Shrinking Discs

Can any one tell me if shrinking discs work? How difficult are they to use? I have a hood that was sand blasted and warped. I want to see if I can remove the distortion the blasting caused. Any other advice would be appreciated.

Jim

 

Never used those, but I have dealt with that issue, both hoods and roofs..

Find a local body shop that has a Lenco puller..

http://www.lencocanada.com/ProductDetail.aspx?Id=188

Now what you do with this is use it in a circular pattern to not pull dents, but just to shrink the metal down.

Works slick, and transporting the hood should be the biggest deal here, cost should be minimal.

JW

 

Wait 'til ya get my age. Everything shrinks!
Years back, I had a '71 Cutlass that got hit in the left quarter. A friend of mine used a very similar method to repair it. When completed, you could not tell there was a repair.

 

Thanks for the replies. I will begin calling body shops in my area.

Jim

 

Do a search at the autobodystore.com forum. It's one of the best forums in the trade.

http://autobodystore.com/forum/index.php


And post back here what you find out!

 

I did join the other forum and I posted the question regarding my warped hood and possible ways to shrink the metal and make the hood usable. The consensus was get a replacement hood as repair would be costly and poor at best. Requiring a "butter coat" of filler over the entire hood. I am going to try the shrinking disc and the Lenco dent puller and see what results I can get. I can't hurt the hood so might as well give it a shot.

Thanks Jim

 

Here would be my approach, unfortunately for me I do this kinda stuff daily, first I would stud and pull any obvious low areas , and pull them and the lowest areas with mud. Then prime with epoxy then a high build primer 4 to 6 coats with appropriate flash times, then block with 80, let the paper and block do the work. Then putty the low areas that show up. Then reprime 4 coats of high build, block that with 120, you may have a few more low areas show up , at this point you should have enough material build up to block the smaller ones out, the ones that don't block out reprime those areas not the whole hood, cut those areas with 120 then at this point it should be pretty well whooped, now reprime 3 coats of surfacer primer or reduced high build.

 

Saw your thread over there. It's a shame as it was a GSX hood too.
Try to find a shop that specializes in hot rods and customs. You'll need someone with some great metalworking skills to fix this one.

 

Here would be my approach, unfortunately for me I do this kinda stuff daily, first I would stud and pull any obvious low areas , and pull them and the lowest areas with mud. Then prime with epoxy then a high build primer 4 to 6 coats with appropriate flash times, then block with 80, let the paper and block do the work. Then putty the low areas that show up. Then reprime 4 coats of high build, block that with 120, you may have a few more low areas show up , at this point you should have enough material build up to block the smaller ones out, the ones that block out reprt those areas not the whole hood, cut those areas with 120 then at this point it should be pretty well whooped, now reprime 3 tts of surfacer primer ordontreprimereprimesurfacer high build.

 

So basically I have one of these also. What happened to those guys that can work metal? I remember a local guy that could do this but he's retired and moved to Florida. Now everyone wants to fill everything with bondo and still charge a ton for their "work". I watched a show where Chip Foose installed a Camaro RS nose on a 79 Elcamino and when finished you could not see the welds and metal work before paint and primer. I doubt many of us would be able to afford his time but it proves it can be done. I want to fix mine too and since its going onto a Sporty I'll be happy with a minimum of filler and be happy. But for a GSX restoration I would use a better hood or just pay 1k to have the best do it its original to the car right? I really do not mind paying for the quality if you get it. Most time you pay for it and get much less.

 

Can you post a few pictures of your hood? The Lenco or any other brand stud puller isn't really for shrinking metal, but, lots of guys use them to shrink metal. If put in the wrong hand, lots more problems can arise. It takes a skilled metal man to shrink stretched steel without causing more damage. You can tighten up oil-canning on the panel, but, will almost always have to block out a layer of mud. Sandblast stretch is usually over a large area with no pressure buckle to relieve so more traditional shrinking methods are usually required.

Matt

 

I only have one picture with me. It shows a tool lying on the hood showing a 3/16 deflection in the metal. This area is typical of every area between the framework under the hood. I'll see if I can get more pictures. Jim

 

I haven't used skrinking discs, but I have experience with using the following methods to "Shrink" sheetmetal: 1) shrinking hammer & shrinking dolly, 2) slapping files and 3) Torch with cold water rag. Bottom line: hoods take lots of time, experience and skill. I learned bodywork back in the late 70s from guys who did bodywork before Bondo and metal finishing hoods is a real art. There are U-tube videos that demonstrate "sheetmetal shrinking" that are helpful if you have some prior experience or a decent understanding of working sheetmetal, that you may want to review before trying it yourself. The most difficult part of a hood, is the metal wants to bend (oil can) with very little pressure. Even new undamaged hoods do this. When sanding try to support the underside that is "oil canning" with several layers of tape and shaped cardboard, don't apply pressure, let the sandpaper do the cutting and work a X pattern with a large semi-flex sanding board. Use all of the other painting prep tips mentioned here, such as different colors to help see the high and low spots. I also like the Lenco process that was mentioned here, the company sells a shrinking attachment. I'm sure a skilled person with time and patience could fix your hood, it just might cost (time) more than buying a decent replacement.

 

I was re-looking at your photo, and I think that the hood already shrunk due to the heat generated from the sand blaster. I would try a stretching first to raise the low spots. Is the hood damaged from other repair, it there bondo on it now? How does it fit the fenders? Looking at the fit when installed on the car will help determine if it needs to be stretched or need to be shrinked.