Proper Crucibles for the Dry Path

Turns out that an iron crucible is really not a good idea for using the dry path, because it will be corroded and attacked by the mighty power of our Alkahest salt.

And a 100% ceramic crucible is out of the question, because it would certainly fail and crack from thermal shock. The two types of crucibles we have to choose from is Clay-Graphite and Silicon Carbide.

The Silicon Carbide is about the best material you can get that isn't metallic. It has a much better resistance to thermal shock than Clay-graphite. Also the stand which the crucible sits on in the furnace should be made of the same material as the crucible. This prevents the bottom from becoming unevenly hotter. But with molten metal inside, the bottom is going to get much hotter than the top anyway.

When working with metals in a Silicon Carbide crucible, there are certain things you need to do for proper care of your crucible. These babies are expensive!

Here is an extract from a website that sells these crucibles:

Silicon Carbide Crucibles are protected with glazes. When the Crucible is heated to 900°C, glaze softens at this temperature and closes the hair line cracks, if any, in the glaze. If glaze is thorough and complete, life of the Crucible increases. In fact, in case of holding applications below 900°C, Crucible must be heated up to 900°C, and held for one hour at least once a week.

Charging

Once Crucible is red hot, first charge light scraps. Charge solid ingots/pieces slowly and continuously. Use tongues for placing ingots vertically. Don't pack the metals tightly. There should be sufficient space for the metal to expand since metals expands almost 7 times more than Crucible expansion. Don't add the flux onto the body of the Crucible.


Melting and Pouring

Maintain proper combustion ratio of Oil and Air for reduced melting time. Melt as quickly as possible. Over heating should be avoided.

Empty the Crucible as quickly as possible.

It is to be noted that continuous use of Crucible gives better performance than interrupted one. This also results in lower melting cost.(less propane needed to heat up the crucible again)

In case there is any kind of delay between the melts, all furnace openings should be closed to avoid heat losses and also to prevent oxidation of Crucible.



Cleaning of Crucible

Crucible should be cleaned by scraping between the melts in red hot condition. This should be done quickly and carefully. In case slag/dross is not cleaned, it results in the following:

-Faster thinning of Crucible wall
-Reducing the overall Crucible life
-Reduction in Crucible's capacity
-Reduced heat Transfer and increase in heating time
-Premature failure of Crucible, due to differential thermal expansion. It is to be noted that dross/oxide expands approximately 5 times to Crucible, and
more gas formation in the melt since some drosses readily absorb moisture resulting in gas pick up.


So as you can see, there is a fine art to using crucibles. Sealing the lid on one can have unknown effects and lead to the crucible failing by cracking or bursting, or simply deforming from the pressure. Its gonna take a lot of trail and error to get things just right. It would be so nice to just be able to use an iron pipe, but it creates a mess and the stone doesn't come out looking very good.

Some jewellers make melting gold seem pretty easy, and no furnace is needed.

Here's an eHow.com example:


#Step1 Gather your supplies. This includes the pure gold for melting, an acetylene torch and a crucible made out of graphite or fused silica, filter paper and crucible tongs.


#Step 2 Heat the solder up to at least 710 and no more than 787 degrees Fahrenheit. Use the torch to preheat the crucible for a few minutes before placing the gold in the crucible.

#Step 3 Wrap the gold with filter paper, put it in the crucible.

#Step 4 Heat the gold with the torch from the bottom and the sides, not the top. Once it's molten, you can run the flame directly across the surface of the gold fluid. The filter paper should have burned up with the heat, leaving the gold pure.

#Step 5Use crucible tongs to pour the gold into your mold or form. Make sure to form the gold while it's still hot. If it cools too much, you'll have to re-melt it, and the more you re-melt and reform the gold, the more you risk the metal's stability.

#Step 6 Once the gold is shaped, let it cool and harden.


And here's tip from another article:

When melting any powdered metal in a crucible pot, preheat the empty crucible to get it extremely hot. Then, slowly add a little metal powder before bringing the torch flame to the crucible.

I think there might also be such a thing as pure graphite crucibles like this one at amazon.com



I might buy those and try them out with my MAPP gas torch. The problems is that graphite cools off nearly instantly as soon as the flame is taken off. That's why graphite is used in that stupid new battery operated soldering iron that heats up instantly, and cools off instantly so you can't burn yourself. But its also a piece of crap and doesn't work at all, not even a little bit.

