Need advice for this weld

[davejcb]

Good morning all,

I'm a novice welder, have a Lincoln SP-125 Plus mig, with 75/25 argon/CO2 mix. I've only practiced on butt joints so far.

I am looking to weld the following piece into a trailing arm on my car, and it looks like this so far. What I need to weld is the slug that was hammered into the arm to the lip to the right of it, all the way around. I have a few questions:

First, do I need to clean the lip up any more? I went over it with a Dremel tool, not sure if it needs any more cleaning...

Second, I'm not sure of the settings I would use? Going in at a 45 degree angle, the lip of the slug is probably 1/4" (best guess) while the lip of the arm is maybe 1/8" thick. So I'm unsure as to what power settings I would use?

Third, any advice on overall technique you would use would be greatly appreciated.

Thank you so much!

 

[wyn]

Was the lip part of the previous setup ? Is it needed ?

I would grind the lip off and grind the arm behind the shoulder of the new part till you have a nice half "V" shape.

Just welding to the lip might be a bit dodgy.

Maybe also drill a hole or two in the arm so the new bit can be plug welded.


Edit: Just had another look at the pics.....is the bit with the lip another seperate part welded to the arm ?

Are the new bits "one off's" or are they a "kit" sold by someone ?

 

[davejcb]

Hi wyn,

Thanks a bunch for the advice- the lip is part of the arm, and I don't see why I couldn't grind it off, good idea. I also thought of doing a plug weld, so with your advice I'll go ahead and do that.

A fellow did grind off the lip and it it turned out like this. He had done it out of necessity, though, due to rust.

And the new part is sold as a kit, not a one-off fabricated part.

 

[wyn]

Pity the "slug" wasn't a bit longer so it could be bolted through the hole as well. Or is it ?

 

[davejcb]

No, it's not...

Since the slug is so thick, would I want to go very high on power for the plug welds? The arm itself is probably 1/4" thick, I would estimate. Also, would 0.030" wire be adequate for this?

 

[wyn]

For the plug welds probably as high as the welder goes if the arm is 1/4"...Maybe preheat it a bit with some sort of heating torch on the plug weld area to warm up the slug.