Non-Chemical Pouring thin bars....

[colu41]

Ive been making sterling bars lately and am getting very good with it BUT. I. Have been trying and trying to make a thin bar. Thin as in like 3/32" of an inch. The thickness of an American Silver Eagle.
Now. I dont use graphite. I make all my molds custom out of ashwood. My problem is, i cant figure out a way to make a mold from wood that is thin like that, without the silver spewing back out of the mold. Not sure why it does that. And one time it actually somewhat exploded. Sending a few grams flying in my garage.

Any tips would be great.

Ill post pics later of some my bars

 

[Oz]

The wood contains moisture, and you are getting steam. You’re lucky you have not had a serious injury from a steam explosion.

 

[etack]

without the silver spewing back out of the mold. Not sure why it does that. And one time it actually somewhat exploded. Sending a few grams flying in my garage.

Sounds like a steam explosion to me. why not buy sterling stock ans cut it it will look nicer in the end. I guess the other question is why pour sterling bars? I never under stand why people melt sterling to pour it in a mold to call it sterling. If any of the Cu oxidizes than it is no longer 92.5% silver. It now has a higher silver content than sterling. So one will lose money on melting by fuel cost and destroying the makers mark, and now by saying it is sterling when it could be 93%+ in silver.

sorry a small pet peeve of mine.

Eric

OZ beat me 8)

 

[colu41]

Nope no injuries. I wear safety glasses and gloves and Ive never had a problem.

I do sterling bars because I get old flatware and silverware usually 20 to 30% less than spot price. And am able to sell each bar for a nice profit. I just love making bars at home. Its fun.
And Ive researched doing 999 bars. But cant seem to find any shot or anything at a good price

 

[RESET]

Why not process your sterling into fine silver to pour your bars?

Lasersteve's thread on processing sterling thru a silver cell.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=50&t=2868

 

[colu41]

Refining silver did always intrerest me but I make small 3 oz bars. Nothing big, and dont think I have the right equipment to do this. And would rather not spend a bunch of money to start this.
I get sterling for cheap and sell them for a decent premium and then I buy Fine silver.

 

[colu41]

Here's a few I've made....Nothing big like all the rest I've seen on here.

http://i49.tinypic.com/x364xw.jpg

Sorry. Too big of pics to post directly

 

[its-all-a-lie]

Those bars look nice. Have you calculated the time you spend polishing the bars and deducted that cost from profits? Time costs money and to make poured sterling bars look that good would take a considerable ammount of time i would assume. This is something i never take into consideration when doing something i enjoy, but when you are in it for money it becomes a different ballgame entirely.

 

[colu41]

Those bars look nice. Have you calculated the time you spend polishing the bars and deducted that cost from profits? Time costs money and to make poured sterling bars look that good would take a considerable ammount of time i would assume. This is something i never take into consideration when doing something i enjoy, but when you are in it for money it becomes a different ballgame entirely.

In the same boat as you. I do this because I enjoy it. Super fun to me. I've always loved making things myself that not many people would ever think about do. And I've had a knack for shiny things my whole life

For profit wise. Time I do not consider as this is my hobby, I love doing it, most bars I make I keep for my collection. But other than that, I've figured out how much use I get from the tank of gas and what not, and for the very good prices I pay for this "junk" sterling, I am still making a very decent profit.

Just 2 weeks ago, I bought 4 sterling spoons. A total metal price of $64, I paid only $35 with shipping! Pretty unbelievable but I try catching those few auctions that not many people have viewed, and I guess I get lucky.

 

[jonn]

Your best bet would be to pour a thick bar and send it through the rolling mill. Works wonders and once your sheet is the right thickness you would use a punch press for any shape to be cut out of your strip. You get the same results over and over. :lol:

 

[kronix]

another thing i would suggest, (although i am a noob and i may be wrong) is to use a mold that you can change the size of the bar. my local jeweler had a graphite one that you could make and ingot, or 4 different sizes of rods just by sliding the 2 pieces back and forth, and clamping once you selected the size like my doodle shown below:


my point is that he poured it vertically, which may allow for a thinner bar if you make your own mold.

im sure someone will correct me if im wrong, im just thinking out loud..

-Ian

 

[MysticColby]

kronix is absolutely right. That is the only way to pour thin 'bars' (rolling them is a better choice, though). Of course, this is an impossible option if you're using wood as a mold. You must use graphite (or iron or steel).
even if the wood is 100% as dry as you can make it, it will still release volatiles when heated to these temperatures, which are gases that are released by the wood and force their way through the metal, causing explosions. safety glasses and long sleeve jackets help, but when globs of molten silver are flying through the air, they won't save your cheeks, neck, wrists, feet, etc.
wood molds can be used for small ingots, where there isn't as much heat involved (as you've been doing). But tall molds like you want would be a lot of surface area for that gas to come from...

 

[qst42know]

Graphite is fairly easy to work with. The same as your wood just very messy and don't breathe it.

 

[MysticColby]

if you're sculpting your own graphite, make sure to have some sort of vacuum or blower to remove the dust from you breathing it in. Also note that graphite dust is electrically conductive, so if it is sucked into the vacuum's motor, it will short out the motor. When that happened to me, I was scared I destroyed my friend's shop-vac, then I blew some compressed air through the vacuum and it worked again. I went and got a cheap one from a thrift store after that - haven't shorted that one out, it depends on the design of the vacuum.

 

[bswartzwelder]

You may not have had a steam explosion at all. I once worked for Anchor Hocking. They make all kinds of glassware. In the particular plant where I worked, they made bottles. Lots and lots of bottles. Clear bottles, green bottles and brown bottles. The machines which mad the bottles had thick, syrupy glsss dripping out of holes from the oven into the machine. Funnels would extend and catch the glass which was cut off the flow with something resembling scissors. The glass would then drop into the funnels and be channeled into the mold. Once, I watched a worker catch a blob of the glass as it came out of the chute before it fell into the mold. The glass landed on a board which I presume was asbestos. It then started to expand blowing bubbles. The entire blob cantained many bubbles formed from molten glass while it was still so hot it had not solidified. Once cooled, it was really kinda pretty and each one was an individual work of art which could not be duplicated. I later learned the air trapped in the asbestos board expanded due to the heat of the glass and made all the bubbles. I had several of these and built wooden bases with lights in them which would shine up through openings in the wood. They were really pretty, but alas, they were fragile. Over the years, they have been broken, never to be replaced. Oh for the good old days.

 

[jonn]

I will sell you graphite blocks PM me, very easy to work with

 

[Jimmy]

I Make molds for guys who make gold jewlery. Basickly they take a form made of aluminum like the one in the photo and put some wood boards around it then fill it with plaster. Then they pull off the plaster and stick it in a oven to drive out the moisture then put a piece of ridgid refractory board flat against the side with the cavity. They they fill it with metal and almost right away break the plaster, knock off the sprus then roll it to desired thickness. Ive done some very thin ones in the past.

 

[Lino1406]

No danger of aluminum get in contact with KNO3 component
of the flux?

 

[g_axelsson]

No danger for that, as the aluminum is only a template to mold the plaster. It is removed before the plaster is fired to remove water.

Göran

 

[JHS]

just cut a vent hole near the pour hole and use dry wood.or get a small sand casting kit.