Resins For Investment Casting

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sgraber
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Re: Resins For Investment Casting

Postby sgraber » Mon Aug 01, 2016 11:41 pm

chill74 wrote:The WaxCast casts exactly like wax with no ash and a smooth surface. However...it MUST be cured all the way...meaning it has to be almost yellow. I can post some castings in a few days. I hade some rough surface castings initially when I did not let the resin cure (it was still too orange..and it reacts with investment giving a very rough texture) ...had the same issues with the B9 Cherry/Red when it is not cured...

B9 has a light they sell that will fully cure their resin and I am told WaxCast as well. There are other means of DIY coating that will seal pretty much any castable resin eliminating the need for curing.

Incidently, I have used both Cherry/Red from B9 and WaxCast and they both are castable when fully cured. I prefer WaxCast because you can literally see the wax in it. It also doesn't settle.

B9 has newer Yellow/Green that people are casting very well...but I have not personally tried it.

~Cam


I think this is the #1 thing people don't do: cure the parts enough. They always want to rush it. Myself, I cure the heck out of it before doing any sort of casting and I have not had a problem with it either at my jeweler.
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jimmyjackson
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Re: Resins For Investment Casting

Postby jimmyjackson » Tue Aug 02, 2016 2:57 pm

Thank you guys.

How many ours do you cure the rings under the UV light. What wattage of UV do you use ?

Can you also post a picture of the all the way cured model to see the color
thank you

chill74
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Re: Resins For Investment Casting

Postby chill74 » Wed Aug 03, 2016 4:16 pm

jimmyjackson wrote:Thank you guys.

How many ours do you cure the rings under the UV light. What wattage of UV do you use ?

Can you also post a picture of the all the way cured model to see the color
thank you


My UV light is probably on the weak side, and I can't really cure it as well as I like...but at least 4-5hrs @ 18watts (LED) or so. I use a coating for now. I will likely buy a B9 cure light, or make one similar.

I suspect I need at least double that wattage to cure in a reasonable amount of time.

There are 2 casting issues with resins that I think most manufacturers are trying to solve.
1) The reaction of the resin with the hardening of the investment - This is the curing issue that causes rough surfaces - Better the cure the better the surface quality of the casting.
2) The burnout where ash can cause pitting etc. -right now, most castable resins have pretty minimal ash content with proper burnout -1350F 2hrs min.

cerriousdesign
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Re: Resins For Investment Casting

Postby cerriousdesign » Thu Aug 11, 2016 3:14 pm

I cure my resin with heat, an old heating element, at 200 degrees in a vacuum chamber for 2 hours. Cures the resin all the way through not just on the surface like U.V. does.
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James
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Re: Resins For Investment Casting

Postby James » Fri Aug 12, 2016 11:07 am

Interesting. I don't see why the vacuum is needed though. Can you explain this aspect?
I prefer to know nothing about everything rather than everything about nothing. :)

chill74
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Re: Resins For Investment Casting

Postby chill74 » Sat Aug 13, 2016 8:58 pm

Test Bracelet Links
WaxCast
R&R Ultravest...
No problems casting WaxCast and these are on the thick side for testing.
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Yianni-VJ
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Re: Resins For Investment Casting

Postby Yianni-VJ » Tue Apr 04, 2017 4:01 pm

cerriousdesign wrote:I cure my resin with heat, an old heating element, at 200 degrees in a vacuum chamber for 2 hours. Cures the resin all the way through not just on the surface like U.V. does.


I also saw the MJSA publications about curing resins in a near vacuum environment, but I have one concern:
As we all know, heat transfer happens via three methods, but under vacuum, it only transfers via radiation.
Therefore, the pieces you cure under vacuum get heated by direct contact with the plate and with a bit of radiation emitting from it as well.
My concern is that heat transfer happens disproportionally, hence you increase the risk of warping effect.
I understand this might not be crucial to your application, I just want to put it out there as a principal.

My method is "deep frying" my models in glycerin at 250F for an hour or less, after post curing them in UV. I feel heat transfer is more uniform that way.
Depending on the resin, cracks begin to form at longer cooking times.