Porosity and other issues with custom casting... Expert input please

[Gypsy]

Hello all.

Forgive my ignorance in advance.

I know that there is a difference between a handmade custom ring and a custom cast piece-- aside from price.

I have a custom design that I am seriously considering for my ring. I can't afford Leon for the design, or Maytal. At least, not in platinum. So handmade, for the most part, is outside of my budget. Unless I consider 18K.

CAD and Cast isn't. Actually it's under budget for me, in platinum.

But the design I want is delicate, it involves a micro pave/beadset halo without a metal frame on the outside (no milgrain, no line of polished metal on the outer edge of the halo to reinforce the beadset stones) so that it's almost invisible set micro pave halo. A THIN one. about .25-.35 carats of diamonds in the halo for my 5.9 x 5.9 asscher. Only enough metal to hold the diamonds.

I've been told that the design might be risky unless it's handmade because of issues such as porosity.

But then I see so many cast pieces on here, and so many happy customers. But then, their rings are new... their happiness now is not a testiment to how the settings will wear over time.

Is it true that to have a true "heirloom" quality custom ring, you really have to go handmade?

Is handmade 18K (by someone like Maytal) more durable than cast platinum?

I'd really appreciate the opinion of our vendors, and also our appraisers on this matter.

It's because of this that I haven't gone forth with my custom project. And have been hoping that a designer like Vatche, Tacori, Sheldon Speyer, or Beverly K comes out with a setting that I like so that I can avoid this whole issue altogether. But I realize that it may not happen, and with platinum prices rising all the time... I need to take some action fairly soon.

Thanks in advance for your input.

 

[strmrdr]

delicate designs need to be made from die struck material in my opinion and the opinion of my bench.
Quest has done some handmade halos with die struck shanks at reasonable rates.
Bill Pearlman may also be able too point you in the right direction.
Get some quotes before you go cast.
My 2c.

 

[Gypsy]

Can you explain to point me to a link that explains 'die struck' ?

 

[strmrdr]

Date: 8/26/2007 9:26:58 PM
Author: Gypsy
Can you explain to point me to a link that explains 'die struck' ?

I had a really kewl link that explained it that Iv posted before but I cant find it.
Will keep looking.

Basically it compresses the metal too 60000 psi making it denser and harder between 2 hardened steel plates with or without a shape carved into them.(making sheet or usually a shank if carved)
Hot rolled(sometimes followed by cold too but it will need to be annealed usually) then die struck is the best.
Hot rolled followed by cold rolled sheet is the second and somewhat cheaper for sheet. (rolled between 2 rollers under pressure, not as much pressure as die striking so not as good)
Cast is a distant third.

 

[denverappraiser]

There are several general techniques for building things.

‘Fabrication’ is where the maker assembles it from components, usually sheets and wires of metal, sawing and shaping them into whatever form they want. This is the classic way to get exactly what you want with one-at-a-time pieces and it’s the reason for the root word ‘smith’ in goldsmith. Assuming the smith has the necessary skills to build things true to the design and assuming that the client has the budget to find the time required, this is the way to make the ‘best’ pieces.

Die striking is where a softer metal (like gold) is hammered between 2 steel plates to shape it. This is the way that a significant amount of mass produced metal items are made ranging from wedding rings to coins to the door panels on your car and it works extremely well for the right kind of jobs. It can be done with great accuracy, hardens up the metal nicely and it’s very inexpensive if you’re making thousands of identical items. The steel blocks are a bit on the expensive side and die striking isn’t a feasible way of making a small number of items but it’s a terrific approach to things like the clasps on chains, the heads that hold stones, straight wedding bands and similar sorts of things. Few jewelers die strike anything but they use a lot of components that were made this way. Die struck heads (the prong assembly that holds the stone) are a common example.

Casting involves pouring the metal into an open cavity and letting it cool into the shape of the cavity. Usually this is done with a plaster-like mold that is only good for 1 casting because it’s destroyed to get the piece out but there are some reusable metal molds that are in place in the production shops if they are making large numbers of identical pieces. As with die striking, cast components can and often are used as parts in an assembled piece. Most of the big catalog houses cast pretty much everything you see because it’s less time consuming and consequently less expensive to make. A bonus is that it’s a lot less difficult to learn the required skills so it’s easier to hire and train workers to do the needed work.

Done well, casting works nicely and a lot of shoppers are thrilled with the results. It’s a relatively inexpensive approach and it brings down the price of certain types of design from stratospheric levels, especially for mass production. Most of what you see in the stores and on the web has been cast. The problem is that sometimes it’s hard to tell what’s been done well. There are some fairly subtle issues like the gas mix and temperature used to melt the metal or the cleanliness of the crucibles that can lead to impurities in the metal that weaken it, sometimes by a lot, and that aren’t always obvious, even with a careful inspection.

