Topic: Question to collectors regarding metal content/weight (Read 577 times)

Hi,

Yes, the clay is expensive. Needs air vents, it's to compact. But good stuff for simple shapes.
We tried closed casting without air vents. Poor results. Open casting seemed promising as an alternative to graphite molds (with us of 'needle' hole venting').  

Yes, the results are inconsistent, so we stick with simple geometric shapes and the logo. Can do some more details, but result will always vary.
Yes, if a detail breaks, start over again...
Resin 3D printers are the best, we use them, are experimenting with wax as well, near perfect detail.
But seems you already have experience with most methods, cool stuff you are making!

Example of our venting:

    

Good luck, am interested in a spoon or fork...
.925 would be best in my opinion, stronger. If possible use rhodium for finishing gilt layer, would be cool and shiny + somewhat scratch resistent.

Pyrite, in layman's terms, is fools gold (some pun intended).

I use Petrobond for less expensive metals like copper and brass when I have the patience to hand finish things or lose detail. I've never used Delft Clay because of the cost. Do you bother cutting vent holes when you use delf clay/green scand/ or petrobond? Ive had pretty decent luck just using the porosity of the material itself. What I really do not like about the sand casting methods, is 3D models with lettering are realllllly inconsistent if you do any sort of lettering or detail where you can break the sand and remove features when removing the model. I had issues where if I applied inconsistent pressure when packing, sometimes I could remove the 3D model, sometimes I couldn't, etc. If I pack too hard vs not hard enough even if I didn't break features off, I'd get inconsistent weights as well which is really tough with this crowd.

I've not used pyrite before, but I'll look into it. I primarily use gold, electrum, argentium silver, fine silver, aluminum bronzes, copper, aluminum, platinum/palladium (though I need to retool to do those better) though I've tried a few exotics with mixed results. Purple gold is by far my favorite but the strangest material I've ever worked with. Its super pretty but has  trash mechanical properties. This is a stock photo from google pictures, as I don't have any pictures of what I've made with it handy.




The primary method I use now is lost wax casting. I've got a Resin 3D printer which is slow as hell but produces unbelievable detail down to a couple of microns. I can buy castable resin for it and go straight from print to mold, but the resin is something like $375 per liter, so I just use the standard stuff that'll provide me with a good finish, and put it in a silicone mold so I can wax inject replicas. Material cost is still sort of ridiculously high for low batch things, but its a lot better than adding up all of the man hours that goes into making things individually.

With the spoon and about 50 other plans I have, the issue I am running into is my furnace size for burning out the molds. Its taken forever but I'm finally getting around to finishing up my 13.5x13.5x13.5 inch kiln. Ive just gotta make some finishing touches and install the electronic controls at this point and I should be all set.



Plaster casts are typically 1 time use, but they give the best detail. Commercial products have all sorts of chemical additives to eliminate air bubbles, (though you still need a vacuum chamber) surfactants to keep the surface of the molds super smooth and without pores otherwise you get pits in your cast, and low shrinkage factors. DIY methods will work if you are careful and do a carefully controlled heat cycle to remove ALL moisture from the mold, but often the size of what you cast will be inconsistent at the very least.

I use commercial investment powders, and while expensive, give expected results more often than not once you deal with a few minor tweaks that you'll need to do regardless of mold material. The burnout cycles are provided by manufacturers, and typically take anywhere from 10 to 18 hours with VERY specific temperature heat soak/ramp schedules. They might require you start at 275 degrees (Fahrenheit) for 45 minutes, ramp up to 350 for 30 minutes, then up to 475 for 15 minutes, 550 for 2 hours, 675 for 3 hours, 900 for 2 hours, 1150 for 2 hours, 1350 for 1 hour, and then back down to 900 before you cast the material. Little things like not following the very particular timing/length can completely ruin an otherwise perfect mold. DIY products don't have manufacturer suggested times, so just know you'll have to do a bit of experimentation before you get it right.

Going to make this post even longer and just throw in a few pictures of things I'm working on.







