Casting jewellery


#313

Anything you need Kerr related i would order ASAP. My supplier said that some of the items will be available from the original mfg who made for them but i would not count on that. I use 2 different type of sprues. When i put the base on manually, i use a 6.5mm wire for the base. Sometimes we have the cad program put on the base. Will give me a base proportionate to the size of the shank.

Using the bluecast resin. hops this helps


#314

I’ve started adding the sprues in ZBrush, which is so much easier. Are you using Matrix or Rhino?

Thanks so much for the info!

Ordering crucibles now!


#315

using the latest version of matrix

art rosenfeld
rosenfeld jewelry
lyndhurst, ohio


#316

Kat

here is one I cast today. this is a milled ring but I sprue the resin the same way.

sprue

art


#317

Same program and 5 revo mills and 4 solidscapes and formlabs2 incase you need anything


#318

philadelphia pa


#319

Art, is this sterling silver? Do you mind me asking what metal temperature? Thank you so much!

And thank you, @George_Earussi!

I’m in Austin, Texas. ZBrush, Form2…


#320

Kat

I use tru silver casting grain from hoover and strong. I cast at 1825F metal temp and 900F flask temp. Using a memco electrovac with a nitrogen/ hydrogen gas mix.

George, any chance you cast stainless steel? have a customer for some motorcycle logo rings but wants stainless

art


#321

Ah…I had to look up TruSilver. I’m using something similar from Rio…anti-oxidation casting grain. I’ve actually had problems trying to get it to take a nice patina. Thanks for the info on the temperatures…I’m casting at around 1865°F (1018°C), which is at the top end of what they recommend…I was having a problem with it not being fluid enough. Using a KayaCast vacuum system. Sounds like you have a really nice setup!


#322

So, The Bluecast… How is the post-print shrinkage? Are you casting immediately as they recommend or taking your time? Seeing your pieces I’m sure you understand the issue here.
I was going to try this stuff but the shrinkage issue has me stalled.

Bob


#323

I have been making the models 2.5% larger in preform. Sizes have been dead on.

Sometimes I cast right away. Sometimes a few days later. Have not had that be a problem yet

Art


#324

I’ve found bluecast to have a variable shrinkage rate, depending on environment and time from print to investment. In the summer, I was losing 1 ring size from the original model to the cast piece. In winter, that went down to half-a-size. However, I get these results only if I print, rinse/dry/repeat 3 times, and then invest on the same day - preferably right away.

If I leave a print for a day or two - even in a drawer or dark cupboard, there’s a noticeable shrinkage.

I now only use bluecast for models where precision isn’t totally required - like pendants without gem settings, or prototype models. For anything else, I go back to formlabs castable. (I’ve found by properly curing my prints, using R&R Plasticast - finally available in the UK - drying my invested flasks overnight at 20°C and holding the oven initially during burnout at 143°C for 2 hours, I’m getting great, non-porous results).


#325

I am using the previous version of BlueCast, and there is a little shrinkage if I leave the model sitting around for a day or so. If I invest within a couple hours, I don’t have a problem with shrinkage.

I don’t have a set percentage, but I’ll add about 0.2-0.3mm to the size of stones, for example. Following that, I can usually bezel-set a stone with little to no cleanup.

I’m in Austin, Texas…we probably sit more on the humid side of the spectrum. I understand that BlueCast is “hygroscopic” and seeks water…

I understand the new version of BlueCast is supposed to have addressed the shrinkage issue.

@Charles_McManus, are you also getting successful casts from the Castable V2? If so, do you mind telling us what burnout you’re using…and what type of casting setup you’re using? Many thanks!


#326

No problem.
I’ve experimented endlessly with different investment powders, burnouts, etc. I’m on the east coast of Scotland, and differences in temp and humidity make a huge difference. What works for me is the following (with Castable V2):

-Print the model (I was getting good results with my formlabs 1+. Since upgrading to a form2, I’ve found the results even better).
-Rinse in dirty then clean iso. Dry with an airbrush. Stick in curing chamber for 4-8 hours, depending on thickness.
-Invest in R&R plasticast. Seriously. I’ve tried 4 other investment powders. Nothing else comes close.
-Place the flasks in a steady, room temp environment overnight.
-Warm your oven up to 143°C for an hour. Put the flasks in. Burnout at:
143°C - 2 hours
177°C - 30 mins
ramp up to 750°C at 200°C an hour - hold for 4 hours
Ramp down to casting temp. Flip flasks to let any carbon monoxide escape. Leave to settle for 3 hours. Cast.