“Custom cast” is something of a can of worms. Jewelers have been handcarving waxes for a long time and recently have started using computers to control the tools to produce designs that would otherwise be difficult or impossible to do by hand. The explosion of micropave type designs in the market is a direct result of this since these are easy to CAD and they’re damn hard to fabricate. The problem usually comes at the casting and finishing steps. The big manufacturing houses and careful jewelers are using techniques and tools that produce few problems at the casting step but this equipment is fairly expensive and smaller shops are a bit less regimented and the error rate goes up. There are cheaper ways to do it. As mentioned above, it’s sometimes difficult to tell by looking which pieces have problems and which don’t and the workmen aren’t always forthcoming about it, even when they know. They’re on the clock and there’s usually a fair amount of pressure on them to get the piece done quickly and move on to the next one. This means that the worker needs to decide if a piece is ‘good enough’. This decision may not be made in the consumers best interest since their paycheck is usually a function of the number of pieces produced in a day more than the quality of those pieces. More production generally means more money.

There’s no short answer to which approach is better. It depends on your requirements and your budget. Bad fabrication is really ugly. Bad casting is unstable and defects are less obvious (and it’s ugly). Cast pieces, especially complex ones, are bunches cheaper and most people need to consider this. The price counts. It is possible to get an excellent piece of jewelry by casting and lots of people do it but it’s no panacea. Fabrication tends to be expensive and it’s likely to get more so. Fewer and fewer craftsmen have the skills to do it so it’s difficult for most people to buy it, even if that’s what they want so this also is no panacea. The answer is in your relationship with your jeweler. They’re supposed to be an expert at this and they should be able to advise you on what best suits the job at hand. If they can’t or won’t do this, or you get the feeling that they aren’t doing it with your best interests at heart, consider finding another jeweler.

Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Appraisals in Denver

 

[Upgradable]

This is one of the reasons I love Pricescope! Neil, thanks for being a contributor to the education of the consumer!!

I thank you, though the maul jewelers do not.

 

[Gypsy]

Wow, that was a great amount of information to digest Neal.


Would love more if anyone else would like a chime in.

I will have to check with them again, but I believe that two of the designers I contacted will ''fabricate'' my design in 18K within budget. From what I''m reading, this may be the best choice for me if the ''stock'' settings I''m REALLY HOPING will capture my heart, don''t.

Would that be a fair assessment?

 

[strmrdr]

Nice overview Neil, I dont disagree but am coming at it from a different direction.
Die struck material can be used as the base material for custom fabrication, which is where I was coming from.
Cold rolled is another option.
Both are better than cast.
In a design with a lot of metal its not going too matter a whole lot but when it comes to delicate designs the added toughness and lack of porosity make a large difference.
agree or disagree?

 

[denverappraiser]

I agree, but I’m always hesitant to make a blanket statement about what is ‘best’. Cast pieces outsell the fabricated ones for a reason and the reason is almost always money.

Cold rolling is the usual approach to making the sheets, bars and other basic materials for fabrication. Although it’s possible to use decorative rollers to produce a fancy product it’s fairly unusual in jewelry applications.

For lightweight and complex things, skilled fabrication from struck, rolled or drawn stock definitely produces the most durable and best looking results. I’m a big fan of skilled fabricators and I think, in general, consumers undervalue it.

Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Jewelry Appraisals in Denver

 

[Gypsy]

Any thoughts on the strength of 18K that''s been fabricated from struck, rolled or drawn stock versus CAD and Cast platinum? Would the 18K be a better choice?

 

[strmrdr]

Date: 8/27/2007 6:40:41 PM
Author: Gypsy
Any thoughts on the strength of 18K that''s been fabricated from struck, rolled or drawn stock versus CAD and Cast platinum? Would the 18K be a better choice?

hmmmm Iv got too think about that one when im feeling better. More tomorrow.

 

[denverappraiser]

18k white is a difficult material to work with for handmaking this sort of thing. It doesn’t roll well without cracking and it’s very stiff for raising the beads. If you’re going to go for a handmade piece, go for the platinum, you’ll get a better finished product. This is the reason the old masters used it as the material of choice for this sort of work and they were right.

Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Appraisals in Denver

 

[Gypsy]

For various reasons I'm not going to go into right now (time constraints) this has been the SINGLE most important thread in my setting quest. Thank you Neal and Storm.

This statement, "The answer is in your relationship with your jeweler. They’re supposed to be an expert at this and they should be able to advise you on what best suits the job at hand. If they can’t or won’t do this, or you get the feeling that they aren’t doing it with your best interests at heart, consider finding another jeweler." In addition to the actual information about the differences in cast, dye struck, rolling fabricators goldSMITHS that do their own rolling, striking/forging, and drawing of metal has been invaluable to me.

THANK YOU. VERY MUCH!

 

[strmrdr]

Before I answered I wanted to check and see if any of the new 18k white alloys were better than the old ones for cold forming.
They aren''t that I can find so I agree with Neil.