APCP propellant formulations

[heada]

This was posted in another rocketry forum I'm a member of. These are the formulations for one of the major makers of APCP in the US.

Red

Magnesium powder, -200 mesh 5.00
Strontium carbonate 5.00
Strontium nitrate 20.00
Ferrocene (burn rate catalyst) 0.50
Binder 19.00
Ground AP 21.70
AP, 200 micron 28.80
Total 100.00


White

Chromium oxide (burn rate catalyst) 1.00
Zinc dust 20.00
Magnesium powder, -200 mesh 15.00
Binder 18.00
AP, 200 micron 46.00
Total 100.00


Blue

Aluminum powder, 4 micron 2.00
Copper chromite 1.50
Catocene 0.50
Binder 19.00
Ground AP 23.00
AP, 200 micron 54.00
Total 100.00


Notes;

Except for Blue , the burn rate catalyst type and amount can be varied to suit
your taste. Copper chromite acts as the flame colorant in Blue - if you use a different
catalyst you end up with a low smoke reasonably quick burning propellant but no blue is all.

Catocene is listed in Blue to further increase burn rate and lower pressure exponent,
but can be omitted entirely. However burn rate will be reduced.

If using ferrocene, make sure you premix the binder ingredients - HTPB and plasticizer - with the ferrocene
until all crystals are dissolved before proceeding.

Note that propellants incorporating ferrocene (or any ferrocene derivative such as Catocene) are more sensitive than those
using burn rate catalysts such as iron oxide. Exercise due caution with these materials in mixing and handling.

These propellants are all pour castable if made as shown and thoroughly vacuum mixed. If ground AP is not
available to you, then a blend of coarse AP may be used, but you will have to experiment to come up
with a workable blend, and chances are that the propellant will no longer be pour castable.

[Ray]

OH MY.

Catocene and Ferrocene are not for amateurs...scary stuff that even the professional motor builders (Aerojet, Thiokol, etc) avoid, except this one.

Sub 20 micron AP can go high order. spontaneously...be very careful with the grinding. Use a ball mill with non sparking media. Treat the AP as a High Explosive when it has been ground. Of note, sub 20 micron is regulated by the ATF in the US as an explosive, and rightly so.

Particle sizes are not given for all the chemicals.

The binder formula is not given either, the amount and type of plasticizer, surfactants, curative, etc is not give.

These appear to be pretty good formulas, but because not enough info is given about them, making them pourable would take a significant amount of work.