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GOT A LARGE DENT IN THE CENTER OF MY ROOF, AND THE OLD OWNER FILLED IT FULL OF MUD .
IAM ATTEMPTING TO GET IT OUT, BUT EVERY TIME I ATTEMPT TO SAND IT THE ROOF BUCKLES, OR IF I USE MY D.A. OR INLINE SANDER THE CRAZY THING STARTS VIBRATING SO BAD YOU CANT CONTROL THE SANDER.
I ALSO TRIED A LONGBOARD AND 80 GRIT JUST LITELY SANDING BUT IT WILL TAKE FOREVER THERE HAS TO BE 1/4 INCH OF MUD,
ANY IDEAS ?:devil:
 

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Someone sat on the roof of my 74 years ago and when I was taking it apart I noticed the inner roof beam was also bent and had a buckle in it. I was able to push the roof skin back up as well as the inner roof beam but it still wasn't as rigid as I would have liked so what I did was take out the roof beam to make it easier to straighten and then took some 1/8" thick steel by about 3/4" wide and bent it to match the curvature of the inner roof beam and then welded this added piece of steel to the original roof beam. I then put the reinforced roof beam back into the car and plug welded it back into position using the drilled out spot weld holes from getting it out.
Once it was back into position I still had a gap between the underside of the roof skin and the topside of the inner brace and filled it with liquid nail. A person could also use the adhesive that is used between the hood skin and the underside hood structure. The factory used some globs of it here and there to help lock the two pieces of metal together.
On mine after the glue dried the roof skin became very rigid in the middle.

I also did the same thing on my 73 years ago when I had it in stereo competitions and it has held up just fine after 15 + years.

If you look in some of my webshot albums I have some pictures of the work I did to the underside of the roof on my 74 Nova. I would post a link but my antique computer makes it hard to do. If you can't find these pictures, let me know and I will post a link next week from work.

If the roof skin on yours is stretched then you might have to work the metal with a shrinking disc. I've never tried using one but I've heard they do work.

Jim
 

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A shrinking disc is the best way to handle all the stretch and will tighten up the complete roof. You'll need to strip it to bare metal and run the disc over it and quench to tighten it up. The bow/reinforcement will mostlikely also need to be straighened and you can use anti flutter foam to adhere it to the roof skin.
 

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A shrinking disc is made of stainless steel and it mounts on an electric grinder. If you do a search under shrinking disc you'll find there are about 5 manufacturers offering them, ebay also has some. I made my first one out of the bottom of a frying pan:D- don't tell my wife where that pan went.....
It removes no metal and won't cause the paint to burn on the backside of your panels.

If you make your own it'll require a press and some dies to make a relief area where the contersunk style spindle nut holds it to your grinder.

The beauty of how these work is if you knock your stretched areas so they are standing up and run the disc over the area the friction created where the disc makes contact with the high spots then creates enough heat to shrink the metal when you quench it with a wet rag. The shink happens only where it is needed. Do this over again and again the the high spots will lower each time untill the stretch is gone and the skin becomes tight again. I've saved some hoods, roofs, and decklids with this tool that would have been scrapped with any other method. Taking a torch or stud gun to the middle of a large panel like this in an attempt to shrink it is usually an excersize in disaster or at least leaves less than perfect results even when performed well. The shrinking disc if used properly will leave you with a perfect finish, metal formers around the world have been using them for a long time but it has never caught on in the collision industry I guess because most times there's just more money to be made replacing a roof than repairing it.

The first hood I saved was a 79 TransAm hood that I'm sure had the fat lady do a dance on it years ago, it was stretched from one end to the other with large mellow dents and sags and all of the anti flutter foam was detached. If you lifter the hood from one corner it would twist with ease as all of the structural integrity was gone. I saved that hood with about 4hrs of bump work and using the shrinking disc, when it was done there was very little distortion and it was tight as hell. You really do need to practice some with it though as there is a learning curve. If you shink low crowned panels too much without monitoring what's going on it'll take the crown right out and pull the edges up on bolted on panels.
 
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