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Post by sev051 on Sept 13, 2015 19:35:20 GMT -5
Hello I was wondering if someone could tell me what the rigidness of clear cast usually is? I have had hit and miss depending on mold shape when it comes to how much it hardens and if it is bendy or not. The piece im working on now however doesnt seem to be getting any more rigid, it still has a soft rubbery like consistency yet is dry to the touch. It is vary flexible and does not hold its shape well, for now I leave it in part of the mold so it keeps it shape in hopes it will harden soon but I dont know if clear cast is meant for such rigidness.
Its been about five or six days now and I plan to recast a new one with just alumilite clear but I need to free up the mold, so if its pointless to keep the clear cast in the mold Ill just start over now but if its still going to harden more I will leave it be.
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Post by mike on Sept 13, 2015 20:47:50 GMT -5
Small or thin areas may need to some help to get them up to optimal physical properties and hardness. One crucial thing is to make sure we mix enough up to give us an accurate mix ratio of 1:1 by volume for the Amazing Clear Cast. If it has been that long, I'd recommend finding somewhere that is warm to place the mold and casting for 4-6 hours ... perhaps in your car if it is hot where you are at. You are looking for 120F for 4-6 hours should help it harden up if it is going to based on the accuracy of the mix ratio. Some people mix pretty small amounts ... less than 1 oz and it is very easy to be off by 5-10% simply because the measuring amount is not adequate for being on ratio or because they pour one cup into another not accounting for the left over that stays in the first cup. In larger amounts, this is rarely an issue but smaller amounts it can be a significant percentage.
A lot of speculation based off your description so I've simply added the common causes. Please give us a call tomorrow to discuss in finer detail if we are off track.
The Alumilite Clear cures much faster and is recommended for industrial applications where degassing and pressure casting processes are more common due to the limited amount of work time and need to remove the air introduced while mixing.
Mike
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Post by sev051 on Sept 13, 2015 21:15:30 GMT -5
I am using it for model based applications where small parts are usually solid colors but I want to make them clearish. But I think I know what I am doing wrong now, when I first got the parts I mixed by weight and not volume. Rookie mistake.
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Post by mike on Sept 14, 2015 6:34:45 GMT -5
Yes, mix by volume and use some heat when pouring small or thin pieces to help cure and you should have much better success.
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Post by frank on Dec 8, 2015 20:07:00 GMT -5
I've got the same problem, I want the pieces to be fixed and rigid and even after recasting to a heavier prototype it does not become hard and unflexable
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Post by mike on Dec 11, 2015 11:13:39 GMT -5
The other option is to switch to the Alumilite Clear. The Amazing Clear Cast is a 68-70D system whereas the Alumilite Clear is an 80D which is much stiffer in this section. Moving to a much faster cure urethane system poses some issues with trying to remove the air bubbles before the resin begins to cure (7 minutes). Typically vacuum or pressure casting does the trick but also allows you to demold much more quickly ... within 1-3 hours ... a post cure still may be necessary when casting thin or small parts.
Mike
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