Thanks to everyone in past postings my TIG Al is going much better. Now, I'm also practicing on some 22 ga SS, 304. I also have some 12 ga 304 and that is not giving me much of a problem. If I clamp the 22 ga to some Cu, I can get a resonable butt weld (for a novice). Without a heat sink like Cu I have trouble controlling warp, and have even noticed a line of very fine black ash next to the weld. What is that? Also, I notice that the filler metal tends to feel "tacky" when dipped in the pool.
To keep it simple for learning purposes, and so I don't pick up bad habits, I would appreciate some advise on just running some beads correctly in the flat position on a 3X5 22 ga SS coupon. Or if other practice tecniques are more advisable to begin with please tell me. The reason I'm using 304 12 and 22 ga is because I was given a little supply of it. My equipment is a Miller Syncrowave 180, pure Ar, and I have Cerium, Thoria, Trimix and pure tungston available. I also have some Solar Flux to protect the back side (...of the metal).
Thanks in advance.
Ken
The filler metal is probably "tacky" due to the low heat input from the process. If possible, try a smaller wire diameter to prevent the wire from absorbing the energy in the puddle when dipped.
Sheet metal welding is not something that I do much but I suggest getting in a position that allows you to progress rapidly across the joint. Just a slight pause in travel can cause problems. Make sure you are using enough current to make a puddle without waiting too long. Its my opinion that 100 amps at 20 IPM is better than 50 amps at 10 IPM. (Those values are to make a point.)
I'm sure you will get some more information here but I hope this is useful.
G Austin
Iuka, Mississippi
Thanks for the reply. Increasing speed seems to help although my technique needs practice. I seem to do better with backing (even steel). Without a backing I always seem on the virge of burn through. The top of the bead is flat and the underside is saggy. I wonder if there is a limit to how thin you can go with sheet without a backing.
Ken
The ability to weld thinner material is probably more related the the ability to reduce the current on your machine, tungsten size/shape, and having a tight fitup. A butt joint on thin material is sometimes difficult because of the gap.
Have a nice day
Gerald
Thanks again. I'll be persistent in my practice.
Ken
I've been welding for 20 years (Not Sheet Metal) and 20 gauge is not something I would say I was as good at as the average sheet metal welder.
The best way I know to learn to weld is by welding and applying concepts either used by others or written about. There is no replacement for actual practice however that extra bit of knowledge gained through study and talking with peers will eventually separate the people that can weld good from the good welders.
If you have access to a digital camera, you can send some pictures of your welds and I could look at them or if you wanted, I could post them on my website and let others look.
Have a nice day
Gerald Austin
http://www.weldinginspectionsvcs.com
Ken, first let me say that thin gauge stainless is one of the hardest things to weld without distortion. It moves whenever heat is applied. Whenever possible a heatsink should be used. You must use alot of tacks, every 1 or 2 inches if possible. Move around when you weld, running a straight bead is nice, but will increase your chances of distortion. Go to a 1/16th tungsten if you haven't already ( I use thoriated, but only because I am slow to change ). Clean your stainless before welding, clean material uses less heat to weld. I use Acetone, just put it away before actually welding. I believe that fast welding at a higher heat causes less distortion than slower welding at low heat. No scientific data to back this up, just my experience. Often on light ga. stainless I will take .035 wire from a spool and cut it into lenghths for tig welding. Keep the wire in the shielding gas coverage and snip the end off with welpers or side cutters before starting a new bead. Keep your tungsten as sharp as possible and try to keep all of your grind marks going in the same direction, by the way, how do you sharpen your tungsten? I hope this helps and that I do not lead you astray. Good luck.
Respectfully,
Mike Sherman
Shermans Welding
Great advice all!
Here is a link to a valuable $free$ resource that with a little digging will give you insight into process, fitup, jigs, heat sinks, distortion and much much more. It appears to be about equal to a good Community College textbook.
Best of all and unlike most information you will get over the net, it is approved by letter by the seceratary of the Army, meaning you have the added value of *sourced* material.
Its a goldmine.
http://www.machinist.org/army_welding/
This chapter is devoted specifically to expansion and contraction
http://www.machinist.org/army_welding/Ch6.htm#s5
Wow, I hit the jackpot. Thanks everyone for the help. I tend to be self-taught in a lot of areas and appreciate the references. Also just ordered a book by Minnick on GTAW. I saw it in a classroom and it looked helpful. I have also learned that self-teaching is a bit light on feedback and corrective suggestions so all of your comments and the offer of looking at pictures of my work is really appreciated.
I have learned how important it is to keep the metal AND filler clean. I use acetone and a dedicated ss wire brush. On aluminum I only brush one direction and after first wiping with acetone then re-wipe. Sometimes I use Scotchbrite and have wondered if that is advisable or not. I'm having trouble locating SS steelwool.
Also, I'm going to try to use a 0.40 electrode - just to see. Mike, I sharpen my tungstons longitudinally, with approx. 2D slope, on the dedicated side of a 3" high speed wheel. I don't have a diamond wheel.
I don't think that is causing a problem.
I have been printing out everyone's feedback and putting them in a notebook. Time to do that again and go practice.
Thanks
Ken
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