Bumping Metal

Machspeed

Machspeed

Member
So I have a roof with oil canning that I posted here last week sometime. Great advice given on that thread and many thanks to those whom commented. Thought before I go jacking around with that roof though, I’d work out a ding in the driver’s side fender and am glad I did. My effort in addressing the issue in this fender is proof that I need a serious education in bumping metal before I address the roof in my project. I had actually worked on this fender and used some filler but was not happy with it and thus stripped it down to work the metal. I spent about three hours on this fender and literally got nowhere. Just seemed to move the bump around and induced some oil canning, which I have since removed. Frustrated, I did some YouTubing and came across the below video which does a great job filling in the blanks. In fact, his video is the best I've seen on the subject.


Regardless, bumping metal is not initially intuitive and can be incredibly challenging. I really respect the skills of people who can work metal and never need filler. Having said all that, I fear I may have stretched the metal excessively. Is it possible to overstretch and damage the panel such that it can no longer be addressed with metal work alone? Comments on how to best address this fender appreciated.

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If you don't have one, you can make your own shrinking disc from a phenolic backing plate that comes with the little 5" air grinders or use the backside of an old grinding disc. Run it over the high, get it hot, let it cool naturally.
 
Chris_Hamilton said:
If you don't have one, you can make your own shrinking disc from a phenolic backing plate that comes with the little 5" air grinders or use the backside of an old grinding disc. Run it over the high, get it hot, let it cool naturally.
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I’ve used this method, with varying results. The trick is to keep a light touch and have patience. Any metal work requires patience.
 
Big Dave said:
I’ve used this method, with varying results. The trick is to keep a light touch and have patience. Any metal work requires patience.
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Yeah I'm not a huge fan of the shrinking disc. Maybe I haven't done it enough to get the "touch" of it but in this case seeing it was brought up I figured this would be a good way for him to try it and not spend any money. And it's safer than other methods in that the shrink won't be too drastic. And the phenolic won't mar the metal like a regular shrinking disc does. I still prefer my small Smiths AW1 torch and small welding tip but if someone has never done this it's easy to shrink to much with a torch.
 
Well, I have a shrinking disc and I used it but aside from it helping to remove the oil canning I induced by bumping on it incorrectly, I really didn't get anywhere. I have like a little volcano formation here. You can see the elevated part with a central low just to the left. Off to the right just slightly is a geographical low.
 
From what I think I’m seeing in this picture, you probably need some shrinks to get that to calm down. A torch works well here. But, if you have a stud gun with a shrinking tip, it’s so much easier. But it’s also easy to overheat the metal real quick with a stud gun. An extra moment on the trigger can lead to extra hammer and dolly work. A torch, on the other hand, gives you a lot of control. A small one like Chris talks about is very versatile. I use a Victor J28. Practice on some junk parts to get the feel of how it works before moving on to your good parts.
 
Big Dave said:
if you have a stud gun with a shrinking tip, it’s so much easier. But it’s also easy to overheat the metal real quick with a stud gun. An extra moment on the trigger can lead to extra hammer and dolly work.
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A stud gun is one tool that going cheap is a better option when using it for shrinking, cheaper means less power, which is great for shrinking. With my cheapo gun, I can shrink the smallist of spots, and it hardly heats the spot at all, its amazing that the spot shrinks--just a light flick on the trigger. A torch doesn't compare at all, and the stud gun is totally acturate.
 
Thank you, Robert! I see you just posted that up today. Funny, I was in Lowes last night and purchased a PVC cap for my donunt dolly. Gonna go after it this weekend. Will post on resulting frustration and results. I'll leave out the colorful metaphors I used in my initial attempts!
 
Machspeed said:
Thank you, Robert! I see you just posted that up today. Funny, I was in Lowes last night and purchased a PVC cap for my donunt dolly. Gonna go after it this weekend. Will post on resulting frustration and results. I'll leave out the colorful metaphors I used in my initial attempts!
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I saw your post here this morning and thought it would help add to the possibilities.
 
Machspeed said:
Thank you, Robert! I see you just posted that up today. Funny, I was in Lowes last night and purchased a PVC cap for my donunt dolly. Gonna go after it this weekend. Will post on resulting frustration and results. I'll leave out the colorful metaphors I used in my initial attempts!
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If you are like me once you start using it and seeing the metal do what you think it should do it will be a game changer.. I could never get my mind around other techniques for shrinking. This one just seems to make sense as you start using it. Note for oil canning and such the way Robert was hitting that was WAY WAY to hard. No exaggeration, just a few light smacks in the right spot will cause a noticeable change once you get to that point.
 
chevman said:
A stud gun is one tool that going cheap is a better option when using it for shrinking, cheaper means less power, which is great for shrinking. With my cheapo gun, I can shrink the smallist of spots, and it hardly heats the spot at all, it’s amazing that the spot shrinks--just a light flick on the trigger. A torch doesn't compare at all, and the stud gun is totally acturate.
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True! Get a cheapo.
Accurate way for sure.
 
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Yesterday was a good day! It's a wonderful feeling to overcome a challenging obstacle and at the end of the day to say, "I can do this!". My weapons of mass destruction are pictured and I used all of them to remove the imperfections in the fender. The Hammer/Dolly and the Donut Dolly were my main tools. Using them correctly, I was elated to see the metal move as I was told it would. No oil canning, no lumpy bumpy, almost perfection! Now, to that oil canning roof!

Friends, thanks so much for sharing both your precious time and knowledge. I can't say thank you enough!
 

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Machspeed said:
Yesterday was a good day! It's a wonderful feeling to overcome a challenging obstacle and at the end of the day to say, "I can do this!". My weapons of mass destruction are pictured and I used all of them to remove the imperfections in the fender. The Hammer/Dolly and the Donut Dolly were my main tools. Using them correctly, I was elated to see the metal move as I was told it would. No oil canning, no lumpy bumpy, almost perfection! Now, to that oil canning roof!

Friends, thanks so much for sharing both your precious time and knowledge. I can't say thank you enough!
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That was my experience too. The donut dolly seems to make the metal do what you want.
 
Well done Machspeed, It's amazing what can be accomplished when one applies themselves. Sometimes it takes many tries to learn a technic/procedure. I look at it as, not everyone will be able to learn how too do bodywork but, those that apply themselves have the best chance of getting the results they want.

Your're hooked now, hell I bet you go out to the garage, grab a hammer and start whacking the car just so you can use your newly acquired talent again.

Enjoy the experience :)
 
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