Smoothing the quarter panel extensions

dmoody

Founding Member
Nov 4, 2002
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Winston-Salem, NC
Hey guys,
I've noticed several cars lately that have the lines from the quarter panel extensions smoothed out. I understand how for example you would smooth out the transition between two steel panels like the rear valance and quarter panel... but how do you smooth out the line between a part made of pot metal (can't weld) and a steel panel? If you just used bondo seems like it would crack.

Thanks,
david
 
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It is such a small line, I don't see how either leading or brazing would stay in there??? ..has anyone ever actually done this? I've seen cars with it done before, just don't know if any of those people are reading this thread.

david
 
Brazing would be too hot, most likely lead would be as well. Filler would work as long as the piece was firmly bolted onto the quarter. Don't know for sure but some of the new structural adhesives would probably work very well for that. I takes almost nothing to melt the pot metal pieces. Ask me how I know;)
 
Some sort of two part epoxy would likely work, maybe even JB Weld.

I've been kicking around the idea of hand forming a set out of steel and welding them on. Even the thought of a California Special type "lip" for the back, but more along the height of the '69-'70 fastback but I doubt that will come to fruition.
 
rbohm said:
you can use either fiberfill or alumafill bondo when eliminating those lines. either one is designed just for that purpose.

Where can I find out more information about fiberfill or alumafill? Where can I learn about different types of bondo, adhesives, etc? I've never really found any good books or articles that addressed these topics.

Thanks,
david
 
I have done exactly what you are talking about. My GT rear valance and my 1/4 panel extensions are molded right into the body. it took us two days to get it all right. Unfortunately, all of my pictures are on my other computer that is down right now. I will see if I have any at home.

We fiberglassed it all in and then used body filler.....NOT BONDO. It is smooth as silk and primed now.

I will see if I have any pics of it at home that i can scan.
 
I'd love to see some pictures. How did you find the room for fiberglass? The gap seems to small for that. Did you use any of the products previously mentioned (fiberfill, alumafill)? How has it held up? Is there anything you'd do differently?

Thanks,
david
 
I've continued researching this topic:

1) Adhesive or the popular 3M two-part adhesive says it will bond to fiberglass, aluminum and various grades of steel but I don't see anywhere in the manufacturer specs where it mentions lead or zinc which are the two main components of pot metal.

2) Alumafill, Metal2Metal, etc are just forms of bondo that don't absorb moisture due to their high metal content. Although I think this would hold up better than normal bondo or fiberglass because it retains characteristics closer to the substrates it is applied to, I remain skeptical it can retain its bonding power and not crack over a long period of time.

3) Lead. This seems to be the winner although I haven't found anybody that has done it. Pot metal is mostly lead and leading has been used to fill seams and dents on cars for many, many years. However I have no idea how to do it even though I'm proficient at welding.

Anybody have any input on what I've found out?

david