And to physically hurt the bullion collectors here

Very cool spoon!

Casting in Green sand, Petrobond or (Delft) clay is indeed less suited for detail and a smooth surface finish. And cumbersome with regard to finish, but a great entry point for casting.  
Will say Delft Clay is best of choice in my experience, more oil in the substance, better cohesion and clearance of model.
Air venting en flow of silver is where we learned the most. Also, heating the clay a bit before pouring seemed to help (but not to much, because of the release of oil when heating).
Have tried a couple of models with detail, but best do detail with lost wax as you mentioned.  
We have been playing with Braluminium, alloy of bronze and aluminium. While not suited for collectibles, nor precious, good stuff!

Thanks for the inspirational post and valuable comments of others.
Maybe a Pyrite version of the spoon for BCH? (though Pyrite is brittle, and toxic when heated)

I did see refractory concrete breaks up after water vaporizes most of the times, I did see some nice molds of that concrete that done pretty well tho maybe making the mixture properly and the brand you use influences but that takes a bit of trial and default i guess.

On the other hand it can't be more than two days that I discovered stone for this purpose, however in past experiences with stone and fire stone can break up and no idea how'd I could carve there.

Thanks a lot for the encouragement, should of answered way earlier but even looking specificaly for this thread I saw nothing in new replies.

I appreciate it. It was serious, but I should be in the clear now. I'd be careful with refractory cements, they really don't handle temperature changes well and aren't designed to rid themselves of moisture to the degree that needs to be done. In the best case scenario and you are lucky and it holds up, your surface finish will likely have issues. As I've found through the years, the difference between the expensive method of metal product production where you use professional products versus the DIY homemade versions is success rate and time. Home made versions fail more often and require a lot of extra manual work to get to a finished product, which by the time you are done with it replaces the cheaper DIY material cost with labor costs.

Titanium is neat, if just sort of blows up if you heat it improperly. I've got a lot of neat and interesting metals I can work with though. I say go for it with the 1 KG copper coins, just a heads up though it'll likely take you a while to get it right. Copper is really hard to work with, its taken me about 5 years to cast my own copper pan and I'm close but still haven't gotten it quite right. Its doable, just requires a whole lot of tinkering, degassing, temperature, and geometry exploration. Best of luck 

Hope you get better and it nothing serious.
Lol the 0.05% goldspoon chance id do it if i could.

So I has quite a while wanting to do some melting and pouring myself, I haven't found much information but my idea is using refractory concrete as mold, as far as I seen in a vid if you careful you can even use it more than once.

I like titanium but I heard its a pain in the arse without argon atmosphere. You could perhaps make a collection of different metals.
Spoon bullion lol.

PS: I plan making 1 kg copper coins as start, 51 of them, with 5 spots for holo and 5 coins on the front , featuring BTC ETH XMR XML and STEEM, however i first thought of doge instead of steem, just can't fit all coins i like .

The project isn't dead, just had some health issues come up a little while ago that prevents me from executing all of my fun project plans. I'll be back at it in April though!

To save other people the googling time:


-Dave

Platinum I can do, zirconium I have no idea at the moment but I can look into it, and Tungsten isn't workable with heat. It has the the highest melting point of any metal (6200F / 3420C) and I believe rather than being melted to combine multiple bits of tungsten together, its sintered.

The mention of the gold spoon was 99.95% a joke by the way.

Platinum? It's less expensive then gold but it does have a much higher melting point so the actual making of the spoon would be more difficult.

I have always thought it would be neat to have some stuff with "oddball" metals.
Zirconium is light so it would be weird to have a what looks like a standard thing but it is much lighter.
Tungsten would also be cool.

-Dave
 

You know... Id be quite an interested buyer of that spoon.

Change "hold" to "hodl" and maybe hologram it. That would be an awesome collectors piece.

