Batch 2019.05.21

A total of 16 Terry-length Everclear grains for 54mm cases, with 0.625 inch cores, cast as 2 batches of 4 6-inch-long double grains with 0.5" delrin coring rods, then cut, cored, and trimmed. Grains 1..8 cast by Bdale, grains 9..16 cast by Jamie and Luke with Terry observing.

The 54mm casting tube I'm using weighs 1.84g per inch.

Third time mixing APCP propellant. Bdale again used the 4.5qt mixer, Jamie and Luke used Terry's mixer, all hand packed with no vacuum processing. Same formula as previously, but with quantities doubled.

Most materials measured with Bdale's new 600g by 0.01g scale, R45 measured straight into mixing bowls using Terry's larger scale that goes by 1g.

These grains were cast on 2019-05-21.

Results

The batch size was pretty good, there was a bit of excess propellant in each batch so we can make density and burn rate measurements after cure. The excess weighed in at g after cure.

Grains were cut, core drilled to 0.625", and sanded more or less ala Terry's process. In the data below, lengths are a bit approximate due to imperfectly squared ends, gross masses are precise using my new 600g by 0.01g scale!

  • Grain 1, 3.015" long, 163.98g gross, g casting tube, g net
  • Grain 2, 3.005" long, 161.27g gross, g casting tube, g net
  • Grain 3, 3.020" long, 163.80g gross, g casting tube, g net
  • Grain 4, 3.045" long, 164.84g gross, g casting tube, g net
  • Grain 5, 3.058" long, 166.03g gross, g casting tube, g net
  • Grain 6, 3.010" long, 164.85g gross, g casting tube, g net
  • Grain 7, 3.040" long, 164.70g gross, g casting tube, g net

  • Grain 8, 3.010" long, 162.85g gross, g casting tube, g net

  • Grain 9, 3.011" long, 164.15g gross, g casting tube, g net

  • Grain 10, 3.008" long, 164.44g gross, g casting tube, g net
  • Grain 11, 3.020" long, 165.51g gross, g casting tube, g net
  • Grain 12, 3.015" long, 164.38g gross, g casting tube, g net
  • Grain 13, 3.030" long, 166.97g gross, g casting tube, g net
  • Grain 14, 3.012" long, 162.41g gross, g casting tube, g net
  • Grain 15, 2.963" long, 160.36g gross, g casting tube, g net
  • Grain 16, 2.957" long, 158.61g gross, g casting tube, g net

The mass per unit length was within ?g/inch.