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View Full Version : Spitting TIG weld makes me spittin' mad



parsonsj
09-06-2004, 06:37 PM
I spent a frustrating couple of hours today trying to weld some tubes to threaded tube end adapters. 4130 tube, mild steel ends.

Piece of cake, right?

For some reason, the weld kept spitting at me. I spent considerable time cleaning the parts (since these welds will be very visible inside the engine compartment), only to ruin them. I checked the gas flow, the machine settings, re-cleaned the parts, etc. It behaved as if was contaminated by oil or something. I've never had that happen before. The weld was awful, full of holes and stuff bubbling throught the puddle.

I gave up, and went back to doing other things and welded lots of other stuff successfully. Then I used the same tungsten that spit at me before and it did it again on different parts. The only thing I can figure is that I have a contaminated tungsten. Anybody ever run into that before?

Any other thoughts?

dennis68
09-06-2004, 07:26 PM
Shouldn't be the tungsten, you used it weld some other stuff right? I have seen metal that was contaminated though, no matter what you do if it's contaminated in the metal as soon as it melts it brings all the junk to the top.

parsonsj
09-06-2004, 08:10 PM
No I didn't use that tungsten. The one I think spits is a 3/32. I was using a 1/16 and .040 tungstens on my other welds.

I don't have any other 3/32 tungstens. Guess I'll be dropping by my welding supply tomorrow.

Do tungstens get "old"? I can't swear to it, but it might one that my brother-in-law gave me from an auction where he picked up a bunch of stuff and the tungstens were included.

Little Bob
09-07-2004, 05:49 AM
A friend of mine had the same problem. He found out that it was the magnets he was using to hold the pieces together. I'm not sure if this is true, because I never tig welded. But it's worth a try.

KendallF
09-07-2004, 06:53 AM
No I didn't use that tungsten. The one I think spits is a 3/32. I was using a 1/16 and .040 tungstens on my other welds.

I don't have any other 3/32 tungstens. Guess I'll be dropping by my welding supply tomorrow.

Do tungstens get "old"? I can't swear to it, but it might one that my brother-in-law gave me from an auction where he picked up a bunch of stuff and the tungstens were included.

I have used 20 year old tungstens that I got when I bought my welder with no problems. Did you give it a fresh sharpening? If you hit it once, the crap will stay on it and give you trouble until you sharpen it again. I try to just kiss the surface of the tungsten for maybe 1/2" or so above the point when I've really blobbed one up. :)

One of my buddies is the TIG God..he showed me a tip for sharpening that has made a significant difference in my weld quality. He chucks up the tungsten in a cordless drill and uses a belt sander to sharpen it. This results in a perfectly conical tip just like those high $$ sharpening rigs.

parsonsj
09-07-2004, 07:00 AM
I've sharpened the tip several times. No difference. I've been using a grinder and spinning it with my fingers (lengthwise as it should be). I'll give the drill and belt sander method a try though.

Salt Racer
09-07-2004, 12:04 PM
That has happened to me several times. IIRC, it happened when I tried to weld a sample 4130 streamlined tubing I got for free, and some low-quality DOM tubes (very rough surface). Same thing has happened when I was in hurry and didn't clean up the metal, so I figured it was caused by inpurity in metal.

Speed Raycer
09-07-2004, 01:58 PM
Any chance someone else used your tungsten only grinding wheel on something? Same thing happened to me. The day before it was working fine and then I had the same problem after I contaminated the tip. I couldn't get a decent weld out of it no matter what I did. Finally I went up and bought some of that sharpening chemical and it worked fine. I think that my pop stopped by the shop and used the grinder on me. :banghead:

parsonsj
09-07-2004, 02:16 PM
Hmmm. I don't have a tungsten only grinding wheel. Never have. Maybe I should? Perhaps the belt sander/drill method will work for a couple of reasons.

What is "sharpening chemical"?

Your story reminds me of when my father-in-law used my shop vac ... without the filter. Or when he turned on the main water supply while I was at Home Depot buying replacement valves. Or when he used my screwdrivers to stir paint. Or when he used my framing nails to hang pictures.

Matt@RFR
09-07-2004, 09:15 PM
Chemical tungsten sharpening:Never used it - no opinion. (http://www.dynaflux.com/pages/productsdescrip/CR600.html)

The only time you need to use a dedicated grinding wheel or sanding belt for sharpening tungsten is if you're welds will be x-rayed. (aside from the ~hopefully~ obvious....no grease, no major dirt, etc.) And, before anybody asks (ala "that" thread in the suspension section), yes I've had numerous welds x-rayed. MIG, TIG, dual shield (innershield), and on several alloys of aluminum, mild steel, and 4130N.

A chordless drill is a very handy way to sharpen tungsten, but in no way will it make better points...that's up to the individual. Just make sure to not spin it too fast or you'll end up with a spiral pattern, and electricity just doesn't like going anywhere but straight. Especially when it's about to jump a gap.

