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Cement mixing drill attachment
Drill (preferably Ryobi)
5 gallon bucket
Nitrile gloves (5 mm minimum)
Hot glue gun
Method
The total volume of the fuel grain is calculated prior to starting the pour. The mixture ratios we have found work best for us are 87% HTPB and 13% MDI isocyanate by mass. Using a rough density of 920 kg/m^3, the masses of each chemical can be found.
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