--- /dev/null
+# Batch 2021.11.12 #
+
+5 grains of 75mm KNER, intended to be a reload for a Loki 76/6000 case.
+with Loki-style #36 short nozzle. Grains to be cast 5.25" long using Delrin
+coring rods of 0.75" diameter. Liner calculates to be 28 inches long. Will
+"glue" grains in liner using clear silicone and o-ring spacers.
+
+Nakka's SRM spreadsheet suggests this could be an 84% L968, with 3473g
+of propellant, a 4.88 second burn time, and max pressure of 655psi.
+
+Will mix a 3500g batch, the formula for which is:
+
+* 65% KNO3, 2275g
+* 35% Erythritol, 1225g
+
+I started by setting the multi-cooker to 300F indicated for this batch, but
+had to turn that up to 350F to get the entire batch melted, or the heating
+element would keep turning off. It still took a very long time to all melt.
+Once it did, I dialed back to 300F indicated. It's true that the ambient
+temperature was lower in the shop than on other days I've cast sugar.
+
+The 5.25" grains were poured to a 122mm fill line, and then an 0.75" Delrin
+coring rod was twisted down into the goo puncturing foil over the coring rod
+hole at the grain base. A casting cap was then placed over the top to hold
+the coring rod centered and protect the grain during cooling.
+
+The first four grains poured easily. There was enough propellant sticking
+high on the sides of the pot that I couldn't figure out how to break loose,
+though, that I paused and added 3 old 38mm KNER grains to the pot and waited
+for them to melt and get mixed in before casting the last grain. The last
+grain was also problematic in that the casting cap didn't want to go down
+over the casting tube, perhaps due to a bit of KNER splash already hardening
+on the outside of the tube?
+
+I noted that there were lots of small bubbles visible on the surface
+of the melt, all of which were popping easily at the time of the pour. I did
+the usual thing of twisting the coring rod as it went in and saw bubbles
+come to the grain surface, then tapped each grain on the table top after the
+cap was on to hopefully further settle the propellant. It's hard to imagine
+vacuuming KNER helping this, as the KN wants to settle to the bottom of the
+pot, requiring re-stirring to homogonize the mixture before pouring... which
+necessarily lets more air back in?
+
+## Results ##
+
+The grains came out very poorly, with lots of cracks and voids. My guess is
+that since the shop was colder than normal, and I could see massive amounts
+of propellant solidifying on the sides of the multi-cooker, that rapid and/or
+differential cooling as the propellant was being poured into cold casting
+tubes and cold Delrin coring rods were inserted was the root cause.
+
+The only credible choice is to set them aside to be re-melted in a future
+batch.
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