# cnc engraving into graphite



## AlisRuss (Mar 28, 2020)

My son wants a carving done in graphite to use as a mold for melted silver. Any advice for working with graphite and the tools that might be needed?


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## JOAT (Apr 9, 2010)

What does he want? Just a bar, or a figure? If just a bar, you can buy a lead ingot mold on ebay, or even make one yourself.


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## AlisRuss (Mar 28, 2020)

He's going to provide the graphite and it will be used to make silver pendants. I am wondering if you have any advice on what bits, speed and feed rates etc to use on a cnc machine. I also will need to add the graphite to my materials list. Would it be more closely related to a metal or a stone? 

As I'm sure you have deduced by now, I am such a newbie.

Thank you for any suggestions in advance.


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## DaninVan (Jan 1, 2012)

Hi, Alison; many years ago (Summer of '64...) I worked at a steel smelter. At that time, Western Canada Steel was still using Iron molds, They looked like 4' tall pipes standing on end,i n long rows.
before we pored into them _each one's interior was sprayed with graphite_. Would that process work for your son?
EZ KOTE? 65 Green Sand Metalcasting Foundry Graphite Core and Mold Coatings


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## JOAT (Apr 9, 2010)

AlisRuss said:


> He's going to provide the graphite and it will be used to make silver pendants. I am wondering if you have any advice on what bits, speed and feed rates etc to use on a cnc machine. I also will need to add the graphite to my materials list. Would it be more closely related to a metal or a stone?
> As I'm sure you have deduced by now, I am such a newbie.
> 
> Thank you for any suggestions in advance.


You are going to have to get answers to all of that from someone else, I don't do CNC machines. Were it me, I would just make my molds out of clay. Instead of silver, I might well use metal clay (at least I think that is what it is called, a combination of clay and whatever metal you will be using). 

Been a really long time since I was interested in any of this type of stuff, and that was in large part just lost wax casting. However, thinking on it, may be worth my time and effort to make a small forge, along with a few custom molds, and make some branding irons. I'll have to see what I have, and what I need to get.


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## MEBCWD (Jan 14, 2012)

Alison I don't know if you really want to machine graphite on you machine or not.

Machining graphite produces very fine dust that is very abrasive to machine parts as well as something you really don't want to breathe.

Most companies that machine a lot of graphite use enclosed systems to contain the fine dust and the parts used to build the machine are better equipped to handle the abrasive dust.

If you still want to look into doing it you can Google "cnc machining graphite" but I also suggest this search "machining graphite hazards"


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## ger21 (Feb 10, 2019)

Google says you want a chip load of about .002", and that it's very abrasive, and can be brittle.
I'm guessing it cut's a bit like Corian.


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