Suffice to say I have followed all prescribed technique such as outlined in Revere’s book. I have used high quality closed molds, clean sterling, premium flux etc…
Yet I have never got a usable ingot of sterling silver!
I have poured what are not good ones and those that look “perfect”. I have annealed and rolled in opposite directions and always get crumbling and pitting to the point of useless.
Considering trying an open mold as a couple friends seem to be having good luck with those. They live far away but “just do it” and get great results! One uses old silverware and gets usable sheet 2" wide and 8" long at 18 ga!
So what are the prescribed techniques that YOU use?
Open or closed molds?
How do you roll the molds; annealing process etc?
Any other advice would be welcome! I have 5 pounds of scrap and would love to get some stock out of it!
How big of an ingot are you doing? Try small ones. Breaking could be the
metal characteristics. I pour out of an open crucible with a big torch into
an oiled preheated steel ingot mold. I’ve had white gold crack on me like
that and I think it’s metal that’s been contaminated or changed enough that
it will not roll nicely. Some insist that you forge the ingot first before
rolling. I don’t know about that. Give it a try. And aneal, aneal, aneal.
This is, or was, a lot on this in the old format. I use a very nice Durston open mold, 2 machined two piece, wire on one side flat on the other side, molds and delft clay. In all cases I make sure that the scrap is clean and don’t use anything that looks suspect. I also run a magnet around the little pieces. Regardless of mold, the scrap is melted in a small whip type crucible that has been well coated with borax. Heat it with a good clean flame with enough heat to do this quickly. Once the melt is fluid, hold it for a moment and then I usually sprinkle a little more borax on the melt. I use a salt shaker to do this. Using a graphite rod sharpened in a pencil sharpener, run it around the melt to dredge out what ever will come with it. Make sure the melt is fluid again and the carefully pour it into whatever you are using for a mold directing the flame on the pour stream and sprue button slowly moving the flame away from the button as it cools.
I coat my open molds with a light layer of 3 in 1 oil. Heat it a bit and then pour. t takes some time to figure out how to keep the pour together. You might try elevating one end of the mold a tiny bit to get all the pour going in one direction. If I am using the two piece steel mold, I open it up and heat it well to drive off any water that condenses from the gas and air mixture, then using a gas only flame, coat the inside of the mold with soot. Put the mold together making sure the mold halves are lined up correctly (use old oven mitts), heat the mold a bit more and then pour as described above. Delft clay is a lot of fun and a separate topic but still melt as described above and pour.
Once you have removed your ingot, regardless of shape, remove all the burs and other sharp paring line edges. I do this on a lapidary sander with 220 grit belt. Anneal again (this may not be necessary but I always do it), then forge the ingot with a forging hammer in all directions front and back. I usually forge it in a rough approximation of what the final shape might be. Anneal again and then start rolling. I only roll in one direction keeping track of what end goes in first with a little sharpie mark. Anneal often. If you see a fissure or sharp opening, file it out or at least even it out. Did I say anneal often. I don’t always pickle after annealing, but just use water to cool it. Pickle can do a lot of damage fast to your rollers, so be careful. There will always be some loss, so roll bigger than you need. Clean up the rollers when you are done. I use simichrome to polish and work it in using a dust free cloth and polish like you would polishing shoes. Then apply a light coating of 3 in 1 oil. Keep your mill covered when not in use but don’t seal and lock in moisture. I use an old pillow case. If you would like to cast an odd shape like a triangle, get pieces of square steel tool rod and lay them out on your anvil in a shape as close to what you want as you can get to with the steel rod. Hold the pieces of rod in place with small magnets and pour. Now you have an odd shaped ingot that can be forged or rolled into your odd shape. This is a lot of fun. That’s it, more when I know it, good luck…Rob
I suspect you do not have clean metal to begin with. It may have some solder with it. Forty some years go when I first started to work with metals and having few tools, I wanted to make a large concha (yes, concha not concho), for a belt buckle. I began with a hardware store propane torch, a crucible and hammer and makeshift anvil to forge the concha. I would melt the scrap silver, stir it with a carbon rod and plenty of borax,skim off the slag and let it cool in the crucible. After that I hammered it against the anvil, annealing frequently until it was the thickness I wanted. I never had a problem with it cracking or crumbling. I still wear that first concha buckle which weighs just under 4 troy ounces. The point is that if you follow the rules: clean metal (NO solder), clean flame, enough borax flux, and frequent annealing and you should be okay.
