# 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 ##