Sandcasting with precious metals can be a bit sketchy. In the absolute best case scenario, the surface finish is just not fantastic and you lose a lot of detail. In the not that bad but still frustrating cases, you'll just get a ton of failures for each success. Even assuming the best case, you end up doing a ton of grinding and finish work which ends up more expensive by the time you are done due to the required man hours. I typically use the lost wax method using 3D printed Resin model, a high quality investment powder (casting plaster), vacuum pumps, and metal. The setup and material costs are higher than sandcasting, but the method allows far more intricate detailing and requires much less time to get a finished product.

Right now the issue I ran into is that my kiln is too small. The ceiling height can't accommodate a flask large enough to fit a spoon into it, so I'm building a new kiln. The fire bricks arrived broken, still waiting for the heating elements and control panel parts to come, and then I've got to assemble the thing.  

i have not cast any metal since the 1970’s in high school foundry shop.

making a sand mold was time consuming. and i had a lot of failed casted items.

but i figured i could ask i some one else got you up to 2000.

here is a merit to go to 2001

I can, but I've pretty much found out that in most cases, making single order custom things is prohibitively expensive.

I am on the cell pushed you to 1999 with the last merit this account has. I have a pewter letter opener any chance you could copy it in sterling? My location is nj I could photo the letter opener. Next to a ruler .

I'm not geared up properly to handle ferrous based metals right now, but if I get into forging so I can make meteorite kitchen knives that could be neat, though I don't know exactly how usable they'd be. I'll do some searching around for something interesting while I'm waiting for all of my kiln materials to show up. Francium spoon!

On a side note, I've got a ton of plans and partial designs for things that aren't spoons with different purposes in different materials. I just got on a kitchen utensil kick recently and decided I wanted at least one silver spoon/fork/knife for when I want to feel fancy eating a bowl of cereal. I've successfully made custom rings with Bitcoin private keys inside so you can have a backup and discrete way to carry your coins on you. A few decisions need to be made about whether I just ask people to encrypt and send me the keys to put on them, or if I could obscure the inside and make denominations of wearable keys. I've got a few solutions for obscuring the keys though they wouldn't be perfectly foolproof as a jeweler may be able to figure out what I'm doing and redeem the BTC. For a self funded model of course you don't have to worry about it trading hands so its not a concern.

I has no idea what to suggest, last time I were searching metals i ended up in radioactivity and discovered europium which just tarnishes very fast even looks very nice if properly protected.

Long ago I were really interested in seeing a physical made of meteorite metal, which is expensive as hell and I think it is not pourable since youd lose the etching pattern.
Edit: I found these things at arizonaskiesmeteorites.com
And just noted they just got quiiite a few new specimens.

Exotics are fun but hard to source and are often full of surprises. That said, if you have a suggestion I'm all ears and I'll at the very least look into it and give you a proper response as to why its a good or bad idea.

I picked silver first because besides being my forte, its actually a suitable material for dining ware. Making this spoon out of gold is really a pipe dream, I mean I could do it, but it'd be something like 4 oz of pure gold or ~0.8 BTC just in metal. Not really that great of an idea.

Ugh I never imagined I'll never get more merit to give.

Gold would be a bit expensive, why you don't try some exotic metals that ain't as expensive.

I've got a general idea of the direction to take, but still looking for input while I wait. The spoons are just long enough that they don't fit in my kiln now and I'm not changing the length as I find them very properly sized, so I'm building a new kiln. While I'm waiting for all of the bits to arrive, please feel free to keep the suggestions/opinions coming in.

My plan as of right now is to make two versions, one in .999 silver and one in Britannia Argentium silver. I expect they'll both be damn near 2 troy ounces, but I won't know exactly until I have them made. Not sure yet whether I'll mark 2 Troy Oz Fine silver on the .999 version if they do indeed remain above but ~ 62.2g of silver after finishing.

I sort of want to make a gold one as well, but I feel like that'd be kind of stupid...

I know... I'll fix my mistake.


Still have not worked with Ruthenium. Besides the blistering high temps required to work with it, its quite difficult to source. I may need to find some to do some platinum blends, but for the time being its still not on my radar.

