# ingot molds



## gbaldwin75 (Jan 2, 2008)

i was wondering how mints get logos on the back and front, and where can i get molds like that with custom logos?


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## Noxx (Jan 2, 2008)

You must buy customs stamps (or make them yourself)
I'm pretty sure Harold can help you if you plan to make your own.

You could also carve graphite to make them but the stamps will be less durable.


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## Harold_V (Jan 2, 2008)

As Noxx suggested, the impressions are normally stamped, not cast. It's doubtful you'd have acceptable results by casting. 

Prior to EDM's, (electrical discharge machines), such stamps were machined on a pantograph, then heat treated. An EDM will create a stamp from hardened steel----but the negative (the electrode) of the stamp must be machined by some means. A CNC can create the electrode, or even a pantograph. The electrode is typically made of fine grained graphite formulated for use on EDM's.

There are companies that specialize in making stamps. Check the yellow pages (if you live in a large community) for a stamp company and inquire of them if the make custom stamps. 

Be advised that, even in gold, the size of the stamp you elect to use can become overwhelming very quickly. You can't indent a large logo successfully without some kind of press. I used a 6 ton arbor press for my logo , and it was only about 3/4" in size. I had three sizes made and couldn't use the largest one because I lacked the necessary pressure. It's been years, but I recall it was about 1½" in diameter. Hitting the stamp with a hammer works to some degree, but you have little control. 

Harold


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## goldsilverpro (Jan 2, 2008)

I have stamped literally 1000's of 10 oz silver bars, one letter or number at a time, with a hammer. I can't be too smart.


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## Harold_V (Jan 2, 2008)

Stamping with a hammer doesn't work well with large surface area stamps. Doesn't matter if you're stamping a silver ingot, gold ingot, or a part on a machine. That alone was my point. I did not imply that hand stamping doesn't work. 

No argument with single character stamps, even large ones. The only negative to them is getting good alignment. You'd struggle with a large logo, just as I said. Been there, done that, got the T shirt. 

Harold


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## gbaldwin75 (Jan 3, 2008)

Thank you for your help


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## shadybear (Jan 22, 2008)

Hey where do you order that t-shirt from


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## Harold_V (Jan 22, 2008)

shadybear said:


> Hey where do you order that t-shirt from



Got mine at the "stupid" store. I used to hang out there regularly.  

Harold


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## shadybear (Jan 23, 2008)

Its amazing we haven't bumped into each other there


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## adrag10 (Apr 3, 2009)

Harold_V said:


> As Noxx suggested, the impressions are normally stamped, not cast. It's doubtful you'd have acceptable results by casting.
> 
> Prior to EDM's, (electrical discharge machines), such stamps were machined on a pantograph, then heat treated. An EDM will create a stamp from hardened steel----but the negative (the electrode) of the stamp must be machined by some means. A CNC can create the electrode, or even a pantograph. The electrode is typically made of fine grained graphite formulated for use on EDM's.
> 
> ...



Harold, can you give a company name that makes the stamps? Google searching brings up a bunch of stamp and coin sites. I have a 6 ton arbor press. I'm interested in pricing.

Al


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## Harold_V (Apr 4, 2009)

adrag10 said:


> Harold, can you give a company name that makes the stamps? Google searching brings up a bunch of stamp and coin sites. I have a 6 ton arbor press. I'm interested in pricing.
> Al


A six ton! That's exactly what I used to use---a Dake, with compound leverage. I still have it. 

I had my stamps made by Salt Lake Stamp Company, but that was more than 25 years ago. They were made by a plunge EDM. I still have the larger two, which were difficult to imprint, even with the six ton press. 

I don't know if SL Stamp still exists. I left Utah in '96. 

Sorry I'm not more help. 

Harold


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## istari9 (Apr 4, 2009)

How can a cast iron mold be had? I have been looking for one and the nearest one I have found is over $200.00. That is a bit rich for my blood...

Thanks, Ray


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## qst42know (Apr 4, 2009)

This outfit has some. They look coarse (as cast) straight from the foundry and are probably made in China.

From the home page under assay tools then under molds. but this should get to the page. They have several types to choose from if you look.

http://www.lmine.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=1839x&Category_Code=molds&Product_Count=4


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## Harold_V (Apr 5, 2009)

istari9 said:


> How can a cast iron mold be had? I have been looking for one and the nearest one I have found is over $200.00. That is a bit rich for my blood...
> 
> Thanks, Ray


Well, if I live enough years to get the house finished, I'm not above making them for those that would like them. They won't be free, but they damned well won't be $200 each, either. I hesitate to quote prices at this point, but when I get near I could maybe take orders and run them all at one time, bringing down the cost. You might think in the $35 range per mold. They would NOT be cast, they would be machined from ductile iron. I do not recommend a cast mold unless you pour very large ingots, 50 oz or greater. I used to have a cast 100 oz mold that seemed to work adequately, but the ingots weren't pretty. 

Understand that with gold, if you would like to pour various sized ingots, you can't use one mold to do the job. I had several, starting with ½ ounce, then 1 ounce, 2 ounce, 3 ounce, 5 ounce and ten ounce. If you try to pour a small ingot in a mold that is too large it doesn't fill the mold. 

