I know a few of you suffer the indignity of rust repair, so thought I would post this up as an easy way to do a sill where you need to make your own part.
Since measuring shaped objects is not easy, this method does a lot of the work for you.
First step is to use tape to mark off the bad zone. Be generous so that you get all of the rot. I guarantee its worse than you think
Now, dont go cutting right away. Take some time to fill in the bad zone with masking tape. I do a layer horizontal and vertical so that it holds together. Mark the bend flange and any other features.
What this gives you is a nice paper template to lay over your sheet-metal so that you don't have to bother with that pesky tape measure and all those silly fractions; just trace and slice with the grinder.
You can then slice out the suspected rusty bit to confirm your worst suspicions. Note that at this point I had to extend by rot zone because the rust went all the way to the B-post. Good thing I did not cut the tin yet!
Now, I hear a lot about fancy spot weld cutters but never found the need for them. A 1/8" drill bit drilled into the first layer and follow with a 5/16" bit till it bottoms out in the small blind hole works just fine.
The trick is to take your 5/16" bit over to the grinder and put a shallow tip on it. This is actually easier and more forgiving than most people think. Hard to screw up.
Little beating with a wood chisel and she comes right apart leaving the lower sheet good for welding back on to.
I like to be generous with the Chassis Saver or POR when doing this stuff. Since these paints are so hard to clean off after the fact, I tape the weld seams before I apply the stuff. Note that the back of the panel is taped off since these areas are a pain to get clean after the fact and paint on the backside of a seam WILL affect the weld bead.
Repair piece fitted. Made to shape with the CO2 bottle and the jaws in the vice to make the pinch weld flange. I like to use 18 gauge tin cause it keeps distortion to a minimum. For a truck, this could have just been painted after the weld was ground down.
When welding thin sheet, I see a lot of people trying to chase the gap. What I find works best is to aim the wire at the leading slope of the tack weld. Just give it a short zap to make a new BB size pool, and let the capillary action guide the molten steel into the gap between the panels. Advance the gun slightly and repeat just as the bead loses the red glow. Keep repeating to make a 1-2" series of beads, then take a break and let cool.
That's where the phone ran out of batteries, but the job was pretty much done. A cheap panel that took no special tools other than the welder and a few Stellas. I use the tape template to make a lot of parts where a measurement is hard to do.
