From f9642d1ca08b912e116227e22336451b2ef7af42 Mon Sep 17 00:00:00 2001 From: Bdale Garbee Date: Fri, 19 May 2017 11:08:14 -0600 Subject: [PATCH] first attempt at making igniters --- rockets/research/2017-batch-02.mdwn | 49 +++++++++++++++++++++++++++++ rockets/research/index.mdwn | 3 +- 2 files changed, 51 insertions(+), 1 deletion(-) create mode 100755 rockets/research/2017-batch-02.mdwn diff --git a/rockets/research/2017-batch-02.mdwn b/rockets/research/2017-batch-02.mdwn new file mode 100755 index 0000000..faabcef --- /dev/null +++ b/rockets/research/2017-batch-02.mdwn @@ -0,0 +1,49 @@ +# Batch 2017-batch-02 # + +We're nearly out of [Quickburst](quickburst.net) igniters, they haven't been +great at lighting erythritol grains anyway, and they're kind of +expensive... So we decided to experiment with making igniters, and the +first ones we decided to try are "epoxy fire" using a formula from +[Scott Berfield](http://www.berfield.com/igniters.html). + +For our first attempt, we made up a 10g batch with the following formula: + +* 68% KNO3, 6.80g, hand ground with mortar and pestle to fine grain size +* 7% magnesium powder, 0.70g +* 1% air float charcoal, 0.10g +* 24% West Systems 105+205 epoxy, 2.40g +** 2.01g 105 resin +** 0.39g 205 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. + +We used Chinese made e-matches with 2m leads, and used plastic drinking straws +about 1/4" in diameter 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 17 May 2017. + +## Results ## + +## Observations ## + +A 10g batch was just enough to make up 6 igniters, and the pot life seemed +a little tight. Next time, it seems like trying a 15g batch with the slower +206 hardener might be a good plan? + diff --git a/rockets/research/index.mdwn b/rockets/research/index.mdwn index 89da801..7f47669 100755 --- a/rockets/research/index.mdwn +++ b/rockets/research/index.mdwn @@ -11,7 +11,8 @@ ### 2017 ### -* [2017 batch 01](2017-batch-01.html) - May 2017 - 16 54mm KNSO grains +* [2017 batch 02](2017-batch-02.html) - 17 May 2017 - 6 epoxy fire igniters +* [2017 batch 01](2017-batch-01.html) - 15 May 2017 - 16 54mm KNSO grains ### Previous ### -- 2.30.2