# I Need Advice On Coring Out Some Carbon Blocks



## Anonymous (Apr 20, 2012)

Hello members,

I recently bought 3 pieces of graphite/carbon blocks, (well, one of them is a bar) and I'm waiting for them to arrive. But I have a few questions and was wanting some advice.

*Q1.* Can I use a zipsaw (a Black&Decker HS600) to cut the carbon into smaller pieces without chipping it or breaking it?

*Q2.* I have a rotary tool and I have a set of Dremel type attachments, but was wondering if any of the attachments can be used to core out the carbon?

*Q3.* How can I determine that the core hole I make out of the carbon will be able to hold 1 Troy oz of gold and also 1 troy oz of silver, or any Troy oz I want to make?

For Q3, I know that the density of gold and silver are different, so I'm going to be making moulds that will be specific to the metal I'm working with and not use it with other metals, so I don't contaminate the metals.

Q4. For the 3 pieces I purchased, how many moulds could I make? Below are the dimensions for each.

*Block 1.* http://www.ebay.com/itm/110838815404?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
*Block 2.* http://www.ebay.com/itm/110854447764?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
*Bar/Rod* http://www.ebay.com/itm/110861996944?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

Thanks in advance.

testerman


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## NobleMetalWorks (Apr 20, 2012)

Here is a link to a youtube video of a guy that has several instructional video's. He also has a video where he is using an AP tank. This particular video he is doing exactly what you want to do, and explains how to figure out how to get the most out of blocks of graphite/carbon blocks.

Anyway, here is the link

[youtube]http://www.youtube.com/watch?v=tykCqxqoQvk[/youtube]


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## Anonymous (Apr 20, 2012)

Thanks for the link SBrown,

If I had the same machinery he was using, I could make them quickly. However, there was one thing I noticed that I've already learned so far, and that is, you should never use graphite/carbon as crucibles. The video was self explanatory once I saw how he was setting the block up with the markings.

Once I get my blocks in I'll be able to at least slice them like a block of cheese, but that still doesn't tell me how I can tell that I made a mold that would make a 1 oz gold bar or a 1 oz silver bar.

I'm going to look around some more and see how to determine how much a mold will hold. or to make a mold to mold a specific weight of gold or silver.

I have everything he has in the video, except mine is on a smaller scale, but I can do it. I'll post back if I find some more information as to the amount I can expect to get out of each mold I core out.

testerman


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## NobleMetalWorks (Apr 20, 2012)

Are you just trying to make a mold to pour into?

If that is the case, get a drill that has a deep point that will drill a 1 inch hole. Then measure and tape off the drill so it doesn't go past a certain depth, drill your hole. It makes a mold that leaves a point on your button, but it works really well. If the point is deep enough you can do small quantities and your button will still have some depth instead of flattening out. Really easy, fast and simple. That's how I made mine.


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## Anonymous (Apr 20, 2012)

SBrown said:


> Are you just trying to make a mold to pour into?
> 
> If that is the case, get a drill that has a deep point that will drill a 1 inch hole. Then measure and tape off the drill so it doesn't go past a certain depth, drill your hole. It makes a mold that leaves a point on your button, but it works really well. If the point is deep enough you can do small quantities and your button will still have some depth instead of flattening out. Really easy, fast and simple. That's how I made mine.


I think you're misunderstanding me. I want to make a mold, but I only want it to be enough to put 1 Troy oz of gold in it. Again, I want to make another mold but I only want it to fill enough to make 1 Troy oz of silver.

The same with 2 oz molds, 5 oz molds, etc,..

Even if I went 1 inch deep into the mold to drill it out, how wide would I need to go and still get the size I need... enough to pour 1 oz of molten gold in? It's the same with the cast steel molds I already have, and I'm wanting to know how did they determine that I can make a 5 oz gold mold from that mold.

testerman


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## philddreamer (Apr 20, 2012)

Hi Testerman!

I made an "adjustable" steel mold a couple of years ago. The mold is 1/2" deep by one inch wide and I had to open it 1/2 an inch in order to pour a one oz. gold ingot. The ingot would be about 3/8 inch deep, (or high). 

I also happen to have a 5 oz gold graphite mold. Its dimensions are 7/8" wide by 1-11/16" long by 7/16" deep.

