Black Powder Die

Once you've mixed and milled your black powder you'll probably be
anxious to start using it. Sorry...it's not quite ready. The powder that comes
out after milling is called meal powder. While it is useful for many things such
as priming and making fuse, you need to process it further to make it into
grains for purposes such as lifting. That's where this tool comes into play.
It's my homemade pressing die. With a little work, you can greatly increase the
efficiency of your powder. Thanks to Lloyd Sponenburgh for the design and
details and to Dan Williams for posting them along with additional info.

The first step is casting the pistons. They are made from a
mixture of silica sand and polyester resin. I was a little nervous to follow
Lloyd's recommendations for materials as I had never worked with fiberglass. It
was actually pretty simple. I used 3 inch ABS pipe for the forms, painted
sparingly inside with a mixture of petroleum jelly and tolulene. The base piston
is 13.5 cm tall and the top is 5.36 cm. I cut the pipe just a hair longer and
clamped them to a piece of foil covered wood (also painted with the mold
release).

You need 24oz of resin and 32oz of sand. Since Lloyd recommends
cutting back to 60% of the recommended hardner, the math becomes simple. Use
exactly half of the hardner directed for a full quart. Then mix in the sand
thoroughly (use an old or glass container because the only way to clean up this
stuff is with acetone). Pour into the molds and let cure, I left mine overnight.
Then they should slip out of the molds with minimal force. Once they're cleaned
up, the base piston fits in a piece of ABS pipe 5 inches tall. The dimensions
are important to enable the powder to be pressed to a specific density. This
picture shows how the base piston extends .8cm beyond the base.

Here you see the top piston along with a 3 inch section of 3 inch
diameter ABS pipe. This pipe becomes the chamber where the powder is pressed. It
sits on top of the base pipe over the .8cm portion of the bottom piston and is
supported by a repair sleeve and hose clamps.

Here is the die ready for use. It shows how everything fits
together with the clamps. The top piston has a reference mark 1.46cm below the
top to indicate when 8oz of powder is properly pressed. The mark isn't visible
because I need to darken it with a permanent marker (you can't etch on these
things to save your life). To press 4oz, the piston is pressed flush with the
top pipe. The cakes of powder obtained after pressing are then broken up and
screened into various mesh sizes corresponding to grain size. You can read a
little more detail about this on Dan's Page.

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