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Firewood Inquisitor
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438 Posts
Discussion Starter #1
A while back I bought the plastic casting kit from Penn State as well as some shredded money, I figured some financial guys might like a money pen. I'm having trouble understanding how to go about making the blank though. If I take a square mold and fill it with the resin mixed with the shredded money then when I turn it down there will be bits of paper breaking the surface of the pen and I'd rather have an unbroken shiny surface.

So for those of you who have cast their own blanks with random material - do you just live with the decorative material breaking the surface or do you do something else to keep it smooth and shiny?
 

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James Daschel
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96 Posts
First, if you cast a money blank you WILL NEED to use a pressure pot, or these will be tons and tons of bubbles. Second, you have to use a top coat finish, such as a CA finish. Then it is all shiny. But money blanks are very very tricky to make look good. Even if you paint the hole after you drill it to cover over the tube. It will still look bad. So the best way is to glue a dollar bill to the tube before you glue the tube into the blank.
 

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Firewood Inquisitor
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438 Posts
Discussion Starter #3
Thanks for the info jdaschel, that was very helpful. For a pressure pot do you just buy one from someplace like Harbor Freight - does it need any modifications? What kind of pressure is needed?

I'm not in any rush on this project, just seemed like something good to do eventually.
 

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Pulling and releasing vacuum works better than pressure at getting bubbles out of resin.

I use an old pressure cooker as the chamber, with the jiggler replaced by a vacuum gauge, and a hand vacuum pump.
 

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Firewood Inquisitor
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Discussion Starter #5
I was wondering about that and when I once asked someone who does this he said that when you lower the pressure the bubbles get bigger, when you add pressure they get smaller. At what level of vacuum do the bubbles escape the resin entirely instead of just getting bigger?
 

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I usually do five or six cycles. Full vacuum, let it (and my hand) rest for a few minutes, release the vacuum, and then do another cycle.

How many cycles is needed is dependent on how thick the casting is, and how viscous the resin is.
 

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jigs-n-fixtures said:
I usually do five or six cycles. Full vacuum, let it (and my hand) rest for a few minutes, release the vacuum, and then do another cycle.

How many cycles is needed is dependent on how thick the casting is, and how viscous the resin is.
I started using vacuum back in my model railroad days to cast epoxy parts for scratch built engines, and have stayed with it. Because I understand it, I use it.

IMHO: The vacuum lets you get all the bubbles out, pressurizing just makes the bubbles smaller and leaves voids you have to deal with later.
 

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James Daschel
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For casting embedded objects, such as shredded the best way is to use pressure. It will force the resin into all the nook and crannies of the shreds and will make it solid. As for the pressure pot. The harbor freight one works good. You will have to take the fitting off, and replace them with a pressure quick connect, and a ball valve, and cap the other side. You will need to also level out the bottom of the pot. I took a drain cover, cut the corners off and put that in the bottom of the pot to relatively level it out.
And you said that you we weren't in a hurry. But you should do this before your resin goes bad. I think PR shelf life is about a year. But who knows how long it was sitting around at PSI
 
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