FFFg Black Powder.

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.


Well-Known Member
TRF Supporter
Feb 5, 2009
Reaction score
Ok, I don't want to start anything here, but I have searched the forum and have found several threads about FFFg powder. However they did not really answer my question so here goes....

I was given a can of FFFg powder and I am a little concerned about whether or not it would be ok to use it in my rockets or not. The only difference I can see is that it is not quite as fine as FFFFg powder.

My question to everyone is, has anyone used it in their rockets before and has it worked ok.


works great. In theory, FFFFG would be better because it burns faster and could "settle" more on the delay charge. In reality, there is almost no difference. Used it in all of my ejection charges, and it had never failed.
They could clear this up a bit, but I believe Cesaroni uses 3Fg in their reloads. I may be wrong, but it is noticably coarser than 4Fg.

AeroTech uses 4Fg powder for ejection charges.

There was a time when we couldn't get 4Fg so we used 3Fg and it worked fine.

Now, I believe that FSI used single Fg powder for it's ejectin charges. :D
I would use 4FG with Aerotech HPR loads because there is not much space for the powder to go with the RMS+ loads. 3FG should be fine if using the old thicker o-rings or with the hobby reloads..... but then again, the hobby reloads have 4FG powder with them.
I use 3Fg in my ejection charges and I'm fine. I got a can of it before a 3 day launch when the local gunstore couldn't get to their magazine and just had 3Fg. I use it fine. Although this also may be due to the fact that I double the number of grams that a calculator gives me.

I have both FFFG and FFFFG black powder and haven't noticed much of a difference in burn rates. If you are worried about FFFG powder fitting in the ejection well of an AT of Dr. Rocket casing, simply get a mortar and pestle (ebay has them cheap) and grind the powder up a bit.

Originally posted by SpartaChris
If you are worried about FFFG powder fitting in the ejection well of an AT of Dr. Rocket casing, simply get a mortar and pestle (ebay has them cheap) and grind the powder up a bit.

I WOULD NOT GRIND BLACK POWDER. It's just not a safe thing to do. On my can of Goex 3Fg powder it explictly says:

Handle with care. Avoid impact, friction, sparks and open flame

Grinding would be both impact and friction. Just a great way to get hurt.

I add water before I do so to avoid the possibilities of sparking, and I do maybe a gram at a time to minimize the danger. I also use a marble mortar and pestle, which helps eliminate most of the problems. Taking these steps greatly reduces the risks of danger, at least in my experience anyway.

What I would NOT do however is use a coffee grinder. Nor would I dry the powder in a microwave, a stove or anything other than simply air drying. Yes it takes longer, but it isn't worth burning down the place.

usually BP can take over 1000lbs of pressure. thats how they grain estes motors, with 1 ton presses. and the friction thing is just there so they can say they make a safe cannister. BP is made in a ball mill, where it is GROUND together. thats how it was first made thousands of years ago. ground together. if you put the ingredients together, and just mix them up, they wont work well and there will be a lot of excess crap left over, water REALLY increases the burn rate as well, because it dissolves the KNO3 into the charcoal giving it a better mesh between the oxidiser and reducer. next time you have some BP, put it on an oak table and smash it with a hammer....i'll guarantee you it wont ignite. however, sparks and static electricity can easily ignite it. heh. so dont to that on the ground with a steel hammer, or you're asking for it.