Posted: Wed Apr 20, 2011 9:30 am
by 98 SNAKE EATER
Thanks for the tips :)

I have yet to touch the AC balance (I just left it on Auto)

Re: Methods for pre-heating aluminum?

Posted: Wed Apr 20, 2011 10:40 am
by kermdawg
If your going to weld alot of 1/4 inch plus thickness I'd think about getting some helium/argon mix in addition to your preheating as well. Blowtorch will work fine for smaller sections, and Jakeru's weed blaster will work great for bigger pieces. Get some temp crayons to measure your heat, those infared thermometers dont work well on aluminum.