OA welding help!!

Thanks for the above link. I still consider myself somewhat of a beginner.

** I really just wanted to point out that one can play around with the numbers at the end of your link and pick up other chapters as well. **

However, if I just delete all back to the last / I lose the link. Likewise if I just put a chapter number past the /. So far I've had to go in and just change, for example, both 5's to 3s or 4s, etc.

Reply to
Al Patrick
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Thanks to another's post. I played with the chapter numbers a bit. Don't yet know how many chapters in that book. It's all online which you seem to need. You might also check with another welder in your local area.

=====

Allippy wrote:

Reply to
Al Patrick

From previous link, chapter 13....

13-6. UNDERCUTTING

Undercutting is the burning away of the base metal at the toe of the weld. Undercutting may be caused by the following conditions:

a. Current adjustment that is too high.

b. Arc gap that is too long.

c. Failure to fill up the crater completely with weld metal.

Reply to
Al Patrick

Reply to
Bev Fanatic

Here's the front page with all the links -

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This one also has very good information
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Mike H. To invent, you need a good imagination and a pile of junk. --Thomas Edison

Reply to
Mike H.

Not trying to be snide, but in general under-cutting is caused by not re-filling the melted edges with filler metal. Either penetration is too deep or re-filling is too small. Try for the opposite condition, excessive reinforcement and a definite edge. Either reduce the heat (set the neutral flame while you still have soot) and/or increase the amount of fill ("feed" the rod instead of dipping it). Or try keeping the rod in the pool. Walk the bead along the rod. It will reduce penetration on thin metals. Maybe this will trigger something that will help with the undercutting. Good luck.

Reply to
John

Well, I'll also light (I mean line!) up behind Owen. A proper flame is a proper flame and there's no hiding it.

As to 100 years of standard procedure, I hate to use a politically charged metaphor, but slavery was once considered "standard procedure".

Be prudent but don't be afraid to try something new. At least that's my philosophy. I have copied Owen's instructions for future reference.

Way to go Owen!

P.S. If I blow myself up I hereby indemnify and hold you harmless.

Gentlemen, start your torches!

Vernon

Reply to
Vernon

Thanks, Vernon. And I'll stand by what I learned the other day: If Kent White recommends it, it can't be all bad, even if this bungler did figure out independently. This side of Ernie, I can't think of anyone I'd trust much more when it comes to welding, and O/A is about all the Tin Man uses.

Owen

Reply to
Owen Davies

I think somebody already mentioned this. But it may be your torch orifice is just not quite the perfect diameter for the tubing you're using. I've heard aircraft builders complain about this many times.

All I know is that ONE time, while completing a square cube in a recent welding class, I got exactly the right torch size, the right flame, the right initial puddle (a bursting fat one) and boys, I hit the groove! Of course it was 3/16" plate and not paper thin 4140 carbon steel tubing.

But every seam on it was pretty near perfect.

Therefore, "if I were me" I'd adjust the flame from the regulators never mind what the needles say. I'd get the blue flame tip where it would instantly turn the metal shiny and produce a puddle within just a few seconds, make sure my initial puddle was plenty turgid, and weld away. If that doesn't do the trick I'd go to the first size tip that's too small and ream it to halfway between that nominal tip diameter and that of the next larger size.

But if you're doing aircraft clusters your skill is already light years ahead of mine.

V
Reply to
Vernon

Everyone seems to thing poorly of the successful self taught yet they never realize that someone had to do it first and trial-n-error will give the self taught more wisdom than the on schooled.

He is a TIGer too isnt he?

Reply to
cl

Sorry to drop in late on this thread...

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This URL has a good chart of tip size vs. material thickness. I have had problems in the past with used tips that have been enlarged from use and cleaning. Obviously, they tend to run like they are larger than the size marked.

This confused me for a long time.

Cheers,

Kelley

Reply to
Kelley Mascher

He certainly knows how to do it, but everything I've read on his site is about O/A, and at one point he specifically says that he prefers O/A to Tig for welding aluminum.

Owen

Reply to
Owen Davies

"John" sednews: snipped-for-privacy@g47g2000cwa.googlegroups.com:

OK, I've read every post here and what a great supply of info! I've been messing around on Usenet for about 10 years and this is easily the most helpful thread I've been involved in. Thanks so much to everyone who replied.

Here's what I tried and the ensuing results...

First I tried different pressures on the regulators. previously I assumed that it was my technique and not the pressures so I tried a range of pressures either side of what I'd been using. Slight improvement when I went a bit lighter with the pressures, but no consistent inprovement in my welds. I tried the next size tip down and just had it blow out when I got it into a tight spot, so I dumped that and went back to my previous tip. Before I started this thread the method i had been using to try and fix this problem was I had been reducing the size of the flame a bit which gave me a tough time starting a puddle in the tight "armpit"where two tubes meet and I think this has beenthe source of my problem. I usually get a slow start there no matter what and put a drop of rod on it to get it started which i then work in. then a slow forming bead comes out from that, gradually accelerating as I move out towards my tack weld. I think what I was doing wrong was keeping the rate of rod feed constant during the weld and it was sinking because of that. I tried keeping the rod almost in the pool and shoving it in more frequently and this helped quite a bit, I'm still getting a bit of undercutting, but I thnk this is more to do with my lack of practice with this technique than anythng else. I think the most important thing I learned out of this thread is aboutthe existence of the Tinman, though! I'm getting one of those Meco torches ASAP!

Thanks agian to all! I'll keepyou posted as to what else i find out on this little voyage of discovery...

Reply to
Allippy

Please let us know how you like it. I have been thinking about buying one to supplement my Harris set.

Owen Davies

Reply to
Owen Davies

Owen and everybody,

Another interesting MECO torch is the "Aviator Jet" model. Unfortunately, they don't make 'em anymore. I bought one after lurking in the aircraft builders' newsgroup and hearing several people say it was their favorite torch.

As you may know, MECO got bought by Victor. The MECO Midget (the one touted by the Tin Man) is the only survivor of the MECO line. I also have a MECO Midget but I confess, I've never used it.

I recently bought a Victor aviation torch, which I've used a little bit. Of interest, the tips for this torch appear to be made of aluminum. At least they're shiny white and I don't think they're stainless. They also have cooling fins.

Lots of people swear by the Dillon Henrob. I bought one of those several years ago but have never used it either...

If somebody wants to use virtually every torch known to humankind before springing for a purchase... come on over to our house.

Vern> Am>

Reply to
Vernon

I put in a number of hours with it. The transition was kind of tough, as I'd never used anything but a Victor at the time, and that only in a few days of practicing at the Sun 'N Fun workshops. After that period was over, though, the Dillon was really nice to use. It did have three disadvantages: Your hand is so close to the welds that it gets really warm! That pistol grip can be difficult to sneak into tight clusters. And this is one of the torches that has tips that are either too small or too large to use on 0.035-wall tubing. Open a small tip out with a #72 drill, and it's perfect. Aside from that, the tips Henrob supplies will do anything, from soldering jewelry to melting a D-9 Caterpillar into several tons of slag.

Where are you?!

Owen

Reply to
Owen Davies

Yeah, those Meco Midgets are great. Be sure to get the lightweight hoses, extra tips, and "fish mouth" wrench too, if you can afford them.

John

Reply to
John T

I'm in Texas, Owen.

Come on down. But come in the winter when it's merely warm.

V
Reply to
Vernon

Many thanks. It could be a while. I'm in Florida, myself.

Owen

Reply to
Owen Davies

You dont like the new half sized tips they sell? (#.5,#1.5,#2.5)

Reply to
NotHome

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