AboutThomas Expertise A lot of hobbyist are out there looking for answers, lapidary, jewelry making craft, etc. I can answer to many topics in those areas. I do not generally deal with costume jewelry but can give some advice regarding such. Note that I do not string pearls(or other bead work) or do twisted wire work jewelry. I can give info on gemstones and jewelry making tools and techniques.
Experience Experience: Over 25 years as a professional jeweler, working at the bench with the everyday problems of everyday people, plus good knnowledge on the do`s and dont`t, what to expect, what is unexpected, how to get beyond the simple into a rewarding hobby.
Clients: Owned and operated a "trade shop" servicing designers, retail jewelers, etc, and owned and operated a school for jewelers now gone by the wayside due to certain personal and economic conditions). I produced fine jewelry for one national opal company. Also lectured, demonstrated, and taught at the request of clubs, societies,etc.
Question QUESTION: hello im Andy im a dental technician working every day with wax and have an excellent knowledge of the lost wax casting process.i have recently taken up jewellery making as a hobby and my first project is a ring for my girl friend.my question is how do i size the ring is it done in wax stage or is it done by stretching the cast metal.also i would like to know if turning the wax ring on a lathe of some description can be done for smooth margins and straight lines etc.i found the info you posted on tools and wax very helpful thank you
ANSWER: Hi, Andy. There is a good chance with your technical skill at casting and perhaps at wax work, you can do a fine job. At least, the casting part should be no problem for you, since jewelry casting offers a “little” more flexibility in burnouts, etc. After a while, we mix investment by feel and look of the slurry and don’t need to bother with measurement. With your work and shrinkage, etc., likely critical, I imagine your casting process is more well disciplined.
Now, to your questions. As for sizing the ring, the best approach I have found is to make the wax very close to right on the correct finger size in the wax. With some shrinkage, the ring will come out a tiny bit too small in most cases but this leaves room for cleanup of the inside of the band without going too large in finger size. With a well finished wax, there will still be cleanup, as you know. How much depends on the quality of the wax and the quality of the casting job.
Stretching will work but please anneal the metal first. This means bringing the gold to a low red color in subdued light. The entire piece should first be coated with boric acid to help prevent fire scale and tarnish. This is easy to do by putting boric acid in a small jar of denatured alcohol, swishing the ring in there, removing and lighting the alcohol. The alcohol burns off leaving a fine coat of boric acid on the metal surface.
When annealing, with white gold allow all color to go before quenching to cool. For most yellow gold, you can quench while a dull red color. Annealing relieves any stress that might be present in the casting which could cause problems with stretching.
Yes, a lathe or even a flexshaft adapted to hold the ring can be used to turn the wax. Soft waxes will not turn well and neither will Kerr Blue Inlay wax. The best waxes for turning are the harder “carving” waxes, like those made by Ferris. Green is almost too hard and brittle. Blue is able to take fine good detail and is the softest of the hard carving waxes by Ferris. I prefer purple, about halfway between green and blue, offering fine detail retention and enough flexibility that you will not easily chip or break it with accidental miscues.
Turning can be done with sharpened dental pics and other similar tools. You can make a tool from mild steel of almost any shape you want and it will work fine on the comparably soft carving waxes.
Andy, please get back anytime if you need more info or have a question about something said here today. You may use the follow-up option that comes with the answer.
God Bless and Peace. Thomas. 05/29/2007 7:11 PM
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QUESTION: thank you very much for your advice.i have actually purchased Ferris green wax and accidently ordered two tubes and a block of the stuff but im sure it will come in useful.most of my tools for work are quite rounded and i have looked for gravers on the Internet but most are quite expensive.do you recommend using a nail and grinding the end down on a micro motor.although i trained in metals i do not have enough experience to jump straight into casting metals as i work in prosthetics so i was thinking of taking my wax carving to a jeweler and asking them to cast it for me.before i do this i wanted to make sure i have a copy in case of a misscast.can a rubber mould be made in the home without the use of a vaccume.and can you recommend a site with some design ideas please.thanks greatly Andy
Answer Andy, I will answer this one tomorrow night. My connection is going in and out for some reason. Please bear with me on this. I will be back tomorrow evening. Fair enough?