For silver I have the cast iron 5 oz to 10 oz mold.
Hope this helps.
Take care!

Phil


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## Anonymous (Apr 20, 2012)

Hello philddreamer,

Yes..... That gives me a starting point on determining how I need to core out my blocks without wasting much of it.

Once I do a few and get the feel for them, knowing the dimension, or, actually the inside depth and width of a mold, I can come fairly close to making the molds to hold the right amount of gold and silver. I am also taking into consideration that there will be some weight differences either higher or lower than the exact weight needed.

I have over 8.7 oz of cemented silver and I'll melt enough to pour into a few of my 5 oz conical cast iron mold I have. I also have a 5 oz steel conical mold too. All the conical molds I have a 5 oz of gold. Would that be around 2.5 oz of silver I can pour into those molds?

Also, if the mold will hold only 2.5 oz silver, do I need to weigh the cemented silver to weigh 2.5 oz and then melt that to fill up the mold?

Thanks again, and thanks to you too SBrown for the help.

testerman


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## philddreamer (Apr 20, 2012)

I'm glad the info helped.

Now, you should always weigh your gold, or silver, prior to melting & pouring the ingot. If you just melt & pour, the discrepancy between each ingot will be too big, unless you don't mind... but, always weigh prior, so the ingots end up very close to the weight you desire. 

I think you can pour 2.5 T oz of silver into a 5 T oz gold mold. Give it a shot.

Phil


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## Smack (Apr 20, 2012)

Nice looking stitch welds Phil.


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## philddreamer (Apr 20, 2012)

Thanks Smack!
I've been practicing for 38 years... :lol: 

Phil


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## MysticColby (Apr 20, 2012)

I made my own graphite ingot molds a few months ago. it went pretty well, but it was annoying work.
couple things:
graphite makes A LOT of dust. make sure to have something that draws it away (vacuum cleaner, perhaps) - but be careful with what you choose, the graphite dust is electrically conductive and will short out the vacuum motor if it travels through the motor. centrifugal fan that blows the dust well away from you outside might be a better choice.
graphite is hard. it will be slow going. The best results I had were with a Dremel 9901 Tungsten Carbide Cutter on a high speed





Then I used a Dremel 125 High Speed Cutter to make the angled edges




As for size: choose a width and height that you want it to be, then calculate what depth it should be. you'll need to convert from weight to volume first. I prefer using metric, but ounces and inches are also possible. in fact, for simplicity, I'm going to use metric anyways . something like this:
silver = 10.49 g/mL
1 troy oz = 31.1034768 grams
31.1034768 g / 10.49 g/ml = 2.9650597521449 ml
1 ml = 0.0610237441 cubic inch
2.9650597521449 ml * 0.0610237441 in^3/ml = 0.1809390475561 cubic inch

So you need to find dimensions of a rectangle that multiple together to equal 0.1809390475561. example:
1 inch height * 0.5 in width * 0.3618780951122 in deep = 0.1809390475561 cubic inch
height * width * x = 0.1809390475561, solve for x:
depth = 0.1809390475561 / ( height * width)

now that you have that, cut the graphite to make a void of that size.
it should be pointed out that gold is almost twice the density of silver. so a 1 troy ounce gold mold will be a bit more than half the volume of a 1 troy ounce silver mold
I should also mention that molten metal has surface tension. That means that if the mold is over-filled, the metal will form a mound above it, which makes an ingot heavier than you wanted (see philddreamer's ingot). That is why it's nearly impossible to pour an ingot of the exact weight you want. measuring the amount you melt goes a long way toward that end, though (only melt a little over 1 troy ounce, and the ingot should be about 1 troy ounce).


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## Anonymous (Apr 20, 2012)

Hello *MysticColby*,

Wow, that is some information I really need. Thanks so much for that. And those pictures you have of those Dremel bits, I believe I have them too. Also, from reading the replies and doing some researching, I am going to also make two-part molds and drill a hold between them both so that I can have almost perfectly even sides for my bars and ingots. 

To *Philddreamer*,
I meant to tell you that I like your mold setup and that piece of gold ingot. I look forward to creating my first one, hopefully soon.

All of you have been really helpful and I appreciate your valuable time in doing so. 

I have so much material to work with and I'm wanting to start out by using certain molds, crucibles and other things just for a particular metal, so I don't contaminate anything. 

