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Mark Strom

working copper

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Just after my comment about sticking to carving wood this was thrown my way. Must be a worldwide virus!

 

A very dear client of mine is getting married and requested that I design and preferably make a bracelet for the groom. The groom's tastes are on the eccentric side as you can tell by the design. I cannot find anyone locally that can work within the time frame (4 to 5 weeks) or the budget. They do not want gold or silver. Below is a design concept, if this is possible to do in the manner described then options are open to make changes. If not we will seek another route, hopefully something gathered from your suggestions.

 

post-727-1181805891.jpg

 

 

I hope the description uses the right wording as I have tried to glean this from the other threads. The plan is to start with a billet of copper 1/4 to 3/8 thick formed from a grounding rod. The rod is 3/4 in diam and copper through out. No idea what kind of copper, only that it is consistent. My plan is to carve it in one piece as I would do in wood. The rough shape will be cut on a scrollsaw and then shaped with a foredom tool using carbide burrs followed with files, sandpaper and finally buffed on a jeweler's muslin wheel.

 

Overall length is 5 3/4 inches long x 1 inch max width x 1/4 inch thick. I apologize, I am not good at conversions to metric. There will be a fossil in the circular area in the center of the bracelet.

 

My questions are:

Can the copper be annealed? to increase the strength of the metal to inhibit unwanted bends?

 

If this isn't possible then can a bracelet made using copper or this method even work?

 

After polishing is there a simple method to get a irregular patina in the brown to orange and red range?

 

Prongs would hold the fossil in place but is there a way to actually push material over the fossil from the end of the bones to achieve the same result? Similar to the technique described to do inlay in metal.

 

Of course time is crucial, my metal working skills minimal, and resources are limited. I hate to let the client down so I am open to suggestions.

 

Mark

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Aloha Mark,

 

Interesting project. I'll take a stab at answering your questions. :D

Yes, copper is subject to annealing. Heat to a light red (about 1400F). Quench in water, although air-cooling is OK. For hardening, plan to do light forging or planishing in the final stages after final heats. Shaping around a mandrel is a good one. Additional planishing on the mandrel with a lead weighted rawhide mallet helps. At 1/4 inch, the diameter of your final stock should be sufficient. The simplest method that I know to get colors in that range quick is to use heat. Try playing a torch flame lightly over the work before planishing to bring up color. What you get will depend partly on surface i.e. burnished smooth versus light sand (about 600G) or gentle sandblast. There's also a technique in here somewhere using garnet sand poured from a cup a foot or two over the piece that actually works. Ushi-arashi? Jewelers use gravers to "raise a stitch" which act as a prong, but it takes practice and might not be strong enough. Raising a continuous type bezel is gonna take some work.

The sketch of your bone "bands" (ulna/radius?) look similar to some of my tansu handles. I've never had much luck power carving copper, and it's hell to clean up. My suggestion is to find some #4 solid copper grounding wire (the kind used for grounding house mains) or something about 1/4" (if you get stuck, I can spot you some). Break the design down to components. Shape the individual pieces on a strip or belt sander. Forge to flair the ends. Rivet (with copper wire) as cold joints. Practice this part to judge stress points when you shape on the mandrel. I can't say more about the center until there is more detail. Keep us apprised.

 

KC

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Karl posted while I was writing so disregard the redundant stuff.

I have spent years working with Carbide burs and copper alloys in the Bronze monument business. I work lots of pure copper these days and have abandoned the burs for 99 percent of the work. Burs will work but they are not pleasant to work in soft gummy metals like copper. The method you outlined is possible, but a few things will make this approach easier. First has do with annealing and hardening. Annealing is the process used to put the metal into its softest condition. Mechanical deformation is the way to harden and strengthen copper such as working it with a hammer or rolling mill. This is called work hardening. I bring this up because copper is easier to saw and tool with the burs in the harder state. This may not make sense until you try it. If you anneal the copper will become more gummy and tend to load the burs and get pushed around rather than cut cleanly. Regardless the burs will generate a lot of heat to the point where you will no be able to hold the piece. You can't mount it in pitch it will get too hot. So you need to mechanically clamp it or temporarily solder it to a heavy backing material that can be clamped in a vice. It will need to be very stable to keep control the bur. The gummy properties of copper hard or soft will tend to grab the bur and the piece gets flung or you lose control of the tool and make bur tracks gouged across the piece. You can snap the teeth off the bur and also break the bur when cutting inside details and opening. Get as much of the shaping done with Saw and grinder or files as you can. minimize the use of the burs save for contouring. You should then be able to use needle files scrapers and abrasives to finish the surface.

