Bob's 57 AGIN is back to the shop (Santini's)

[57AGIN]

Well there has been a slight setback in the progress toward painting the 57.  One of the things I was having Santini do is deal and blend in the seam on both the tail light bezels to the rear fender and the headlight eyebrows to the front fenders.  Naturally this has to be done very carefully as it involves bonding two dissimilar metals (pot metal and sheet metal) together.  Sounds simple enough.  However, these two metals have different heat expansion and contraction ratios, which can end up causing a small crack to develop.  This did happen, just where the front fender eyebrows end on either side of the fender.  Fortunately it happened before application of the final paint job.  Pete is trying some carbon fiber patch, which is supposed to be very tough and we'll see if this helps. I've got photos of the crack repairs, but I haven't reduced them in size yet.  I'll post them as soon as I can.

Meanwhile, he's painting the oil pan and valve covers again so I can begin reassembling the engine, which I was just cleaning up after two years of shows and driving.  I do have the reduced size photos of that.

Bob
57 AGIN

[RICH MUISE]

Bob...I had exactly the same thing happen on my car. I don't think it had anything to do with heat, dissimilar metals, etc. Mine happened after assembly. (My fenders were painted for several years and were stored in a metal shed in North Texas' extreme heat and cold without any indications of cracking.) It happens when the fenders are assembled onto the car and the nose piece is bolted on...3 bolts each side...just below the bottom of the eyebrow. I believe that bolting distorts the headlight surround enough to seperate it from the eyebrow. Mine eventually cracked both sides  for about an inch at the bottom.
You didn't say whether it was the lower outside edge, or the lower inside edge, but based on what I talked about I'd bet money it's on the inner sides. I'd also bet the eyebrow work was done with the fenders off the car.
After my accident when my driver's side eyebrow was hit pretty hard, I now know, except for that assembly distortion, if done correctly, the eyebrows can be done with no worry about cracking. Note in the picture below there is no cracking at the eyebrow seam, even after the hit.
For what it's worth, I used the same approach on the tailight bezels (lots of bonding surface) and the headlight eyebrows with next to nothing for bonding/mating surfaces. After roughing up all bonding surfaces, I used a epoxy adhesive putty with a one hour setting time to allow more working time, and squished that in with the mechanical fasteners/mounting studs. This allows enough time to get the pieces aligned. After the epoxy set, I forced in as much por-15 wherever I could by brushing. That stuff is an incredibly strong adhesive, and it's 4 hour dry time allows it to seep into cracks and creaveses. I'm convinced it's the por-15 that makes this work. After everything is cured, the por-15 has to be removed from any visible surfaces that have to have filler/paint applied, so it's best to minimize that apoeration by cleaning offany visible excess with laquer thinner.

[RICH MUISE]

Bob...what I described above is probably too late for your eyebrows since the fill has been done, but at any point, the por-15 can be done to the tailights by brushing in lots of the stuff between the tailight bezel and the body. Just load up a brush and use the bezel to scrape off the excess as you would on a paint can lip after dipping the brush. Get lots in there and hope you never have to remove it!!

[57AGIN]

Rich:

Mine was quite different.  The fenders had not been attached back onto the car, they had been setting out in the sunlight allowing the black primer sealer to thoroughly gas (at least I believe that is why Pete likes to wait a bit before applying color over the primer sealer).  The fenders have been sitting both outside and inside the garage area for about 3 weeks.  The cracks appeared where the eyebrow end meets with the fender and no where else.  The tail light bezels were done months ago and no cracks or trace of where the seam was are visible.

Bob
57 AGIN

[gasman826]

I used panel adhesive to bond the fender extensions on both front and rear.  It was a gamble and was not completely successful.  The extensions were bonded on about five years ago.  The paint is nearly 1-1/2 years old.  After the bonding, I used AllMetal as filler which also works as a moisture seal.  Then finished with standard plastic filler.  The body has set in the sun a little...enough to get good and hot and exposed to below freezing temperatures...several of the typical Michigan temperature swings.  There is no paint cracking but upon really close inspection, I can see where the two dissimilar metals have moved.  Though very slight, I expect a crack or paint failure sometime in the future.  I'll live with it until I can't stand it anymore and remove the OEM extensions and fad some sheet metal ones.

Seam doesn't show from 5' and even closer...at least for now.  With thousands of dollars in paint work at risk, I will not do it again without fabbing out of sheet metal.

[RICH MUISE]

Bob...I'm curiousseems like I remember you having chromed eyebrows...were they stripped or replaced? I can't imagine Santini's guys would be trying to bond something to chrome.

[JPotter57]

he switched those at the last repaint/restore.  Santini talked him out of the chrome eyebrows, tail light housings, etc...

[57tudor]

Hi Guys,

Bob never had chrome eyebrows. He gave it some thought after I did my eyebrows but James is right, Santini said the car wouldn't look right with the then paint scheme. I chromed my eyebrows as it went well with my Atlantic Blue and the stainless side trim.

Rick. 

[57AGIN]

Gasman & Rich:

Thanks for your observations and experiences with the dissimilar metals bonding problems.  I can certainly see how the severe winter temperatures followed by some hot summer s could lead to shrinkage & swelling to a substantial degree. As a former geology major in college, I learned that solid granite mountains which when subjected to alternating heat & cold coupled with water getting into cracks & crevices & freezing & thawing can eventually cause catastrophic failure.  I'm hoping that the relatively mild climate here in Southern Calif and storage of the 57 in my garage when not being driven will allow the bonding to outlive the time I've got left driving. (odd thing to speculate on, isn't it?)

Anyway, here are a few photos showing the area the cracks developed in and the subsequent repair efforts.  Also, just as the eyebrow cracks were being repaired on the driver side fender a new set of cracks were discovered to the rear of and slightly below the eyebrow.  I believe this was a result of the impact of the accident.  This wasn't discovered until after the initial media blasting, followed by gray primer & 200 grit block sanding and the black primer sealing and 400 grit block sanding & sitting in the sunlight for a few weeks.  Santini's body man Jeff strengthened this area with welding and I believe some additional sheet metal applied to the inner fender.  It has now been treated to the normal body repair process and is once again ready for the black primer sealer and color application.  And the beat goes on and on and etc.

Bob
57 AGIN

[57AGIN]

Finally, here are the rest of the photos of the crack repairs on the fenders & eyebrows.

Bob
57 AGIN

[gasman826]

I really like the look of the smoothed seams.  I will smooth the next set of fenders.  The Michigan 100 degree temperature range has to be a sever stress on the joints of dissimilar metals.  The next time, the extensions will likely be sheet metal.  This doesn't mean that I will do anything with the current project.  I'm still quite pleased.  Santini will make it work.

[57AGIN]

Gasman:

I hope this works out.  I talked to Pete today and his plan is to put the 57 into the paint booth and have it sit overnight Tuesday.  Then if no new cracks develop overnight he's planning on painting the color coat on Wednesday morning.  We'll see how it all turns out.

Bob
57 AGIN

[57AGIN]

It took a little longer, but 57 AGIN finally has some, not all, of its color on again. Here are some photos of the preliminaries and a portion of the final results. There is lots left to paint and a number of steps yet to come before it is ready for the road  again, but I'm hopeful it will happen soon.

Bob
57 AGIN

[57AGIN]

Here 57 AGIN is in the paint booth and not just for primer.

Bob
57 AGIN

[57AGIN]

Here are a couple of more and this is where they will all stay over the weekend while a mild Spring storm passes through So Cal.

Bob
57 AGIN