Sunday, January 16, 2011

The Indentectomy.

Update 1/30/2011:  A fellow VMFer (thanks Steve!) from a neighboring town was kind enough to take time to come over and examine my work.  He has an exceptional amount of hands-on auto body experience and showed me how far off these patches are from being flush with the body among many other tips and tidbits of knowledge.  His recommendation for cutting the patches out were to make much smaller patches.  He recommended cutting out the indents right at the edges of the indention instead of an inch out like I did.  The resulting patches would have been much easier to blend with the quarter than these that I did are.  The result is that to blend these patches into the quarter will take quite a bit of filler over the entire rear section of the quarter which pretty much nullifies my purpose of doing this in the first place. 

Sometime back in the 80's Ol' Rusty had endured a "restoration".  This involved riveting thin sheet-metal patches over rust holes, welding reinforcement plate in the rusted-out inner rocker, slathering bondo all over the torque boxes, screwing aluminum and fiberglass sheets over the holes in the floor pans, and replacing the rear quarters.  Well, at least they actually replaced the rear quarters but they used the incorrent panels from 68.  It seems like a really minor thing but prior to 2/15 in 1968, the rear quarter reflectors were installed in indentions.  After 2/15, the indentions were deleted in favor of flush-mounted side markers.  Well Ol' Rusty was built on the 28th of February and should have the later flush-mounted markers.  The restorers must have known that this was the case because they simply filled the indentions with body filler.

When I had the car media blasted, I had the blaster leave the filler in the indentions with the intentions to "top it off" so to speak and be done with it.  I did this just before Christmas as evident in my blog entry from 12/14/2010.  The more I thought about it, the more of a bad taste it left in my mouth.  The filler was upwards of 1/4" thick in the indentions.  What if it cracked?  What if it simply popped out because I didn't replace it with completely fresh filler?  What if it caused the paint over it to bubble or peal?  Then one day a fellow VMFer posted a request for indention patches for a 68 Mustang.  Although such a patch doesn't exist for sale, I felt that I could be of assistance and solve my indention problem as well so I went down to my local hardware store and bought a sheet of 20 gauge sheet.  I had decided to perform an indentectomy. 

Now THAT's gotta go.

The first step was to clean out the indentions.  I started on the passenger side and used my angle grinder with a knotted wire wheel.  What a MESS!

All cleaned up
I then measured the area about an inch around the indention and came up with a patch size of 11" x 4" and marked two patch blanks on my sheet metal plate.  I used my new Harbor Freight electric sheet metal shear and cut out the patches.   I recommend this shear by the way.  It works as advertised.

11" x 4" squares.  Just enough to overlap the indentions by about an inch.

Ready for forming
I marked out the area to be cut away with masking tape for visibility.

Before cutting, I had to put a slight bow in the patches to conform to the curve in the rear quarter.  This was accomplished by using a section of my heavy floor jack's handle and a 1/8" bar stock to roll a slight curve in the 20 gauge sheet.  After I got the curve started, I could use my hands to adjust the curve of the patch to match the indention area of the quarter.
My high-tech sheet-metal roller.
Using thin cut-off wheels on my 4 1/2" angle grinder, I carefully cut out the indention out as best I could.  My brain was screaming at me during this phase to just put the grinder down and step AWAY from the car.  I had to just grit my teeth and have faith.

What the hell am I doing?
Ack! Did I just cut a huge hole in my quarter panel!?!
After many many minutes of fine-tuning the patch to the hole came the tedious job of stitch welding the patch into the quarter.  I think a pro with a good heat-sink could have welded this patch in with a steady bead but the most reliable method for me personally is to just stitch it in one tack at a time alternating tacks about an inch or more apart to keep the heat dissipated in this way.  Another way to weld in a patch like this is to use a heat-sink behind the weld like a copper or aluminum plate or even a wet rag but I didn't have a good way to hold such a thing up against the back of the joint.
Welded in. Phew!
Finally, I ground the seam down with a grinding wheel and flap disk  Something I've learned along the way is that grinding down welds will heat and warp sheet metal as surely as seam welding so I try to do the grinding lightly.  Just letting the grinding wheel do the work and do not try to force it.  If I see the metal turn blue under the wheel/flap disc, I back off.

I followed the same procedure on the drivers side except instead of using a wire wheel to clean out the indention, I used my air chisel which proved to be the way to do it.  The old filler literally popped out of the hole which also confirmed my fears of what might have happened had I left it the way it was.
The indentions were cleaned up to be reused and shipped to Maryland to start their new life as part of a father/son restore project.

So, that concludes Ol' Rusty's indentectomy and now she's not an "inney" any more.


  1. Wow that's great, certainly the right thing to do...also, I was looking for some help on how to patch my wheel arch and this is the perfect "how to"...just have a quick question: you used 20 gauge steel - how critical is the thickness?

  2. Nice little patch job there Alex... I know the feeling of horror as you start to cut bits like that - am I doing it right, what if I got it wrong... ha ha ha! Agree it was the right thing to do

  3. Alex! Awesome work there! Sooooo.......tell the class just how puckered up your various orifices were when the first spark left the "death wheel" when the indents were coming outta there! LOL!

  4. @Joyr1der: It's semi-critical for aesthetic purposes and preventing blow-outs from dissimilar heat tolerances. You won't get an exact match though because of how these pressed panels have thin/thick areas from stretching and shrinking at curves. 20 ga was the closest to my repro quarters.

    @Mike: Thanks! Yeah, you know that little voice that says, "hey dummy, don't do that!"? I had to beat mine deep into unconsciousness.

    @Sven: LOL! Pucker factor 10!

  5. You had me laughing at, "slathering bondo all over".

    Great work cleaning up the 70's Restore mistakes! Kept saying, "that sounds like my car!" Nothing like bondo and undercoating to cover up problem areas.

  6. Nice patch. I will definetly be performing similar surgery in the near future. Mike

  7. Alex, Great job on the your car and the patches! And thanks again for cutting your car up so we would have the right marker lights!
    Pat & Kurt

  8. No problem Pat, good luck on the Bullitt project and thanks for the reflectors!

  9. Found your blog last night and had to comment.
    I've had my 68 conv. for 31yrs. Purchased the car (without my father knowing) when I was 15 for $1,200.00 (got grounded for a month!) because I didn't ask permission to do so. Well, 31yrs later still I still have her and the long awaited adult restoration is about to start.

    Yesterday I pulled he engine and transmission.

    Your blog is excellent, and truly has inspired me to do the restoration she truly deserves. Thanks for the narrative and great photo's. Today I'm starting on the battery box!
    Here goes nothing!

  10. Good luck with your resto project caa5a750-4278-11e0-9cd7-000bcdca4d7a!!

    (My, what a loooooong name you have.)

  11. Alex- Nice work and congratulations on finding someone to guide you in the body work. My 68 vert is at the restoration shop now for paint. That is, right after they fix all of my alignment issues and other mistakes! Like you, I thought it was ready for a quick prep and spray... how wrong I was.

    Lessons learned: 1) make sure everything fits BEFORE you dissassemble the car, 2) you can NEVER do too much fitting/alignment and 3) it costs a lot more for a pro to fix mistakes...

    Luckily, the guys at the shop have been very kind and have gone out of their way to explain where I went wrong and how they will fix it. I'll get there in the end.

  12. Great lessons JAPR! I've arranged to have the pro take the car to his shop in April to prep it for paint. I think it's for the best given my complete lack of skill with a sanding block. :-)