Mr. Apex, magnetic fields will definately f*** with electricity. In stick welding, they call it arc blow, which is caused by poor placement of your ground, causing magnetic fields. Basically, it makes accurate deposition of filler metal impossible when using stick, and is more prodominent in DC.

JP, if only 3/32 tungstens are doing this, it seems that your 3/32 collet/collet body is screwed up. If it's a gas lens, the screen might be plugged up. If that's the case, buy a new one. Cleaning them just results in frustration and a FUBAR'd screen. (For the record, I've never had this happen, so I'm just guessing)

parsonsj
09-08-2004, 03:25 AM
So far, just the one tungsten. I bought a couple new ones yesterday. I'll give it a try tonight. I have two gas lens caps for 3/32 and as best I can remember neither one worked any better than the other.

Tig Man
09-08-2004, 05:44 PM
I've ran into this problem several times with generic tungsten. And also bad gas mixture. Don't skimp on quality when buying welding supplies.

KWIKND
09-09-2004, 04:10 PM
I was using my Miller Trailblazer to TIG and it did the same thing. Found out I had polarity wrong. :screwy: Probably not an issue if you have a TIG only machine.
Dan
http://www.strangemotion.com/html/whats_happenin.html

David Pozzi
09-09-2004, 10:02 PM
maybe the tungsten you used is the Thoriated type only for aluminum?
David

Matt@RFR
09-09-2004, 10:28 PM
Thoriated tungsten works quite well on aluminum, and is actually what I use for everything. (I'm experimenting with different blends currently though) Pure tungsten is "for aluminum" (green stripe). Although you can use thoriated, lanthenated, zironiated, etc etc on aluminum and magnesium with excellent results, especially with an inverter machine with adjustable balance and frequency.

Pure tungsten, when used on steel (DC) will just ball up.

Remember, the properties of tungsten only effect its performance, NOT neccessarily what material it should be used with. All things being equal, tungsten choice will NOT contaminate the work, itself, nor will it compromise gas coverage.

parsonsj
09-12-2004, 01:15 PM
And the answer is ...


... backpurging.


In desperation, I tried backpurging the tube. The problem went away immediately. I must have been some perfect tube length to draw air from the back side through the tube (remember I'm welding mild steel threaded ends into 4130 tube) around the joint and through the weld puddle. The ends were an annoyingly loose fit and it all must have been just so to pull air into the weld from the back.

I nearly ran out of threaded ends. Thank god I got this problem solved.

jp

Matt@RFR
09-12-2004, 04:19 PM
So where did you buy the tube adapters? I'll make sure to stear clear of 'em in the future.

I hate to suggest this, but I don't think you've solved your problem. I can weld open-air gaps on mild steel all day long with no back gas. It's not pretty, but it's not contaminated either. By chance, did you have the tube sealed off? (allthread through with nuts/washers to hold the loosie goosie tube adapters in place, for example) I don't know if you know this or not, but if you weld a tube shut, when you get close to the end of the weld (thus sealing the tube), the air inside is expanding from the heat, and will literally blow the weld out. (This is incredibly interesting with aluminum!)

Just a thought.

parsonsj
09-12-2004, 04:43 PM
Yeah, I know 'bout drilling a hole in the tube if it's gonna be sealed. I've forgotten enough to know exactly what happens. :)

The contamination in this weld was a similar phenomenon, which is why I tried the back-gassing idea.

These welds are not heavily stressed, so I'm happy now. If we were talking about suspension components, then it would be a different story.

I'm gonna blame the tube before I blame the adapters. When I cleaned up the tubes by sanding with some 400 grit prior to tossing some primer on 'em, they had little pits all over them. I think I'll call my steel supplier tomorrow ... and see if anybody else had problems with that tube.

jp

parsonsj
09-12-2004, 08:05 PM
An update:

I took a couple of hours tonight and cut apart all the funky spittin' welds. I cleaned everything up and welded similar materials together. Oddly enough both materials spit up. Both the mild steel threaded inserts, and the 4130 tube. It wasn't the material I was welding.

So then I switched my torch back to regular, rather than the gas lens.

Whammo! Perfect welds again. I even fixed the spitting welds by just running the torch over it. I must have gotten a couple of clogged up gas lens collet holders, because they both worked about the same ... poorly.

I do remember using them successfully when I did some aluminum welding about 3 months ago.

When I back purged, I must have been getting just enough extra shielding to get by.

I'll be making a trip to my welding supplier tomorrow.

jp

Matt@RFR
09-12-2004, 09:05 PM
I'll be making a trip to my welding supplier tomorrow.

Make sure to be pissed off when you go...they'll probably give you free replacements. :)

parsonsj
09-13-2004, 03:00 AM
Yeah ... and a new bottle of gas too.

jp

parsonsj
09-21-2004, 04:29 AM
Final report: with new gas lens collet bodies, the spitting problem is gone. I've ordered replacement parts for my 1/16 and .040 setups too.

The new parts look like much better quality than the old ones. That cost me a weekend and a lot of aggravation.

jp