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Old 12-24-2011, 02:59 PM
BrassBuilder BrassBuilder is offline
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Default Tuck Shrinking Questions HELP!!! Arrgh!

Decided I needed to learn the finer points of tuck shrinking. I've read more forum postings and watched more YouTube videos than I can count now, but the metal evidently does not like my technique at all.

What I am trying to make is a copper grille shell for a model truck.

Let me see if I can explain all the pics.

1. The wood pattern. It is approximately 5" x 6" with a 1/4" radius rounded edge.
Pattern.jpg

2. This is the second shell that I attempted. As you can see, I am getting close. I think the issue is I am not getting enough shrinking.
Corner1.jpg

3. A view with the second shell and the first shell that I mostly finished. On the first shell, I cut the corners to get them to lay flatter. I would prefer not to do that. I should be able to shrink it enough without cutting them.
Corner2.jpg

4. Another view of the 1st and 2nd shells.
Corner3.jpg

5. A practice piece.
Corner4.jpg

6. The start of my technique. I lay the copper over the pattern and lightly bend it around the wood buck.
tuck1.jpg

7. The first three tucks. I changed my techniqe a little after reading KenB how-to. (Note: Bummer that he passed away. Always got a lot out of his postings.)
tuck2.jpg

8. Closeup of the tucks.
tuck3.jpg

9. My collection of hammers. I usually use the hammer on the left.
hammers.jpg

I anneal the copper at the point I left off. I've been starting at the outside edge of the tuck and working in. I have not tried starting on the inside working out.

I'd like some suggestions on my tucks first before I proceed. Let's take this a step at a time and see where I am messing up.

Thanks

Mike

edit: Thought my pics would show up automatically in the thread. I see that it doesn't. I'll see if I can get them in the thread later so you all don't have to open attachments.
Mike
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Last edited by BrassBuilder; 12-24-2011 at 03:05 PM.
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Old 12-24-2011, 03:03 PM
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Kerry Pinkerton Kerry Pinkerton is offline
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Mike, thin copper is a bit soft to tuck shrink imo. I've never actually tried it but I'd think it would just fold over and that's what I see in your photos.

If you do want to continue, I'd go VERY slow and make sure that you don't let it lay over and get mashed flat. Once that happens you're pretty much screwed.

I edited your post to get the photos to show up. You have to actually insert your photos into your post. Click on the paperclip and select INSERT ALL when your cursor is where you want them to be. Or you can do them one at a time.

Some good tutorials on posting photos in the getting started forum.
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Old 12-24-2011, 03:07 PM
BrassBuilder BrassBuilder is offline
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Quote:
Originally Posted by Kerry Pinkerton View Post
Mike, thin copper is a bit soft to tuck shrink imo. I've never actually tried it but I'd think it would just fold over and that's what I see in your photos.

If you do want to continue, I'd go VERY slow and make sure that you don't let it lay over and get mashed flat. Once that happens you're pretty much screwed.

I edited your post to get the photos to show up. You have to actually insert your photos into your post. Click on the paperclip and select INSERT ALL when your cursor is where you want them to be. Or you can do them one at a time.

Some good tutorials on posting photos in the getting started forum.
It can be done. I'm following a technique that Gerald Wingrove uses to build his museum masterpieces.

I also have some 22 guage sheet metal if that would make my life easier. But I have a whole framework that needs to be soldered inside.

LOL...I think we were editing it at the same time. I saw how to fix it and thought I'd go in quick and repair it.

Thanks

Mike
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Old 12-24-2011, 03:11 PM
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Marty Comstock Marty Comstock is offline
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Make one tuck at a time. I am betting that is part of your issue here. Plus, that is a TON of shrink to get it to go around that corner. Anneal often. It'll go, eventually.

Good luck, and nice grille, that will be a really neat project.

Marty
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Old 12-24-2011, 04:23 PM
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Hi. Why dont you make in 4 parts and solder together. Then get some round stock, and gently hammer the corners round.
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Old 12-24-2011, 05:00 PM
mark g mark g is offline
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Mike,

Scribe a radius and cut away some of the excess copper at the corner of your blank. There will be less to shrink.

You can make shrinks further each way around the corner. Go nearly twice as far as you have so far. There will be less concentrated shrinking in the corner.

Shrink in stages. Plan to get there in a few rounds. For example, shrink and planish to 30 degrees of bend on your sides, then 60 then eventually to 90. The point is to take a series of shallower tucks and sneak up on it.

You could try hammering the ruffles down from the inside, even on a small depression on a stump. The stump work may result in a bit of a mis-shapen corner, but if you focus on getting the shrink you need first, then getting the proper shape of the corner will be a matter of small adjustments with stakes and dollies.
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Old 12-24-2011, 06:08 PM
Dyce Dyce is offline
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All good advice. I would try making a bowl to start. Stretch the center and make a rectangle bowl. Rough cut the center out, then flaten the front of the shell in a press or planish over the buck. This will get the front flat stretched a little, requiring less shrink on the sides. Also I would taper the shell to match the hood. You never see a grill shell with a straight 90 degree side.
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Old 12-24-2011, 10:40 PM
BrassBuilder BrassBuilder is offline
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Quote:
Originally Posted by Marty Comstock View Post
Make one tuck at a time. I am betting that is part of your issue here. Plus, that is a TON of shrink to get it to go around that corner. Anneal often. It'll go, eventually.

