A 16 mesh screen is more 1f that won't pass thru it.
But play with what you have and make the best of it
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A 16 mesh screen is more 1f that won't pass thru it.
But play with what you have and make the best of it
Below is the size and mesh for different grades of BP. Several different places seem to give same specs. My understanding is the Fg passes thru the 12 mesh and stays on the 16 mesh. FFg passes thru the 16 mesh and stays on the 20 mesh. FFFg (and fines) pass thru the 20 mesh. Am I way off base?
Fg -12 mesh - 1.7 mm. (0.0661 in.)
FFg - 16 mesh - 1.18 mm. (0.0469 in.)
FFFg - 20 mesh - 0.85 mm. (0.0331 in.)
This was a quick search and copy, from Skylighter
Cannon Grade 4-12
1FG 12-20
2FG 16-30
3FG 20-50
4FG 40-100
5FG +100
It sounds like you are correct.
I mark my powder with the first number being the screen it passed thru.
And the second number being the number it didn't pass thru.
My 1f is marked 16/20
Like for 2f I also mark mine as 20/30
My 3f is marked 30/40
My 4f is marked 40/60
Thats commercial info and seems to be accepted numbers
I will not put up with those overlapping screen sizes at my place - we can do better than that!
Heres my version (its what I have as far as screens go)
Fg 12 -16
FFg 16 -22
FFFg 22 - 40
FFFFg40 - 100
Lot of other variables here though, gauge of wire in the screen makes a serious difference particularly in the finer mesh, the mesh number is only how many wires per inch - says nothing of how thick (or thin) those wires are - lot of difference in the hole size between a heavy gauge and a light gauge screen at the 40 mesh end
I shake my screens until stuff stops falling through - most commercial operations do not do that hence the overlapping numbers. More diligent screening I believe is one way we can improve the consistency of our powder.
I just posted those numbers because the search kicked it out first.
Joe is right on the screen wire size being critical to grain size. I just looked but didn't immediately find the Goex and Swiss grain sizes listed in thousandths of an inch. What ever those numbers are, quality screen manufacturers will list what screen will pass a certain grain size.
My considered 2F is 16-24 and my considered 3f is 24-50. That's pretty well all I have call for.
I screen at:
Hold on 20 mesh = 1F or coarser
Hold on 30 mesh = 2F
Hold on 40 mesh = 3F
Hold on 60 mesh = 4F
Pass thru 60 = dust
None of us are selling on a commercial basis so it’s probably a bit arbitrary so long as we are in the general vicinity.
@Frank D
You are correct.
I too go by the numbers given by HWooldridge.
And yes , there are differences in the screen Hole Sizes based on the size of the wire used to make the screens.
But for the most part.
The holes per inch gets you consistant in what you are making.
I guess maybe I need to change my hold 3f screen to 40. I bought it when I first started and thought it was correct. Never gave it any more thought. And, of course, it is the only one I had to buy and it was plenty high.
Edit: I found this page and it says if my '24' screen is U.S. mesh, it is actually 25 mesh. There is no U.S. 24. Maybe it's Chinese.
Pretty interesting tidbits. https://www.ecologixsystems.com/reso...s-mesh-micron/
I found this interesting page on screens and sizes of them, and the MM or Inch equivalents of openings and particle size. This was what I was talking about if you know the size of powder grains you desire. https://www.azom.com/article.aspx?ArticleID=1417
Yes Joe.
I have run my Factory powders thru my screens.
I did find that the factory powder was not consistant size thru the whole pound.
But,
I blamed that on the cans of powder being Old and had been moved around a lot over the years.
A couple cans were over 30 years old and had been taken to the range or hunting as back ups.
But I did screen out the fines that I figured had ground down over time.
But I had one Newer can of Goex that I screened.
It too had a range of different screen sizes all the way down to 100 that caught the powder.
But.
I just figured that got ground up from the shipping and handling to get it to the LGS to sell it.
So our Homemade powder doesn't have to go thru that rough shipping and bouncing around.
So our grain size might stay consistent longer if we make it and store it.
Over the past weekend, I tumbled a half pound of homemade 2F on itself, inside an old cloth shot bag but with nothing else in the barrel, then I screened it again on my #30 screen. Almost nothing fell through as dust - maybe 1/8 of a teaspoon. Some dust did stain the bag but it appears that pressed powder is pretty durable and doesn't break down easily. Of course, this was a fresh batch and I did not transport it across country. I have never screened commercial Goex but might be a good exercise for comparison.
Yes.
Screening my Factory BP was the way I kind of got started in sizing my BP.
Because back when I started , there was No internet..
So I had to scrounge up info where I could.
But back then.
Most of my BP was for rockets and fireworks.
So minor details were not needed to try and make some competition level powder for my rifles and the cannon I had back then didn't care.
I made some charcoal from a cedar fence board. Tumbled and pressed it into powder. I tested density of both the 2f and 3f compared to the GOEX powder I have. Both came at 90 percent of GOEX. I tested both the 3f GOEX and my powder in 32 S&W in a S&W 1 1/2 with a 3 1/2 inch barrel. GOEX ave. velocity was 455 fps with an 84 grain bullets. My powder average velocity was 395 fps with the same bullet. So, this new powder is like maybe 87% of GOEX. I guess this is my best powder yet. I have some questions about these ballistics as the powder charge weight and performance is less than I expected. I guess I should fire some factory ammo. I have both modern and ancient ammo.
I am going to talk more about this in Black Powder Cartridges.
Tim
most of my competitive shooting life I used 5FA and 4FA grades - knew a bloke that knew a bloke and we could get it in 25pound containers - this was so called fireworks grade powder - I believe those days it was the same powder only screened a bit different and packed in bulk instead of in little tin cans - the bloke that used to get it was a picky dude and a seriously good flintlock shooter, he did exhaustive chrono testing of Goex 5FA - said it was about 2% faster than their FFFg but when he switched to ungraphited the difference was 5% - all this was before the Moosic plant in Pa went bang sometime mid 1990's
It can be. But it can also be of benefit in reducing ignition rate so as to reduce tendency to slump noses on long conical bullets.
Flow characteristics are improved too. I believe Swiss is so heavily coated specifically for target shooting with long conical bullets because making extremely large grain size to compensate by way of reduced surface area comes with it's own downside like reduced propellant mass.