Tuesday, November 27, 2012

A Milestone Reached & Another Chapter on the Horizon

Sometimes, it seems major milestones are marked with small accomplishments.  Such is the case with the most recent few bits of work I have completed.  Specifically, I was able to confidently declare the major damage and rust repairs complete on the car and man does it feel good!

All that remained in the way of welded repairs was a small rust perforation at the right lower corner of the rear window opening and the eight rear louver hinge bracket holes that will no longer be used.  Following that, a small bit of clean-up on the roof drip rails marked the work complete as well as a significant change in the work plan moving forward.
The repair in the window opening was as textbook as it gets.  A combination of a cutoff wheel and pneumatic body saw, coupled with a little file work, was all that was required to prepare the aperture for the welded patch.  From there, simple paper patterns were made to replicate the inner and outer structural patch “coupons” and a few minutes of fab work had the patches duplicated in metal and ready for installation.

Starting with the inner repair, I tacked the patch in place in several locations to allow the outer patch to be fitted before final welding.  Next, the outer patch was punched for plug welds.  Then the patch was clamped, tacked and then fully welded into place.  Final finishing of the welds was accomplished with deft use of the angle grinder and the job was complete……..no drama, no blood, no cussing……just done.
Rounding out this phase of work was a revisit on the roof drip rails.  I had been struggling with effective seam sealer removal procedures in confined areas like roof rails.  Sand blasting is not an effective method of removing old seam sealer, and the roof rails are quite restrictive in terms of tool space to simply scrape the sealer out effectively.  Secondly, old seam sealer is often as hard as rock and doesn’t lend itself to removal with even forceful application of tools.  Obviously, this is quite different from easily accessible sealed areas where many different tools (some even dedicated to the job) can be employed.

I have been experimenting with a few ideas intended to make seam sealer removal easier from restricted areas (like drip rails) and have managed to devise a combination of tools and methods that make this a much more approachable.  The first ally in this battle is acetone.  Acetone works very well in softening old seam sealer and loosening the bond to the metal substrate.  The second tool I use is a version of “mini-scraper” I made using a very long, thin flat-blade screw driver with the end sharpened to a slightly angled cutting face.  This tool has a bit of flexibility to allow it to reach sealer in what are otherwise inaccessible areas.
The process is rather simple.  First, I apply acetone to the sealer with a rechargeable sprayer and allow it to soak a bit.  It helps to scar or prick the surface of the sealer to allow deeper penetration of the acetone into the sealer.  This softens the sealer much more quickly and the removal process is much more efficient.  After a minute or two of “soak time”, it’s simply a matter of scraping layer after layer of sealer away until you get down to the parent material.  This simple process can be used over and over, until the majority of sealer is removed.  As a final step, I use a combination of wire wheels in my drill motor and small picks to remove the last remaining bits of sealer residue with the acetone softening treatment in between each cycle.  While somewhat labor-intensive, the end result was a pair of drip rails that were exceptionally clean and (fortunately) almost rust free.  As I have experienced in the past, old seam sealer is notorious for hiding rust and the removal of it is absolutely critical to a long-lasting repair.  With this method, hidden rust can be exposed and removed/treated such that it is no longer a concern.

The final project in this batch was simply welding up the eight drilled holes that were left over from the long dispatched louver hinges.  I welded these up is short bursts from the MIG gun and then quenched the hot spots to reduce warpage.  The real key trick in getting this to work well is the use of a copper backing plate on the back side of each hole.  The copper acts as a casting surface to let the weld flow and form in the hole while molten.  The copper dissipates heat so quickly that it doesn’t melt into the puddle.  Secondly, the copper acts as a gas dam, preventing the shielding gas from simply flowing through the hole and out the back rather than remaining around the weld puddle where it belongs.  In fact, this method is so effective, I had all eight holes welded up and dressed down in under an hour.
Well, there it is.  The major repairs on the “tub” are complete and I now have a solid car that I can confidently move forward into more “cosmetic” work without concern for the foundation.  Two years of constant work has led to this point and it is interesting and exciting to begin thinking and planning the next phases of the build.  The immediate plan is one more round of chelation to remove the rather minor surface rust on the interior panels that were primarily bare metal from the factory.  Then priming, sealing and painting the interior in preparation for the move to the finish work on the underside of the chassis.