seems most of this conversation is revolving around the molds . in making ingots the most important point in most precious and non ferrous metals is the heat source.not the mold. the second important point is your metal. I would highly recommend anyone interested in these processes to watch a video of Ford Hallam pouring his own alloy for making Japanese sword guards. he pours the ingot into water. no mold. it is one of the better and cleaner ways to go and keep your alloy.
the heat source, is key if you are using acetylene for fuel you are already cutting your chances down in success, its very possible to get great ingots but you need to do the right thing with the tools and supplies you have at hand. Propane and butane is a little cleaner burning so better chances of success. Mr Hallam also shows you how to forge and begin to process the ingot before you roll it down or draw it down. it is always recommended to hammer forge your ingot in total to a thickness and shape so the molecular structure is more homogeneous on the inside all the ay through, like dough. it could look beautiful on the outside but there maybe fissures and all sorts of anomalies on the inside . I was having a lot of trouble with my silver at one point pouring into an open mold ,so I brought it to my caster and he poured it for me in a atmosphere controlled oven with an argon dome covering it while he poured it . it was the only way the old silver could stay from getting exposed to oxygen and form oxides while being poured which then would be the beginnings of cracks . the heat source is important ,to be neutral, it is also important to cover the metal with your flame at all times so no oxygen gets to it , that is a huge feat to achieve depending on the size of your ingot. NOW if you use clean and new metal then it is less prone to a few of these problems, but as you pour the ingot and fail and remelt and re-pour the metal starts getting overworked/ over heated and looses some of the alloy’s zinc or silicone that keeps it from faults. the formula is 50% new metal every pour other wise you run chances. I have been known to pour 4-5 times before I needed new metal. after 35 years of experience when I first watch Ford pour his ingot , I was mesmerized, I would highly recommend it ,it is on Utube . even if you dont use his style ,just watching what it is ,you will get great ideas of what to do. good luck
Warren-We’re old school fabricators so I pour a lot of ingots.
If you are using clean silver and getting pits and crumbling you may be
over heating your silver. I use a rose bud tip with natural gas and oxygen.
Not too hot a flame. Too much oxygen makes for a more oxides in the metal.
I pre oil and pre heat my ingot mold and when it’s hot enough I then the
position my metals crucible so that as I’m heating my metal the flame also
keeps the mold hot. After picking I always forge my ingots with a polished
sledge hammer before rolling. I frequently anneal when rolling and take
small bites at a time. I never cross roll unless I anneal it first. Hope
this helps.
Have fun and make lots of jewelry.
-Jo Haemer www.timothywgreen.com
New means casting grain from a refiner. Every time you heat metal it
changes little bits. Something that is already a ring has been at least
heated once when it was cast. So if you use it that will be melted twice.
To be honest you can get away with a lot but karat could change some.
I’ve tried with 100% fresh, never heated or soldered scrap and use oxy-propane and a Smith Little torch with the melting tip. No problem getting the metal melted.
What I meant as open mold was the “trays” you lay flat and are open to the air on the entire top. As apposed to the clamp together adjustable style.
I have neither at the moment and want to invest in the open to try out but would get a good quality Durston or the like. Seen carbon molds too but don’t know anyone who uses them.
Love to see a video! Off to search one up but suggestions still welcome.
Not clear if you are annealing between rolling in opposite directions, which is imperative. Must roll in one direction only–can change direction only directly after annealing.
The temperature of the mold is crucial. I do small amounts (gold, not silver) and now just melt in a groove scraped out in a carbon block instead of melting in a crucible and then pouring into a metal mold. It avoids the heating-the-mold concern and eliminates having to pour, as well as providing a reducing atmosphere.
