Tig'ing mild steel with different thickness....
 

Tig'ing 3/8 mild steel flange to a 2-1/4 downpipe. How do you keep from burning a hole in the downpipe before you get a good melt on the flange?

What settings would you guys use?

Re: Tig'ing mild steel with different thickness.... (catchawave)
 

Current has to be high enough to melt the thickest pipe.

The trick is to use a nice pointy electrode and point it at the thick material, only occasionally "bumping" it over to the thin. Think of it this way, if one piece is 5x the thickness of the thin piece, it needs 5x the heat. In other words point the torch at the thick piece 80% of the time.

Re: Tig'ing mild steel with different thickness.... (kb58)
 

how could this be applied to mig when the filler is constantly coming out

I would suggest welding at about 75-85amps and adding filler to get the two peices connected. Also i suggest using 1/16" Filler rod size, anything larger takes to long to melt down into low amperage welds.

Re: Tig'ing mild steel with different thickness.... (Optiks.)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Optiks. &raquo;</TD></TR><TR><TD CLASS="quote">how could this be applied to mig when the filler is constantly coming out</TD></TR></TABLE>

thats the benefit with Tig , you can actually put the heat where you want it.

Re: Tig'ing mild steel with different thickness.... (Doctor CorteZ)
 

you can easily do the same with mig.

just point your nozzle at, and keep you puddle on the larger peice.

Re: Tig'ing mild steel with different thickness.... (joeseph)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by joeseph &raquo;</TD></TR><TR><TD CLASS="quote">you can easily do the same with mig.

just point your nozzle at, and keep you puddle on the larger peice.</TD></TR></TABLE>

Not True if you actually if you could see it in slow motion. With SMAW process the arc could jump do to magnetic force(arc blow). Also there are 4 other factors to welding with MIG....

1. short circuit transfer
2. Globular transfer
3. Spray transfer
4. Pulse spray transfer

And the when welding with MIG to get ideal pentration for welding distance could vary, ussually 1/4'.

With TIG, the weld pool is easier to control depending upon what the shape of the Tungsten electrode, current type(DCEN, DCEP, or AC), what metal is welded, and etc. https://honda-tech.com/forums/images...s/emsmilep.gif

Re: Tig'ing mild steel with different thickness.... (JunY)
 

You're not making any sense.

Why are you listing all the transfer types? It's great that you know them all but I don't see what you're trying to say.

I only posted my response, because Dr. cortez seemed to be implying that a) this type of weld was impossible using MIG and b) that MIG gives you no control over the puddle. Obvoiusly TIG gives you greater control, but any halfway decent mig welder should be able to produce a similar result.

I've welded a thicker peice of plate to thin tubing hundreds of times with mig (short circut transfer). It's really no different than a lap joint. Hell, I'll do it with stick,

maybe i'm not understanding this guy's question.

Re: Tig'ing mild steel with different thickness.... (joeseph)
 

I previously had people say, "I know how to weld, and don't give me shit about it that I dont know how....blah blah blah" kind of deal. And once I saw there work, I basically laughed at many of them for not knowing how to MIG weld. Too far away, not enough pentration, couldn't weld straight on a fellet weld, dont know what the dial does on the machine, amperage, and so on....

Also I've had people say MIG and TIG are the same, and I say "Bull Shit." I basically used all kinds of welding machines in the past. I'm just trying to prove my point that some MIG welders cannot weld thick to thin sometimes.

Sorry if I offended you in any way. I'm just trying to point out some factors that could miss lead people. https://honda-tech.com/forums/images/smilies/emwink.gif

Re: Tig'ing mild steel with different thickness.... (JunY)
 

I used to have to weld diff. thicknesses to each other all the time when I was doing maintenance on helicopters. Like mentioned above keep the heat on the thickest piece. When you start out and the metal is cold, get the thick piece hot, get your welding rod in there and draw it over to the thinner piece to start your bead. As you continue along keep the tungsten pointed more at the thick piece. Dont have the amps turned way up, keep em down and just go slower. What you set it at is going to vary depending on your machine.

Re: Tig'ing mild steel with different thickness.... (JunY)
 

i don't think that's what joeseph is trying to say. i think he's just saying it's possible and i agree with him. it might not be the best choice to mig it if you had a choice but if you where stranded on a desert isle and your only chance at survival was to mig a thick and thin piece of mild steel together, it can be done.
i've done it many times, minus the desert island part. of course my choice would be to tig it but in any case, either way it's possible with some practice.



Modified by stock steve at 12:00 AM 11/17/2004