Issue casting class rings with emeral resin.

B9 Core Series - Ideas and Discussions
kcm
Newbie
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Posts: 5

Issue casting class rings with emeral resin.

Post#1 » Sat Oct 07, 2017 4:15 pm

I was wondering if anyone had advice on casting class rings with emerald resin and plasticast?

I am using a b9 v1.2 (30 micron / 25 slice) and I am having issues with the letters and number on class rings filling in (I've attached a close up shot). The image shows the left side but even the letters on top of the ring keep filling in the same way. It's not the whole number or letter it's just the edge that is closest to the recessed wall.

I have never had an issue casting with emerald resin before, however this is my first set of class rings casting with emerald resin. I have cast thicker solid plain signet rings and again have had zero issues. I believe my pieces are fully cured. Once the prints are finished I put them in water and let them cure under the uv light for about an hour then let them sit under the sun for the rest of the day. Finally each model is left to sit and cure two days before casting. I've found this gets the resin solid as a rock.

As far as mixing the investment and casting times, I follow the plasticast instructions and everything comes out perfect for the most part. However this order of class rings have been giving me hell, ha.

I've tried casting the class rings with both vacuum and centrifugal force and each casting has come out with the same defects.

I have been trying to cast the rings for the past week, but I have run out of ideas and I was hoping someone might be able to help me out.

Also, I am casting them in 14k yellow using new grains.

Image:
b9classring_defect.jpg


Thanks!

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Robert Howle
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Posts: 6358

Re: Issue casting class rings with emeral resin.

Post#2 » Sat Oct 07, 2017 4:37 pm

What is the distance between the bottom of the letters and the edge of the recessed panel?

Don't try to cast with thinner than .5mm thickness of the investment, and thicker is much better.

I would mold the cured print and shoot waxes.

Robert Howle
Dance like nobody's watching!

kcm
Newbie
Newbie
Posts: 5

Re: Issue casting class rings with emeral resin.

Post#3 » Sun Oct 08, 2017 8:04 am

Robert thank you for the reply.

The distance from the walls to the numbers (from the images) is 2mm. I tend to not have a gap smaller than 1mm.

I have cast class rings with half and half and plain cherry resin that have come out perfect (still casting with plasticast). I didn't know if this might be an issue with the emerald resin during baking out? I have cast the ring six times now and the same defects have happened in all six castings. The rest of the shank (that would usually indicate other issues such as flashing, porosity, or just not filling in) is coming out smooth and fine.

I have made a mold of the ring and that is my next step to try.

I've attach an image of the resin, since it's easier to see.

b9classring_resin_defect.jpg


Thanks again.

rkundla
B9 Maker
B9 Maker
Posts: 72

Re: Issue casting class rings with emeral resin.

Post#4 » Thu Oct 12, 2017 12:58 pm

Looks like erosion of the investment because those are positive defects, right? Could the metal be hitting that hard edge during the casting and blasting it away? You don't see any negative defects from the missing investment in the top of the ring?

kcm
Newbie
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Posts: 5

Re: Issue casting class rings with emeral resin.

Post#5 » Thu Oct 12, 2017 7:10 pm

Erosion is what I have been leaning towards but there aren't any inclusions in the casting nor does any debris fall out when I blow off the bottom of the flask right before casting. I was thinking maybe the investment is not curing or hardening enough in the oven? I did two test casts by leaving the flasks in the oven for a tad longer. On the first flask the sides of the class ring (the numbers) came out perfect, but the letters on top still filled in. On the second flask it came out looking the same as the images above. I am just at a loss because all other pieces, that are in the oven along side the class ring, are coming out fine.

A little more info on my casting process. My ratio for the investment is roughly 40ml/100g and the flask usually sit for about 6 hours before they go into the oven. The oven times are 300F for 2hrs, 700F for 1hr, 1350F for 2hrs, and then 1hr soak time at casting temp. The flask themselves are either 2.5x3 or 3x4.

Thanks

rkundla
B9 Maker
B9 Maker
Posts: 72

Re: Issue casting class rings with emeral resin.

Post#6 » Tue Oct 17, 2017 7:01 am

40:100 may be a little too wet for this type of detail. You might want to try 38:100 or 36:100 to stiffen up the mix and hopefully hold the detail.

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Metalcaster
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Re: Issue casting class rings with emeral resin.

Post#7 » Tue Oct 17, 2017 6:47 pm

definitely 36/100 ratio for class rings with lots of lettering.

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