Fe-Wood Posted May 29, 2009 Share Posted May 29, 2009 Hi all- I've been spinning copper for almost 6 months now. I am beginning to get the hang of it :confused:. So much so that I ordered a bunch of sheet stock, tired of fussing with scrap.... Anyway, somewhere along the way I read .040 copper was the recommended thickness for spinning. MAN is that tough!!!!!! I am trying to spin some big bowls, about 16" across with a depth of about 4". After spinning and annealing about 5 times, I'm about halfway up my blank. There is so much volume in the copper, I had to rob the burner from my forge in order to get it hot enough to anneal, even with that I can just bearly get a dull cherry red. My question is: Did I get to thick a copper and is Revere Copper a different composition so it is less malleable? This stuff seams really tough, even though it is almost twice the thickness I'm used to. Any isight would be great! Thanks- Quote Link to comment Share on other sites More sharing options...
Frosty Posted May 29, 2009 Share Posted May 29, 2009 I wish I could be more help. I don't have a clue about "Revere Copper". What's the alloy? We wouldn't've had a problem spinning 0.040" copper. If it's a reasonably pure copper alloy it shouldn't be work hardening before you can make one pass unless you're playing pitty pat with it. Fussing around instead of getting on with moving it will work harden it pretty quickly. It's the same effect you run into drilling copper alloys, if you don't feed it fast enough it'll work harden in front of the bit and gall. If you make too light a pass copper will harden in front of and around the tool stopping progress quickly. For example Dad would spin a copper half sphere in maybe three passes with scissor tools, maybe 5-6 with hand tools. It takes more feel to hog the movement but sometimes it's the only way. Just bear in mind this is speculation on my part, there's too much I don't know about the alloy you're spinning, your set up, tools, etc. and the simple fact I haven't touched a spinning tool in a good 40 years and those were scissor tools. Frosty Quote Link to comment Share on other sites More sharing options...
mike-hr Posted May 30, 2009 Share Posted May 30, 2009 FE, If you get the 16 inch diameter discs figured out,I'm gonna drive down there and watch you.. I've been trying to spin 16 inch steel discs for about 3 months now, I've tried 16Ga, 18Ga, 55 gallon drum lids, even a door skin from a chevy S-10 pickup ( I thought they might be a deeper draw steel..) The sombrero effect is driving me crazy.. I get after it, and pull it to the form, the outer third of the disc whangs backward towards the tailstock. I push the sombrero brim back, and it wrinkles up like a many-fluted ashtray. It's still fascinating, and I have enough wrinkled ashtray shaped rejects to keep me in rifle gongs for years to come. Quote Link to comment Share on other sites More sharing options...
Frosty Posted May 30, 2009 Share Posted May 30, 2009 (edited) Mike: Before you start spinning use a slitted stick, we put the slit in the truing stick, and bend a crimp 3/4-1" wide in the edge back towards the tail stock. This is done as a process of spinning using the rest. Just slip the slit over the spinning blank and put the crimp in it. It's shallow maybe 15* or so and should look like a pizza pan rim. This will prevent the "sombrero effect" by reinforcing the rim like flutes in flat sheet do. Do not turn it towards the headstock as that will make the "sombrero effect" a LOT worse. It'll also help prevent the part from scalloping on you. Steel likes to spin at higher RPM than copper or aluminum and you should feel the sweet spot when you're pushing it far enough in your passes. Mild steel was my hands down favorite to spin. Frosty Edited May 30, 2009 by Frosty Quote Link to comment Share on other sites More sharing options...
Fe-Wood Posted May 30, 2009 Author Share Posted May 30, 2009 Thanks guys- I'm using streight tools. My lathe (modified 1960's version 12" Rockwell) won't handle sissor tools. I'm getting after it pretty well. like Mike, if I hit it to hard, I warp it....:mad: Off to the anvil I go to streighten it out:). I did a search for Revere Copper and couldn't come up with a formula although it is 99.5% or 99.8% pure as far as I can tell. I played with a small piece today to see if the alloy was harder than I'm used to. So far, it doesn't seem to be. Small pieces, I could get hot enough to SEE red and anneal. I'm thinking I need two burners so I can keep up the heat... It looks like I'm getting it hot enough but maybe it cools to much before I quench it. So I'm not getting a full anneal.:confused: Mike- I'll keep you posted:D Quote Link to comment Share on other sites More sharing options...
Frosty Posted May 30, 2009 Share Posted May 30, 2009 You don't really need to quench it, air cooling is close enough. The trick is getting it evenly hot. A BBQ with a layer of charcoal will do nicely. Briquettes will work just fine and you can make a hot lunch while you're at it. Frosty Quote Link to comment Share on other sites More sharing options...