The setting can be done by pushing metal over the Fossil be it a bezel or prongs. You will need to leave suficient material in place to push over, or solder a setting in.

I know time is critical, but you might consider carving it in a medium that you are well versed in and having that cast in bronze. It is not difficult to find a foundry or jeweler, but getting something done in a hurry is often a challenge. There might be someone on the forums that could help with that?

There are many approaches that could be used to create this piece, but given your a novice with a time crunch you probably want to stick with tools and techniques you are comfortable with. It may not be the most efficient or elegant way to get the job done over all, but it is straight forward and workable.

Good luck,

patrick

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Guest ford hallam

Hi Mark,

 

Karl and Patrick have made some very good points, particularly regarding the difficulties in following a grinding approach. Do you have any experience in hard ie; silver soldering ?, Berlin Karl! we may need an emergency soldering tutorial intervention asap :) .

 

Patrick,s suggestion to make up all the bones as separate elements is, to my mind, under the circumstances, the most practical route to follow. As for the bezel ( or setting ) for the fossil, I'd suggest making that in fine silver, it will make a nice contrast and setting the fossil will be really easy as it's very soft. Alternatively you can set the fossil from behind. Make up the setting so that the fossil fits in from underneath and make provision for some prongs at back which can then simply be pressed over. This will also allow you to finish the setting in front perfectly before the stone goes in. If you want to follow this approach I can do some sketches. Actually, if the fossil is a perfect circle and constant thickness you could send me the measurements and I could make one for you and get it to you in a week, it's only a couple of hours fiddling.

 

I'm sure the guys here will get you through this with flying colours :D:lol:

 

regards, Ford

 

p.s. I'm serious about making the setting for you if you like.

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Hi Mark,

This is a cool design - seems you've got the bases covered in regard to how to proceed. I would just want to say that I agree with making the parts seperately and then assembling them - I think I would probably join them all together on the flat and then forge the assembly around a metal or rock maple form using leather or wooden mallets ( or nylon). I would tend to want to silver solder them ( hard silver solder) rather than rivet - though the rivets could become an interesting design element - if this was made from bones they would have to be mechanically joined. I like Ford's idea of setting the fossil from behind.

Best of luck with this ambitious project Mark!

Blessings,

Magnus

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Thanks for all the information and input. You guys cleared up some questions and problems for me.

 

I did some experimentation and seemed to have found what some of you described. I heated and hammered (forged) some small pieces and did notice that it was easier to work than raw copper. The billet is being made by a blacksmith friend, it will be heated and forged? into a workable piece from the round original. If I understand correctly this will harden the metal to a workable state. The finish form will be shaped on a mandrel so this should help stiffen it more.

 

I also tried carving with burrs and found that my older burrs (worn) seemed to work better with less chatter although the cuts were rather rough. The Foredom has variable speed which helped correct some of the mess along with using different types of burrs. The heat slowed things a little but I had a cup of water near and dipped when needed. With a little file work and additional sanding the forms came out. I put the piece on the buffer and to my surprise the finish was clean although some lines soften a bit much. I assume this is the result of aggressive buffing.

 

Ford, good idea about mounting from the back of the piece! I will be able to shape the bones to hold on top and pin from the back. I appreciate the offer for the setting, your suggestion has opened up several options that I can pursue and hopefully use. The idea is to drill or saw through the blank and shape the opening to the fossil, pins will be left in place or soldered on later.

