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Post by redman67 on Dec 29, 2016 20:16:42 GMT -5
Hi.... trying to cast very small parts but after 20 minutes the parts are still somewhat flexible using the Alumilite Kit that includes the resin RC-3. I wonder if i need to wait 24hrs for it to harden or is this the end result. Never done this before. Seems like i wasted money on the RC-3 Resin. Here is a pic of the size.... Very small as you can see. It did harden a bit more while i was uploading the pic but still has too much flex to work. Any ideas on a stronger Resin that will work... The mold came out great using the Amazing putty
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Post by mike on Dec 29, 2016 22:20:54 GMT -5
Simply warm the mold and keep the resin warm while it cures. The RC-3 and all of Alumilite's casting resins are exothermic ... meaning they generate heat when they cure. The bigger the casting, the more mass it has ... the more heat it will generate ... and the faster it will cure.
Unfortunately ... your piece has very little mass ... so it creates zero amount of heat ... and struggles to cure at a normal speed.
IF you are using a silicone rubber mold, simply put it in the microwave for 30-45 seconds. When you pull it out, it will be warm to the touch. Then mix and pour your resin in the mold. The resin will cure at almost a normal speed and will harden much faster. After you've poured it and it has gelled, if you want ... put it on a register, a hot plate, in a toaster oven, or somewhere warm (100-130 degrees F) for 10-15 minutes. Then allow it cool and demold your cured/rigid cast piece.
Side note: Be sure to measure precisely when measuring small amounts of resin as IF you are off ratio when mixing small amounts ... the percentage you can be off ratio can be very high and may affect the cure/hardness of your cast piece.
Mike
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Post by redman67 on Dec 30, 2016 10:52:21 GMT -5
Wow this is really good information! I surely appreciate your time and thanks for sharing your knowledge.
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Post by redman67 on Dec 30, 2016 12:01:34 GMT -5
Thanks so much! It worked. I did exactly as you said and that did the trick. Rock solid! Thank you thank you thank you.
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Post by Brian on Dec 30, 2016 16:35:17 GMT -5
I might add 1 other thing...I use RC-3 as well for very small parts similar to the size you posted...once you have poured you amounts of resin and catalyst ("A" & "B") stir the part "B" to help insure that any separation that may still be present is gone prior to adding and mixing it with the part "A". I pour several small molds at once...on an average I am using 40 - 50g of total combined "A" and "B"....with that being said, I do go 1g more of part "B" to compensate for what is left on the stirrer before mixing w/ part "A" .....so far, so good. As Mike pointed out, the mix ratio is so very critical w/ RC-3 when used in the fashion that you and myself are dealing with. I use a digital Gram scale...I am looking for a more accurate Gram scale that can display in the 10th's or even 100th's to take some of the guess work out of a pour verses just adding 1g extra "B"...I been lucky ,so far,I would like to get down to the 10-20g pour, but the only way that is happening is if I can measure a half or quarter Gram or less.
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Post by redman67 on Dec 31, 2016 20:00:24 GMT -5
Thanks for the advice... I would like to get one of those scales too. If you see any decent ones around like on ebay or something let me know... that would definitely help with the small pours... I think i can do better if my ratio is more accurate... that's probably half my problem.
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