Re-Welding factory subframe ?'s

[Sundance]

The secret to good penetration with a small 110 machine is to use the small wire so the heat is concentrated longer in one spot. Course this goes against anything I've ever seen in print.

Easy way to see for yourself is to take a couple of 1/4" pieces of scrap, set the gap between the pieces around 1/16" inch. butt weld the pieces using .045 wire and .023 wire and see which gives you deeper penetration. Make sure you speed up the wire feed just a little for the smaller wire.

Also penetration really isn't too big of a concern for strengthening of a sub frame because a) the frame is already welded and has lasted 30+ years just fine, and b) the pieces will be lap welded.

If your patching a hole and using a small machine, bevel the edges to gain the needed penetration depth.

[JRouche]

Originally Posted by Sundance

The secret to good penetration with a small 110 machine is to use the small wire so the heat is concentrated longer in one spot. Course this goes against anything I've ever seen in print.

Easy way to see for yourself is to take a couple of 1/4" pieces of scrap, set the gap between the pieces around 1/16" inch. butt weld the pieces using .045 wire and .023 wire and see which gives you deeper penetration. Make sure you speed up the wire feed just a little for the smaller wire.

I totally get yer thinking on the smaller wire with the weaker machine. I use the .023 wire on my 220 machine even at full power. And it does give a sharper penetration, digs right in where the .045 wire will consume more heat just to melt the wire and I get too much build-up of filler before I get to melt the base metal. So my joint is filled rather than welded. The .045 wire melts faster than the base metal gets heated and so the joint gets filled with melted wire and I need to move on. But with .023 wire Im melting less filler so I can heat the base metal up to molten before the joint gets filled up with filler. Ok, hard for me to splain, but thats the best I can say it. Now with a more powerful machine I could really crank up the heat and get the base metal melted at the same rate as the filler on 1/4" plate. But that machine isnt nice to work with for 22ga sheetmetal and .045 wire. So a 200 amp machine with .023 wire IMO is the best for car work.

I love welding, not great at it, but its fun to melt metal.. JR

[BRIAN]

Isn't it the exact opposite in regards to wire size??? Do not go down on wire size for thicker metals. Think about it... why would you go down in size when running higher amps through it?

[JRouche]

Originally Posted by BRIAN

Isn't it the exact opposite in regards to wire size??? Do not go down on wire size for thicker metals. Think about it... why would you go down in size when running higher amps through it?

Umm, I thought I posted the why for me. Lets see if I can try to splain it better. And really, Im just talking about MY personal preference and my equipment. I did spend a few semesters at the local community college and did get taught the proper methods of welding. But we dealt with gas, stick and TIG processes. There wasnt any shop time dealing with MIG. Some book work, but no shop work.

My machine (220VAC 175 amp machine) will weld with a .023 wire at full power without burning the wire back into the torch tip. The feed speed of the wire is fast enough at full power to be able to use it. If the machine was more powerful, say a 300 amp machine then maybe not. You would start to melt the wire before the weld puddle, not good. You dont want to be melting the wire on the stick-out, only at the weld pool.

Now, why do I use a thin wire with higher currents on thicker metal like 1/4"? Controllability, for me. I can focus the very hot but smaller weld pool (smaller wire) exactly where I want it. So if Im welding say some 1/4" plate I can actually see the root of the bevel and weld pool and work on that as Im moving back filling the joint and creating the weld. I like to see the weld pool. Ive used .045 wire and it really isnt that much larger. I can do the same thing. But it just happens so much faster (thats a good thing if yer welding really long joints). And with it, the 45 wire, I dont get as good of a looksee on the weld pool cause its filled so quickly.

I do like to weld fast, but to a certain extent. I would trade speed for control for what I do.

So if I was welding nuthing but thicker plate then YES, I would have a spool of .045 wire on the machine. But I weld body panels too. I love the fine point of the 23 wire and the ability to lower the current to melt the thin sheet without having to crank up the amps to get the 45 wire to melt. I wont weld body panels with 45 wire, too much filler being laid down.

For sheet metal I want to accurately focus a pin point source of heat and not lay down alot of filler. So the 23 wire shines there.

So, I dont want to be swapping spools, tips and drive wheels every time Im welding something diff. The 23 wire does great on both so thats really why I use it. Not cause its better for one specific application but mainly cause it works for all of my applications. I may have given the impression I thought 23 wire was better for thicker steel. My bust, I didnt mean to convey that. Its just better for me and my overall situation.

Ok, any better on why I use it. LOL I know, Im not the best at explaining crap.

Here is an example. This is a piece I made for my watts link. 1/4" wall tube and 1/2" plate. With 23 wire. And really, its a solid joint, it was hotter than hell. I think it is sufficient. Would 45 wire done just as well, or better? Just as well, not better IMO. JR

Tacked up with the TIG on the bench.





Then out to the driveway for the final welding with the MIG and .023" wire.





Some flattening of the outside beads for clearance..



And in the car for final welding..