My setup is pretty old-school. A large oven, an electro melt, a vacuum pump and chamber, and a MAP torch to cover the metal as it’s pouring.

It’s not always perfect, but I get more successes than failures these days. You can check out my work at www.circinn-studio.com to see the kind of stuff we’ve been casting.


#327


I cast the piece on the right using the newer version of Bluecast, the piece on the left is done in FL castable, the issue I’ve had with the FL product is the orange peal that you can see on the left, I invested the Bluecast within 24 hours of printing , the material is 14k white gold, there were 14 pieces in 4 flasks, a mix of yellow, white and sterling, I’m still processing these and 2 of them were for clients right now,
you can see that I’ve tried multiple spues and more , honestly I’ve tried everything and have more time into this than I want to. I hesitated to use the Bluecast and went ahead and ran a batch use FL castable last week…again , just to give the product a solid shot at this thing, I’m sorry I did because it was a waste, the Bluecast is the answer to the problem of poor castings using V2.
I’ll post some more here later, thank you guys for all your help in this, your experience and willingness to share has been invaluable to me
Paul


#328

Paul

thanks for posting the side by sides. Have had good success with the blue cast. Had the same issues with the FL castable… Also kike that i don’t have to cure the bluecast

art


#329

I’m a huge fan of not having to cure, and having good results with BlueCast, but am going to go back and apply what I’ve learned over the past year to my Castable V2 and see how it works.

Paul, I’m wondering if a longer burnout would work on the Castable V2 version? There was one of your other rings that might have had residue (one of the heavier signet rings).

Thanks so much for showing them side-by-side!


#330

Converting for those of us who live in a backwards country that never embraced the elegant metric system:
143°C is 290°F for two hours
177°C is 350°F for 30 minutes
1382°F for 4 hours (392°F/hr ramp)
Ramp down to casting temperature (I’m using 975°F for general casting).

Thanks so much, @Charles_McManus!


#331

You’re welcome.

I have more news. So, I use the same vacuum setup for investing and casting. The other day, I’m casting. My vacuum pump is a heavy duty model that cost me quite a few pennies. It stops pulling a vacuum. I shrug, figure it needs the oil changed (probably clogged with investment particles) and switch over to my backup pump (about 2/3 the strength of the big bubba). I have a lot of commissions to get through, so I put the big pump on the to-do list of future Charlie and carry on.

My next 2 casts are terrible. Really bad - orange peel, porosity, and flashing. Not just the formlabs, but the wax models too. I adjust my burnout schedule to a slower ramp, etc. but it’s even worse. So, I email R&R and get no response. Finally, I download the datasheet for plasticast, and find the answer: The initial degas of the investment has to happen in under 2 minutes. Normally, that’s fine, but with my smaller pump, it’s closer to 3 minutes. Plasticast does not like that. It especially does not like me reducing the amount of time I’m mixing the investment so I can pull a full vacuum on the slurry.

Long story short - the quicker you can get a collapse on your initial degas of your slurry, the better your casts are going to be.

I don’t think this is true of all investment powders - I’ve tried 4 so far with this resin. However, it does appear to be true of the R&R plasticast. The bigger your pump, the smaller your chamber, the better.


#332

Interesting observation…I read the R&R instructions awhile back, but never noticed anything about that.

Charles, do you know what your elevation is? I’m in Austin, at 489 feet from sea level, or 150 meters. When I was in Denver (5290 feet, 1612 meters), I know that my pump acted differently, although I’ve been back in Austin for almost three years. Mine’s a Kaya-Cast, but I’m guessing that doesn’t have a “bad boy” pump!

Other than a larger pump, is there any other way to affect the speed? I saw you said “smaller chamber.”

I’ve actually never timed the initial degassing. I’ll do that on my next casting session.