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dvontedlores

dvontedlores

Member
Joined
Sep 2, 2023
Messages
12
Location
North carolina
Hello,
I am attempting to cast palladium into a few small rings. I have made an argon vacuum casting chamber. I am hoping to use my induction heater to melt it but I am having difficulty doing this and understanding some of the lingo used in this industry.
Currently, I have one of the common blue and white "15kw" 240v induction heaters from amazon, which is definitely only 7.5kw and we all know this. Anyways, I also currently have a 1kg fuzed quartz crucible. Since I am unsure if it is even possible with my equipment, I decided to source the cheapest palladium I could find, just to see if I could even melt it. I bought a 1 gram bar of palladium from etsy. I am not really worried about the purity at the moment since this is just for proof of concept. I can not seem to get it hot enough. I have made a more tightly wrapped induction coil and this helped tremendously with other metals but now I can not fit my curcible in the coil, and the palladium flies around and sticks to the coil if it is not in the crucible.
I an not even sure if this is the best form of palladium to attempt to melt. I keep seeing threads where other people have unsuccessfully attempted to melt palladium powder. I am not familiar with palladium powder or even why a metal element would be in powder form in the first place, maybe this has something to do with how it is mined? I am very new to this industry and I am only a hobbyist so please bear with me. Secondly I keep hearing of palladium sponge. I also have no idea the significance of palladium sponge or why I would need this instead of a solid piece of palladium. These are all very new terms to me and I can not seem to get a clear definition of them. I read a thread that seemed to indicate that I should use a combination of powder and sponge to somehow melt palladium easier.
I have not found a smaller fuzed quartz crucible that would fit into the coil. The kind I currently have is a large white crucible with a spout, I am also seeing some smaller clear ones that also claim to be fuzed quartz but they have much lower advertized temperature ratings.
I have also heard of a few people successfully melting palladium with oxyacetylene, while keeping the atmosphere as rich as possible with acetylene. I am afraid to try this, and I feel like I will screw up the palladium. I would potentially try it if I can fabricate a way to get my oxyaceylene torch inside the argon chamber but I dont even know if it would burn without atmospheric oxygen, and I also wonder if just the amount if oxygen in the oxyaceylene mix would contaminate my palladium.
I am also considering switching to platinum if that seems to be easier in some respects. The rings must be hypoallergenic, and thats why I am doing this...
 
dvontedlores said:
Hello,
I am attempting to cast palladium into a few small rings. I have made an argon vacuum casting chamber. I am hoping to use my induction heater to melt it but I am having difficulty doing this and understanding some of the lingo used in this industry.
Currently, I have one of the common blue and white "15kw" 240v induction heaters from amazon, which is definitely only 7.5kw and we all know this. Anyways, I also currently have a 1kg fuzed quartz crucible. Since I am unsure if it is even possible with my equipment, I decided to source the cheapest palladium I could find, just to see if I could even melt it. I bought a 1 gram bar of palladium from etsy. I am not really worried about the purity at the moment since this is just for proof of concept. I can not seem to get it hot enough. I have made a more tightly wrapped induction coil and this helped tremendously with other metals but now I can not fit my curcible in the coil, and the palladium flies around and sticks to the coil if it is not in the crucible.
I an not even sure if this is the best form of palladium to attempt to melt. I keep seeing threads where other people have unsuccessfully attempted to melt palladium powder. I am not familiar with palladium powder or even why a metal element would be in powder form in the first place, maybe this has something to do with how it is mined? I am very new to this industry and I am only a hobbyist so please bear with me. Secondly I keep hearing of palladium sponge. I also have no idea the significance of palladium sponge or why I would need this instead of a solid piece of palladium. These are all very new terms to me and I can not seem to get a clear definition of them. I read a thread that seemed to indicate that I should use a combination of powder and sponge to somehow melt palladium easier.
I have not found a smaller fuzed quartz crucible that would fit into the coil. The kind I currently have is a large white crucible with a spout, I am also seeing some smaller clear ones that also claim to be fuzed quartz but they have much lower advertized temperature ratings.
I have also heard of a few people successfully melting palladium with oxyacetylene, while keeping the atmosphere as rich as possible with acetylene. I am afraid to try this, and I feel like I will screw up the palladium. I would potentially try it if I can fabricate a way to get my oxyaceylene torch inside the argon chamber but I dont even know if it would burn without atmospheric oxygen, and I also wonder if just the amount if oxygen in the oxyaceylene mix would contaminate my palladium.
I am also considering switching to platinum if that seems to be easier in some respects. The rings must be hypoallergenic, and thats why I am doing this...
Click to expand...
Welcome to us. :)
Some task you have undertaken.