I'll take some pictures of what I have to work with when the blocks arrive and after I cut a few molds out to show you all my progress. I'm going to eventually go with steel molds as soon as I get a hold of the right steel to use. I have a business associate that owns a wrought iron business and he probably has all the equipment I would need to use, when needed. 

I now have more information to work with, which in turn gave me a better understanding of how I need to approach the mold making.

testerman


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## philddreamer (Apr 20, 2012)

I would like to make clear, that I made the steel mold out of necesity.

If one needs to keep the PM's pure, it is best not to pour into metal molds. (Never melt in a mold!) I use the steel mold, or the cast iron mold for the scrap PM's that I'm sending to the refiner, & graphite molds for my pure PM's. I always boil in diluted sulphuric the ingots so to get rid of borax, any surface impurities &/or oxidation.

Take care! 

Phil


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## NobleMetalWorks (Apr 20, 2012)

Sorry for misunderstanding, that must have been frustrating.

I didn't bother to mill mine to exact size, I weight the gold dust, melt and pour into the mold I made. My intent was to be able to use the same mold, no matter how much gold I poured, after all I am not casting gold to re-sell to an individual, I am selling it for cash and retaining my silver/platinum/palladium/rhodium, so I have no need to make it look pretty.

Couldn't you just read the specs of a round mold, then drill a round hold with a bit that has a flat point to get the exact measurement?

I did a quick search and couldn't find any specs for gold molds, but I am sure somewhere you will be able to find the,.. Whenever possible, I benchmark off others and then try to improve upon it. Also, if you copy someone's design, you are assured that you will have the correct size.


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## Anonymous (Apr 21, 2012)

To *Philddreamer*,

That ingot looks good. I forgot to mention that I do have a melting dish and about a dozen brand new crucibles. When I pour into my molds I want the molds to be as perfect as possible, even if it won't be perfect. I'll eventually get better at making molds.

To *SBrown*,

No need to be sorry about misunderstanding anything. That's how we learn and how I'm learning too, and also to be more specific if I'm not and give more information. All of this is exciting to me and I am pleased to be doing what I'm doing. That's how I'm going to get better at this and be in a position to help others out too.

Even down to the melting dishes, I'm gong to start buying the clay and (or) powder firebrick mix to make my own crucibles to the specs I need. It takes time to do this and it takes patience, and most importantly, it takes the understanding to know the dangers involved. 

I still need insulation, glass rods, and a few other things. But for the most part I have what I need to start refining... but I'm still in the recovery stages because I have just about all precious metal bearing items/components the average person is working with to this day to recover and refine precious metals, with the exception of catalytic converters.

I'm almost sure that if a metal in the mold is near perfect condition and purity it'll bring more money than just what it's worth as scrap or spot value, simply because some items may be bought from you and not used to melt down or scrap. It's the uniqueness that can bring in the extra money. As I learn, I'll get better at my molding, pouring and polishing skills.

testerman


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## NobleMetalWorks (Apr 21, 2012)

testerman said:


> Even down to the melting dishes, I'm gong to start buying the clay and (or) powder firebrick mix to make my own crucibles to the specs I need.
> 
> testerman



I have been playing with the idea of making my own crucibles also, there are some fairly good if not at least instructive video's on YouTube on the subject. I would really like to figure out some way of re-using the fine ceramic material left over from processing CPU's, I have several 5 gallon buckets of the stuff. I'm thinking about using it as part of the ingredients that are not refractory/clay/etc. I was also thinking about using it in cement. Unfortunately, I just don't have free time and the way things are going, I am not sure when I will to play around with it. Maybe if I didn't read and post so much on the forum, ha...



testerman said:


> I'm almost sure that if a metal in the mold is near perfect condition and purity it'll bring more money than just what it's worth as scrap or spot value, simply because some items may be bought from you and not used to melt down or scrap. It's the uniqueness that can bring in the extra money. As I learn, I'll get better at my molding, pouring and polishing skills.
> 
> testerman



Well I commend you, and you are right. There are some really interesting things you can do with your refined metals. And you are also right about increasing it's value. If you can make a beautiful gold bar that brings more money, then that's just simply brilliant.

By the way, same guy, but this video might help you a bit more. He actually makes a mold, it's in two video's I'm posting them both.