If it just had more power, it would work like this:

How to make a soldering iron from pencil graphite

Here's a furnace with a graphite crucible embedded into it, and able to handle 100 to 30 oz of gold depending on which size you get.





From TekCast.com

I'm liking that baby a lot because you don't need to worry about using a separate little crucible. You could just heat it up, then put 30oz of gold in there, with 30z of dew crystals, all powdered and mixed together of course, and wait an hour for it all to be converted to a ridiculous amount of the Stone!

I found one that is very similar on eBay for only $300! I placed a bid and the auction ends in 2 days. I hope I win that bastard! It also comes with an extra graphite crucible and the crucible tongs for holding the crucible by itself for pouring.



It keeps oxygen out and heat inside, which means it would indeed work perfectly for the Dry Path! Can melt up to 30oz of gold. You just set the temperature to what you want, then leave it, and it brings the metal up to that temp. and holds it there. The pic of those two graphite crucibles above are actually the replacements for this unit.

AWESOMENESS!





So far nobody else is bidding on it, but 112 people have visited the page took look at it, and 2 people asked questions about payment, so I'm hoping I won't get into a bidding war with anyone. Worse comes to worse, I can always just buy the same exact model instantly for $530 plus S&H. But I wanted to get this awesome deal on it, because its just perfect for the new year. No more playing around with a ridiculous MAPP gas torch!

NDC wrote:

Here's a furnace with a graphite crucible embedded into it, and able to handle 100 to 30 oz of gold depending on which size you get.

This is exactly the type I'm saving up for

The one I have my eyes on costs around 700 Euros (including the graphite crucible and other needed accessories), and it comes with the benefit of being sold in a local store - so there's reliable warranty and someone to talk and get pro advice from.

But the most interesting part is that when I first found the store and talked with one of the owners, he told me of someone who bought one of these units and used it for extended periods of time until the unit broke and he had to buy a new one - but "it was appearently worth it" (this the store owner said with a mysterious smile on his face...). I felt this strange yet familiar alchemical vibe emerging from between the lines of the story, so I asked the owner if he is still in touch with that person, to which he replied: "Well, he's in a different place now..." with the same mysterious smile. The store owner wouldn't say any more about it, but that was a major clue for me that I'm on the right track.

Ahh man, that's great Andy, because now we'll be able to easily replicate each other's experiments, and give advice on how to use this thing.

What accessories does yours come with? Gloves and facemask or just some tongs and molds? The heat resistant gloves cost like 100 bucks, and so does the apron. And molds are ridiculously expensive too. Seems like everything for metallurgy is way overpriced for some stupid reason.

I need to get a mold for making little bars of gold.

I'm sure about the graphite crucible(s) and about the tongs and stirring rods. There is also a powder he said he'd give me that makes gold melt easier (I don't know what it is...). I'm not sure about the gloves and face mask, though... Molds are not included in the price...

How about that mysterious story the guy told me? There may have been a successful Alchemist not far from where I live ! ! !

And yes, absolutely, these things are ridiculously overpriced. I could have one made to order, paying for parts and labor, and it would come out cheaper - but I think I prefer to save for the ready-made unit from the aforementioned pro-store.

And BTW, I was told that the graphite crucibles are not meant/fit for use with gas furnaces, only with the electric type we're both aiming for.

I use exactly that kind of electric furnace with graphite crucibles.

The material/powder you are supposed to melt gold with is Borax. I would NOT advice to use it because of its toxicity and its only really necessary if you want to melt 1kg or 2kg of gold at once. (fully filled crucible)

You can set the temperature and the furnace keeps it +- 20°C.
The sensor is a little bit deceiving because it takes about +10mins until the material in the crucible will have the temperature you selected...

so set the furnace to 400°C to melt lead, the furnace will stay at 400°C but it takes like +10mins until the lead finally melts and probably like +30mins until gold finally melts if you set it to 1150°C (maximum)


Anyway this is the most safe, easy, convenient and rather cheap way of melting metals which I can everyone recommend.


The graphite crucibles are made to last only for about 10 times I have been told. And the Borax would prolong the lifetime of the graphite crucible. But my furnace came with 2 graphite crucibles and a new replacement is cheap.


