Expansion during burnout

A 1:1 mix of Red and Cherry, yielding a lost wax capable resin tuned for 30 - 70 micron slice thickness
jljr99
B9 Maker
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Expansion during burnout

Post#1 » Mon Aug 24, 2015 6:32 am

Occasionally I have noticed when casting a part that leaves a very tiny thin detail of investment that the investment disintegrates during burnout. Does the resin expand during burnout?

Apart from all the details temps, time, investment, concentration and so on. I'm just wanting to know if the resin expands during burn out. I cure with 2 cycles of microwaving 5mins in water and then at least 30mins in UV light.

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RobertW
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Re: Expansion during burnout

Post#2 » Mon Aug 24, 2015 12:58 pm

short answer: yes.

mwm
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Re: Expansion during burnout

Post#3 » Mon Aug 24, 2015 1:30 pm

I've had slight to moderate finning - caused by shell damage due to resin expansion - in some castings recently. My B9 models were printed in Cherry resin. This is not usually a problem with my process but it has been - some pretty nasty finning - for the past coupe of weeks.

I cast platinum in Talladium Galaxy 2 investment. This is the hardest / toughest investment I know of.

My last platinum flask had two of the same models in it. My daughter's wedding band. One was vented with ~1mm wire running from inside top of a lady's ring model to the base of the flask. That one didn't show any shell damage or finning in the cast metal. On the vented model- which didn't show any shell expansion damage, there was pink ash residue showing at the bottom opening of the gate of the ring and also way down at the bottom of the tiny vent.

The other EXACT same model in the same flask was not vented and it showed shell damage / finning on the lower half of the ring model and down into the gate.

What makes no sense at all is that I cast some silver from Cherry models in Satincast 20 Gypsum investment - no added chemicals - boric acid or anything - over this Summer and I had no breakage or finning at all.

mw
Mark Morrell
MWM Jewelers Services

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panastation
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Re: Expansion during burnout

Post#4 » Mon Aug 24, 2015 3:22 pm

resin expands and becomes a blob monster after 550f anything before that its just giving off fumes and becoming black while maintaining detail.
U need the right investment for the right job.
on the other hand ---platinum investment should work for cherry....U need to wash with alcohol+then water and soap right after print get it clean as posible ...
microwave or oven cure.... even over cure if posible but dont damage 3d print
If its fully cured using that plat investment u should get clean results especially since u can go to 1550f and leave it there for few hours.

jljr99
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Posts: 403

Re: Expansion during burnout

Post#5 » Tue Aug 25, 2015 7:33 pm

What investment do you recommend. I've used Satin Cast 20 and Ultra Vest Maxx. I think Ultra Vest Maxx has given me better results.

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panastation
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Re: Expansion during burnout

Post#6 » Wed Aug 26, 2015 12:39 pm

satin cast and ultravest work with tweaks u have to find out what those steps are for the setup and equipment u are using at shop. But it does take time to figure it out ---its diff for everybody.
If u have experience mixing investment, casting metals--Spruing in right places and most important *curing* prints .
These brands will not fail with *pure cherry*
I havent tested red-1-1mix or black or any other 3rd party resin. based on a year of trials id say the best three u can get starting from most expensive to least are----------
invest cp from ti research
docs casting plaster
srs cadcast

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