frame welding

[Iburyyou]

Is a 135 amp mig welder enough to weld closeouts on my frame for the dse tubs?

[derekf]

Don't have an answer to your question, but I did want to welcome you to the site. Post up in the "Welcome to the site" forum and introduce yourself..

[yody]

in my opinion it should be fine. 110v's can usually handle up to 1/4" max, I think the frame is like 1/8" max

[CDJr]

Yes, its plenty.

[Matt@RFR]

Yes, its plenty.

Right.

110v's can usually handle up to 1/4" max

Wrong. There are no 110V MIGs on the market that will reliably weld 1/4" plate. Most are rated at 3/16", and that's being generous.

[yody]

your right mine did say 3/16 on the box, thought it was 1/4" till I checked it Its a lincoln 3600 or something. Now I am not saying that it would be ideal. That is just what they rate them at. I have welded 1/4" and 3/16" plate with mine with decent success, not sure I would want to try on something structural though . Obviously If i X rayed it or whatever it most likely wasn't the best weld or had the greatest penetration. It does do 3/16" pretty nicely. Again I'm not a professional welder like you so I can't elaborate on how great of a weld it was. Anyway my point was that it would work. and it seems you agree.

heres an old pic of some 3/16" steel welded, you can see it appears to have decent penetration on the top, but due to my error i didn't bring the puddle low enough on teh bottom to get penetration/contact. Does the top part look like decent penetration? it was I believe 3/16" steel, although this was awhile ago. Also someone told me the orange was from too slow wire speed, I thought it was rust???



BTW this is not supposed to be a "Great" weld lol

[Matt@RFR]

Does the top part look like decent penetration?

Here's the problem with MIG. All the manufacturers claim you can be a weldor within 30 minutes of setting up the machine. The further one delves into MIG welding theory and non destructive/destructive testing(NDT/DT), the more scary their claim becomes. I've welded 1/2" plate (fillet joint, no weld prep) with a 135 and I could get the weld to look like it was a good weld. The toes were tied in just fine, the throat wasn't excessively convex, etc. I then threw it on the concrete floor, and it broke in two. That's an exhagerated example, but hopefully you get my point. Generally, bad looking welds are bad, but the transverse is not allways true.

It's been suggested many times that, if you were to bevel the hell out of the joint, and employ a gap, you would get full penetration. This is absolutely true. However, penetration and fusion are two different things, and both are required to create a sound weld. To use an exhagerated example again, you could put a full bevel on a 1" plate butt joint and weld it at 150 amps in 15 passes. You'd have penetration of the actual joint, but nearly zero fusion with the base metal.

Now, even if you have the correct amount of amperage available to make a good weld, you're still not garunteed of one. Far from it, actually. For example, if your travel speed is way too slow for an otherwise good setting, the wire has a tendency to just sit on top of the puddle, building up on top of itself. The arc has to have a chance to dig into the base metal if you're to have a chance at penetration, and that requires you to move ahead of the puddle, and only then whip backwards to fill the joint if necessary. This problem really gets guys when trying to weld downhill.

Other possible problems can be things like a shaky hand causing undercutting, missing the joint completely (or to a lesser degree, being lopsided and not having good fusion on one part of the weldment like Cody confessed to above), and a setting that's too hot causing grainular crystalization.

The only ways to prove if your settings are acceptable is with either NDT or DT. NDT are things like ultrasonic, die penetrant, radiography, etc. DT would be things like the backwards bend test (home shop/BFH), bend tests, pull tests and sectioning/etching.

So, to answer your question Cody, the utter lack of a heat affected zone (HAZ) on the top piece would have me concerned, however, you didn't grind the mill scale off the metal (shame on you), and mill scale can hide the HAZ sometimes.

Also, the brown stuff is mainly oxides that float to the top of the puddle, via deoxidisers in the filler metal alloy, and is caused by grease, dirt, mill scale, etc. Brown smoke, on the other hand can be caused by those things, plus wire speed being too slow and lack luster gas coverage.

[CDJr]

Very informative Matt.

Welders: The only people that think a co-worker catching on fire is funny. <----STILL cracks me up every time

[Iburyyou]

The closeouts are 1/8" thick so I shouldn't have a problem then. I always heard you are not supposed to weld on a frame because it weakens it. any truth to that. What kind of metal can I get to simulate the frame for practice?