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Mid Plate Install

Posted: Thu Jul 21, 2016 8:04 am
by Rick Finsta
I'm installing a mid plate between the SBO and TH350 in my '72 Cutlass. No big deal only runs 11s but I wanted it to be easier to remove the tranny or engine without have to remove both all the time. I already run a front plate (3/8" aluminum) and limiters on both sides, plus an ultrabell on the tranny.

Anyways, I am welding 0.125" 1018 steel to the stock frame rails for the mounts and was just looking for guidance. I was going to TIG them in using ER70S2 but I can't get a good gauge on the thickness of the frame metal. I'm been told it is 3/32" (0.093") but it seems thicker in some areas; maybe it is just built up paint and grime. Any idea where I should start for juice? I was going to just start at 125A on the dial and then back it off with the pedal if I needed to. Also, should I look at -6 rod since the frame is pretty old and I'm guessing prep won't be the best (it is hard to get into the area with my flap wheel).


Re: Mid Plate Install

Posted: Mon Aug 15, 2016 11:05 am
by Rick Finsta
Just to update on this - I ended up tacking things in place with about 125A and then during the welding I ran 100A and the pedal was wide open. I should have used -6 rod. I had to wait to boil some skuzz (technical term) out of the puddle in a few spots and ended up with a wider and flatter bead profile than I wanted, and also put more heat into everything than I wanted to. I had to stop three times on one side to get around header tubes with the torch, and twice on the other side (it wasn't possible to lay one continuous weld). If I were to do it again I'd run 130A with a 3/32" ER70S6 rod and just scream along as fast as I could.

So in short:
100A DC 1/16" ER70S2 rod 3/32" E3 (purple) electrode, #5 gas lens with 12-15CFM got the job done but wasn't optimal. This is the uglier side but the better looking side can't be photographed easily.