# Batch 2017-batch-04 #
-4 grains of 29mm using sorbitol, intended to be a reloads for the
-second-longest GMA 29mm snap-ring case. Grain length 45mm with 1mm spacing
-per grain, so we'll make the casting tubes 46mm long. Delrin coring rods of
-5/16" diameter.
+4 grains of 29mm intended to be a reloads for the second-longest GMA 29mm
+snap-ring case, *and* 6 grains of 54mm intended to be 2 3-grain reloads, all
+in one sorbitol melt.
-Formula for a batch size of 135g:
+29mm grain length 45mm with 1mm spacing per grain, so we'll make the casting
+tubes 46mm long. Delrin coring rods of 5/16" diameter.
-* 65% KNO3, 87.75g, taken from the big bucket
-* 35% Sorbitol, 47.25g
-* 1% RIO, 1.35g
-* PolyStep B1, 2 drops
+54mm grain length 76mm with 2mm spacing per grain, so we'll make the casting
+tubes 78mm long. Delrin coring rods of 1/2" diameter.
+
+Formula for a batch size of 1kg:
+
+* 65% KNO3, 650g, taken from the big bucket
+* 35% Sorbitol, 350g
+* 1% RIO, 10.0g
+* PolyStep B1, 15 drops
+
+With left-overs from batch-01, this was enough for all but two of the 29mm
+grains. We added enough materials for another 100g and were able to finish
+up with a bit left over.
Presto Multicooker operated at 275F indicated.
--- /dev/null
+# Batch 2017-batch-05 #
+
+Another try at making our own igniters, using the "epoxy fire" formula from
+[Scott Berfield](http://www.berfield.com/igniters.html). Moving from the
+pre-made ematches that "pop" to home-made wire-wound bridge wires with 6
+turns of 30ga nichrome wire, and we'll try the "slow" West Systems
+hardener. We'll also try using slightly larger magnesium particles, sifted
+from the "saw chips" bag, not the powder.
+
+Made up a 15g batch with the following formula:
+
+* 68% KNO3, 10.20g, hand ground with mortar and pestle to fine grain size
+* 7% magnesium powder, 1.05g
+* 1% air float charcoal, 0.15g
+* 24% West Systems 105+206 epoxy, 3.60g
+** 3.03g 105 resin
+** 0.57g 206 hardener
+
+Two folded papers were used to weigh out the KNO3 in one, and a mixture of
+the magnesium powder and charcoal in another. The epoxy was mixed in a small
+disposable plastic cup with a popsicle stick, then the magnesium and charcoal
+were poured in and mixed until complete wetted. Then the KNO3 was added and
+mixed until everything became a homogenous mix. It was a dry-ish, crumbly
+consistency, but packed into lumps easily.
+
+Two sizes of plastic drinking straws used. One is about 3/16-7/32" diameter,
+the other about 1/4" in diameter. Both were cut into 1" lengths. The
+procedure was to slide the
+ematch through the straw, pack material into the straw from the "back" end
+until it was mostly full, then pull the ematch lead until the match head was
+just at the forward end of the straw, then pack more material in the front
+end of the straw until the match head was just covered. Using nitrile-gloved
+fingers, it was then easy to mash on both ends simultaneously to make sure
+we had good packing with minimal voids, leaving both ends flush with the
+straw.
+
+The matches were left to cure overnight, and then the straws were carefully
+sliced lengthwise with a razor blade and peeled off, revealing what looked
+like very solid cylindrical igniters. They look a lot like the Quickburst
+ones.
+
+These igniters were made on 2 June 2017.
+
+## Results ##
+
+We got 6 of the larger and 3 of the smaller igniters out of this batch. It
+was very difficult to pack the smaller straws, probably due to the larger
+Mg particle size. It could be that we need to go back to using the finer Mg
+powder when making smaller igniters, and reserve the "chunky" stuff for large
+ones?
+
+## Observations ##
+
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