Good luck, and nice grille, that will be a really neat project.

Marty
Thought of that but haven't tried it for some reason. When I first started trying to do this, the Gerald Wingrove book I have showed him putting in all the tucks at once. But he is a pro and I am a noob. Maybe I need to slow down.


Quote:
Originally Posted by Mark Fox View Post
Hi. Why dont you make in 4 parts and solder together. Then get some round stock, and gently hammer the corners round.
Thought of that too, but I'd really like to do this in one piece. Since I've been practicing, I've been cutting the copper to do one or two corners at a time.

Quote:
Originally Posted by mark g View Post
Mike,

Scribe a radius and cut away some of the excess copper at the corner of your blank. There will be less to shrink.

You can make shrinks further each way around the corner. Go nearly twice as far as you have so far. There will be less concentrated shrinking in the corner.

Shrink in stages. Plan to get there in a few rounds. For example, shrink and planish to 30 degrees of bend on your sides, then 60 then eventually to 90. The point is to take a series of shallower tucks and sneak up on it.

You could try hammering the ruffles down from the inside, even on a small depression on a stump. The stump work may result in a bit of a mis-shapen corner, but if you focus on getting the shrink you need first, then getting the proper shape of the corner will be a matter of small adjustments with stakes and dollies.
I've cut some of the excess corner material out, but I think I could easily cut more. I agree, I may be doing too much at once and trying to make it move too far. I've been working from the inside in my previous pieces. I was going to move to the outside on this one. I don't have a stump and had I been thinking about 3 weeks ago, I could have gotten a big one from a tree I cut down. It's all firewood now.


Quote:
Originally Posted by Dyce View Post
All good advice. I would try making a bowl to start. Stretch the center and make a rectangle bowl. Rough cut the center out, then flaten the front of the shell in a press or planish over the buck. This will get the front flat stretched a little, requiring less shrink on the sides. Also I would taper the shell to match the hood. You never see a grill shell with a straight 90 degree side.
Yeah, the sides are not perfectly straight. There is a little taper to it, but not much.

OK...you guys gave me some more to try.

Pics later.

Thanks

Mike
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Old 12-26-2011, 03:53 PM
BrassBuilder BrassBuilder is offline
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Round 2:

Broke the original wooden pattern:
PatternBroke.jpg

So...made a new one. This time I left the center part in until I get a good outer edge.
PatternNewFront.jpg

Attached a block on the back side so I can hold it in my vise. I also left my paper template taped to the back side. When I get the shell done, I'll cut the center out and finish the grille surround.
PatternNewRear.jpg

For giggles, I tried making my part using 22 gauge sheet metal. I think it is cold rolled. I got it at the local lumber place. I went back to see if they had anything thinner and they don't. This was tough stuff to work with. I tried heating it to make it more pliable and I think that just hardened it more. And actually, I liked working with the steel more.
steel.jpg

I found a little thicker copper locally. The stuff I was using is .011. This stuff is around .015 or .016. It's a little stiffer and seems to be better to work with. Alas, I could not get enough shrinkage in those tight bends with this either. I finally cut the corner, annealed the copper, and then lightly tapped it around my pattern. I then cut the corners of the overlap so they met and silver soldered it together. You can see a little spot I missed. This was just practice so no big deal.
Corner5.jpg

I was really hoping to be able to make this in one piece without cutting. I still need to make the roof section for the truck and it is going to have as tight as curves if not even tighter.

Was also thinking about making a hole in the center of a 3/4" thick piece of plywood the same profile as my pattern but just a tad bigger. I'd then anneal a sheet of copper and press it through the hole with my pattern. Not sure how well that would work anyway.

Would rather learn how to do this manually though through tucks if possible.


What do you all think?
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Last edited by BrassBuilder; 12-26-2011 at 05:08 PM.
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Old 12-26-2011, 07:53 PM
TheRodDoc TheRodDoc is offline
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You need to try clamping the copper down first with another board. Trim the copper to just the right size with round corners. Then push the copper down over the sides in the center of the straight areas.

Don't make any tucks with a tool in the corners. Use a chisel shaped small hammer with the chisel end well rounded. Start at the top of the corner and work down. work in a semi circle, back and forth. slowly move your hammer rows down. the metal will start to tuck on it's own. As it does flatten only the very top of each. work down. As more form flatten only the very tops again and etc. Your hammer will be forcing the metal down at the same time it is smoothing out the wrinkles.

I tried to draw it but it is tough to draw what you need to see. Going to have to do. (A little at a time. Easy as you go!)

coppercorners.jpg
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