#11
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Ok, I've restarted a new piece, and documented each step. I took the flange out of the original and tried to make due, but I was afraid that flanged area was too out of wack with my various shrinking/stretching.
I have stretched the corner with all my might using the big blocking hammer. Notice both the old and new curve upward towards that corner. I also developed that same hump in the middle, like the other, so I over blocked the sides to counter. IMG_20190329_101931583_HDR.jpg IMG_20190329_102443144.jpg IMG_20190329_103054036.jpg IMG_20190329_113819834.jpg
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Rob 1950 Cadillac 1956 Cadillac Looking to build my own car from scratch |
#12
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See the curvature? I can't quite figure how to fix that. Those lines were straight when I drew them, and I really tried to pay attention and evenly block.
IMG_20190329_114942198.jpg IMG_20190329_114921074.jpg IMG_20190329_114840412.jpg
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Rob 1950 Cadillac 1956 Cadillac Looking to build my own car from scratch |
#13
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I have yet to tip the edge on the new one, but as you can see it's curved just like the previous one. Boy I'm worn out! (New piece in front)
IMG_20190329_123202831.jpg
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Rob 1950 Cadillac 1956 Cadillac Looking to build my own car from scratch |
#14
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Quote:
Hi Rob, What you see is normal, as the metal flows into a new shape dragging the lines along with it. After you get your part to good shape and fit - then smooth it out. Trim the edge so it lays flat on the table. Then scribe off your flange setback, using the table top as takeoff. Then whang over the flange.
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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. |
#15
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Quote:
The only piece of critical information I have is that flat template which gives me the perimeter where the flange must lay. IMG_20190329_144542394.jpg The 2 inch depth is that maximum amount of room I have to work with where this piece will be. So I just drew a radius by hand and cut it out of cardboard. 15538855731304532683526205696462.jpg I'm continuing to make sure that radius gauge fits. As I slide towards the corner, it still fits fine, but the line curves up. I started with excess material, and as I stretched and stretched, I trimmed down to the edge of my flange line. I dont have any more material to trim away and "straighten" it now. Did I go wrong there? The hard part is, regardless of the shape and uniform radius I might achieve, that flange has to lay right on my template in the same path. For what it's worth, for experimentation I pie cut the corner of my previous piece, mig welded it, then trimmed as straight a line as I could, then tipped it. The mig area was too stiff to tip, even hammering it.
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Rob 1950 Cadillac 1956 Cadillac Looking to build my own car from scratch Last edited by RB86; 03-29-2019 at 02:01 PM. |
#16
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I'm trying a new method. I cut out my blank. Keep in mind that area of the flange on my blank has to remain in position against the template before I hammer anything right? And, when I start blocking the inside perimeter of the flange, that creates tucks, which shrinks that area, sortve throwing my "flange track" off course. So this time I took a planishing hammer and pre-stretched the flange, then blocked the inside perimeter, really focusing to lift the corner (the part that keeps dipping). Then I go back and restretch the flange, keeping it tipped from the very beginning.
A small bit of blocking, keeping the panel open, then back to re-stretch. So far is the closest I've gotten. I'll update more later.
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Rob 1950 Cadillac 1956 Cadillac Looking to build my own car from scratch |
#17
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Rob
unless I misunderstood ???? I would simply mark the corner out, then tuck shrink the corner(only) turn the two connecting sides down as you doing the tucks a bit at the time on a pipe with the right size radius ,that will leave the sides flat ready to turn the flanges outwards ,then fill in the center to suit on the wheel or by hand (if needed) . Only light blocking and blending would be needed to blend the corner with the rest of the 2 sides turned radius Peter. EXPLANATION on your problem 1. when blocking in that mater the two sides will shrink and become shorter there for changing the draw line (which must be re drawn back flat) 2. knowing the above factor ..more material must be allowed 3. blocking in that mater the center will cave in, meaning a lot of stretching in the center part of the panel, and possibly create fullness when not needed ( if that happens you need to stretch the edge and by lifting the panel on the top wheel let the center shape out to the now stretched edge (this exercise can be done a few times)
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P.Tommasini Metalshaping tools and dvds www.handbuilt.net.au Metalshaping clip on youtube http://www.youtube.com/watch?v=WEAh91hodPg Making Monaro Quarter panel: http://www.youtube.com/watch?v=KIpOhz0uGRM Last edited by Peter Tommasini; 03-29-2019 at 06:40 PM. |
#18
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Quote:
I find that I continue to get stumped on something needing stretching or shrinking. When I see that curved flange my mind argues - Maybe its too much material in a confined area and thats why its bulged up and therefore it needs shrinking. OR its drawn too tightly being pulled up like that, and it needs more material to relax back down. Its funny how simple it is and isnt at the same time for us amateurs. Thank you Peter
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Rob 1950 Cadillac 1956 Cadillac Looking to build my own car from scratch |
#19
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I'm estimating that much as 2/3 of each side of the part can be gotten with no blocking. Choosing the hammer to round up the edges where blocking is not needed is the main problem I see. That's where the stretching that's working against you is coming from.
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#20
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I think your main problem is you are drawing your lines, banging the hell out of it and then expecting to still adhere to your lines. Forget the lines. Form the panel including the smoothing, THEN draw your line at the tipping point based on the formed (upper?) portion of the piece. This may mean placing the dished portion on the table and mark the piece one or two inches above the table. then tip the edge at the line and it will be flat.
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Norm Henderson |
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