Race Cars and More Body Work
First, thanks for all the productive comments in my last entry. Please keep them coming! I don't know if I should be grateful for that link to MP&C's tutorials or if it is an “ignorance is bliss” type of scenario. Regardless of the situation, that Garage Journal thread has been a complete time suck but incredibly motivating and answered my previous questions about master auto body technicians – Yes it can be made perfect. This guy does it with all his panels. Here is the link, again.
After reading pages and pages of the thread, trying out different things then venting my frustrations to my loving and patient wife; she hit me with a very stark remark.
“Comparison is the thief of joy.”
Truer words, one might say. And I am most certainly one who would say that.
Not to make this any longer, but here are a few pictures from our trip to the 24 hours at Daytona. It was a much needed trip out of dodge to a warmer, sunny (read bitter cold and rainy) place. This is my 4th or 5th outing to the 24h race and it never disappoints.
The M12 was not in the E21, I looked.
She looks good in a red 356 right?
One thing that has changed that I was bummed about is that you can't stand next to the fence at turn 1 of the tri-oval anymore. That was always a religious experience. There was a new BMW “art” car by Baldessari. I put art in quotes because it was far from an art car if you ask me. If you go, make sure to get the garage pass, it is well worth the extra 25 bucks or so and will satisfy all your late night hunger for fast and furious race car repair.
Anyway, that was just a few pictures.
I started piecing the driver side rear wheel well back together. Taking advice from the comments as well as the Garage Journal thread, I took the time and filed the wheel arch panel to fit without gap. This took a few hours but it was well worth the time. I first cut the panel long then roughed it into shape slowly pausing to make sure that when I removed metal in one area I would not be creating a gap in another. I took my time filing the panel down to shape. I made indicator marks on the body so I fit the patch panel up the same way each time.
I finally got it to fit up very well with great consistency in the contact between the panels.
I neglected to mention that I did all this because I found rust between the original panels eating into the inner and outer fender.
Throw away the butt welding clamps!
Or only use them for test fitting a panel. I will never use them for the actual body sheet metal welding process anymore.
Here is what I found.
When using the butt weld clamps you have to bridge a gap, albeit small, with filler. This causes a huge heat dump into an edge of metal. The heat has only half of the material to dissipate into since it is not contacting the other panel yet, thus you have a very good chance of burning through the panel not to mention almost 100% chance of warping. To account for this, you may turn your heat down on the welder (#1 on my Hobart), and maybe turn up the wire feed.
However, if you butt the two pieces of metal together the heat can dissipate into both panels making it less likely to burn through the panels. With the panels butted together I had my welder set to #3, a whole 2 clicks up on heat, with a slow-ish wire feed. The slow wire feed kept the weld proud low but the weld penetration remained complete. I did not burn through the metal once.
I used the spot weld, planish, grind method outlined in the Garage Journal thread with good results. Honestly, I wasn't sure what I was doing or looking for at first. I slowly started to understand the on dolly, off dolly planishing techniques and how they actually work, or don't work.
The process, as I understand it, goes like this:
1. Fit up the patch panel snugly and tack in place. I don't know how far to space the tacks, but I tried to space them about 6 inches apart and had what I think were good results.
2. Planish the panel to fit the contour of the body. I noticed that the wheel well patch panel does not have the same contour as the original body. The vertical curve, or “the hotdog” as I was told it was called, is not present in the patch panel.
3. Grind the welds just proud of the sheet metal. I only have a 4 1/2” angle grinder so I used a old cut off wheel that was worn down so it was easier to control.
4. At this point, I double checked my panel alignment and did little adjustments as needed.
5. Weld another spot weld over the last set of spot welds. I did about a 50% overlap of the previous spot weld.
This is a long and tedious process, but the time consuming nature of the process has a secondary benefit of making you wait for the weld to cool whilst (I sound like a bloody Brit!) staying productive. This tends to keep warping down to a minimum.
After all the weld was completed (it took me an entire day) I took my 120 grit flap disk and started taking off what was left of the weld proud.
I did notice some low areas especially in the lower back corner of the patch panel. I thought heat would be necessary but I was able to pop it out with the hammer and dolly. I applied pressure to the low spot from the inside of the trunk with a dolly that closely fit the desired shape of the body panel then, using the off dolly technique, I planished around the low spot. I could not believe how well the low spot was lifted. I am every bit of a novice at this and it worked very well for me. By no means is it perfect but I lifted about 95% of the low spot.
Apparently you want to leave the on dolly planishing for the final small adjustments to the sheet metal distortion. On dolly will stretch the metal, so if you are not close to the final desired shape you might want to avoid on dolly planishing – from what I understand.
Also, for Valentines day the lady got me a bead roller! It's pretty cool. I will be reinforcing it with some square tube or angle iron. It came with six sets of dies so I made a little hanger for the dies that are not being used (top right of the picture).
I will say this is addicting work. I never thought I'd be this far into a project like this. It's a great learning experience.
Cheers,
Pete
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