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ramaroodle

ramaroodle

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Well this pen is my second attempt at casting. (The first ended up looking like an elementary school volcano experiment).
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Lesson learned. My question is regarding dyes and powders.

I put some gold powder into the resin as I mixed it. It almost looks like they are small bubbles but on closer inspection it is the gold powder (or maybe both). Am I using the powder incorrectly?
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I'm using my phone so I can't see real clear as to what your referring to but I don't think there's any way to use it incorrectly. The issue with powders is usually if it isn't stirred enough and it leaves lumps but I haven't used all of the powders on the market. If you have air in the resin it might be that it began to set before you got it in the pressure tank. I don't add powder until after I have mixed the resin so I can see that I have it mixed well enough. If the resin is thick it will be harder to mix. I use a clamp light next to the cups and warm the resin for 15 to 30 minutes depending on its thickness. This will thin it out and mix easier and quicker. Just be sure to let it set for another 15 min or so and occasionally stir it to let the excess heat leave. You want it thin not hot. Heat will cause it to cure much quicker. It's a learning curve that we've all had so don't give up. Take notes so when you have success you can repeat the process and be consistent. Good luck!
 
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Don`t think so , I can`t see any defects . Shouldn`t be visible bubbles if pressure was on while the resin set . Insufficient stirring could leave small pockets of powder that haven`t been wetted by the resin , but I suspect you are just seeing the way in which light scatters from the mica flakes .
 
If you can only see the bubbles and not feel them, I agree with Wayne. The light can be deceiving. If you can feel the dimples on the turned and polished surface and you did not see pockets of your mica powder, it must have been well over 7 minutes after mix that you got things under pressure.

When I say "well over", from my limited experience, I have had Alumilite clear beginning getting stiff at 7 minutes already in the mold when going into the pressure pot, tightening the lid and adding pressure, which I am sure took 1-2 more minutes and not had bubbles at 55-60 psi.


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The photos are rather small, but based on the reflection of the purple pen, the surface doesn't appear to be completely smooth. That can be caused by many factors, that a closer and larger photo, may help to determine.

Urethane resins can be warmed, and I prefer a hot water bath. Although, when using urethanes, caution needs to be taken to prevent the water from contacting the resin.

If there are air inclusions, they should be evident on the surface. Placing a light source opposite of the viewing angle, and getting a reflection across the surface, will reveal little holes.
 
Thanks for the replies guys.

MRDucks2 said:
John, I believe Andy is using Alumilite Clear, not PR. The warming doesn't apply and the working time is very limited.
Click to expand...

OK. This might be important! I am using Alumilite Clear. So, warming the mold and resin isn't something that I should be doing? I get the impression that I should warm the mold and the resin, (thoroughly mixed) before adding the hardener then let the whole mixture sit for a few minutes until it starts to thicken? If I was going to add a little white accent swirl, would I add that after it is in the mold?

I think I mixed it pretty thoroughly. When I showed it to a co-worker who is a woodworker he asked if those were bubbles or sparkles. Since he couldn't tell that means that customers might also not be able to tell which is not good.
 
If temps are above 70 degrees, it shouldn't be necessary to warm anything.
Warming the mold is required when using fast cure urethanes, to prevent thermal shock.
Warming either the resin, or the mold, will affect the pot life. This is true for any exotherm resin.

If you are unable to determine if you have air inclusions, maybe you should try a clear cast to evaluate the finished cast, and try a single colorant without a lot of shimmer, like a solid color.
Once you can determine there are no air inclusions, then start experimenting with micas and multi-color casts.
 
Terredax said:
If temps are above 70 degrees, it shouldn't be necessary to warm anything.
Warming the mold is required when using fast cure urethanes, to prevent thermal shock.
Warming either the resin, or the mold, will affect the pot life. This is true for any exotherm resin.

If you are unable to determine if you have air inclusions, maybe you should try a clear cast to evaluate the finished cast, and try a single colorant without a lot of shimmer, like a solid color.
Once you can determine there are no air inclusions, then start experimenting with micas and multi-color casts.
Click to expand...

Thanks. That was my plan. Process of elimination. 4 blanks. Clear, clear with sparkle, colored and colored with sparkle. I know I should have done that to start but thought I might get lucky. Time to order some more Alumilite.
 
Bubbles in Alumilite are caused by moisture in the casting IE contaminated product, moisture in the wood if a hybrid. If the pressure is released before properly curing that can cause bubbles on the outside of the cast.
You wrote "(thoroughly mixed) before adding the hardener", not sure you are mixing in the correct order. Should be mixing Part A and B thoroughly mix then add any colors and/or powders and mix again.

You can call Alumilite (they actually answer the phone) talk to Carol and she will be more than happy to spend as much time with you as needed to help you.
 
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