Screen mesh sizes?

[Eagle66]

My questions are about screen sizes. I’ve been looking but haven’t found much. I am wondering about what screens I should have and what some chems should screened to.

 

I have the following: 2, 4, 8, 10, 16, 20, 40, & 70. Should I get more, say 100, 200 or even 325?

 

I screen my best BP after corning to 20-40 for 3fg, 40-70 for 4fg, and -70 for either meal or reworking. Those are mostly graded for shooting, 3fg behind the ball, 4fg in the pan of my flintlocks. I see a wide variety of differing advice about using these grades in pyro. I granulate my non-corned mixes through a kitchen colander.

Specific questions: I mill Bentonite from kitty litter for nozzles & plugs. Is -40 OK? Or go to -70?

 

Oxidizers; I’ve been buying prilled KNO3 and milling it, then screening it -70. I have KClO4, Sr(NO3)2, and Ba(NO3)2 as they come from the suppliers, but haven’t used them yet. I’m planning to get some AP, supplied @ 200 or 400 micron. Should I use them as supplied or mill them finer? Or, screen them to (xx)?

 

Metals? There is a wide range from chunky to air float. I assume the specific composition dictates the size?

 

Other chems, again I assume the specific composition dictates the size?

 

BTW, I have NO INTENTION of messing with flash or other nasty compositions (except maybe as recommended for star primes) until I have lots of experience. If the published formulations have recommendations, I’ll stick to them. If anyone thinks I’m asking for too much hand-holding I won’t take offense if he says so. In that case, all I ask is is to be pointed in the direction of some recommended reference material.

 

And, thank you for the advice.

Edited September 2, 2014 by Eagle66

[dagabu]

Nope, you are good to go 66. I use the 4, 8, 10, 16, 20, 40, 60 and 100 in a stack. I can't get much through the 100 mesh screen in the first pass so I don't go on to the smaller screens. I don't think you are going to get any of your chems to all pass anything smaller than 100 mesh without lots of work.

 

I also think you have your BP mesh sizes wrong.

 

 

GRADE MESH RANGE

FA 3 - 5

 

2FA 4 - 12

 

3FA 10 - 16

 

4FA 12 - 20

 

5FA 20 - 50

 

6FA 30 - 50

 

7FA 40 - 100 Meal D + 50

Edited September 2, 2014 by dagabu

[VaterAraignee]

My inner bean counting scientist is driven crazy by mesh count.

50 mesh Tensile Bolting Cloth: opening = 0.3683 mm

50 mesh Mill grade: opening = 0.3175 mm

50 mesh Market grade: opening = 0.2794 mm

And those are just the 50 mesh specifically designed for grading. There are meshes that are produced much much much cheaper so it can be sold at say 5 cents cheaper per linear inch tricking one into thinking they got a helluva deal. It might be, if you are replacing window screens.

 

lucky for me I have ODD and ADHD, so everything has to be perfect but not for very long.

[Shadowcat1969]

Actually Dag, his BP mesh sizes are fairly close to correct, considering he is using the Sporting Grade (Fg) scale rather than the Blasting (Fa) scale.

 

According to the tables at Skylighter anyway, 4Fg is about equivalent to 7Fa in size for instance.

 

http://www.skylighter.com/fireworks/help/Black_Powder_Size_Charts.asp#grades

Edited September 3, 2014 by Shadowcat1969

[wildcherryxoxo]

AP stars eh? Are you aware of the risks?

[dagabu]

Actually Dag, his BP mesh sizes are fairly close to correct, considering he is using the Sporting Grade (Fg) scale rather than the Blasting (Fa) scale.

 

According to the tables at Skylighter anyway, 4Fg is about equivalent to 7Fa in size for instance.

 

http://www.skylighter.com/fireworks/help/Black_Powder_Size_Charts.asp#grades

 

Missed that, thanks for the correction Shadow.

[rogeryermaw]

eagle, i have been using 200 mic ap and milling it for 2-3 hours. perhaps it is not long enough. my blues look pretty good in mines but are far too dark in the sky. other coarse oxidizers i run in a coffee mill. yes your mesh sizes can be dependent on application. super fine is not always desirable. some flasher comps come to mind iirc.

Edited September 4, 2014 by rogeryermaw

[Eagle66]

AP stars eh? Are you aware of the risks?

 

The AP's for "Happy New Year" set piece lances. For now that's about all I have in mind.

 

I'm trying to keep to the K.I.S.S. principle, at least until I learn enough to knock off the last "S"

Edited September 4, 2014 by Eagle66

[wildcherryxoxo]

Just make sure you are aware of the incompatibilities of it. It would be disappointing if you made some nice stuff but it turned to mush because of something simple.

 

Lances sound fun! Where are you findin tubes?

[dagabu]

Ned Gorski sells lots of 1000 for $80.00, they sure are nice and the paper doesn't lend too much white or yellow when burning.