I thought about the screwed on iron pipes to heat our alkahest (GW, dew) salt with gold in this crucible. If you put the iron pipe in the graphite crucible it may not reach the gold melting point inside the pipes but I dont really know. The other possibility is to simply put the iron pipe in the furnace instead of the graphite crucible.

I havent used it in half a year now. I have been busy making the said salt first .

Wilfried

Wilfried wrote:

The material/powder you are supposed to melt gold with is Borax. I would NOT advice to use it because of its toxicity. The graphite crucibles are made to last only for about 10 times I have been told.

Vielen Dank, Wilfried. Ich wusste das nicht.

Many thanks, Wilfried. I didn't know that...

Take a look at this ridiculously inexpensive melting furnaces that come with the same graphite crucible:

R-Series of Compact Kilns


I like the square one that's only $160. I kind of wish I saw this one first, but it doesn't have a digital temperature control, or a pyrometer. It looks just like the one Patrice used in his Seminar back in 2008. I wonder how reliable it is and how long it would actually last. There is a $300 version that comes with a digital converter, and I'll probably get that one if I loose the auction on this other one.


If the graphite crucibles can only be used 10 times, then it's probably worth investing in a fused silcon carbide one.


The one I'm trying to win on eBay right now has a max temp. of 1200C and a temperature control accurate to +-5F(3C). so it seems like the better deal even though it costs three times more. But now I'm in a bidding war with someone else, and its up to $400.

NDC wrote:

If the graphite crucibles can only be used 10 times, then it's probably worth investing in a fused silcon carbide one.

Actually I believe as long as you dont fill it up everytime (1 to 2 kg of metal) it will be useable way longer.

These furnaces are made to melt gold/silver therefor any information you get is in regard of a full crucible of gold/silver heated until liquid.
In this case the graphite crucible without borax will be reusable for about 10 times.

Besides that for projections to proof our work you only need a few grams of eg. lead which you need to heat only up to 400°C. This wont harm the crucible at all.
On the other hand I have also been informed that melting other non precious metals (like lead) is problematic if you fill the whole crucible. Something like the gases cluttering and damaging the inside of the crucible although that is hard to believe. The seller probably thought about filling the crucible with lead and melting all that at maximum of 1150°C which you should not do in any case.

Wilfried

NDC wrote:

Here's a furnace with a graphite crucible embedded into it, and able to handle 100 to 30 oz of gold depending on which size you get.





From TekCast.com

I'm liking that baby a lot because you don't need to worry about using a separate little crucible. You could just heat it up, then put 30oz of gold in there, with 30z of dew crystals, all powdered and mixed together of course, and wait an hour for it all to be converted to a ridiculous amount of the Stone!

Mine pretty much looks like that one.
The lid has a hole on top in the middle (about 5mm diameter) to let out any fumes or pressure.

So if the gw/dew salt mixed with gold needs to be heated in a sealed crucible we still face the same problem.

Wilfried

All you have to do is plug that hole. That one in the photo doesn't have a hole in the top -- it's completely sealed so no oxygen can enter the crucible during heating, and it keeps the heat trapped inside. But that's a $1,000 furnace, so it might be of different construction than the $500 ones with holes in the top.

This one here has a lid that seals the crucible, and it's probably the one I'll be buying because I probably won't win the auction for the other one.

And I really like the square design for some reason. Maybe it's because I've already seen this one working in a video, or maybe it's because those other ones just look goofy with their coffee-pot style construction.

The block design also seems like it holds in more heat because there is much more ceramic or whatever the white material is that surround the crucible. And it's looks easy to take apart and replace the heating element if it every burns out from being left on too long. The temperature is adjustable from 32F to 2012F, so it could also be used for any temperature digestion. And if you take the graphite crucible out, you could put an iron pipe in there that's the same size as the crucible, for heating cinnabar and gold.

This photo here gives people a good idea how small those graphite crucibles are:

NDC wrote:

Ahh man, that's great Andy, because now we'll be able to easily replicate each other's experiments, and give advice on how to use this thing.

What accessories does yours come with? Gloves and facemask or just some tongs and molds? The heat resistant gloves cost like 100 bucks, and so does the apron. And molds are ridiculously expensive too. Seems like everything for metallurgy is way overpriced for some stupid reason.

I need to get a mold for making little bars of gold.

