I spent a lot of time working with wood but never did much with sheet metal. Now I would like to have a recessed license plate on the back of my roadster. I decided that I should first try to make one on a scrap of sheet metal that I had already. It is .050 thick. I hoped to fold over a 1" flange and I made pieces of wood that I clamped on either side of the metal to help hold the metal around the opening flat while I hammered the flange.
The particle board pieces that I started with didn't work so I began again using solid wood pieces. In hammering, I got the metal to fold, but also got some splitting. Maybe a one inch flange is more that this metal can do or maybe I need to heat the areas to help the stretching. I used a piece of 1" pipe against the metal and hit the pipe with a heavy hammer. Maybe someone can tell me the correct way to do it. Thanks for any suggestions. HFH.
Yes, asking the 1" flange to stretch all that way in the corners without some splitting is probably unreasonable. Maybe could be done with some heat, but cold it'd say it's too much. A 1" flange seems a bit too deep for me anyway. I think I'd prefer a 1/2". When you build your real buck for the real tail panel, make sure to grind a slight arch into the face of the inside and outside bucks. Your real panel has a slight curve and you want that in the opening's flanges too. Make the outside buck opening a half inch bigger all the way around. That way you can get your hammer right in there on the bend to tune it up. Also use a few bolts through the buck, sandwiching the panel. It will keep everything together and won't allow slippage. Easy to weld up a few 1/4" holes later. If your tail panel is original Ford, it's 19 ga.
I know you're having fun doing it yourself, so there's that. But plate recesses are available pre-made for cheap, ready to weld right in.
If he does it this way he might only have a couple inches of weld, verses welding in a ready-made recess with three feet of weld.
Thank you all for your suggestions. I think I will try another one with 20 gauge, only a 1/2" flange. I did make some saw cuts part way through the maple that I used, thinking that it would then conform to the body shape. But I could shape both wood pieces to fit the body if this is better. I also was hoping that clamping the wood pieces to the metal would be enough. If drilling holes is better, I will do that. Thank you again. HFH.
Yes, thank you for that idea. Maybe using a shorter flange (so that I still have some fun) and combining it with a ready made pan is the best way for me to go. My welding skills are limited but it will be fun to work on those skills too.
I recessed the plate in the roadster. It was pretty simple. Sorry, but no pics. I cut the hole in the rear panel. Then cut a flat piece of Sheetmetal for the plate to sit on. Cut 2 strips of 18ga that were 1-1/2" wide and made the soft 90* bends (2 on each strip) over a piece of pipe. Stood the strips up on the flat piece of Sheetmetal and tacked them to it along with tacking the 2 strips together. Finish welded using a low setting and .023 wire. Then I tacked the newly formed piece to the inside of the rear panel and finsh welded using the same procedure. License plate lights are required so I ran to Pick-N-Pull and found one that'd fit my 1-1/2" wide strip. I think it came from an '80s Buick. Yeah, I know the plates are different! On edit: It looks like your metal is way thicker than 18 ga. My metal came from the side of an old washing machine which is roughly 18ga. Also, don't hit the pipe with a hammer, hit the Sheetmetal forming it over the pipe.
He's either going to hammer the parent steel, or a whole lot of weld after he attaches a doner recess panel. Personally I'd rather try his method first and do plan B if the first one fails.
Worth doing just for the experience of hammer forming Sent from my moto g(6) play using The H.A.M.B. mobile app
Might consider trying it the other way. Instead of starting with the flat panel and trying to form the recess, cut a strip to be the recess and hammer the outer flange over. Still stretching in the corners, but maybe less. Or you could notch the corners and weld in small pieces.
If I was going to do this, and it is in the someday plans, here is how I would go about it. I would make a couple of bucks like you did only a little thicker. When I cut the hole in the bucks I would use a thin bladed small diameter circular saw to start the straight cuts and a saber saw to do the curves and ends. Save the cut out pieces for the bucks to make the pan for the license plate recess. (Witness mark both the forming bucks.) Contour the bucs to fit the curvature of the panel. As suggested by alchemy, open up the clamping buck a little larger than the forming buck. Then I would cut the hole in the panel 1/4" to 3/8" smaller than the hole in the forming buck, clamp the bucks in place and bend a lip inwards. To bend the metal over the bucks I would make some hardwood "drivers", maybe an inch wide, and chamfer the ends so they won't split. I'd make one with a square end to start driving the flange over and one with an angle across the driving end so I could get a good, free hammer swing as the flange folded toward 90*. For the corners I would round the driving end to match the radius of the corner. Using wood drivers instead of a hammer will give better control and a smoother finish. Take the cut outs and trim the clamping buck smaller than the forming buck. I would also put a small radius on the forming buck. To keep everything lined up I would drill two small guide pin holes, where the license bracket is going to be, through both bucks and my sheet metal. (Use the witness marks to keep the two forming bucks oriented.) The sheet metal gets cut large enough to form the desired flange depth. As the sheet metal is being driven over the buck to make the pan, it may be necessary to remove it from the buck occasionally and use the pipe or whatever else fits the corner radius as a stake (dolly) to gradually shrink the corners. The stake needs to be put in a vice and the metal held against it. Also the whatever is being used needs to be as smooth as possible .(It may be necessary to cut a V out of the corners and weld it shut, depending how deep the plate is being Frenched or how tight the corner radius is.) Next I would orient my pan to the flange on the rear panel. (Using the cut out as a buck should mean that the flanges line up well.) Trim them to a tight fit and start tacking. Having a flange on both pieces should help control warpage, but a wet rag can also be laid on the rear panel to control how far the heat travels. I would weld on the back side with alternating short tacks and plenty of cool down time between, making sure the edges stay lined up. After that, it is a skim coat of Bondo. As far as welding skills, that's what scraps are for.
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