Thanks for the fine rating...that is encouraging. Thomas.
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Here is the Follow-Up to your second contact:
Andy, I am pleased you got back. I will relate what I know on your concerns and combine my knowledge with that of my coworker, an excellent jeweler and metal former. We discussed this today.
Ferris Green Wax. I was not knocking the green wax in the previous answer. This is excellent carving wax and takes the best detail of all. The only negative is the brittleness of the wax. You simply do not want to drop a thing carved item on a hard floor or push a carved ring up a ring mandrel…the risk is a break. Carving tools should be sharp enough to peel the wax right off without much pressure.
Carving Tools. Yes, gravers work quite well and can even be used in a reverse position, with the cutting part on top for a different effect. Yes, gravers are expensive and a hard nail such as one used in concrete is a tough enough steel to do the job. Even regular nails will work but it is harder to get a fine edge on the steel. We are not cutting metal here or even wood; even hard carving wax is much softer than those substances. Still, try to get the shape you need by experiment then gently hone the cutting edge to a nice sharpness. The nails should work just fine. As I said, old dental tools work pretty well, too, and may be reformed to new shapes. Generally, to cut wax, the tools do not need to be tempered. “As is” will work ok.
THE COPY OF YOUR ORIGINAL WAX. I put this in bold since this is really the biggie in your question. The requisites for making a mold of a wax model are these: 1) NO heat needed to cure the mold material. 2) See Through compound so you can cut the mold and not damage the original. You have to be able to see where you are cutting with sharp razor or scalpel blade; with a metal model, cutting can be done with out vision of every detail. With a wax model to be preserved, you must see where each cut goes.
Mold Material. You need an RTV compound of the “see through” sort. RTV simply means “room temperature vulcanizing” or curing out without heat. Ferris makes a see through compound but it requires heat of close to 350 degrees F to cure. That one is out!
The recommended compound is called DITTO CLEAR. A company called Rio Grande sells it as may others. This Ditto Clear is not inexpensive. A 1.1 pound kit costs about $45 and will make about 25 cubic inches of mold. The recommendation with the product says: “Vacuum for best results”. You can still get some and try it. An old trick used for investment casting without vacuum was to paint the model with the plaster, cover it over with a fine mix of investment then fill the flask. This was done to help prevent bubbles which would show in the casting. You might try the same with the Ditto material but frankly I don’t know how well that will work. The material is sort of “slippery” in consistency and I have no clue how well a dip in the material or a gentle painting on with a soft brush will do. I suspect it is worth a try. Then you would fill the mold frame with the rest of the compound and wait for it to cure.
Keep in mind, a small bubble or two on a mold is not a so much a problem with wax. The bubbles can generally be cleaned off of any duplicate you make from the Ditto mold, using the same tools (perhaps more gently since injection wax is not quite as carvable as hard carving waxes).
The other option might be to simply make two models to start with. This might be quicker in the long run than trying to make a mold of the original wax. That would be my approach.
As for a site with designs, I have no idea where to send you. The net is full of jewelry but it all depends on what you might have in mind. You might start by searching “wedding bands” (not saying that is the purpose of the ring but that a variation of designs does exist out there). Then try all sorts of searches for rings. You will see much of the same stuff but once in a while will find a new and interesting design.
The Casting. Be sure the jeweler is experienced in casting, if you can find that out. Since most castings do go well, there is no much worry but once in a while there is a mess up and the jeweler cannot be responsible for that. Be sure you have the freshest metal you can use and not too much scrap. A few jewelers of the “other sort” will take nice ring bands, etc., throw them in another place and use too much of their scrap metals for casting and you never know. The result may not have the surface you need for a good finish and might have pits and other defects. Check around on this if you can.
Ditto Clear is available from Rio Grande. www.riogrande.com
There is not an online catalog but you can likely order directly without a catalog. You will need a mold frame, too. Those run about $12. You can get the “Tools” catalog from the Rio site.
Andy, let me know sometime how this project goes. I am glad to see you interested in this work. For me much is mundane but once in a while, the client comes along and our work is true art..that is the gravy of personal pleasure in it all.
