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Post by sev051 on Sept 4, 2015 1:14:33 GMT -5
I just read this in the Faq yet I am confused,
Q: It has been 4 hours and my clear resin is still flexible, will it harden?
A post heat cure is strongly recommended for all clear pieces, but less than 1/8" must be post cured. Post curing the clear on the lowest setting on the conventional oven typically 140-160 F. for an hour or two (parts may require some support during heat curing) will minimize part distortion and shrinkage, while giving maximum toughness. It is also highly recommended to preheat molds to 125F. prior to pouring your resin in the mold.
So I am a bit confused here and although a video tutorial would help best I figured I'd ask first. Usually my parts are tiny recastings for my models that usually have a different clear or even a solid color usually intercut parts that need to hold shape and fit properly. With heating being recommended for such small parts I was wondering if I need to heat the mold, pour resin, then heat the resin inside the mold as it cures? Or preheat part a, and b then mix? So on and so forth. And will it bubble or make a mess I should be aware of, maybe place on cookie sheet?
As for syringe question I was wondering if its a accurate way to measure each side? Would a cough syrup type work as I don't need a huge one? How do you properly clean it so the resin doesn't get stuck? Sorry I know this is alot, but already messed up buying clear cast and not realizing just clear is what I needed, so want to understand this the best I can.
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Post by carol - Alumilite Corp on Sept 4, 2015 11:30:47 GMT -5
Sev051,
Preheating your mold will drastically reduce the demold time when pouring the Clear, especially in thin or small pieces. Heat will also help the resin cure more uniformly in thin and thick cross sections, so warming the mold is beneficial. The Clear being of the polyurethane, exothermic (creates heat when it cures) sometimes needs help in the thinner pieces. It is highly recommended that you heat the mold prior to casting (125-140F) post curing at the same temperature for an hour in the mold giving it support for the piece. No need to heat the resin before putting it in the mold.
At the low temperature is shouldn't "bubble" in the oven however... it would be good to put it on a disposable cookie sheet, piece of foil as a just case measure.
The Clear is measure by weight, not volume. Are you using a scale, are you doing any kind of degassing? Please feel free to call at anytime, we are happy to help you via, forum, phone, email, or stop in! Have a great Labor Day Weekend!
Regards,
Carol
800-447-9344
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Post by mike on Sept 4, 2015 12:30:44 GMT -5
To expand a little on Carol's reply ... the syringe measures volume, the Clear mix ratio is by Weight so we do not recommend the syringe. Try finding an accurate scale that measures by weight.
Alumilite Urethane casting resins generate heat when the cure (exothermic). The heat helps them cure and harden properly. Extremely small castings don't have enough mass to generate enough heat so they harden much slower. Therefore, supplying heat helps thin parts cure better. You can do this by warming the material prior to casting, preheating the mold prior to casting, post curing the mold and resin after you've poured it and after it has started to cure (gelled), or any of the above in combination. All of which will help it cure properly and to its proper hardness and physical properties.
Mike
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Post by sev051 on Sept 5, 2015 9:57:27 GMT -5
I use a digital scale but it isn't sensitive for small amount so I end up over using resin at times, I don't have anyway to degass, and if I have any issues I plan to try to get a pressure pot. As its more for a hobby then anything investing in a setup is more then I usually budget. So would that type of syringe at least work if I premix first, as a method of pushing it into a mold. As for calling I have social anxiety so the forum is easier on me sorry.
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Post by mike on Sept 5, 2015 10:23:52 GMT -5
Using the syringe to inject the mixed resin is a great idea and works well.
Pressure pot is the way to go.
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Post by sev051 on Sept 10, 2015 16:14:21 GMT -5
Ok, so I got my clear today and as soon as my part is done curing out of clear cast Im going to attempt to cast it in clear. With clear cast being epoxy however should I still heat it or avoid heating it? Also is it just the nature of clear cast that its still soft? Its dry to the touch and been slightly more then 48 hours not fully cured but I have had pieces more then a week old from my first attempts vary from being rigid like a hard plastic, to soft and malleable like rubber.
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Post by mike on Sept 13, 2015 20:31:07 GMT -5
Mix ratio needs to be 1:1 by volume to achieve full physical properties and full hardness. If you are doing extremely thin or small castings, yes ... heat will assist in getting to cure more thoroughly faster but even small or thin castings my stay pliable as that is the nature of the Amazing Clear Cast ... slightly softer than our clear urethanes but offers great impact resistance as coating applications as it is slightly softer.
Mike
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Post by sandyscrim on Feb 10, 2018 14:02:19 GMT -5
How do you know how long to post cure a piece?
How long to warm the mold?
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Post by carol - Alumilite Corp on Feb 11, 2018 17:25:36 GMT -5
Good Afternoon Sandyscrim,
Depending on what resin you are using the post cure can be from 15-20 minutes to couple of hours using the Clears or Flex products. The 2-3 minute open times are about 15-20 minutes for a post cure at right around 130 F., 130 F holds true for most all of the resins for post cure, length of time varies.
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Post by carol - Alumilite Corp on Feb 11, 2018 17:40:35 GMT -5
Sandyscrim,
I am sorry hit the send button before I was finished...the preheat temperature is about 130F too or just until it is good and warm to the touch. DO NOT put resin in the microwave but you can put a silicone mold in the microwave for a preheat prior to pouring the resin.
If there is anything else please let us know by forum, email, or please feel free to give us a call.
Warmest Regards,
Carol
800-447-9344
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