Harold


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## semi-lucid (Apr 5, 2009)

Why couldn't you just machine one out of a chunk of cast iron?

I assume you want regular gray cast iron? (lots of graphite)

Why couldn't you use stainless steel with a polished cavity, and blacken it with soot from a flame just before you pour?

John

Edit: Uh Oh, I didn't see Harold's post above before I posted :!:


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## Harold_V (Apr 5, 2009)

semi-lucid said:


> Why couldn't you just machine one out of a chunk of cast iron?
> 
> I assume you want regular gray cast iron? (lots of graphite)


Gray iron works, but ductile offers better ductility, thus better resistance to heat shock and cracking. The difference between ductile and gray iron is usually nothing more than the shape of the graphite. Gray iron, low in sulfur, is inoculated with a magnesium compound which causes the graphite to form spheres instead of flakes. Tensile strength rivals that of mild steel, yet it behaves almost exactly like gray iron as far as machining is concerned.



> Why couldn't you use stainless steel with a polished cavity, and blacken it with soot from a flame just before you pour?


You could, but I don't think I'd encourage the idea. You're far better served with a material that will oxidize readily, which helps avoid soldering of the pour to the mold. Stainless is also considerably harder to machine, even the free machining grades, so there's no real advantage over iron molds, which are cheaper in the long haul. An iron mold should last a person a life time. 



> Edit: Uh Oh, I didn't see Harold's post above before I posted :!:


That's perfectly OK! You brought up a couple things that may help others make decisions. No harm done, eh? :wink: 

Harold


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## istari9 (Apr 7, 2009)

Harold_V, Yes I would be very interested in a set of molds. As you stated, machined sounds just fine. I thought of remaching the ones on the page given for the cast iron molds. To have a better lokking ingot. 


" Posted: Sun Apr 05, 2009 12:11 am Post subject: 

--------------------------------------------------------------------------------

istari9 wrote: 
How can a cast iron mold be had? I have been looking for one and the nearest one I have found is over $200.00. That is a bit rich for my blood... 

Thanks, Ray 

" You might think in the $35 range per mold. They would NOT be cast, they would be machined from ductile iron. 
Understand that with gold, if you would like to pour various sized ingots, you can't use one mold to do the job. I had several, starting with ½ ounce, then 1 ounce, 2 ounce, 3 ounce, 5 ounce and ten ounce. If you try to pour a small ingot in a mold that is too large it doesn't fill the mold. "


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## Harold_V (Apr 7, 2009)

istari9 said:


> Harold_V, Yes I would be very interested in a set of molds. As you stated, machined sounds just fine. I thought of remaching the ones on the page given for the cast iron molds. To have a better lokking ingot.


That may not be as easy as you think. Depending on the quality of the castings, it's not uncommon for cast iron to have sand imbedded in the surface. It raises hell on cutters, and refuses to cut cleanly. The mold may also be slightly chilled, making the surface quite hard. That's not uncommon with thin cross sections in cast iron. 

The very best quality is to make molds by machining, from material that has been cast oversized and cleaned up to remove the surface skin. It's the same as starting with bar stock, but with ductile iron instead of steel. That's how I'd make them, and is the method I used for the molds I used to own. 

Harold


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## istari9 (Apr 7, 2009)

Yes sir I am a machinest of sorts, welded for 35 years and can turn most any thing on a lath or mill as needed I have done some very nasty cast that would crumble as soon as a tool touched it. I realize the limitation of working with this type of metal. However I have done some quality jobs on fine cast in the past as well. So I see your point. Which is why I would reather pay you to make the molds as deal with an unknown quality of cast. I figure your approch is a better deal then the time and money wasted on a piece of junk. So if you get the time and inclination I wouldbe very interested in stirking up a deal at you pleasure. O and I do not own a lath or mill at this time. Still have some tooling though. 

Thanks, Ray


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## Harold_V (Apr 8, 2009)

istari9 said:


> I wouldbe very interested in stirking up a deal at you pleasure.


Sounds like a plan, Ray. Now if I can just get that damned house finished.  



> O and I do not own a lath or mill at this time. Still have some tooling though.


I don't know if I'm happy for you, or sad. I am not fond of machining, having burned out on the process many years ago. That's part of the reason I allowed my refining to become a business. It was a lot easier to face the lab daily than it was the machines. 

I envy you your welding skills. I took two years of welding at the community college in Salt Lake City, before we moved. I'd like to get good enough to weld a boiler for a model steam loco. I managed to pass x-ray vertical up with 7018, but I have a long ways to go until I'm happy with my welds. Welding, to me, is much harder than machining. No question in my mind, it requires considerably more manual skills than running machines. 

Harold


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## nicknitro (Apr 8, 2009)

I believe there is a member of the forum who offered to make hand stamps for coins and whatnot in the for sale trade section. I'm sure with his machining capabilities he could make what you need at a descent price.

Nick


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## silversaddle1 (Apr 18, 2009)

Here you go!

We use these guys all the time to make die sets and they re great. The prices are right too!

They can make any type marking stamp you want. They even sell holders so you can stamp by hand!

http://www.henryaevers.com/

Tell them Scott sent you!


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