Lift Charge.

[DontBlink]

Ola.

 

I`ve been browsing for a couple of days for this, can`t quite find it.

I`m shure this must be by some exponential law/powder.

 

But assuming you have a BP charge.

With a burnrate of X.

You should be having a general height (maybe V) for a specific weight of shell.

(leaving the fuse to burn within V 'or outta the equasion' )

 

Sow something like: V = "Bp type" vs "Amount" vs "Weight"

Would like to make a backlog for this.

 

greets Luk.

Edited January 9, 2009 by DontBlink

[Richtee]

There are standard recommended lift amounts Vs. shell size tables here SOMEWHERE. Another rule of thumb for smaller shells <4" or less> anywhere from 1/10 to 1/16 shell weight... ALL depending on the quality of your powder of course.

[DontBlink]

Assuming this is of the finest milled/pressed qt..?

[Richtee]

Assuming this is of the finest milled/pressed qt..?

 

Fire some dummies of course...but start with the 1/16 shell weight then. I make some dammm good powder and use around 1/12 tho. I HATE low breaks.

Edited January 9, 2009 by Richtee

[andyboy]

Assuming this is of the finest milled/pressed qt..?

 

To many variables to figure out such as burn rate of your BP (which in turn is affected by your chems, density and so on...), shell weight, mortar-length, humidity....

 

 

Some reading:

 

http://www.skylighter.com/fireworks/how-to...lack-powder.asp

 

http://en.wikipedia.org/wiki/External_ballistics

 

Anyway, for my smaller shells, up to (but not including) 3" I use 1,7 cm's of visco coated with teflontape (home-made time fuse ) for a delay of 1,7 seconds. As lift I use about 1/16th the shell weight of a 1,7grams/cc density of FFg-FFFg equivalent so it bursts slightly before apogee or approximately there . Assuming the shell is launched at 200 feet per second, the estimated height at burst would be around 340 feet (100 meters) not counting wind resistance, drag and such (probably around 240 feet or 75 meters).

 

The best method of learning is empirical studies but to use the old-timers advice as a starting point. So here it is:

 

Lift should be 1/16th to 1/10 of the shell weight depending on your powder.

 

Burst-time for a 3" shell should be around 2,5 to 3 seconds

Burst-time for a 6" shell should be around 4 to 4,5 seconds

Burst-time for a 12" shell should be around 5,5 to 6 seconds

 

If you are really serious about learning a lot more about this I would recommend you buy "Selected Pyrotechnic Publications of K. L. and B. J. Kosanke".

 

Any faults on my behalf are purely coincidental.

[DontBlink]

Thanks for the request!

I see a lot of educated guessing.. only im empty headed .

 

I could imagine.., x energy acting on a mass, with a specific weight, reaching a velocity.

Only to be held back by tube friction, leakage, surface area, wind resistance, youngs modus, angle, gravity and stability.

would be so boring you`d fall asleep lighting it .

 

Yea ratio`s best.

[tentacles]

Xetap: Ned (who wrote that article) is now recommending using 2% RG solution for the granulated BP, it results in appropriately durable grains.. And it only slows it down the slightest bit. Another option is to granulate with 2% NC - but the NC is a whole different mess to clean up (acetone). The NC doesn't bring an oxygen deficiency to the table so the resulting BP is effectively as fast as it can be.

 

I have been granulating my BP for a while now, it's fast, simple and I can get a range of grain sizes that suit me with *very* little that is too small or large. I did 3.5lbs last time and at the end I had about 4oz of "7FA" - which is actually a great size for priming stuff.

[Richtee]

Isn't RG basically a fuel? OK...so it helps shitty charcoal, right? ISn't GOOD charcoal cheaper?

[tentacles]

The red gum is a fuel, but for granulated BP it's used as a binder - make RG/alc solution (I use 2.5%), wet the BP and granulate through a screen, 4 or 8 mesh depending on what size you want. I think there's very little difference in speed between the 4 mesh granulated and 8 mesh, simply because all the grains are quite porous, rather than the hard solid grains from pressing and corning.

 

The cost is minimal, at 2% of your BP weight (30g of RG to do 1500g BP) and it will speed up otherwise unusable BP, or make fast BP even faster.. I use red alder for my BP (have a big bag) so I don't have to do it this way - but it's actually a lot easier than pressing and corning.

Edited January 13, 2009 by tentacles

[Mumbles]

I can't really explain the speeding up of lift. I believe the idea is that the alcohol doesn't dissolve any of the components keeping the particles as fine as possible. I suppose there is an increase in surface area. Normally straight from the mill, the particles are so fine that a pile, that it acts as a single surface. At least for me, from the mill, it still burns pretty fast.

[DontBlink]

Maybe room to add more oxidiser, with the added fuels.

Only thats a long shot.

Edited January 13, 2009 by DontBlink

[Bonny]

I'm still pressing and corning BP with homemade willow charcoal. The main reason I don't want to change is the extra component (Red Gum) that I find is a hassle to get up here. I have also more or less dialed in most of my (common) lift charges already and don't want to start over...afraid of change I guess as they say.

