Silver casting/forging

[Greenbeast]

Never done anything with silver but a colleague who knows of my smithing has just asked about melting down a load of scrap solid silver cutlery and doing something with it.

I guess i could cast to shape.

Or I was wondering if i could cast a simple bar/ingot (simpler than a sand mold) and then forge it out to something?

[beth]

what do you want to make with the new silver? youd imagine it would be easier forged if you cast pieces in scale/shape of the work your planning.. ? sounds like fun though... :)

[Don A]

For what silver is worth now, I'd hesitate to do anything that would result in waste.

Perhaps save a bit for specific projects in mind later, but it has become too costly to play with.

I'd sell the silver and buy some stuff I could really use.

[Greenbeast]

what do you want to make with the new silver? youd imagine it would be easier forged if you cast pieces in scale/shape of the work your planning.. ? sounds like fun though...

Quite, i've asked what sort of thing they're like made so i can try and cast an ingot into a rough approximation

For what silver is worth now, I'd hesitate to do anything that would result in waste. Perhaps save a bit for specific projects in mind later, but it has become too costly to play with. I'd sell the silver and buy some stuff I could really use.

It's not mine to do as i wish but more a commission to turn scrap into something desirable.

[beth]

its tempting to forge straight from the cutlery... im interested to know what they want you to make :)

[Greenbeast]

Yeah i'll wait to see what they say and how much they've got.

I'm interested in branching out though! I've got another commission in brass to attempt at the moment, it's exciting moving away from steel briefly

[bbales]

WAIT!!!!!!!!

Before you melt it down, sell it off, or forge on that silver, take note of the hallmarking and do a little research online. Depending on when and what the mark it is stamped with, that silver could be worth more than its weight on a scale.

If that flatware does prove to be collectible, your friend's positive results are twofold: the first being a nice boost to their personal economy, the second being a part of the preservation process. Your friend might have a piece or ten that might have historical significance to those of us on the non-ferrous side.

If not, melt 'er down and get nutty with it.

A couple of things to think about if you are going to play with it.

Casting an ingot, bar or some such activity with silver is a little different than playing with iron or steel. Take alot of care with your atmosphere around the silver once you start to heat it if it is anything but fine silver (.999). The alloy in sterling will attract oxides (cuprous oxide, and cupric oxide), which if moderate to severe can cause profuse profanity down the road when working the ingot. It can make the metal brittle and porous, which can lead to shattering and cracking (see previous note on profanity) and can also make it very cranky to silver solder. Using a reducing atmosphere, proper melting and alloying procedure, and good flux go a long way to keeping the shop profanity free.

There is a technique recently developed by the japanese for casting larger ingots that helps to mitigate firescale AND produce finer grain in the final project for the small shop. I have used with success on a number of occasions. I have tweaked it a little over time to suit my working methodology, but by all means do the same as you see fit. The following steps assume you are following safe procedures and have a general knowledge of casting, pouring and handling molten metal.

materials needed:

copper ring, mine is 2" tall, by 6" across, by 1/4 inch thick
a metal bucket, tub or container and stand that can hold enough water to cover your ring and accommodate twice again the weight of the ingot for compression and evaporation.
fine cheesecloth
water
a heat source to boil the water in your bucket, i use a propane burner converted from a turkey deepfrying rig scavenged at a garage sale.


Process

1. Fill your bucket with water (I use distilled, Im finicky that way) and start the boiling process. Make sure that this apparatus is sturdy and stable for obvious reasons, and that the boiling is robust.
2. Secure the cheesecloth to the copper ring in such a way that the middle of this form is suspended 1/4" from the bottom of the ring. You want the pour to be suspended above the bottom of the bucket. Strap it, tie it, clip it, just make sure its tight and wont move or slip.
3. This step is optional, but I bring the water to a boil and boil off the excess water just before I start the melt so my exposure between crucible, air, water and cloth is minimal (finicky)
4. Pour your ingot directly into the center of the cheesecloth. ( I have seen metal molds that create regular ingot/bar forms but have not experimented with them. YMMV.) The cheesecloth will suspend the metal as it cools in the boiling water and a steam jacket will form around it at once. You will hear an immediate increase in the volume of the boil, followed by a thump ( sorry best description).
5. Once the ingot ceases to make noise, you can pull it out (use tongs, its still at 212 Fahrenheit).
6. Forge the ingot down to 1/2 its poured thickness, annealing as you go, and you should have a nice, tightly grained, workable chunk o' silver.
   

If you plan on hot forging sterling, you still want to be finicky about your starting ingot. You should also practice hot forging sterling on some scrap before pounding on red hot silver........it WILL shatter. Hot forging sterling isn't hard, it just takes some practice to get a feel for the right striking temps. I forge in a low light, using a medium red silver to lay on my anvil. The heat sink provided by the anvil is perfect for "black heat", the temp range safe for forging silver. You will feel the metal stiffen under your hammer just before its too cold.......get a feel for it like anything else.

Have fun, be safe and consider yourself very fortunate to be able to play with that amount of silver........I am completely envious! :D

[ThomasPowers]

I've hot forged silver before, it's a lot of fun compared to working say D2. And as hot you don't need to anneal as you go along---just reheat.

However you do want to not MELT your silver when re-heating as it's a pain to extract it from the clinker in your forge.

If you keep it de-oxidized it will work great.

Note that cutlery usually has minimal silver in it and most of it is other materials with a thin sheet of silver over it.

As mentioned: if it's in good shape it may be worth much more than silver price as replacement pieces and there are several places that specialize in such.

I'd cast as close to final form as possible to save time and effort.

[Greenbeast]

Thanks guys!
Yes, if/when i get my hands on the items i will be researching them!