In an induction furnace, the metal need to be in a form that the furnace's frequency can create eddy currents in.
This means that powder needs very high frequency and metal bars lower frequency.
Powder comes from the refining and sponge is just fluffy powder and also comes from refining.
It is preferred when creating alloys and melting with ordinary ovens/furnaces.
In induction furnaces, one can overcome the frequency issue,
by either using a heel (a piece of solid metal) or a (susceptor) usually a graphite crucible outside the melting crucible.
 
Yggdrasil said:
Welcome to us. :)
Some task you have undertaken.

In an induction furnace, the metal need to be in a form that the furnace's frequency can create eddy currents in.
This means that powder needs very high frequency and metal bars lower frequency.
Powder comes from the refining and sponge is just fluffy powder and also comes from refining.
It is preferred when creating alloys and melting with ordinary ovens/furnaces.
In induction furnaces, one can overcome the frequency issue,
by either using a heel (a piece of solid metal) or a (susceptor) usually a graphite crucible outside the melting crucible.
Click to expand...
This was extremely helpful. Thank you. When using a susceptor, Is the graphite crucible being heated directly by the induction heater, thus causing more heat to pass into the melting crucible or is there some other purpose. I have not used a graphite crucible with this induction furnace but I previously assumed that graphite would not be affected by induction.

Also I assume with a heel, you are just adding a large chunk of solid metal within the powder?


Thank you so so much. It has been very difficult to find answers to seemingly simple questions regarding this industry. I wish i had a mentor that is experienced in this!
 
dvontedlores said:
This was extremely helpful. Thank you. When using a susceptor, Is the graphite crucible being heated directly by the induction heater, thus causing more heat to pass into the melting crucible or is there some other purpose. I have not used a graphite crucible with this induction furnace but I previously assumed that graphite would not be affected by induction.

Also I assume with a heel, you are just adding a large chunk of solid metal within the powder?


Thank you so so much. It has been very difficult to find answers to seemingly simple questions regarding this industry. I wish i had a mentor that is experienced in this!
Click to expand...
Yes, the susceptor is heated by the Induction Furnace and transfers the heat to the inner crucible.
When the metal start to coalesce the metal starts to be directly heated as well.
 
Yggdrasil said:
Yes, the susceptor is heated by the Induction Furnace and transfers the heat to the inner crucible.
When the metal start to coalesce the metal starts to be directly heated as well.
Click to expand...
Very nice, thank you. I will be shopping for such a crucible with a graphite shell and a fuzed quartz inner crucible. It seems these are a little difficult to find. I am seeing many that are opposite of this, with graphite on the inside, but I have read graphite will cause palladium to be black.
 
dvontedlores said:
Very nice, thank you. I will be shopping for such a crucible with a graphite shell and a fuzed quartz inner crucible. It seems these are a little difficult to find. I am seeing many that are opposite of this, with graphite on the inside, but I have read graphite will cause palladium to be black.
Click to expand...
The use separate crucibles.
One outer susceptor and a inner of a quality suited for the job.
 
