Finally bought a tig when it came on sale. After less then a couple of hours practise I thought I would already have a go on the Willys panels. So this is my first weld ever with the tig while also doing just fusion welding too. The weld above was done without stopping and shows the backside penetration as well.
I am just a passing on what worked for me after lots of reading and watching, so by no means an expert but sharing in case it helps some one. This also applies mainly to a inverter tig which are more sensitive to electrode size. So this is the setup that worked the best for the cowl and old tailgate pressing which is 1.2mm/18Ga, and 1.6mm/16Ga. A 1.6 mm/0.065 inch, 2% lanthanated tungsten electrode. Best if you use one as close as possible to the thickness of the metal being welded for the easiest time. I am using lanthanated as can be used for steel and aluminium etc and you don't have the problems of breathing in the radioactive dust with sharpening it. Using a no.4 cup with the gas flow around 6 L/min-20cfm.
All welded in using fusion welding mainly. A couple of the corners had a slight gap so used mig wire as a filler rod when welding those. Torch angle was at 105*, or 15* off vertical, leaning away from direction of travel. The filler wire was added at a 15* angle off horizontal just in front of the puddle. It is recommended that the wire be 90* to the torch angle, which this adds up to. I used the principle of 30-35 amps per 1mm/0.40 of metal thickness that my tig welders manual recommended. Only draw back with using no filler wire and doing fusion only, is that you can still see where the weld was after planishing and sanding smooth.
For panels this is generally regarded as being quite acceptable and structurally sound. I did however go back over it with filler wire to see how it would come out. In the foreground of the right picture is the outside part of the cowl. The centre part of the cowl does not blend in with it. Partly due to the fitting of the tailgate piece in the middle of the cowl section after removing the centre vent, but also due to the fact the cowl changes width and curvature over its length. Don't forget that the centre part is 9" longer than what was in there before.
Just used a bossing mallet and the rounded flipper over a beater bag to shape it to match. Took quite a bit of mucking around to get it all curving evenly between the too. Next I checked the top edge and had to alter that to match the piece under the windscreen. I did not want to change the angle in the windscreen piece as it must stay the same to match the upper roof section so the glass is sitting flat. Something else I did was lower the Willys pressing more and allow the material to curve around it while keeping the pressing flat. Sits now at the same height as the rib in front and it also released the twist the panel had at the same time.