That won't melt/fuse with the base metal - welding beads for practice von a smallv plateb . I think what's happening is the filler is close enough to melt , but not shielded by the gas . I'm trying to "slip the rod in under the reflected heat" but still see it droop at the end . First instinct is to shove it into the puddle ... which is exactly the wrong thing ... I think . Practicing as much as I have time , and starting to figure out the hand motions/rythms to get a fairly decent bead - sometimes . -- Snag rank neophyte
What I do is melt the puddle, then stick the rod in the leading edge of the puddle which melts a bit off the rod and also cools the puddle some. Advance the torch a bit, melt, rod,,,,
Yup , that's what I've been trying to do . Problem is that between dips I haven't been pulling the rod far enough out of the heat envelope . It gets hot enough to sag , but it's not close enough to be shielded by the gas . I'm thinking that it oxidizes , which makes it harder to flow into the puddle . It might be molten in the center of that glob , but the oxidixed "skin" won't let it flow out . I think ... I also find TIG to be more like OA wlding than any other type . It's just that my foot controls the heat instead of backing off a bit with the torch when things get too hot . I did manage to lay down a few inches of bead last night that looked pretty good . I just need more practice , keeping the rod out until I dip it in the puddle . I'm finding it easier now to tell when there's a puddle to dip into with aluminum . I figger if I can get al down the steels will be a lot easier too .
Are you sure that you have your stock clean, nearly chemically clean? If you are getting much or any scum on the surface it may be because the aluminum isn't really, really, clean. You can also adjust you machine for more of less cleaning.
I'm not sure about the rod but it is probably 1/4" inch or so forward of the puddle once you get going. I'm sitting at home but it seems to me that I hold the rod, maybe an inch or so ahead of the torch until a puddle is started then poke the rod and sort of drop a bit in the puddle, lift the torch a tiny bit, retract the rod just outside the puddle, move ahead a bit, and so on.
Look for some you tube clips on TIG welding. the better ones show out the technique very clearly. Try
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This guy is welding chrome-moly tubing but it very clearly shows the torch and rod action.
Way back when we used to start off on a piece of flat stock, say 1/8"
- and simply go across it with the torch. Melt a puddle, raise the torch a tiny bit and move forward a bit, maybe half the puddle diameter, melt, back off a tiny bit, move forward. Once we got so we could make a nice even width with the "stack of dimes" (although I don't remember that term being used) even across the path - bead - then the student could use the rod and when he got that down we had some jigs that held two tags and one started to go for setup - tags just "that" far apart and 100% penetration welds.
The A.F.'s certification test was thin to thin (1/6" - 1/16") flat, and tee, a 1.8 - 1/8" flat and tee and a 1/16" - 1/18" flat and tee. All done in jigs.
The aluminum tags were in some sort of cleaning bath and the instructor fished out a pair and handed them to you just before you were to weld them. They were persnickety enough that if you touched the to be welded edges with your fingers you failed that set and had to start over :-(
After you learn aluminum..steels and just about anything else will be much easier to do. They ALL have their own learning curves..but aluminum is the mountain top. Its heat transfer is so quick that half the battle is keeping the puddle hot enough from moment to moment. Other metals do not have that problem.
Gunner
"There are no leftists in mainstream American politics.
Just two right wing parties, one hard right and one softer." Christopher A. Lee, 8/18/2013
"round brush I've got in my air router is contaminated "
That's your problem right there! Never use a powered brush for weld zone prep. The oxide layer will only get thicker! Use a carbide burr instead... or even a hand held scraper. And that stainless steel brush is only used on aluminum, btw..
My SS hand brush is clearly marked "stainless steel only" . Never to be used for anything else , until and unless I get a new one for aluminum prep . Didn't know that powered brushes are a no-no ... -- Snag
A bigger problem for me is putting too much heat into the work . A bead that starts out a bit proud will start lookin' pretty good , then spread out too much as the back side sags . Successive passes just make it worse , gotta let the piece cool some then come back and practice some more . -- Snag Got plenty of amps ...
If you can't see the puddle clearly then that's a problem. I find with both MIG and TIG the puddle and weld area are far harder to see clearly with an auto darkening helmet than a plain fixed shade filter even when the auto dark helmet is set at a lower shade. Maybe put the auto helmet, if that's what you're using, aside and try a fixed shade and see if you notice a difference.
The problem wasn't not being able to see the puddle , the problem was recognizing it . I'm past that problem now , and am beginning to get a handle on the glob situation . I just have to back the filler rod out of the heat envelope .
Stainless steel brushes are what you use to buff up aluminum before tig welding. Seriously.
Might I suggest you ask our very own Tom Gardner (on rec.crafts.metalworking) to send you a few? He is the owner of:
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These work very well
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Check the columns for Stainless..such as # 20010
The large Scraper Brushs in the next catagory below...work mighty fine on the BBQ btw...
