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Help with roof insert
Looking for some advice from the experts here. I have a 36 Ford 5W Coupe that already has a roof insert welded in. The problem is that the middle has more crown than I think it should have. Also, around the welded perimeter the shape appears to run lower than perimeter of stock roof before rising up to crowned area. I'm wondering what you guys think happened and what would be the best way to rework it? Specific methodologies would be greatly appreciated.
Below i've attached a pic, but it's kind of hard to show it. 36 Insert front view (2).jpg
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Thanks! Bruce Last edited by 69rrbruce; 09-17-2021 at 11:28 AM. |
#2
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Can't see how it was welded, but welding does shrink, no matter which method, and welding will bring those edge areas down flatter, as we think we are seeing in this picture. Straight edge application to the surface, both across the weld and along the weld can better illustrate so the camera can then show contours clearly. And so we stretch the weld areas back up, using hammer/dolly or handheld planisher, to recover the shrinkage. But this operation itself may not fully resolve your further issue of the center crown being too proud. This involves shrinking, and the methods you have available to you may not be fully feasible to do this to satisfaction.
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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. Last edited by crystallographic; 09-17-2021 at 11:50 AM. |
#3
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A C hammer in the frame would solve it in a moment. If it is necessary to reduce, the shape by heat and cool ?? It takes experience.
DSC07299.JPG
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Jaroslav |
#4
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Hammering the welds out with a handheld planishing hammer: (gas welded, Rattle A roof filler panel, metal finished, primer -> paint.) gas weld, steel, 20ga,.jpg gas weld, steel, 20 ga, hammered.jpg steel roof panel, ready to weld.jpg steel weld, hammered, hammer on right.jpg Handheld hammer, working out the roof weld.jpg roof panel, welded, hammered, filed.jpg roof panel welded, metal finsihed, front view.jpg roof metal done, L side.jpg roof metal finished, rear view.jpg Ram's Head die set, partial.jpg (3 piece steel panel simulates orig roof, w/eyebrow/rain-rail details spot welded and soldered) Got a lot of scrutineers at the meets.
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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. |
#5
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If the insert was correct before welding, you know it is only the welding that changed it as it shrank when cooling. Press up harder with your dolly than you are hammering down directly on it from above and it will stretch and lift it back.
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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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The only thing I might humbly add is this:
Your situation being what it is, fairly wavy... If a guy was to make half a dozen vertial cardboard templates as-is, that fit across the roof from drip rail to center with one pair over each: near front, near rear, then a center pair over the B pillar-ish... ...and he trimmed those until fully closely fitted, and marked a level line on each... then he was to lay halves over one another and average the contours (correcting where obvious), why then he'd have himself an initial target crown to shoot for. A handy quick-check go or no-go gauge for while he planishes each section. Revisions may be required as he sneaks up on it, but initial side to side radius comparison of halves would likely give a rough idea of where the bigger problems are. Planishing is most of the answer, and flexible yardstick in good hands can help guide each side of the filler individually and thats a good way once it's ironed out a little but right now you have a bit rougher of a sketch than that and it is murder trying to restore order without some sort of guide. Because my eyeballs can't always pick out whats wrong and the potential for going off course majorly is so high. I say this as input learned from a ribbed insert job on a chopped Model A. Roof sides were total chaos as was the rear panel that a tree fell on, etc. When something is all out of whack like that, I need a guide even if it is crude. Fortunately in my case the original wood supports were something I could start from.
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Matt |
#7
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You were wise to add a photo, I’ve never been help to anyone from a description of a problem. It’s even hard for me to comment without running my hand over the panel to feel what’s going on.
I would get some sheet steel strips sheared (16 or 18 gauge, 1” to 1 ½” wide) and lay them on the roof after you’ve crowned them a bit. With a bit of tweaking you should be able get the crowned strip to lay on the roof where it flows and looks correct to your eyes. You might have to move the car outside to get a more distant perspective. When that strip looks like it flows correctly with the roof skin it will show you right away where your low spots are. Some lows may be able to be bumped up with an appropriate dolly with some weight to it. Where you’ve welded will likely need on dolly hammering to stretch out the shrinkage and correct the panel flow. Progress should be constantly checked with the steel strips. I’ve had problems trusting wood roof ribs as a guide, they just weren’t accurate to be a guide for a flowing steel roof IMO. Good luck, this job may take some time . ~ John Buchtenkirch
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John Last edited by John Buchtenkirch; 09-19-2021 at 09:16 PM. |
#8
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Thank you all for your responses.
It looks like I need to create some metal strips to establish the desired crown and to see where in fact the metal is either too low or too high. I'm going to start by plannishing the welded area in hopes that it will raise the adjacent area. Then I'll deal with the crowned area. What are your opinions as to whether or not welding this roof insert caused the middle area to crown, or do you think the roof insert was over developed before welding? Looking at this another way, if prior to welding in place, a sheet metal panel is over developed, what would be the process to reduce it's crown? Does this process change once the panel is welded in place?
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Thanks! Bruce |
#9
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I'd suggest that you: 1) Make the metal "contour check strips" and check the contours. 2) Planish the weld areas ... best to pick a real flat area and see how much your hammer and dolly can bring it up - counting the swats needed as you go. (technique, technique, technique) 3) Check contours with strips as you go. 4) As you bring up the welded flat areas you will notice that the crown likely does not change - but that its crown might appear to be lessened, somewhat. 5) Establish how high the crown is, after planishing the welds, by measuring 1/16's. Then it will be time to figure our how to reduce the "over developed" crown.
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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. Last edited by crystallographic; 10-01-2021 at 03:35 PM. |
#10
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Thanks Kent
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Thanks! Bruce |
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