Salty, bit off topic but curious if you’ve worked with Ruthenium yet? We talked another this a year + ago and I know you hadn’t at that time, just curious if you have since. Overdue for a BTC ruthenium coin imo.

You spelled hodl wrong.

So the issue that I was apparently rightfully concerned about is that purity marks are legal standards, and in my example 98% fits no standard. You may have seen things marked as .900 or "Coin silver" those are all legal definitions of the material, meaning that they promise a minimum of 90% silver, but no information is given regarding the remaining 10%. You can legally call .999 silver bullion "Coin silver", "Sterling", or "Fine", but you can't call it .9999. Obviously its in most people's best interest to accurately mark their material, as a craftsman could legally call their 18 karat gold 10 karat, but they'd be losing a lot of money doing that. If I whip up some crazy alloy that is 92% silver, 2% copper, 1% cobalt, 2% palladium, and 3% germanium, the highest designation of fineness that I can legally mark it as is .900 or Coin silver. I could also use another legal mark guaranteeing a lower quantity of silver such as .800, but I could not mark it as sterling or .925 since its only 92% silver and not 92.5%.

If I mark something, I have to follow those standards, I can't mark something made of 94% silver as .940 as that isn't a recognized legal mark, .940 means nothing. On the other hand, the designation .925 means that I guarantee that the silver content is not less than 92.5% which 94% is not. Theres nothing saying that I can't tell people exactly what I use, but I can't stamp the metal with a number that isn't a recognizable purity mark. My options in this case are to stick strictly to legally defined marks, or just make sure people are completely aware that a spoon marked as 0.950 is actually .980 or whatever should I decide to use that alloy.

Heres what I can stamp: https://en.wikipedia.org/wiki/Silver_standards

I like purity but 95% seems acceptable somehow.
You would be too generous with that extra silver purity and I preffer truth and precision when possible.

I like the spoon btw.

Thanks for your input   I picked up a knife forge by accident so we'll see what happens. Silver handle with a steel blade might be neat, I know a lot about the metallurgy of steel but not the forging process. That takes a lot of dedication to learn, and I don't have the proper know how right now to produce something I'd be comfortable with someone else owning.



And thanks to you as well. I got it damn near 2 oz in fine silver, we'll see how close I can get after sanding and polishing. I'll mark them as appropriate. The obvious solution to me is to make them in both fine silver for people who want a silver spoon shaped bar, and alloyed silver for people who want to eat their cheerios with it. I was going to have the fineness and mint marks directly on the model so I wouldn't need to hand stamp everything, but I suppose I can just go that route. Leaves the door open for a gold version if anyone is feeling fancy. Mostly I'm just tried of the airtight perfect condition collectibles market. I like collectibles that you can handle and use, then when you go to sell them, polish them up and good as new.

I should have the first one made fairly soon, I want to run a few strength tests on my heat aging and work hardening procedure to make sure they will be good to go for regular use.


*Edit*

As a side note, I couldn't bring myself to have the text say Hodl Tight, even though I had a feeling it might get more attention if I did. I'll show pictures of the final version when its ready, but the design is really super sleek, the Hodl would kill that in my opinion.

Feel the same as OgNasty on this one

Btw, the spoon looks very nice!!

I'll start by saying I'm not really a precious metals guy. If I'm holding as an investment, I would rather just have a non-descript bar.

The collectibles I buy are intended as display/conversation pieces.

A steak knife made out of silver would be badass. A broken steak knife made out of silver would suck. So for me, I'd be fine if it's marked as less silver than it really contains. I'd prioritize strength/durability and show it off to my friends.

Just going to leave a few pictures here, they absolutely don't mean anything...

