My next project involves alot of sheet metal TIG welding - seeking advise

[748R]

Hello all,

first poster here A few words on where I'm at. Over the years I have built up a halfway decent shop, I have a Bridgeport mill, a Colchester lathe and a Dynasty 200DX welder. I have done small projects involving these machines (well not the lathe as I just got that), but I'm still very much a noob. Next project up is a go kart for my kids. Kids are very young so I have plenty of time

I am planning a 1:2 - 3:5 scale 1932 Ford roadster for the kart. Needless to say it will involve all machines and a steep learning curve.

First up will be fabrication of frame rails. I have exact digital drawings of the deuce frame which can be printed full size at any scale for a template. I plan 1/16" or 3/32" mild steel sheet for the frame.

I'll cut the profile of the frame from sheet and weld together 4 pieces for a box section with the correct shape. I'll also try to cut, bend and weld the outer side pieces to imitate the ***y reliefs on the 32 frame.

The TIG calculator on this site calls for the following:

1/16" sheet:

1/16" tungsten (I have thoriated and ceriated)
1/16" filler
50-80 amps + 10% for mild steel
11-20 gas
1/4" - 3/8" cup

3/32" sheet:
same, except 80-110 amps + the 10%

Onto the questions:

- any input on the sheet metal thickness? Frame will be around 75" long.
- would you reckon the parameters from the tig calc a good starting point?
- someone told me I should go with a closed corner with some stick up even to eliminate the need for filler? Or just go with an open corner and add filler?
- I believe no gap between the pieces is important ie very accurate cutting?
- Do I need to use a heat sink ie copper plate on the back side?
- Should I break out the hammer and dolly and work the weld every few inches?
- How close would you space your tacks?
- How long a bead would you lay before moving to another part of the construction and continue there?

Looking forward to hearing what you think

JT