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Full Time Metal Junkie
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It's really not a trick question, :) How much do we really understand metal.
It's something we use to repair holes, we pull dents from it, we weld on it, we sand it, prime it, but do we understand it :mooooh:

So many cars , planes , trucks, boats, they all have different shapes bends and contours. In fact there's thousands of them, but there are only two things that make any shape you want or need, that is Stretch or Shrink.....
These two processes will make or repair any shape in any car, boat or well you get the idea.
Let me give you an example.........Here is a flat piece of the metal



Even a mild tap from a ball peen hammer will change the entire panel.



Notice the lines drawn, very similar pattern change happen to the panel after being hit with the ball peen, much like ripples in water.



Now were not going to notice the change from one tap but place many taps in a predetermined area and there will be a significant amount of change....
Watch this next panel change and keep in mind this can be applied to any shape and by hand with common tools and get great results.



After about five taps , lets see the changes.



Now repeat those taps threw out the area between the lines.



Now looking at the panel below it appears to just have a two dimensional roll which would be much like a barrel or a tube.



Three dimensional is basically a compound curves, much like a basket ball cut in half.



Notice that each corner is touching the bench and the rest of the panel has air space beneath it.



So lets look back at this photo and this starts to make sense, the ball peen hits the metal thinning the area it hits and sends a (three) dimensional wave threw the whole panel. This is why the panel shapes in a compound, not just a roll, The shape of the ball peen is not able to send the change in just a two dimensional form.
Lets look a little deeper in to what happened after the change went threw the panel. We now understand that the metal directly under the ball peen is thinner, so if its thinner , the surrounding metal had to get thicker.
This explains why the area thats thinner raises, like the panel below.



It raises because it seeks the path of least resistance, wich confirms the outer area is thicker.
Now thinning is also or mostly refered to as stretching this is one part of shaping . in the next thread we will look at shrinking, so we will use terms like thikening and gathering.........:)
 

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Full Time Metal Junkie
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Shrinking

This part of the thread we will look at shrinking, or gathering, or thickening.
To be able to gather is a little more tricky or difficult but not impossible. If you don't have a shrinker or an elaborate piece of equipment with dies just for the purpose of gathering there are few ways to accomplish this with more obtainable tooling.
first lets look at how we gather metal to thicken.
This is a set of tines that is used to tuck shrink.




A tuck looks quite like a half an ice cream cone pulling metal around from the surrounding area. Now this is only part of what needs to be done to shrink.
To keep the metal on the outside area to gather you need to drive the metal into it self.




Now this has to be done quite a few times until you have gathered enough metal to get the desired shape.
This is one way, the next way nets quicker results and with practice is very efficient, and the tooling is very obtainable and cheap.





OK the next technique is quick, and with very little effort you can be shrinking while stretching at the same time.
Now in the next photo I took a few blows of my hammer inward of the edge, and in the center of the panel and it cause a ruffle on the edge of the panel which is the same shape as a tuck.



Now the ruffle (same as tuck) gets driven into it self by trapping the ruffle in the bowl of the stump. As I hammer the ruffle I move the ruffle up towards the edge of the bowl causing it to drive the metal into it self.



Now lets fast forward, which in real time took less than 30 seconds to accomplish.





Now this three dimensional shape was made from a bowl shape in a stump and a hammer made from UHMW (ultra high molecular weight) plastic. I dose not get simpler than that....:)
 

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Thanks Steve, very informative.

I watched a fabricator do this at a metal workshop and he made it look easy, as you do! I have tried it and it is amazing what practice can do...probably still need filler........but a lot less than before!!!

Keep up the posts, Cheers
 

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Full Time Metal Junkie
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Discussion Starter · #5 ·
Hi Digger
Even less filler is a great thing. Not many customers can afford to have a shop spend the time to build a totaly filler free body. But to keep it to an absolute minimum in most cases is a bit more realistic.
I have customers that tell me they want a filler free car and I show the a hi end job and explain what extra time it takes they realize not ever one is willing to spend the extra.
But working towards that for your own satisfaction is well worth the extra time spent.

Craig as allways thank you and more is on the way :tup:
 

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great thread but i think metal does not undersand me .:D
 
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