Really appreciate the instructions/tips

I believe they are solid silver rather than plated but we'll have to wait and see

[tzonoqua]

Also when (and if) forging, keep surfaces, ie. anvil face/hammer faces/tool faces very clean, highly polished is best, as silver being very soft will pick up anything being pounded into it. Any dents in the anvil, or uneven surface on your hammer will be transferred to the silver.

[ThomasPowers]

I wasn't referring to plated. A lot of sterling cutlery is very thin layer of silver sheet over another material so the bulky table knife handle may have a non-metallic composition inside it and very little silver. Forks and spoons tend toward more solid silver save for those whose handles are done like the knives I mentioned.

[Steve Sells]

I must add that when when water casting, use multiple layers of cloth, the larger the pour; the more layers you will need, and make sure all of the air is out of the layers. Also I will repeat the suggestion that Distilled water is perferred, because other forms will have contaminants that could get into the billet

[John B]

In the UK all solid silver items are Hallmarked with date, maker and assay office stamps, be they cutlery jewellery or other items, so there should not be a problem in id'ing it Sterling is I believe 99% silver content, no doubt Beth or Colleen will correct me if I am wrong.

[tzonoqua]

Sterling silver is I believe 92.5% silver content, Britannia silver, I can't recall exact but I think about 95% and Fine Silver being 99.9%. and John B is quite correct if it has a uk hallmark you can quite easily ID it. Fine Silver would not normally be used for cutlery or functional items because it is so soft.

[ThomasPowers]

Lets add in 90% coin silver---though the exact percentage ranged wildly depending on where and when the coins were made. My grandfather has a massive book listing coins by country and date and their silver content as he used to buy silver at fleamarkets.

[Frank Turley]

Primitive pouring. I must've lucked out like Perry Mason. In the long ago days, a silversmith, David Dear, came to me wanting to make a concho belt of fairly thick silver conchos. He wondered whether we could melt and pour them, and he had collected some old, silver forks and spoons. Neither one of us was to hip to proper procedures. My old horseshoeing mentor, Al Kremen, used to cast lead weights on top of his anvil by forging a steel ring of maybe 3/16" x 1/2" bent flat and welded. It could be made into various shapes and placed on a flat portion of the anvil.to receive the hot lead. I thought we could do that with silver, and we did. I forget what we used as a ladle, but I'm sure it was made of something to be non reactive. We used lots of borax on top of the melt, as I had heard that a large percentage of silver could be lost to the atmosphere without fluxing. After the pours, we had some fairly rough looking slugs. David took them to his shop to forge and flat them. I'm fairly certain that he annealed and Sparexed them as necessary. He made a nice, heavy belt from them.

[Bentiron1946]

Brian Brazil has posted several examples of hot forged silver work on the forums. I usually work mine cold and then anneal when it starts to work harden. It is easier for me to do it this way since I'm working in the house and using an air/acetelyne torch for a heat source and not a forge. This works OK for copper and brass too, takes a bit longer but that's fine with me for now. I've been buying scrap Sterling silver from a jeweler friend of mine, .925, and melting it in a small crucible along with some boric acid and then pouring it into an ingot mould that has three different sized holes, 3/16", 1/4' & 3/8". This mould makes ingots that are about 3" tall. Usually they are put through a rolling mill until the diameter is reduced to a size that can then be put through darw plates to make wire but since I don't want wire I skip this step and just start hammering it out to make my rings and bracelets. Once in awhile I do run into prosity but not often if I preheat the mould that doesn't happen. Also soot up the mould so that the silver won't stick to it.

[ThomasPowers]

For hot forging ingot silver I use a one soft firebrick forge powered by a plain old plumber's propane torch. Easy to use inside.

[Greenbeast]

Thanks guys

[ptree]

I have melted scrap many many times in a simple cheap ingot mold from Rio Grande jewlers supply. it is a simple half moon round shape of ingot mold refractory. Been using the same one since about 1977. I use a siple propane hand held torch, and plain pure borax, 20 Mule team in the US. I place the scrap in the mold, heat and as the silver starts to slump I add a pinch of the borax. I continue to heat and flux as I see anything but a mirrow shiney puddle, and once clean I simply cool to solid and slide the button into Sparex to pickle. From there I cold or hot forge as needed to sheet and then fabricate what I need. Silver is pretty simple and easy to melt and forge. If you use the same scrap several melts the alloys are oxidized out and the silver approaches fine silver and gets softer. If you are seeing cracking when forging, you either had non silver in the melt, or forge to long for cold work or too hot for hot.

One technique I have used is to use a slightly rough anvil surface, and then the last forging is a planishing peening with a tiny little ball planishing hammer and the leave the peened surface. If you are carful in the polish you get a woonderful grainy surface that has fantasic highlights and a random grain.

I used the exact same technique for gold scrap.

When poor and in college after the ARMY in the late 70's I used to give wedding rings to good friends as a wedding gift. THEY supplied the metal, as I told them bring the old jewelery from previous loves and we will forge them into new rings for your new love. The folks got to watch/help, with both doing a little hammer work at minimum, and I would shamelessly tell them how the last traces of previous loves were gone, hammered out and new forged from the old. That usually got a good cry from the girls:) once sheet had been made I sawed out the ring blanks, and often saved a little strip when they were not looking that went into a envelope with their name. When they announced the birth of thier first, I would make a tiny little babies ring, suitable to fit a newborns finger but with a ribbon of pink or blue as needed. The ribbon is clove hitched to the ring, and has tails long enough to gently tie around the babies wrist to prevent loss and swallowing:) Mom and baby get a one time photo with the ring, and then the Mom wears the ring on a necklace. Those baby rings are darn hard to make as they are so small, but the ring with ribbon and a card explaining the tradition and where the metal came from usually got another good cry.

All are free to copy this as needed as it is a wonderful gift to close friends.