Hey Nick
Have you tried this site for molds? http://www.graphitesupplies.com/servlet/the-Casting-Industry-Tools-cln--dsh--Graphite-Ingot-Mold/Categories

Thankfully, I lost the bid for the $400 furnace that I didn't want anymore. It was down to the last second, and someone outbid me right before it hit zero seconds. I really worried I would have to buy it.

I save a hundred dollars buy getting the square one, and I really wanted it much more than the other one. Unfortunately it ships from London, so it's gonna cost $60 just to ship it. But the use a styrofoam cooler to ship it in so it's well protected.

Wow it was actually only $300 USD total (190 GBP) because I went to their website instead. I have a feeling they're gonna bill me for the extra cost of international shipping, because they only had one shipping option on their website, and it was only 14 GBP ($22 USD), but on eBay, it was 37 GBP ($60 USD). quite a big difference.

I am thinking of getting a quartz crucible for making the red glass. A very small crucible that is plenty big enough for that purpose is only about $20. They are clear so it would be very cool making the red glass in them.

Hi Bluefloor,

I have only about 10 years experience with furnaces and crucibles.

Graphite crucibles have the advantage of high heat stability and are quite resistant against breaking while hot. But if you have anything that includes sulphur the carbon and the sulphur unite and break or make holes into the crucible.

As Nick already mentioned the glassy substance gets dirty by the carbon. Most professionals use graphite for gold and silver melting. In South Africa they use a special ceramic crucible which is cleaner. My favourite is a special dense fire clay from the company www.l-f-goebel.de/ which they call gold crucible.

Quartz crucibles can not stand temps beyond 1100°C they promote devitrification by which the quartz gets milky white. If the only requirement is to heat the crucible red hot for one hour it might stand the test. But then you would need a quartz lid to keep most of the vapor inside.

Hope this is helpful.

Frank

Through only brief internet surfing I found the quartz to be a good choice mostly because it was much cheaper. It can withstand the temperature needed and is resistant to thermal shock. I am sure I can make it work to get me through numerous runs in a furnace. The $20 one I am talking about is 2 1/2 inches tall. I like that it won't discolor the red glass like graphite or steal the stone's energy like iron. It would also be nice to see glowing stone stuck to its walls. But the price is probaly about as low as we will find a crucible. I just want one of us to succeed so we can get on with the show.

Bluefloor,

The quartz looks interesting. Perhaps it is what one would require when making multiplications. Incidentally, ∴N.D.C∴, I was curious if you could expound upon the problematic issues mentioned on the "about.com" article that involve radiation in multiplication and transmutation...I don't want it to go too far, but it's still unclear to me what that would involve in terms of transmuting.

Just for reference for those using or purchasing crucibles: I've been working with zirconia and porcelain (along with iron and other options which I've since stopped working with), and found that they eventually take on some peculiar colors when the salts are melted in with the metals.
These experiences come from working with dew mostly, but also with the gw path.

After melting with the silver powder there was clearly white salt, but it was also clear that the sides of the crucibles made of porcelain and zirconia had a purple tinge to them which became stronger after a few days of sitting out (presumably left from some of the silver, since whatever salt like material that was left dissolved in water after the melting and cooling). The gold on the other hand left red spots all over the zirconia crucible, but also penetrated the sides of the crucibles on occasion and became darker red (one of these spots even turned green in the zirconia one...).
I also had some experiences where I think the salt volatized and evaporated some of the stone with it into the iron lids I was using (they subsequently had silver on them in nice starlike patterns...not sure if it transmuted or simply silver evaporating).

My best to you all,

:-)

Bill

Hello Nick,

I am going back to France this week and will start real work.
Can you give me the email of the kiln maker in London, the one where you bought your furnace, I want to contact him directly because I don't want to register on ebay.
Thanks,
David

PS: and happy birthday by the way

Salut David,

here is your link: http://www.technicalsupermarket.com/index.php?page=shop.product_details&flypage=shop.flypage&product_id=742&category_id=386&manufacturer_id=0&option=com_virtuemart&Itemid=4&vmcchk=1&Itemid=4

Frank

bonifaesh wrote:

∴N.D.C∴, I was curious if you could expound upon the problematic issues mentioned on the "about.com" article that involve radiation in multiplication and transmutation...
l

I don't know what article you are referring to. I haven't written any articles on about.com