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  #11  
Old 12-31-2009, 11:54 AM
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Steve Hamilton Steve Hamilton is offline
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OJ questions like this are hard to answer just from looking at pictures. Some times an area that is higher than you want, is not excess metal just metal formed to the wrong contour in that area, commonly referred to as "out of arrangement". since you re bent the roof this could now be an out of arrangement problem. Think of an aluminum beverage can, on it's side so the radius looks like the side of your roof. if you gently squeeze the sides of the can, the top raises up. you did not stretch the metal you only changed its arrangement.
So if the side of the roof is in and the top is up too much, You may be able to pull out the side while hitting with a slapper on the top, to correct the arrangement.

The weld zones need to be stretched back to the correct shape first as they will create stress that will lock or hold the panel out of arrangement.

I like to use a hand held shot bag when working on arrangement it offers support and back up, but you can't create an on dollie stretch by accident.

Another tip to help decide what you need to do to correct a panel is to use the long rule you showed in photo #1 and lay it flat across the roof from front to back. holding it closer to the ends and pressing until it contacts the metal, let the rule show you where the high and low areas are and how smooth the flow of the panel is.

Slide the rule across the roof and around the radius to the door opening observing where the high and low areas are. I even use a marker to circle areas that need to be corrected.

Hope this helps

Happy New Year

Steve
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  #12  
Old 12-31-2009, 07:06 PM
Dyce Dyce is offline
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Do you have a porta-power? If I was working on this I would have a jack pushing up on the low spots. You push up on the spots you need to bring up, then you see how it effects the rest of the panel. If it's an arrangment issue Steve is explaining, it might start poping into shape. If it needs shrink or stretch it may lift or drop in another area. If you have the good luck in the first senario great.... If not you need to study the panel and how it reacts to the pressure.

The shrinking disc is a great tool for shrinking big or small areas. I like the torch for panels that have been stretched from some impact or trama..... Shrinking large areas you need to pick a center and work out. You need to pull the metal into the center, stretching most in the center, and working your way out blending. Like you do deep shrinking with thumbnail dies.

Jeff

Edit: Shrinking in the center of a panel works better if you shrink from the outside in.... You still need to shrink more in the center. It all depends on the damage and the amount of shrink you need.....

Last edited by Dyce; 12-31-2009 at 11:06 PM.
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  #13  
Old 12-31-2009, 08:37 PM
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Gleeser Gleeser is offline
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I'll add to the port-a-power comment by mentioning we did a roof like this with a port-a-power inside. Took a section of leaf spring from a semi, about 12" long and approx. 6" wide, very low contour then polished it with a DA and mounted that on top of the port-a-power and used the spring as a very large low-crown dolly. This worked very well for doing a roof as it is pretty hard to reach the center if you have to hold a dolly top & bottom.

This is more for when you get to the point of actually dollying out the roof.

I agree with everything Steve said above as well.
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  #14  
Old 12-31-2009, 11:09 PM
Dyce Dyce is offline
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Quote:
Originally Posted by Gleeser View Post
I'll add to the port-a-power comment by mentioning we did a roof like this with a port-a-power inside. Took a section of leaf spring from a semi, about 12" long and approx. 6" wide, very low contour then polished it with a DA and mounted that on top of the port-a-power and used the spring as a very large low-crown dolly. This worked very well for doing a roof as it is pretty hard to reach the center if you have to hold a dolly top & bottom.

This is more for when you get to the point of actually dollying out the roof.

I agree with everything Steve said above as well.
That's a good tip Grant. Nice thing about the springs is you can tweek them in a press to any radius you need. I'll remember that, thanks and happy new year!!!!!!!
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  #15  
Old 01-01-2010, 09:00 AM
ojh ojh is offline
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Great idea! I don't have a porta-power but i have a floor jack that i can take the saddle off and stick tubing into that hole and make whatever kind of attachment/tool holder for the business end. Theres no floor in the truck cab and i can bolt it to the frame jig so i can put tension on it. If i get something that works good i'll post a pic. I'm on it, thanks oj
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  #16  
Old 01-01-2010, 09:31 AM
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Kerry Pinkerton Kerry Pinkerton is offline
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I have this image that will probably NEVER leave my head. We were up at Dutch Comstock's meet one year and we chopped the top on a 56 Ford Panel. Obviously some areas couldn't be reached from the door openings.

Bill Firth volunteered to get INSIDE the panel and hold the dolly while others worked slappers and hammers on the outside. At the same time, others were working on other parts of the cab.

