#31
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I believe since you're at the edge of the sheet, it will "allow" more shrinkage as there is not material on either side of the weld.
Clear as mud? |
#32
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your problem came from poor alignment of all the parts.
This is sometimes very hard to get everything shaped right to get it tacked together. you have to get both the back part of the roof and front part of roof aligned before the strip is cut. The front and back must sit aligned without the filler strip. use your straight edge or a strip of sheet metal laying flat to check in spots all along the gap from one side to the other. get them fitting just right then cut the filler strip and shape to lay over the gap. on inside mark it for cutting. Then cut and tack in carefully. Doing it this way everything should end up pretty straight except for the normal stretching of the weld area.
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The Rod Doctor, Richard Crees |
#33
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Pugsy is also correct, you will get more shrinkage right at the edge but it should also hammer / stretch back to shape very easily there too. When I looked at your first photos the entire filled area of the radius looked sunken so I’m with Richard, I have to wonder how well the filler strip flowed with your roof before you started the welding ? If you can’t get those radius areas to your satisfaction you could always cut them out just outside the welds, shape new patches & weld them in. Or you can just keep hammering and stretching, you do seem to be gaining on it . Have you tried the directional hammering / stretching I had suggested earlier ? ~ John Buchtenkirch P.S. I will just add that back in the days of hammer welding body men had to learn how to hammer out & level welds. With today’s technology & methods those skills have somewhat faded but here is an example of where they are needed. I’m happy the new technology has come along but the old ways still carry some weight with me. I guess I’m semi old school if that makes any sense. Last edited by John Buchtenkirch; 02-04-2010 at 10:57 AM. |
#34
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I think Richard is right. When i welded the filler there were no gaps, i tig weld and the backside is a rusty mess so the fit had to be perfect. When i cut the roof it lost all its shape, nothing held it together as Richard surmised. Guess i should have made a frame of some sort to hold the roof.
Either way, i'm having a ball moving metal around and developing my hammer and dolly skills. I don't work on it as much as i should, but i have the passenger door hung now and am working on the windshield header/A pillars then onto the drivers' side. Couldn't have gotten this far without your help and support, thanks oj |
#35
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I'll remember this when I chop my top. Always happy to learn from others troubles. |
#36
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As far as putting bracing in to hold things in place being a solution --- forget it. What you have to do is tack everything together and sight over your panels (from many different directions) and make sure your panels flow correctly. Lightly grind the tops off your tacks and then you can run your hand over the panels to also check for flow. You want to make corrections in your panels before you weld them in , not after welding. Finally, I have suggested you use and asked you if you have used a directional type hammer on that sunken area without response. If you don’t understand what kind of hammer I’m talking about I can post some photos. I wouldn’t hit the metal in the rain gutter area with a radial stretching hammer, you could easily lengthen it causing yourself more problems . ~ John Buchtenkirch |
#37
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#38
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All the hammer faces in the photos are directional stretching but some would be too aggressive for that roof job. Any hammer face that stretches in mostly one direction could be called directional. I personally wouldn’t use a doomed faced hammer that stretches radially on that roof, if you stretch the skin lengthwise in the rain gutter area you’re just creating more problems . ~ John Buchtenkirch
!1dir2.jpg> |
#39
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There is no such thing as a directional stretch hammer. Those in your pictures are not for that.
Randy and I have both already pr oven that on MetalMeet already. You will have to go there and do a search to find all the posts about that if you want. There was great discussion about this subject. No matter what shaped hammer face you use no matter if it is square, round, oval, egg shaped, hex shaped or what ever the same amount of stretch is had by hammering the same area with each. lets say you use one of the barrel shaped faces you show. make a row of hits along a weld area about 6 inches long. you would do the same thing as if you used a smaller barrel shaped hammer face going the other way in the same area. just like the English wheel tracking in one track over and over again like some here use to pre stretch for a bead roller bead. the whole area that you rolled will rise up from the surface. stretching equally both ways. With your theory it would only get longer. But that's not so. If you were to hit the sheet metal with out a dollie behing it with the barrel shaped face you showed you would leave a stretched dent the same as if you would have used a round face except that the ends of the barrel shaped hammer would leave sharp dents at only two sides of the dent. but the stretch would be from all directions. In order to raise a area inside the outer edges of sheet metal the metal has to be stretched in all directions. No matter how or what you hit it with. hammertracks.jpg
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The Rod Doctor, Richard Crees Last edited by TheRodDoc; 02-05-2010 at 11:35 AM. |
#40
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