Why a 5 blank mold instead of 3

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DLGunn

Member
Joined
Jul 31, 2009
Messages
285
Location
Paragould, AR
Most larger molds are made around 5" by 5" and around 1" deep. That will typically yield 5 pen blanks.

Is there any reason for the number 5? I am new to casting and I don't see me needing 5 pens of the same color scheme. Is there any reason a mold made to yield 3 pen blanks wouldn't be ok?

I plan on getting some plastic cutting boards to make a few molds out of, if I can find some thick enough. Or I may end up making a couple of silicon molds by using the tutorial in The Library.
 
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Just guessing, but the 5x5 size might be somewhat standard so it will fit into a pressure pot for those folks who pressurize their castings (very helpful with Alumilite casting).

If you don't plan to do pressure casting, you can make your own molds whatever size you want and for as many blanks at a time as you want. If you do plan on pressure casting, you can still make them whatever size you want as long as they will fit in the pressure pot.
 
Scott, I forgot to put in the OP that I will be casting with Alumilite. I know you can still use PVC for that, but I think I would rather have a mold. I may do some worthless wood casting as well.
 
I like making my own from the white plastic cutting boards from Walmart or Target. That way I can make them whatever size I want. I currently have a few different sized depending on what blank I'm casting. Most of them are around 1/2" thick and work just fine. You just cut them to size, predrill and screw them together. Just be careful not to over tighten the screws or you will blow out the hole by going right through it and ruining the mold piece. If they are slightly textured, sand them smooth or apply a little silicone. I put a large X on the one side to remember which side to unscrew if needed when removing the blank. That way you maintain a good seal on all the other joints. I've been using mine for several years with no problems in both polyresin and alumilite. If blanks start to stick, just get a little mold release and rub in there prior to pouring. I've poured everything from shredded money, pinecones, acorns, antler pieces, you name it..... with no issues.
 
Hey David, when you come to the March meeting I'll show you one I made that's about 6" X 3". It fit's in my pressure pot just fine. Like John, I've used it for both PR & Alumilite.

There's also a kitchen supply store in NLR. You may be able to stop by on your way home. They have restaurant sized cutting boards that are maybe 3/8" thick. And even better is they're about $20 (IIRC) for a really large cutting board. The mold I'm talking aboiut came from one of these cutting boards.
 
I use a three blank mold..

image-2273229864.jpg





image-2330483901.jpg

Works great!
 
DLGunn said:
Scott, I forgot to put in the OP that I will be casting with Alumilite. I know you can still use PVC for that, but I think I would rather have a mold. I may do some worthless wood casting as well.
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Ah....that would be much better for the Alumilite. Sure would be easier to not have to turn the PVC off the casting:eek:



Scott (I didn't know....) B
 
I have had release problems with the white cutting board material I buy at Walmart. It is textured and the blanks tend to hang in the mold requiring me to disassemble the mold to remove them. I tried PVC boards available at Home Depot but they won't stand the heat generated during curing (I cast with Alumilite) and eventually distorted. Until I can order some smooth HDPE from the Internet, I have been using melamine coated boards with great success.
 
Ah....that would be much better for the Alumilite. Sure would be easier to not have to turn the PVC off the casting:eek:
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Regardless of using Alumilite or PR you shouldnt have to turn off the PVC. Alumilite castings pop right out using a dowel and hammer. As for PR, spray the inside of the pvc tube with mold release. Again, just knock it out with a dowel and hammer. No problem.
 
efrulla said:
I have had release problems with the white cutting board material I buy at Walmart. It is textured and the blanks tend to hang in the mold requiring me to disassemble the mold to remove them. I tried PVC boards available at Home Depot but they won't stand the heat generated during curing (I cast with Alumilite) and eventually distorted. Until I can order some smooth HDPE from the Internet, I have been using melamine coated boards with great success.
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Have you tried spraying your mold with a mold-release before pouring in the Alumilite? I expected problems with the textured cutting boards, but the mold release makes them work fine.

I remove one end, flip the mold upside down, and whack it again my bench top...out pops the blank.
 
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