Tom will likely give you a good discount.
BTW....these work very very well and last a long long time on an angle grinder....
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Look down at the Crimped Wire wheel, 5/8 shank, 3" .020 SS...stainless steel. Works quite nicely on aluminum prior to tigging. Been using them for years with very good luck. And the non stainless ones for rust removal in Knot type, 3" .020 or 4" .035 for the nasty rusted jobs. Once you buy Toms brushes..you will never go back to anything else. I aquired 15 of them 3 yrs ago. I have 12 left..and I use them on everything. They last a very long time.
Good shit Maynard!!! US made in Ohio. One of the last of the breeds.
Gunner
"There are no leftists in mainstream American politics.
Just two right wing parties, one hard right and one softer." Christopher A. Lee, 8/18/2013
Good suggestion! And if possible..get one of those nifty gold plated lens. Seems to help a lot for some reason. Someone here suggested it years ago, I tried it and it helps a lot.
For me. Your mileage may vary.
Gunner
"There are no leftists in mainstream American politics.
Just two right wing parties, one hard right and one softer." Christopher A. Lee, 8/18/2013
All I use is an auto helmet. I'll _never_ go back to the fixed shade! My neck is still suffering from that GD flip down piece of s..t. Many years ago a friend needed a shield and asked if he could borrow my flip down one. Sure, it's here somewhere in the junk pile. Found it and told him he can have it. What do you want for it? I want you to promise me that you'll never bring that S.O.B. back, ever! ;>)} Auto helmets were made for TIG and they rule! Mine is a Morsafe made in USA by Jackson. No problems in 15+ yrs.
I'm sure Tom is a fine fellow ... a while back I sent him some carbide router bits , he wanted to try the shank as a pinch roller in one of his feeder units . Not sure if it worked , he never got back to me . He also didn't send the knotted wire brushes he said he would . Might be he forgot or something , but I was kinda disappointed .
Imwas having trouble seeing through my auto darkening helmet. It was a cheap Harbor freight one that I bought to experiment with. So I borrowed my son's helmet, a $250.00 unit, I forget which one. I couldn't see through it very well either. I was curious about this so the next time I was on the mainland I stopped in at Central Welding and at Harbor freight to sample the goods. I could see OK through the expensive hoods at Central, but not as well as through a normal lens. I then sampled the Harbor Freight hoods and found that of the three hoods they were selling I could see very well through the one with the blue flames on the side. All three hoods were made by a different factory in China. Anyway, I am really impressed with the "Blue Flame" helmet. I'm gonna buy another just to have a backup and for visitors to use. Eric
Greetings Snag, You've guessed it right. Keeping the rod out of the heat is important. You want to use the rod to help control the heat. So you get the puddle formed and then introduce the filler. Make a quick stab into the puddle and then back out. You will find that once you get the hang of it your beads will look like the "stack of dimes" that folks strive for. Keeping the rod cool really helps control the heat of the puddle. Letting the puddle melt the rod instead of the arc really goes a long way toward controlling the puddle. Also, with aluminum especially, the cooler rod will form an oxide layer much slower. As you know, aluminum will form an oxide layer quickly. This layer, when formed at normal temps in free air, is quite thin and stays thin for a long time. But when the temp is elevated a much thicker oxide layer forms quickly. And the oxide melts at a much higher temp that the rod. It can also form a layer around a molten droplet that can prevent the droplet from fusing properly with the parent metal. And speaking of oxide layers, I read recently that it is better to use a brass brush than a stainless brush to clean the weld area just prior to welding. If I remember correctly this is because the brass will remove the oxide layer easily but will not scratch the aluminum underneath very much because the brass is fairly soft. Stainless brushes will scratch the aluminum comparatively deeply and as these scratches will have much more surface area than just a flat surface so will the oxide layer be that much greater. And of course this extra oxide interferes with welding. Eric
I can't even start to think how I move my hand on flat stuff. My hand is sort of resting on the little finger side and it (somehow) just follows along :-)
But there really isn't any reason that you shouldn't stop and rearrange things as you go along. just be sure to remelt the last "dime" in the stack as you start.
Ref a couple of other replies: No reason that I know not to use a stainless brush on aluminum. I believer that it is a recommended practice. By the way, all aluminum's are not weldable. 2024, for example.
If you are learning aluminum it is useful to use something for a backer for a while. A piece of flat steel will absorb some of the heat and if you get it too hot it will keep the puddle from falling on your shoe.
One thing that people have to get used to is that unlike arc you don't get an almost instant puddle when the arc starts. You want a bit of a wait while things warm up and the puddle forms, particularly with aluminum.
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