how to solidify the fuel for model rocket engines.?

Question

I am interested in finding out how commercial model rocket companys solidify their engines fuel. There are plenty of places online that explain how to make your own model rocket engines but the only ones I have seen end up as a powderd fuel. When you cut ope a commercial engine its all pressed into a little solid fuel chunk. I would like to be able to do the same.

Answer 1

You are talking about Estes motor, I am assuming. Small motors like that are made by compressing black powder (75% KNO3, 15% C, 10% S). Estes adds some dextrin as a binder, I believe. Anyway, BP is realitively stable and not exactly shock-sensitive (unlike flash powder), so its realitively safe. However, BP ignites very easily from a spark, so care needs to be taken to eliminate static charge along with other things. IF you are trying to make your own BP motors, is probably a book written about it. Buy that book and learn the saftey and procedure - after all, making any flammable mixture is very dangerous.
You should look to the listed website concerning recrytsallsed KNO3/ sucrose. This seems a little safer than making your own BP.

Be careful, and make sure you know the entire process and its dangers before you start any project

Answer 2

Solid fuels vary in type.
Some are cast, some are compressed.
The type determines the process.
Commercial outfits know what they are doing
and have precisely monitored equipment to do it.
You do not.
They know the limits.
You do not.
Some fuels can be ignited by pressure or impact.
In a home made packing jig this can cause
an explosion that can kill.

The rule in amateur rocketry is:
If you don't know what you're doing - DON'T.

Answer 3

It is poured in molten (e.g, "candy" - KNO3 in molten sucrose; **very** dangerous), or consolidated with a binder (Zn/S with maybe 1-5% powdered paraffin. Warm to abut 50 C, tamp in; also dangerous), or polymerized in place. Space Scuttle SSB fuel is ammonium perchlorate, aluminum dust, iron oxide catalyst, hydroxyl ends-terminated polyether plus isocyanate ends-terminated hard block to give polyurethane rubber.)

I_s up to 265,

HTPB + AP + Al + additives.
PBAN + AP + Al + additives.
CTPB + AP + AL + additives.
PBAA + AP + AL + additives