 

The design is based on the ulna/radius bones as Karl said and will probably be modified to accommodate my skills and resulting problems. The plan is to do a morph between bones and French Art Nouveau furniture carving. This will give me some room to accommodate the softening of the buffer and allow for more filing of the form. The attempt will be to carve it from one piece...appeals to me for some bizarre reason. I am probably jumping in a little over my head (especially after the pros recommend another course!). Even as a kid I was never was one to go into the water just to my knees...had to get out into the deep water!

 

Again thank you Karl, Patrick, Ford and Magnus for all your information and offers. This should be interesting!

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Aloha Mark,

 

"once you've gone metal, you'll never settle..." :D Looks like you've lined up your support group. Go for it.

If you go this route, I have an idea to reduce the number of parts and support the central piece at the same time, as well as tips on riveting and quick and dirty mandrel making. I guess your decisions will depend on your soldering abilities.

FYI to everyone is this place, Metalliferous, which is listed in the Sources section. Mark, the offer stands, but check out their extensive base metal section for ideas. The "dropping sand" technique (ushi-arashi?) can be viewed at Technique>Tortoiseshell>link to Tokyo Tourism Info>Intro to Traditional Craft>#29 - Metal work>#5 (?) courtesy of Tim Blades. Try the 300 band for better detail. I think there is a pic of Jim doing a demo at a INS meeting, but I can't find it.

 

KC

 

Mark, passed you on the fly. Disregard info not pertaining to your direction.

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Aloha Mark,

 

If you are going to hard solder, try Victor>Thermadyne>Silverflow SF-1. It is a phosphorus bronze , lead free, fluxless, brazing alloy that subs for silver alloys. (I use flux anyway.) It's color is closer to copper and not so silver. You can find it at HVAC supply houses as it is used by air conditioner repair guys.

 

KC

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I might step in here and suggest also, along with silver solder, to look at a soldering rod that is used in the airconditioning trade. It is a low temp solder, quite red and does not need any flux. I think it is more tin based. It is used for joining copper to copper piping. It is brittle and hard. I use it for soldering when I do not want an obvious 'silver' line. Any airco shop will point you in the right direction.

Also, if one patinas the piece then a good quality car wax or 'renaissance' wax will prevent further oxidisation. ( clear laquer tends to kill the colours) Ganoksin.com has a large archive on this subject

Cheers, Hans Meevis

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ok guys..I am going to my studio for more experiments. I have some of the solder you describe (silver solder as the hvac guys call it) left over from years ago. I will give it a try and see what comes up.

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Hi Mark,

 

Just thinking outside the box, have you considered carving the piece in wax, and having a lost-wax casting done? It could save some time. However, the experience of doing it as discussed would be fun.

 

Just food for thought.

 

Phil

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Aloha Mark,

 

In case you get tired of listening to this pack of metal junkies, here's a few references.

 

Silversmithing by Rupert Finegold and William Seitz

Silversmithing and Art Metal by Murray Bovin

Silversmithing by Frances Loyen

 

The first is by far the best thing I've ever found on the subject. Well written, photographed and laid out. Well worth the money. The other two are also good, as smaller trade text. Though focused on silver, they all include copper references and all the techniques apply.

 

KC

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Ford,

The bracelet is still in progress. I tried carving with burrs and found that it did work for my purpose. On the first attempt, the carving went well but the welds did not hold up. The second attempt just was ugly.

I ordered a piece of 1/4" thick copper sheet and will cut the entire piece from that and start over with the carving. The sheet is so nice that I will probably attempt more than one piece.

There will be pictures when completed. Thanks for asking.

 

Mark

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Guest ford hallam

Cheers, Mark,

 

I look forward to seeing how it works out. I'm sure your experience will inspire others to "have a go" too.

 

regards, Ford

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Mark,

 

It might be nice to see progress images. Seeing only the final product sometimes is deceptive as to the process used. I too am looking to see the bracelet.

 

best,

Fred

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