I use my silver sheet metal scrap for casting. I could roll out sheet but time is more valuable than the money you can get out of the scrap as a trade in for new sheet. Rio Grande and Stuller along with many other places will give you a great price for your scrap if you trade it in for new materials. Your only going to loose 20 to 25% of the value. So if you send them $100 dollars worth of scrap silver you can get around $75 worth of sheet. It takes a lot of time to roll out and anneal a 3mm thick ingot into 18 gauge sheet. And no matter how good you are at it you will never come close to the quality of materials that they can produce in a big factory making wire and sheet. So you loose even more time working with sub par materials and producing lower grade finished products. I’m sorry, I know it is an interesting process and even fun to do. And it is a good set of skills to have. I still roll out gold when it makes economic sense to do so. But silver just doesn’t. Do it as practice but not for the sole purpose of producing stock.
Love the steel rods to form odd shapes like triangles. Going to try this. I have Durston open mold. I use a spray lubricant that came with the mold or 3 in 1 oil to coat & pre-heat mold. Have a Smith big torch with acetylene & borax. With clean scrap free of all solders, I have had a few ingots that had fissures but usually that was in the flat sheet side of the ingot & not an even pour. My error. On the wire side, pours come out fine. I do initially hammer my ingots down a bit, anneal (not pickled but brass brushed well with some Dawn soap to clean then dry), then roll one direction in my Durston mill. I roll typically about 4-5 times then re-anneal. It is nice to make my own 3mm thickness pieces into small shapes for pendants with flush set stones. I love the heavier handmade look of them.
I am sorry I did not realize you were asking also for the carbon molds , I do use them they are fantastic. not so much or at all for White gold or palladium, Platinum. but for yellow , red golds and silver they are great.
you have to keep in mind that the atmospheric bubble you create while doing the melt and moving it to the mold and pouring is more important then the materials you are using for the mold. so the gas you are using , the flux or borax, and if there is any argon gas being used to keep oxygen away. that is your main goal in a melt to keep direct oxygen from hitting the melt. there is a few videos from the guy that sells the mini carbon molds to show how he has designed and uses them, I believe he is in Australia. I did purchase from him and watched the vids and do it the way he does it , it works well with his recommended ways and amounts . google search small or mini carbon ingot molds he will come up.
regards, Hratch
I Highly recommend everyone watch Ford Hallam’s vid . it is shibuichi but it makes no difference. it is highly specialized pour, he is not just willy neely pouring into a bucket of water like the 60’s hippy jewelry making crowd that got off of the shapes that shattered. I tried it it works. he gets ingots of 1/2 inch thick and about 4-5 inch round. because it is being poured into warm water the metal is completely enveloped and does not oxidize. copper alloys are even harder to pour then silver and gold. I would advise all to watch the video. spectacular education to say the least.
Hratch
Hratch, I have always poured gold that I have alloyed into water to make casting grain, It has always formed into small random shaped pieces. I have watched the video you refer to several times and have always been puzzled by the pour. Next time I will try warm water but I can’t understand how that would make any difference. You mention that it causes the metal to be completely enveloped". So does cold water, so what’s the difference?
He is doing one big pour and it was copper I believe. I think he had
charcloth in the bottom of the water. That metal would fuse to the metal of
the bucket if there was nothing there to keep it from contacting the bottom.
Sterling silver ingots. There are several ways to do this depending on the source of your melt. The following is how I do it.
Method 1
a) Fine silver granules 92.5%, fine copper granules 7.5%, in that order into a clay graphite crucible, and cover with flux.
b) I use a micro furnace (easy to build) to melt metal, because it always works and if you follow these steps you’d have to be doing something seriously wrong for it not to work.
c) Melt your metal in your furnace. When melted take a green stick (a stick from a living tree), and stir the melt.
d) Pour the clean melt whilst applying a torch to the flowing metal into your mould.
Method 2
a) Scrap sterling, plus some fine silver probably 1-2% should be sufficient.
b) as method 1
c) as method 1
d) as method 1
The Mould.
Most people use a steel ingot mould, but I prefer to use delft clay for the following reasons.
The internal grain structure is uniform across the ingot
You do not need to heat the mould prior to pouring the melt
You can make any size ingot you want, and far smaller, or larger than any steel mould
If you make a mistake with the pour, you can reset the sand mould very quickly.