Technical Glass Products sells custom made fused silica parts, beakers, joints, etc. I would start your search by giving them a call. I've used them for numerous custom fused silica items and they are great to work with. Bring your wallet, they aren't cheap.

Steve
 
I looked up my last purchase from TGP. It was a 3/4" OD x 9.5" overall length tube with 24/40 joints on either end made of clear fused quartz. Total with shipping was $190 USD.

Steve
 
dvontedlores said:
Hello,
I am attempting to cast palladium into a few small rings. I have made an argon vacuum casting chamber. I am hoping to use my induction heater to melt it but I am having difficulty doing this and understanding some of the lingo used in this industry.
Currently, I have one of the common blue and white "15kw" 240v induction heaters from amazon, which is definitely only 7.5kw and we all know this. Anyways, I also currently have a 1kg fuzed quartz crucible. Since I am unsure if it is even possible with my equipment, I decided to source the cheapest palladium I could find, just to see if I could even melt it. I bought a 1 gram bar of palladium from etsy. I am not really worried about the purity at the moment since this is just for proof of concept. I can not seem to get it hot enough. I have made a more tightly wrapped induction coil and this helped tremendously with other metals but now I can not fit my curcible in the coil, and the palladium flies around and sticks to the coil if it is not in the crucible.
I an not even sure if this is the best form of palladium to attempt to melt. I keep seeing threads where other people have unsuccessfully attempted to melt palladium powder. I am not familiar with palladium powder or even why a metal element would be in powder form in the first place, maybe this has something to do with how it is mined? I am very new to this industry and I am only a hobbyist so please bear with me. Secondly I keep hearing of palladium sponge. I also have no idea the significance of palladium sponge or why I would need this instead of a solid piece of palladium. These are all very new terms to me and I can not seem to get a clear definition of them. I read a thread that seemed to indicate that I should use a combination of powder and sponge to somehow melt palladium easier.
I have not found a smaller fuzed quartz crucible that would fit into the coil. The kind I currently have is a large white crucible with a spout, I am also seeing some smaller clear ones that also claim to be fuzed quartz but they have much lower advertized temperature ratings.
I have also heard of a few people successfully melting palladium with oxyacetylene, while keeping the atmosphere as rich as possible with acetylene. I am afraid to try this, and I feel like I will screw up the palladium. I would potentially try it if I can fabricate a way to get my oxyaceylene torch inside the argon chamber but I dont even know if it would burn without atmospheric oxygen, and I also wonder if just the amount if oxygen in the oxyaceylene mix would contaminate my palladium.
I am also considering switching to platinum if that seems to be easier in some respects. The rings must be hypoallergenic, and thats why I am doing this...
Click to expand...
Welcome to the adventure: here are a few issues I don't think have been addressed:

"argon vacuum casting chamber" -- argon is a gas, vacuum is "no gas at all" In critical applications, argon or some other gas might be used to flush a chamber prior to vacuum, but I don't see the need here.

“I am hoping to use my induction heater” that means wrapping a coil around your casting chamber with a crucible inside, if I’m understanding you. Magnetic flux heats your stuff, that flux is a function of the number of coils, amount of current flowing through those coils, The size and shape of those coils, the frequency at which that current changes direction, and how susceptible the stuff inside the coil is to induction heating.

Added to “I am having difficulty doing this” and I suspect that you might have too large a coil diameter or too few coils.

Here’s where I say “I have worked with RF equipment. It will hurt you if you fail to respect what it can do. Yes, if you’re far enough away from the coil, the magnetic flux from the coil is zero. Other things happen outside the coil. At the very least, get an RF detector in the range you’re using and never touch any exposed metal unless the machine is unplugged.

“1 gram bar of palladium” – that’s not much. I think “size might be an issue” but I don’t know the relative frequency between resonance for your bar and the frequency of the machine.

“palladium flies around and sticks to the coil if it is not in the crucible” – what? — Then yes, I’m pretty size is an issue. Not sure how much is that and how much might be coil related.