Bill wore hearing protection but still expression on his face after a few minutes was priceless.
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  #17  
Old 01-01-2010, 10:15 AM
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From what I remember of the picture (can't see it anymore) I would be hesitant to use a porta power or jack on that to begin with. It looked to me like the metal needs more than a push from below, or simple on dolly stretching if you want to get it done in a timely manner.

Stretching into a shot dolly, bumping, and smoothing will gradually raise the low without the risk of pulling other parts of the roof out of whack. Or did I miss something in the picture?

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  #18  
Old 01-02-2010, 10:19 AM
John Buchtenkirch John Buchtenkirch is offline
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It’s really hard to tell from the photos but what I see is 2 sunken welds with proud beads. I think you really need to stretch those welds (& maybe the filler strip) crosswise to the roof with a directional hit. You need a hammer with barrel type face that that is turned at a right angle to the handle for hitting the inside while using a flat dolly on top. Hammering up is very tiring so you might consider turning the body up-side-down on a mattress with the problem area over hanging the edge of the mattress. If those are mig welds it’s going to take a lot to flatten them and stretch them up to true surface, you might even decide on replacing that part of that strip . Putting a strip in a roof like that and maintaining a correct loft line is probably a good few steps above a novice job --- I wish you perseverance and good luck with your efforts . ~ John Buchtenkirch
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  #19  
Old 01-02-2010, 06:27 PM
louieb63 louieb63 is offline
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The photo in post #1 shows the top edge of the door jamb pulled in toward the centerline of the body. The metal areas along the welds across the roof look to be flat to 1 to 1 1/2 inches out from the welds.

In post #7 he says the joints were a tight fit prior to welding. For discussion I will asume the panels were in arrangement.

Welding Always shrinks the panel edges to a shorter dimension than before welding. The shrink occurs both across the weld ( causing the flat) and along or in line with the weld (causing the pullin on the door jambs). You have a 1 to 2" wide HAZ across the weld and a 4-5 foot HAZ in line with the weld. A 4 foot haz shrinks a bunch. I know it was done by skipping around but it is still a 4 foof HAZ. Could have shrunk an inch or two acroos the roof!

Careful work with hammer and dolly will stretch the material back to the fitted size. Remember, stretch both perpendicular and in line with the welds. Start by working on the butt joints in the added strip.

Before any dolly work,get rid of the excess (not all proud) filler on the bead. Let the metal move freely in response to your stretching and planishing. The use of jacks or pushing will only add confusion.

Best of luck.

Louie
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  #20  
Old 01-03-2010, 03:06 PM
John Buchtenkirch John Buchtenkirch is offline
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[QUOTE=louieb63;6884]The photo in post #1 shows the top edge of the door jamb pulled in toward the centerline of the body. The metal areas along the welds across the roof look to be flat to 1 to 1 1/2 inches out from the welds.

In post #7 he says the joints were a tight fit prior to welding. For discussion I will asume the panels were in arrangement.

Welding Always shrinks the panel edges to a shorter dimension than before welding. The shrink occurs both across the weld ( causing the flat) and along or in line with the weld (causing the pullin on the door jambs). You have a 1 to 2" wide HAZ across the weld and a 4-5 foot HAZ in line with the weld. A 4 foot haz shrinks a bunch. I know it was done by skipping around but it is still a 4 foof HAZ. Could have shrunk an inch or two acroos the roof!

Careful work with hammer and dolly will stretch the material back to the fitted size. Remember, stretch both perpendicular and in line with the welds. Start by working on the butt joints in the added strip.

Before any dolly work,get rid of the excess (not all proud) filler on the bead. Let the metal move freely in response to your stretching and planishing. The use of jacks or pushing will only add confusion.

Best of luck ~ Louie

I really would be very hesitant to recommend radial stretching on that roof. If you look at the second & third photos in post #4 you will see that the lower edge the roof skin actually looks pretty straight, any radial stretching in that lower / rain gutter area will make it longer and make the hollow area in the radius above the gutter area worse than it is now. That is why I recommended directional stretching (crosswise to the roof) to raise up those welds.


Looking at a 2 dimensional photo to give advice on a 3 dimensional object is tuff at best if not impossible at times . For example there seems to be a dent in the in the front corner of the roof in the first photo but I can’t see it at all in the second or third photos ???


I do agree with you 110% that trying to push out that low spot will be a disaster, it’s an area problem, not arrangement, the metal needs to be stretched so it will raise. Also the fact that there’s no firewall or floor in the cab makes it impossible to push anyway and it would just rack the cab if you could do it. ~ John Buchtenkirch
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