Fe-Wood Posted May 30, 2009 Author Share Posted May 30, 2009 Hmmmm I'm definatly getting it that hot and way more even than a BBQ. Maybe its just plain work! This is the thickest by twice I've ever spun... I'm moving the copper too, the tool groves tell me that. Good tip on the rim job, I'm getting that anyway but maybe a more deliberate rim will work better... Something new to try You Da Man Frosty! Quote Link to comment Share on other sites More sharing options...
Frosty Posted May 30, 2009 Share Posted May 30, 2009 The deliberate crimp is good, letting it back up on itself is bad even if the two resemble each other. What can I say, Father was a metal spinner and he made me work in his shop. One pic he's spinning a radar dish of some sort (I think) in a basement of one place we lived and the other pic he's spinning hot. It's almost undoubtedly a jet or rocket engine alloy for the gvt. We did a LOT of that. One of my jobs was holding torch. Frosty Quote Link to comment Share on other sites More sharing options...
Fe-Wood Posted June 12, 2009 Author Share Posted June 12, 2009 Thought I would post a picture of the finished bowl, well, almost finished anyway:) And another one with the intended use in progress. These will be catch bowls for small water features I'm making... Frosty- Thanks for the crimp tip... It works swimmingly:D I was able to finish in one anneal cycle AND correct some other issues. Next round will be much easier. One more question, at what diameter should I consider using an edge crimp like that? Quote Link to comment Share on other sites More sharing options...
Frosty Posted June 12, 2009 Share Posted June 12, 2009 Looks pretty good. Does the anvil come as part of the set? I don't know what thickness to dia ratio to start crimping, it's been too many decades since I touched a spinning lathe. You know what problem to watch for so if it occurs crimp the next one. I wish I could give you something more solid but. . . Frosty Quote Link to comment Share on other sites More sharing options...
Fe-Wood Posted June 13, 2009 Author Share Posted June 13, 2009 My wife thought the anvil made a nice stand too.... Quote Link to comment Share on other sites More sharing options...
Spun_It Posted July 28, 2009 Share Posted July 28, 2009 Try using a 2nd pair of hands. After your crimpe your material and spin it 3/4 of the way up your tool, have someone hold a skinny board behind the part where your spinning. This will give your material backing as if it were on the tool. Resulting it no buckles. You can also try adding stiffners while you spin. As your spinning up the tool, take a backstroke to the tool. Keep repeating to make steps in your material. Slower speeds are usually better for softer materials, be smooth, and don't be afraid to move the metal... ;) Quote Link to comment Share on other sites More sharing options...
Frosty Posted July 28, 2009 Share Posted July 28, 2009 Welcome aboard Spun it, glad to have ya. I'd forgotten about backing with a board! Man it's been a long time, I gotta get a lathe set up. Best of all we now have a resident spinner to field these questions and I can stop trying to remember things from 40 years ago. Oh yeah, I almost forgot in my excitement. If you'll click "User CP" and edit your profile to show your location it can make a big difference. IFI is represented by more than 50 countries and a lot of info is location specific. Frosty Quote Link to comment Share on other sites More sharing options...
Fe-Wood Posted July 31, 2009 Author Share Posted July 31, 2009 Thank you spun-it!! :)So glad to have a fellow spinner to answer questions. I've done the "back stick" method and it works pretty well. I usually remember to do that AFTER I wrinkle the edge:o Tell me more about the way you are making steps... Your not talking about working what would be the inside edge of the piece and spinning an angle on that are you? Kinda what Frosty was talking about... I've taken the next leap and ordered a sheet of 22 Gu mild steel. Any tips on spinning that? My tools are all burnishers, no rollers yet except for one bead roller. I'm using a soy oil base liquid lube (made for spinning) and it works really well for the copper. I have a wax stick too but I've heard lard can be a good lube for steel. Any thoughts or insights? TIA for any tips and tricks!! Quote Link to comment Share on other sites More sharing options...
Frosty Posted July 31, 2009 Share Posted July 31, 2009 Make bronze tools for spinning steel and turn it a lot faster. Once you get the feel steel is easy to spin. It was my favorite back when. Frosty Quote Link to comment Share on other sites More sharing options...
Fe-Wood Posted August 1, 2009 Author Share Posted August 1, 2009 Thanks Frosty- We'll get you on a lathe yet:rolleyes: Does it matter what kind of Bronze? Manganese or silicone?.... I have some manganese... Quote Link to comment Share on other sites More sharing options...
Frosty Posted August 2, 2009 Share Posted August 2, 2009 I don't know what kind of bronze to use but if I had to guess I'd use a free machining bronze for it's self lubricating properties. Basically you never NEVER spin a metal with the same metal tool or it'll gall. Not talking about roller tools of course. I'm hoping to have a lathe set up by next spring, I have a couple little projects in mind as well as potential visitors who like to spin. Frosty Quote Link to comment Share on other sites More sharing options...
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