“seeing some smaller clear ones that also claim to be fuzed quartz” – seek advice on the forum for crucible suppliers and materials. Quality matters. There a lot of inexperienced producers of inadequate products. Spilling hot metal is bad.

“I dont even know if it would burn without atmospheric oxygen” – you’d need 2x as much oxygen and you’d be making water vapor, so, no vacuum. Well, none to speak of and the whole purpose of vacuum is often to remove oxygen. Water vapor is a very good source of oxygen.

“keeping the atmosphere as rich as possible with acetylene” – no. If – and I’m taking someone’s word for it here – Palladium will combine or attract carbon, a carburizing flame will ruin your palladium. I don’t work with palladium, so I can’t actually speak to that. Platinum and rhodium take an oxidizing flame nicely, but a Tig welder makes a better finish.

Powder metallurgy is a very dangerous enterprise. It’s done in cleanrooms with ante-chambers because sub-micron sized powders of even heavy metals will float in air for longer and move farther than you’d think. Without extraordinary controls and fastidious cleaning, it gets everywhere. It’s necessary if you’re refining pgms by dissolution and precipitation, but if you’re not, I recommend limiting your project to solid metals. Precious metal powders are classified as irritants, I think, but I still don't want them in my clothes, hair, and house.

If you’re making a few palladium rings, I recommend using a torch, hammer, rolling mill, and then induction melting. I had to look up palladium. It’s hardness is 4.8 on the mohs scale, so that kinda sucks, but if it’s like platinum, you can start with a commercial bar. I would shear the bar into strips less than 8mm wide (2 -4), arrange the strips into a square bar 2 strips thick, then roll the square bar with a rolling mill to a final size. Welding a ring shank without defects is hard, so making a trench mold with a tapered seat for the donor ring seems reasonable.
 
Sorry, forgot the part about "melting the strips into a single, 2mm thick bar, with a torch." in the last paragraph of the previous post.

The addition goes after "arrange the strips into a square bar 2 strips thick," and before "then roll the square bar..."

-- I don't think it would come up in a commercial setting; volumes spread costs, 3rd party verification is expected. But, for someone who's making "a few small rings," it seems simpler to make your own stock from something that is realtively trustworthy and fairly easy to verify than it is to pay the markup charged by online retailers--if you can.

Fusing metal completely with a torch requires welding skills -- if that's a non-starter, sorry.
 
hoytSmith said:
Welcome to the adventure: here are a few issues I don't think have been addressed:

"argon vacuum casting chamber" -- argon is a gas, vacuum is "no gas at all" In critical applications, argon or some other gas might be used to flush a chamber prior to vacuum, but I don't see the need here.

“I am hoping to use my induction heater” that means wrapping a coil around your casting chamber with a crucible inside, if I’m understanding you. Magnetic flux heats your stuff, that flux is a function of the number of coils, amount of current flowing through those coils, The size and shape of those coils, the frequency at which that current changes direction, and how susceptible the stuff inside the coil is to induction heating.

Added to “I am having difficulty doing this” and I suspect that you might have too large a coil diameter or too few coils.

Here’s where I say “I have worked with RF equipment. It will hurt you if you fail to respect what it can do. Yes, if you’re far enough away from the coil, the magnetic flux from the coil is zero. Other things happen outside the coil. At the very least, get an RF detector in the range you’re using and never touch any exposed metal unless the machine is unplugged.

“1 gram bar of palladium” – that’s not much. I think “size might be an issue” but I don’t know the relative frequency between resonance for your bar and the frequency of the machine.

“palladium flies around and sticks to the coil if it is not in the crucible” – what? — Then yes, I’m pretty size is an issue. Not sure how much is that and how much might be coil related.

“seeing some smaller clear ones that also claim to be fuzed quartz” – seek advice on the forum for crucible suppliers and materials. Quality matters. There a lot of inexperienced producers of inadequate products. Spilling hot metal is bad.

