Originally Posted by
ChrisPer
I added up my last six batches' yields, and broadly speaking when I crush and sieve the sizes I get are:
>15# - first pass about 60% but I re-grind until it all goes through the 15# sieve.
FF 15-20# - 28%
FFF 20-40# - 28%
FFFF 40# -100# 25%
Fines < 100# 19% go into next batch of pucks (except a teaspoonful for a poof test).
I chose to design for a 500g mill batch, which limits the size of risk if something goes wrong. I have been putting in about three to five hours work to make each batch. This means that at the end of processing a batch, I have about 160 g of FF and 160g of FFF, the two important sizes for most of us.
If I could buy it, I would be better doing so.
I am trying a few different puck breaking and grinding ways, and they don't seem to make much difference. Last time I tried a wood-chisel to 'cut' them on a hardwood block but it didn't improve yield. Next time I plan to use a sharp edge to slice before drying the pucks, and spend more time to reduce them below coffee bean size with the sharp edge, before drying.
almar, your PID controller uses a mathematical algorithm rather than an 'on-off outside a plus and minus switching temps' like a bimetallic strip switch. I am thinking how a better screening method or sizing choice could improve my yields or reduce the input effort.
I am considering targeting 15- 30# for FF, increasing its share, and re-pucking 4F as well as fines. 3F is good, but 2F needs more bulk as its used for the 100m heavy charges, ie three times as much powder per shot as a 3F pistol charge and 45% more than a 3F 50m charge in a rifle.
That means I need some different sieves for the deck.