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Hammer form/tear
Hi guys
I have an issue with the sheet metal tearing in the corner, I guess the material is beyond the point of stretching so it tears. Any ideas how to prevent this? The first picture shows the corner had torn so I had to form a little patch which is fine, I can weld and file but if this extra work can be prevented even better. In the pictures, I have one part formed with the small patch, another in process and the bondo (bog) form. Recently made shrinking dies which did make life a little easier. 94390389_1600871146738034_8595470276563566592_n[1].jpg 94608285_239976230714879_9008915613866786816_n[1].jpg 94143901_3211475498877331_2535016820541227008_n[1].jpg 93857564_160218562002197_3905864446056071168_n[1].jpg Thanks Bart
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Bart Risuccia Last edited by Steve Hamilton; 04-22-2020 at 07:22 AM. |
#2
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rips
The obvious first step is to anneal the metal (looks like steel) This will prevent tearing but you may then have real thin material. I am not very good at it, but I have seen Peter Tommasini do it like magic. You have to "move" metal from the surrounding area so the stretch is spread out. I sometimes use stakes or other objects as a rouging form, just concentrating on moving metal into the stretch area. Check out Peters videos for a better explanation..
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Bill Funk |
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Very good points. thank you.
Where are Peters videos? Where can I buy them? Quote:
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Bart Risuccia |
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There's more info on Peter's DVDs at http://www.handbuilt.net.au/dvds.html and you can always message him on here. |
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thanks mate
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Bart Risuccia |
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Heat
Another trick I've used (just yesterday) that I picked up from Kent White, is to simply add a bit of heat. It doesn't have to be red hot, but just a little heat to get it moving. Because I don't have the skill Kent does, sometimes I use a propane torch to not get carried away.
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John Ron Covell, Autofuturist books (Tim Barton/Bill Longyard) and Kent White metalshaping DVD's available, shipped from the US. Contact lane@mountainhouseestate.com for price and availability. |
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Why does dust stick to everything, but nothing sticks to dust? |
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thanks guys
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Bart Risuccia |
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Hi Bart, When you "flare" out a flange from an outside corner, you are thinning the metal a lot - meaning reducing the thickness by one-half, and sometimes more. !! If you have to ask more than a half-inch of flange width to do this .... URK! "Warning Will Robinson - DANGER." In production - squares of added (welded) metal are seen when flanges of any significant width are needed 90deg around an outside flanged corner. For the craftsman shaping his way out of the corner, over 90deg, and then fanning around that spread, you have to "borrow" metal from the surrounding area. This means using a cross pein hammer and going at the surface to stretch it out first. Make it nice and wavy as you practice your targeting whacks. Then work the flange over, but not with heavy blows - use tentative blows to see if you have generated enough "pre-stretch." Then you can always knock the flange back vertical and whack some more. (I just use a little heat to soften the metal so my cross pein can borrow as I drive the flange over the form - but this I learned from carefully examining the work on the coachbuilt cars I restored as a young pup metalboy at HAC. Since we restored 12-14 cars per year I saw a load of metalwork under my own hands for the 5+ years I worked there. And I learned to highlight the back side and illuminate it to show me all of the tracks of the guys making the panelwork originally - no matter England, Italy, Germany, or US of A.) - end-
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Kent http://www.tinmantech.com "All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919. |
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Quote:
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Marcus aka. Gojeep Victoria, Australia http://willyshotrod.com Invention is a combination of brains and materials. The more brains you use, the less materials you need. |
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