“I dont even know if it would burn without atmospheric oxygen” – you’d need 2x as much oxygen and you’d be making water vapor, so, no vacuum. Well, none to speak of and the whole purpose of vacuum is often to remove oxygen. Water vapor is a very good source of oxygen.

“keeping the atmosphere as rich as possible with acetylene” – no. If – and I’m taking someone’s word for it here – Palladium will combine or attract carbon, a carburizing flame will ruin your palladium. I don’t work with palladium, so I can’t actually speak to that. Platinum and rhodium take an oxidizing flame nicely, but a Tig welder makes a better finish.

Powder metallurgy is a very dangerous enterprise. It’s done in cleanrooms with ante-chambers because sub-micron sized powders of even heavy metals will float in air for longer and move farther than you’d think. Without extraordinary controls and fastidious cleaning, it gets everywhere. It’s necessary if you’re refining pgms by dissolution and precipitation, but if you’re not, I recommend limiting your project to solid metals. Precious metal powders are classified as irritants, I think, but I still don't want them in my clothes, hair, and house.

If you’re making a few palladium rings, I recommend using a torch, hammer, rolling mill, and then induction melting. I had to look up palladium. It’s hardness is 4.8 on the mohs scale, so that kinda sucks, but if it’s like platinum, you can start with a commercial bar. I would shear the bar into strips less than 8mm wide (2 -4), arrange the strips into a square bar 2 strips thick, then roll the square bar with a rolling mill to a final size. Welding a ring shank without defects is hard, so making a trench mold with a tapered seat for the donor ring seems reasonable.
Click to expand...
Thank you so much for your information. Regarding the casting chamber, It is a little difficult to describe completely. The bottom of a crucible is sticking out of a sealed box. Vacuum is applied inside the box, and then argon is introduced to the box in order to remove oxygen. Vacuum is then turned off to the box. There is also a casting flask protruding from the sealed box 90 degrees from the crucible. When the metal inside the crucible is molten, the entire box rotates 90 degrees and pours the metal into the casting flask. The vacuum is then applied to the bottom side of the casting flask, just like any other vacuum casting chamber. The vacuum helps the molten metal to pull into the mold by pulling air through the plaster. Therefore, the chamber is difficult to accurately label as "just a vacuum casting chamber" or "just an argon chamber". The atmosphere around the molten metal will be argon, and the vacuum will be primarily applied to the bottom of the casting flask with the plaster mold inside.

I do think you are correct about "size matters". I made a smaller coil with an extra loop and it heated much better, but still not quite molten. I am planning to do two things; purchase a crucible with a graphite susceptor/fused quartz lining, and increase the amount of metal being melted. I only used 1g because I wanted to test my machine before investing lots of money into a metal that I cannot melt. I am currently undecided on whether I should purchase palladium powder or try to find palladium grain/beads. Ultimately, the palladium I buy will probably not be used for the final product, rather I need a usable amount for experimentation inside and outside of a controlled atmosphere. I think if I buy powder, I can press it into a formed chunk with my hydraulic press as others have suggested, and hopefully it would remain stationary until it is molten. But maybe I would be wasting my money to buy anything other than palladium casting grain.

I am also considering using solely a graphite crucible rather than one with a fuzed quartz liner, but I am concerned it will cause the palladium to be dark, as I have read somewhere.

If I end up using powder, I will take your advice and at least use a respirator.

Thank you for your advice!
 
