Sugar Motor Research Page

Sugar Motor Formulas

I have cast Dextrose and Sorbitol grains. My current favorite is Sorbitol. It melts at a lower temperature, but more important to me is it has better working and casting properties. The sorbitol casts in a manner more similar to my PBAN with rolled logs mostly not sticking too much until packed. A couple raps on the table will slide the log to the bottom of the casting tube. I found Dextrose to be extremely sticky to work with and difficult to cast in 54mm tubes (with mandrel).

Candy Motor Workbench - KNSB, KNDX

KNSB Candy Propellant Melting and Vacuum De-Gassing Workbench

I use a Waring Kitchen Kettle to melt directly with no oil or wax bath. I do use a Router speed controller set at low to minimize local hot spots by lowering the on-temp of the heating elements. Do be extremely careful if you don't use a double boiler or wax bath! In particular thin pots can be very problematic.

Vacuum Processing

I  find improved grain density and quality by vacuum processing. My Candy Motor Workbench picture illustrates my complete setup, but I do have a Vacuum Processing page with additional detail on the vacuum processing system and on that page will maintain any improvements I make.

Casting

I use Loki casting bases and mandrels and Lyngdal liners.

Sugars

Sucrose, Dextrose, and Soribitol are all common. I prefer Sorbitol as it's casting propertites are far superior to the others. In particular it's the least sticky to handle and it's melting temperature is also the lowest of the 3

Jimmy and a few others like to add or substitute some Karo to facilitate processing.

Formulas

Basic

65% KNO3
35% Sorbitol

Sparky

Generally metal additions should be about +10%

58.2% KNO3
31.3% Sorbitol
0.1% Graphite
10% Titanium Flake

Properties

Properties of various sugars
Click on table to visit table source web page.

Candy Motor Links

Jimmy Yawn's excellent practical website
Trailer Trash Aerospace excellent large motors
Richard Nakka's king of Candy