[youtube]http://www.youtube.com/watch?v=QtzqDkhyWbw&feature=channel&list=UL[/youtube]

[youtube]http://www.youtube.com/watch?v=4p4VPNgenew&feature=channel&list=UL[/youtube]

Post pictures when you are finished if you would, I am really curious now to see what you come up with. I might end up trying this myself!


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## Anonymous (Apr 21, 2012)

*SBrown*,

Thanks for the video posts. They compounded on the ideas that I have for the molds too. Also, when he showed the Xacto knife with the scraper, that was an idea that I needed because I just bought an Xacto knife a few weeks ago and now I know I'll need to get that blade. 

I'm so excited because I know I'm going to make some magnificent ingots, bars and other molds when I get the hang of things. Being as though I have plenty of aluminum, I'm going to make a few testing molds to use to prefect my pouring and end result molding. My main goal from what I learned from those videos, especially the 2nd one is that I need to do as I said before, and that is to make 2-part molds. That's my main goal.

I thank everyone for the help and information provided to me. It will last me a lifetime. 

Oh... and I will be providing pictures and hopefully videos of how I've done so especially the beginners like myself can learn from.

testerman


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## NobleMetalWorks (Apr 21, 2012)

If you want to make two part molds, that same guy that I posted youtube video's of also has a video on a mold he made, then loads into a custom made apparatus, I think he said he can load 3 molds at a time in it or something.

He also recovers/refines gold, his wife I think, designs and makes custom jewelry.


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## Anonymous (Apr 21, 2012)

SBrown said:


> If you want to make two part molds, that same guy that I posted youtube video's of also has a video on a mold he made, then loads into a custom made apparatus, I think he said he can load 3 molds at a time in it or something.
> 
> He also recovers/refines gold, his wife I think, designs and makes custom jewelry.


I'm going to save him in my YouTube account and look at his other videos.

And speaking of custom molds, that's what I do need. Do you know of where I can get some custom molds (2-part molds) for silver? But I will want them made of high tension/grade steel as they will last almost a lifetime... I think.

testerman


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## lazersteve (Apr 22, 2012)

For two part graphite molds you can use a jig saw and two equal sized slabs of graphite stacked together.

Wear your proper safety equipment (gloves, goggles, and particle mask) when working with graphite.

Start by clamping the two slabs together and sketching out the rectangular shape of your mold cavity on the top slab.

Next make 'key holes' between the two slabs by drilling two 1/8" holes in opposite corners of the top slab, outside the area marked for your cavity. The holes go all the way through the top slab and _*only 1/2 way into the bottom slab*_. These key holes will have 1/8" metal alignment dowels ( cut the sharp tips off of two 16d nails to be used as dowels).

Seperate the two slabs and drill two 1/4" holes all the way through the top slab making sure to the edge of the drill hole stays inside the area of the mold to be removed. One hole in each of two opposite corners.

Use your jigsaw to cut away the area of the mold you want to fill with metal. Be very slow and steady so your blade does no bend or make wavy walls on the mold. 

Finally hand sand out any imperfections in the walls of the mold cavity and try to add a slight angle to the walls. The draft of the angles should be around 5-10 degrees. A medium grit paper or emery cloth works great for roughing the walls in and a fine grit is used to put a nice finish on the walls so the cast bars are smooth. 

Soot the mold with actylene before each cast to give your bars a nice shine and smooth finish. Preheat the mold before using to drive out any moisture and to help the molten metal flow smoothly around the mold.

Here's a photo of one I recently made for making silver anodes (not perfect, but cheap and effective):






If you are using small pieces of graphite you will need to clamp the two pieces together when pouring.

With a little patience and attention to craftsmanship, you can easily make a mold that will produce beautiful bars.

Steve


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## Anonymous (Apr 23, 2012)

Thanks* lazersteve*,

I will be following your instructions and I'll post pictures and my progress when I'm ready to cast a few bars.

This information is priceless to me. I'm so glad to be part of an elite group of people and being a part of the most worth while forum on the Internet.

Thanks so much...

Kevin


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## Digitaria (Mar 30, 2014)

I heard that kaolin clay first cooked to make metakaolin, then cooked to the point of destroying it, makes excellent high temperature material which is used to make molds for fused quartz.


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