Also, use a respirator with a faceplate, and a disposable cover all. PGM powders are worse than irritants, and in a primitive foundry environment, you coul generate minute amounts of highly toxic PGM salt micro powders. Some members have had nearly fatal experiences with this, so read the safety posts. I recovered four grams of rhodium and created a sponge button using suggestions from Yggdrasil Orvi and others. I am looking into induction melting myself, but think a Mig/tig setup may be simpler. In terms of casting PGMs, remains to be seen. My set up is fine for gold, silver, bronze, PGMs require extra care and expense.bIt is highly crystalline and flaky. I take care handling it. It was a by product of refining several kilos of Rh plated sterling scrap. My work room is safe, nobody is ill. Be safe.
 
hoytSmith said:
Welcome to the adventure: here are a few issues I don't think have been addressed:

"argon vacuum casting chamber" -- argon is a gas, vacuum is "no gas at all" In critical applications, argon or some other gas might be used to flush a chamber prior to vacuum, but I don't see the need here.

“I am hoping to use my induction heater” that means wrapping a coil around your casting chamber with a crucible inside, if I’m understanding you. Magnetic flux heats your stuff, that flux is a function of the number of coils, amount of current flowing through those coils, The size and shape of those coils, the frequency at which that current changes direction, and how susceptible the stuff inside the coil is to induction heating.

Added to “I am having difficulty doing this” and I suspect that you might have too large a coil diameter or too few coils.

Here’s where I say “I have worked with RF equipment. It will hurt you if you fail to respect what it can do. Yes, if you’re far enough away from the coil, the magnetic flux from the coil is zero. Other things happen outside the coil. At the very least, get an RF detector in the range you’re using and never touch any exposed metal unless the machine is unplugged.

“1 gram bar of palladium” – that’s not much. I think “size might be an issue” but I don’t know the relative frequency between resonance for your bar and the frequency of the machine.

“palladium flies around and sticks to the coil if it is not in the crucible” – what? — Then yes, I’m pretty size is an issue. Not sure how much is that and how much might be coil related.

“seeing some smaller clear ones that also claim to be fuzed quartz” – seek advice on the forum for crucible suppliers and materials. Quality matters. There a lot of inexperienced producers of inadequate products. Spilling hot metal is bad.

“I dont even know if it would burn without atmospheric oxygen” – you’d need 2x as much oxygen and you’d be making water vapor, so, no vacuum. Well, none to speak of and the whole purpose of vacuum is often to remove oxygen. Water vapor is a very good source of oxygen.

“keeping the atmosphere as rich as possible with acetylene” – no. If – and I’m taking someone’s word for it here – Palladium will combine or attract carbon, a carburizing flame will ruin your palladium. I don’t work with palladium, so I can’t actually speak to that. Platinum and rhodium take an oxidizing flame nicely, but a Tig welder makes a better finish.

Powder metallurgy is a very dangerous enterprise. It’s done in cleanrooms with ante-chambers because sub-micron sized powders of even heavy metals will float in air for longer and move farther than you’d think. Without extraordinary controls and fastidious cleaning, it gets everywhere. It’s necessary if you’re refining pgms by dissolution and precipitation, but if you’re not, I recommend limiting your project to solid metals. Precious metal powders are classified as irritants, I think, but I still don't want them in my clothes, hair, and house.

If you’re making a few palladium rings, I recommend using a torch, hammer, rolling mill, and then induction melting. I had to look up palladium. It’s hardness is 4.8 on the mohs scale, so that kinda sucks, but if it’s like platinum, you can start with a commercial bar. I would shear the bar into strips less than 8mm wide (2 -4), arrange the strips into a square bar 2 strips thick, then roll the square bar with a rolling mill to a final size. Welding a ring shank without defects is hard, so making a trench mold with a tapered seat for the donor ring seems reasonable.
Click to expand...
Wow, fantastic advice. You are great! It's not my project but I learned so much from your interchange.
 
Shortish answer:
If making jewelry or things that need to be ductile then don't melt it in graphite unless it is a liner/susceptor for the actual crucible. Use a ZrO2 crucible and start with solid material that couples with the inductive field.
Also, it needs melted under argon or vacuum, or preferably cycles of both (it's called washing).

You know your hygiene is good enough when you can melt some titanium in a crucible and it comes out shiny.
 

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