Hello,
I recently purchased a Precision Tig 185, some wire and a couple books on welding. After reading the books, running up my electric bill laying practice beads on some aluminum sheet metal I'm starting to get to the point where I can fabricate some simple parts.
With that I'm starting on a little more ambitious project, creating an 3"x3.5"x6" aluminum box out of 1/16" sheet to hold water for a water injection system. This is giving me experience welding 90 degree outside corners.
I'm having mixed results. If I can the puddle started and flowing I can get a beautiful shiney bead. The first problem I'm having is getting the bead started. Its very easy to melt the edges of the sheetmetal and when that happens the aluminum quickly turns to a dull blob. I've tried heating the metal slowly and heating it quickly and so far I've found that its difficult to find just the right point where the sheet metal starts to puddle so that I can dip the welding wire in. Often the wire starts to melt before the sheet metal does and I end up with a round blob sitting on top of the sheet metal. Heating it until things start to merge doesn't work very well, typeically the whole mess turns dull and eventually starts to melt. At this point I end up with an ugly melted blobby piece as opposed to a beautiful weld.
I've been wiping my welding wire and the work piece down with MEK to clean everything. I try to fit the parts so that there is no gap between them, though sometimes there is a small gap. The second problem is that sometimes the weld starts to fail if there is a small opening (and sometimes it will open up from the heat put into the piece).
Once things start to go bad its downhill from there. Seems like the more I try to fix things the more I end up with a mess. Sometimes it seems like the weld gets contaminated with black stuff. Don't know if that is the aluminum superheating and starting to burn or what.
While I'm thinking about it - what's the best way to fill burn through on thin material?
I've got the machine set at 60 amps and the gas at 20. I'm using 1/16" wire (I guess that's the right term - I used to call it welding rod) 1/16" pure tungsten electrode (AC polarity of course) and the work is 1/16" 3003 aluminum.
Can anyone give me any ponters to help me get my beads started flowing, or for that matter I'm always interested in any and all pointers.
Thanks,
Eric Marsh
The best way I found is to use a clean piece of angle on the back side of the joint. It will work as a heat sink which will give you more time to add filler if needed and also you can clamp to it. You will always need to add some filler to start 2 edges unless the fit up is really tight. If it is a long joint a couple of tacks would be in order due to the expansion of the aluminum from the heat being applied.
Hope this helps,
Dave
Are you running the machine on AC? You should be, for aluminum.
Aluminum is hard!
Chris
Slow Poke!
I/16" Alluminum welds real fast my friend. You don't have time to speculate about it. Once you start the puddle you have to start running with it or back off on the heat. Not an easy task for a beginner.
Do you have a foot pedal control? I hope so or you have some rough times ahead.
Get some thicker cross section material to pratice on or as already mentioned a heat sink.
In simplest terms you have to learn to move a long as fast as the heat does. Or you can do a lot of tacks and then go back and connect them.
Good luck.
Hi Eric, getting the bead started is also the hardest part for me. Put a piece of angle inside as was mentioned. Once you know that your piece will not melt away suddenly, it takes some of the pressure off you. If you find yourself making a bad start, stop and clean it up and start again. Get the base metal molten before you get the rod too close.
The best way to tig aluminum is with AC-high frequency, Pure Tungsten and straight Argon and you'll have to have a liquid cooled torch as this process makes the torch get quit hot....think about it, 60 cycles per second buzzing through your hands.
You also really need a reostat to control the amperage, wait till both edges of the angle gets hot (will look silvery at the puddle) and then add the wire. The parts to be welded must be very clean with no dust, dirt & grease.
It's alot of fun and not that hard with the right set-up. They say you can weld aluminum with DC_SP but I have never used that process to to it.
By emarsh
Date 09-14-2004 01:44
Guys,
Thanks for the feedback. I'll try to incorporate your ideas and practice practice practice.
Eric
I am new to the group, but have two cents if thats OK?
Make sure the wire brush you are using is stainless steel and is used only for cleaning aluminum. If you use the same brush to clean LCS you will contaminate the brush and will not be able to use it on aluminum.
Trae
Trae has the right idea, dedicated tools can't be over emphasized. Clean joints are a must. Clean and then weld, don't wait around or you will have to clean again, oxidation is your enemy when working with aluminum, and it forms so fast. The archives in this forum have lots of discussions about welding aluminum.
John Wright
