[sschefer]

I did a spark test on this and it looks just like mild steel. It's 3/16 3x4 (+3/16) square and the mild steel square tubing is 1/8.. This piece slides over the 3x4 tube. I don't have anyway to test weld so Here's what I'm thinking: Twist up some .035 ER70 S6 MIG wire for filler (all I have is S2) and spending a good amount of time cleaning it. Tack it on all four sides. Start with about 100 amps and use a long post flow while making short 2" welds with cool down periods in between. I'll probably use a #10 cup with a gas lens.

This is a Fulton Swing away trailer hitch installation.

I was thinking I'd just MIG it but I don't think I'd get the penetration I will with the TIG.

Any thoughts?

Thanks

Steve

[sschefer]

Got er done, Turned out to be about 1/16" gap all the way around so I ground a bevel on the cast pieces then MIG'd them with S6 to fill the 1/16" gap and give me a good base. I then went over the welds with the grinder to get a better look at the penetration and as I suspected, the cast steel sucked the heat away from the tubing and the bond wasn't very good. It was probably OK but I'm not O.K. with just O.K. (was that redundant or what).

The MIG bead gave me a good S6 base so I weaved back over them with the TIG and touched them up with MIG wire where needed. I'm satisfied they'll hold..