chrisf
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| posted on 15/12/08 at 02:15 PM |
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TIGing
Hi Gents:
I have some questions regarding TIGing methods. It seems like I am able to lay two different types of welds. In the pic below, this is how I imagine
TIG welds should look (apologies for the size):
Then, when I really crank the heat up for heavier welds, the weld bead lays really flat and wide. Is this right?
For reference, the electrode is 3/16" and the filler rod is 1/16". I'm using a gas lense and the electrode extends past the cut
around 5mm. I try to keep the electrode as close to the puddle as possible--around 1/16"-1/8".
Also, what I am calling the "nice weld" is 1/8" wall mild steel. The wide, flat weld in question is 3/16".
Any help is well appreciated.
--Thanks, Chris
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Mr Whippy
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| posted on 15/12/08 at 02:45 PM |
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the same thing happens when you MIG as the pool is wider and the metal runnier due to the heat so it levels out like water. Just turn the heat down.
Fame is when your old car is plastered all over the internet
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Mad Dave
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| posted on 15/12/08 at 03:29 PM |
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I'm no expert but in the top pic of the shock mount you have quite a lot of undercut. I think more filler wire is needed
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mark chandler
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| posted on 15/12/08 at 05:51 PM |
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When butt welding, second pic the art is to get it flat so you have done a fine job if the underside looks similar.
Top does look a little undercut, but if the tubes were well matched before you started and the weld has full penetration then its fine, more of a
camera playing tricks I think.
It looks like you have already developed a good technique BTW, people would pay a lot of money for welds like that!
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Hugh Paterson
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| posted on 15/12/08 at 07:52 PM |
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tig technique
The weld bead on the shock mount is quite good, although your stop/start are too obvious, do u have a variable power switch on the torch or a foot
control? How long have u got the gas overun set at on your Tig if at all, when u cut the juice to stop the arc are u keeping the torch in position
over the weld pool until the gas overrun completes its cycle? The weld bead on the sheet steel I would suggest has been done at too high a power
setting, the alternative is to use a larger gauge filler rod and compare the bead u produce. A good hint to find the ideal setting for each gauge
steel sheet/tube u play with is to try welding without the filler rod "washing" the steel from each side of the material to produce the
molten pool. Try it with a few bits of scrap to see what results u get before u add the filler rod! With a little practice u will be surprised how
good u can get the bead  Remember to keep a note of the different settings for reference when u get the best results.
regards
Shug
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chrisf
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| posted on 16/12/08 at 12:21 AM |
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Gents:
Many thanks for the suggestions. Yes, I struggle with the obvious start/stop. Any help on how I might do better is well-apreciated! I do have a foot
control. I have the post flow set at 2 seconds (do you think I need more?) I do hold the torch over the pool until the post-flow goes off.
I too was thinking the sheetmetal joint needed a larger filler. Perhaps an .095" filler for the 3/16" joint? I think I had the amps set in
the 150 range. I was shooting for maximum penetration, but on that joint, the puddle got huge and was just sucking the filler in like mad. It was
almost hard to keep up.
Also, I'm using a gas lense with the bottle set at 17CFM. I think for the thinner material, I'm going to have a go with a .060"
electrode and play with the .035" and .040" filler rod I have. But it seems like if I stay in the 130-140 amp range I get great
results.
Also, I try to keep the electrode very close to the puddle, but how far away is too far? 2mm? 3mm? 5mm?
Again, many thanks!
--Chris
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Peteff
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| posted on 16/12/08 at 10:32 AM |
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Your 3/16" tungsten sounds too big for the 1/16" rod you are using. Your weld pool will definitely be too much for you to keep up with the
rod. I don't really understand the inches as we tend to use metric for rods but you should be nearer to the thickness of your material with your
rod size although I do tend to use 2.4mm for most things. 
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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