Welding improvement

[parsonsj]

Matt,
Can you recommend a similar pump from McMaster-Carr? Or let us know what criteria you used to pick that particular pump? I've got an unused aluminum fuel tank complete with AN fittings just sitting around taking up room. Might be fun to get something useful from it.

jp

[68protouring454]

i also made a tank that is about 4-3/4 gallons, and made a cart so i could mount it below my lincoln tig welder.
i got threaded bushings from msc, that were 1/4 pipe and drilled hole in tank and welded them so i could run a hose from pump in tank to bushing, then screw feed line of water torch into top side of it, then i welded another on other end of tank so that return line screwed in, mine works awesome, otrch stays so much cooler, and i can only imagine if i tig'd alot. i used same pump as matt, as he got a new pump, by the way i ned to finish my tank and make a covere for access hole for pump, well make it so it screws on, i have it setting on now.
i got my water torch used from my gas supply house for 60 bucks, in new condition, then a few fittings and some aluminum and i got a killer set up, probaly have like 200 into whole deal and i can cart it anywhere in my 3,000 ft shop and weld.
jake

[Matt@RFR]

The brand is Little Giant. I'm sure others would work, but those are pretty cheap and quite durable. Pick a pump that will pump a head of water higher than the torch would ever be. In other words, if you forsee welding on the top of a 10' ladder, you need a pump that will pump a head of water higher than 10'. Preferably by a factor of 2. The pump I have will pump a head of water 17.5' if I remember correctly. I don't have time to look up pressures/flow numbers, but I would think any pump that can pump a head of water that high would have the other numbers to support a water cooled TIG torch setup. They flow very little.



If you use this setup, and have a pump that produces pressure greater than 5psi or so, you can NOT have a shut off valve in the system. TIG torches are not designed to have much pressure in them. I don't know what you're running, but my torch is $300, so no pressure for me. Also, with a water cooled torch, if you forget to turn the pump on and proceed to weld, you WILL be in the market for a new torch and power cable.

After awhile, the pump itself will heat the water up, so if it will be used for hours on end, a small radiator with a fan would be best. I used an aluminum Banshee radiator.

[HotRod4PaPa]

Thanks for the help! I will have to go the "cheap system". I will start scrounging for parts soon. I am trying to pick up tig welding on my own. Are there any good instruction videos that might help me with welding mild steel tubing (1 1/2"X.125 wall). My biggest problem is undercutting the tubing at the edge of the filler metal. It seems to worsen as the tubing heats up; maybe half way through the length of the weld. I may be running too much amperage to begin with. I have been setting amps at 1 amp per .001" wall thickness.

[parsonsj]

Sounds like it to me. You need to back off the amperage as the tube heats up. I'm amazed myself at how little filler metal most good TIG welders use, at least for steel and stainless. I saw a certified cage that looked like very little filler material had been used.

jp

[Matt@RFR]

I have been setting amps at 1 amp per .001" wall thickness.

That's for aluminum, and even then usually isn't accurate. For 1/8" wall, you should be around 70 amps, give or take. Your amperage setting is very personal, so only you will be able to make it perfect. As a hint, though, you could weld that same tube with your machine set at 200 amps. It's all in the pedal, and with as much finesse as you can muster.

Undercutting can be lots of things. The most popular is not too many amps, it's a bad torch angle. If you're welding a 90º joint of the same thicknesses, your tungsten needs to be pointed into the root at 45º. If it's very far off of that, the arc can pull metal from the work into the weld in a place where you're not adding filler. If you want to prove this, fit up a tube/tube joint at 25º and weld the skinny side.

Along those same lines, if filler deposition is really shaky, it's possible to drag the puddle out of the weld, sometimes resulting in an undercut.

...at the edge of the filler metal.

That's called the toe.

If you're trying to space filler 'dabs' far apart to get the 'look', stop. If that's the case, that could be part of your undercutting problem - not enough filler. Also, for structural things like roll cages (I'm assuming that's what you're practicing for), all that technique does is add relatively large stress risers to an otherwise sound weld. The first attached picture you may have seen...the only reason I ran the weld that way is because it's "pretty", and it's a part for my parents entertainment center. A good structural TIG weld will look something like the last two pictures, with your 'dabs' as close together as you can get them. For reference, the last picture is 2 1/2"x.120" stainless tubing. Second picture is also stainless, and too hot. First picture is something like 3/4"x.120" DOM.

[HotRod4PaPa]

I really appreciate you guys replying. I can relate to Matt's comment on co-workers catching fire. I just about let my buddy burn his shirt half off before I put him out. I was the fire watch! It's hard to get good help. Ha. Looks like I may be running too many amps to control with the pedal once the metal heats up. I also have a lot of trouble keeping the correct torch angle as I move around the tubing. My frame jig "32 Ford" does not rotate, so that puts me on my head at times. I try to keep an even width filler weld puddle going and don't concentrate on the "row of dimes" look. I figure that will take care of itself once I get this other figured out. One of the reasons I have been using this amperage setting is because it seemed to take too long to heat the metal enough to get the weld started, but now I have created the undercut problem. I will cut the amperage down and concentrate on keeping the "dabs" as close as possible. I will let you know how this turns out. Thanks

[Matt@RFR]

Arc length plays a big part in all of this. Keep it as short as you possibly can. Like 1/16" or less.

Pictures will help immensely.

[parsonsj]

ah yes, keep the arc length short ... but don't dip the tungsten into the puddle. I go through cycles. Some days I can weld all day, just touching up the tungsten occasionally as it oxidizes. Other days I dunk it all day long! And man, does that piss me off!

Here's a frustration, let's see if you have any ideas: when I'm welding with .040 filler rod, I have a lot of trouble getting precision about where the "dip" occurs. The filler just flops around since it's so thin. Man, that's annoying.

jp

[Matt@RFR]

Cut it in half. Or do you do that allready? If so, less coffee?

[parsonsj]

Yeah, I cut 'em in half. Maybe I'll try in quarters.

What's wrong with 12 cups of coffee a day?

jp

[race-rodz-inc]

i wish this topic would have been around bout a year ago when i started tig welding on a regular basis... i allready went through the turn it down, turn it down, turn it down on the amperage.... control the pudle with speed (or lack of)deal. now i just need to work on the less cafine deal... some days im fine... other days i shake like a crack head thats been "clean" for 2 days. man those days of touching up the tungsten every 30 seconds really suck

[boodlefoof]

Man that is bee-utee-ful welding! I have something to aspire to! :thumbsup:

[Matt@RFR]

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