In this shot, I have already removed the inner and outer rust damaged areas of the right lower corner of the rear window opening.  This is the last rust damaged area that requires welded repair!

Here is another view showing the outer window flange repair area already cut out.  With these edges dressed, I was able to make simple paper templates for each repair "coupon" and fit them perfectly before welding.

Looking down on the repair, you can see the curvature that will be required in the inner repair and the simple flat repair required on the outer flange (on the left).

With little ceremony, the repair is tacked into place on both sides and then welded into place.  This is the outer flange after finish grinding.

Here is the inner window flange repair complete.
Fore removing seam sealer from drip rails, I needed to devise a flexible, thing scraper.  This slender old screwdriver was just the ticket!

I carefully ground the tip into a sharp, beveled chisel point to allow easy scraping without bending or dulling the tip.  Works great!

Here is another priceless tool in the restoration shop!  Sure Shot rechargeable sprayers are worth their weight in gold!  I fill this sprayer with acetone and pray old seam sealer with a generous mist to soften the sealer for easier removal.

After about 30-45 minutes of softening with acetone and scraping (repeated as necessary), the drip rails were surprisingly clean.  You can just see slight evidence of hidden rust that can now be effectively removed before priming.

Here is a look down the A-pillar drip rail after the sealer has been scraped away.  The lead joint filler is clearly visible in the middle of the frame.

After a few minutes work with a wire wheel in my drill motor, the drip rails are ready for chelation to remove the slight traces of rust found underneath the old seam sealer.
To weld up the louver hinge bolt holes, I back each hole up with this copper plate.  This acts as a dam, keeping the weld puddle in contact with the repair surface and prevents the shielding gas from blowing through the hole and past the weld area.
With the copper backer, you can rather easily weld up holes in thin sheet metal like this.  A very thin skim of filler will be all that is required to complete this repair.



  1. Awesome work Sven, congrats on the milestone. I can't wait until I reach this point myself. That is still a long ways down the road for me though.

    1. Thanks Grant! if you keep working your plan, you will be right there before you know it. Keep thinking of the car as therapy and it's easy to keep coming back to it. Ha!

  2. Congrats Sven - a nice hurdle to get past. Now the fun stuff can begin :)


    1. Howdy RJ and thank you! I am looking forward to bigger jumps in progress just over the horizon now that this "reconstructive" work is complete. I'm ready!

  3. Well Sven, you've got to be feeling good about getting to the end of the rust repairs. I hope to join your club in 2 or 3 months. That's also a great idea on the drip rail seam sealer too. It beats going after it with a wire brush and hoping you get it all.

    1. I am definitely thinking about things in a different way after reaching this point and thank you. Your project is coming along great and there is no doubt you will be ready for similar things by working your plan. Is it time to heat up the shop down your way yet?

    2. Yeah, the old garage is pretty chilly. My last post was with the torpedo heater running. Right now, one bay is full of Christmas decorations and "stuff" since my entire family was home over Thanksgiving and we did Christmas then. Hopefully, I can regain that space and get on the car this weekend, especially with the highs in the low 60's. Finishing up the trunk drop-off will be fairly straight forward. The booger repair is the upper right trunk lip and surrounding are on the body. That's all going to be hand-fabricated. Nothing ventured...nothing gained.

    3. Warm is good Dennis! Warm is good! (Hint, hint!) I'm pretty sure your 'ol girl is as much therapy for you as mine is for me. Notheing ventured indeed! Looking forward to your next updates and here's hoping the winter is a good one.

  4. Congrats on the milestone Sven! You have done some awesome sheet metal repair on this car. It's lucky to have you as it's current ward (we never really own these cars, we just care for them for the next driver).

    1. Alex, as always, I appreciate your encouragement. And you are absolutely right about preserving these old cars for those that follow. I have every intention of seeing this car and the work put into it outlive me by at least one more lifetime! Of course, that does not mean I won't put a lil "wear" on her in the time between!