Thanks for your responses so far guys, its very helpful and addressing exactly what I was concerned about. Just something I wanted to clarify, we aren't talking about bars or coins here. Lets say for example that I'm making steak knives out of silver (no that wouldn't be a good idea) but thats kind of what I mean by I'm looking to see what people would be alright with. There are legal stamps such as sterling, .999, FINE, Britannia, etc that all mean something particular, but lets say for example as far as function goes, .999 would be too soft, .925 would have bad tarnishing properties, .950 is actually 100% stronger if its .958 but there is no legal .958 designation so it gets marked as .950 or .925



This is one of the most important parts to me as I'm a much better metallurgist than smith. It is 100% unacceptable to mark something as 22k if its 14k, but a jeweler can absolutely mark something that is 22k as 14k. I don't know why they'd want to do it, but you can. My intent isn't to deceive anyone of course otherwise I wouldn't be openly asking here, its about the case I mentioned above where you can get superior properties with modification. Adding palladium at $1700/oz to silver isn't a cost effective move to cut corners, but its a really interesting option for getting ideal properties. I can't legally mark something with a designation that doesn't exist so a .958 silver blend has to be marked as .925 or maybe .950. That doesn't necessarily need to be a secret from a buyer, but its something I absolutely wanted your opinions on before moving forward.

Once again, thanks and please feel free to keep your opinions coming if you feel like responding.

None of the ones above bother me if I am buying coin/bar/anything at spot or below spot


This is unacceptable, even if I am getting 98% metal while paying for 95%, I will report this, whatever is printed should be truthful, lot of people put their hard earned money into jewelry or other items and they should know what they are buying and storing for future needs. I have seen 100s of times when people walk into gold buying shops only to find out that their 22k marking is just 14k or 18k gold or maybe not even that..

Personally, I rarely buy metal that isn't .9999 anymore unless I really like the coin, then I'd buy a .999.



I tend to like my collection to all fit nicely together, so uniform capsules or storage tubes is a must for me.



I no longer buy US gold eagles because of this.  I much prefer the purity and finish of Canadian coins.



It would bother me if it were marked something that it wasn't.  That should not ever happen.  However, if it were marked "~1 troy ounce" it wouldn't bother me at all, because I'd feel like it was meant to be as close as possible to 1oz but maybe the maker didn't have the necessary equipment to do it perfectly and was still trying to be completely honest.

All that being said, if you made something unique and it was meant to be a show piece and not something stored in a collection, I think 90% purity would be a better choice due to being able to better maintain it's shine over time.  Just my 0.00000002 BTC.

---

(edit)

I should clarify that I don't feel this way about purity.  If something is marked 95% silver, it should contain 95% silver.  The other 5% could be more silver, as that wasn't specified.  It is only if you claim something is there that isn't in your coin that it becomes a problem.

Hi guys, I've had a few question regarding Bitcoin collectibles and how you guys view metal purity and piece weight if you feel like taking a moment to share your opinions. There are a lot of legal standards inside of jewelry and precious metal marking that I'm curious whether they'd bother you as collectors. If you've been around for my occasional post or question, you may know that I do non ferrous metal work, and my current focus is on usable collectibles. If its not just a circle or bar of metal that you put inside of a plastic case, but rather something that you can handle, pass around, use functionally, etc the material properties become important, and I'm looking to get an idea of what people might be open to.

Final note before asking your opinions, everything that I would potentially mark would be 100% honest, transparent, and legal.


1) Is .999 Fine a must have for you? Be it gold, silver, platinum, palladium, how do you feel about alloys (sterling, white gold, purple gold, 90/10 Plat/Irid)?

2) Are standard weights a must for you? 1 troy ounce vs 1.3 troy oz, 17.983g, etc?

3) US 1 Oz Gold Eagle question: The 1 Oz US Gold eagle weighs 1.09 Oz because its 22K gold instead of 24K. Its marked as containing 1 troy ounce of fine gold, though the metal is not fine gold, its 22/24 % gold. Is that an issue for you?

4) Under marking: Marking is a minimum standard, would a piece marked 1 troy ounce gold that weighs 32.3 grams bother you? Same question with regards to purity, if I used 98% silver and marked it as 95% would you have any problem with that as long as you are getting more than promised?


Thanks for taking a moment to answer