I'm in the process of building a corning drum a-la passfire so that will make corning much less of a PITA.

[Ventsi]

With my fresh batch of KClO3 I've been making H3.

 

My question is can i use to lift small shells?

Stuff like 1" ,2"?

 

And what would the appropriate amount to use be?

[Miech]

I wouldn't use that for lift, personally. It's a pretty strong break charge, so if you do it anyway I'd recommend using not too much. Somewhere in the range of 0,5 to 1 gram would be sufficient for 1" shells, and 1 to 3 grams would almost be too much for 2" shells. Obviously you will need to test how much you'll need exactly, but keep in mind it is a quite unforgiving composition if used as lift (by means of, blows your mortars easily).

[LGM]

I've never used it as lift, but I've read that you'll need to prime the time fuse pretty well for it to ignite. I can say from experience that H3 doesn't always ignite stuff reliably, so I'd believe it. I think wherever I read that it said that priming the fuse with powder H3, then priming the prime with granulated H3 will produce reliable results.

 

As Miech said, don't go too much above one gram.

[jrin0630]

There are standard recommended lift amounts Vs. shell size tables here SOMEWHERE. Another rule of thumb for smaller shells <4" or less> anywhere from 1/10 to 1/16 shell weight... ALL depending on the quality of your powder of course.

 

 

For a 3" ball shell weighing about 130G, would 9G of commercial BP be ok? I'm using Hogden Triple 7 FFFG.

[Ventsi]

Sorry to ruin your parade but HODGON 777 is a BP substitute so no , you wont be able to use it , somewhere around 12g GOEX^tm FFFA should be good though.

[jrin0630]

Sorry to ruin your parade but HODGON 777 is a BP substitute so no , you wont be able to use it , somewhere around 12g GOEX^tm FFFA should be good though.

 

Ok, so GOEX FFFA is not a BP substitute also? I just assumed the only difference was the manufactures. Sounds like that was the wrong assumption. I guess the main question I have is what makes one BP a substitute and one not? thanks for the help.

[Ventsi]

GOEX is true BP .period.

 

HODGON 777 is a blackpowder substiute - its something that is used instead of BP in firearms. While blackpowder contains Potassium Nitrate, Charcoal, Sulfur, BP substitute usualy contains Nitrocelulose and some other stuff which I dont know about. In firearms its prefered over BP since it doesn't rust the barrel of the gun.

 

But for our purposes substitute BP won't work, it has different gas output , burning characteristics, etc.

Just buy some GOEX from the same place you bought HODGON's.

[jrin0630]

GOEX is true BP .period.

 

HODGON 777 is a blackpowder substiute - its something that is used instead of BP in firearms. While blackpowder contains Potassium Nitrate, Charcoal, Sulfur, BP substitute usualy contains Nitrocelulose and some other stuff which I dont know about. In firearms its prefered over BP since it doesn't rust the barrel of the gun.

 

But for our purposes substitute BP won't work, it has different gas output , burning characteristics, etc.

Just buy some GOEX from the same place you bought HODGON's.

 

Got it. Thx.

[Swede]

Commercial BP is becoming MUCH harder to find in the US these days as the storage requirements for the sporting goods store are much more restrictive. The BP substitutes are considered smokeless powder for legality and storage purposes, and are cheaper to stock for stores like Cabela's. But real BP (Goex, Elephant) can still be mail-ordered, and there are muzzleloading gun guys who simply will not use anything except real BP in their firearms.

 

I think making it is best, definitely the cheapest, but otherwise, mail order of 10 to 25 pounds is a good way to go.

 

It would be interesting to try 777 or similar as burst, but my guess would be that it would have poor ignition characteristics. The shell would go BOOM, but you'd have stars not ignite.

Edited June 26, 2009 by Swede

[swervedriver]

Man that commercial stuff is expensive to buy, even in bulk. But I guess it's one way to do it if money doesn't matter or a ball mill isn't an option. I figure I'm spending under $1.50 a pound for BP, and it could be made for even less than that.

 

I can't find commercial BP anywhere locally in my area. There's an Outdoor World nearby, their gun supply section is huge. But no real BP, just the fake stuff.

[jrin0630]

Commercial BP is becoming MUCH harder to find in the US these days as the storage requirements for the sporting goods store are much more restrictive. The BP substitutes are considered smokeless powder for legality and storage purposes, and are cheaper to stock for stores like Cabela's. But real BP (Goex, Elephant) can still be mail-ordered, and there are muzzleloading gun guys who simply will not use anything except real BP in their firearms.

 

I think making it is best, definitely the cheapest, but otherwise, mail order of 10 to 25 pounds is a good way to go.

 

It would be interesting to try 777 or similar as burst, but my guess would be that it would have poor ignition characteristics. The shell would go BOOM, but you'd have stars not ignite.

 

I was thinking the same thing. In fact I'm going to try some 777 as burst in a test shell. I ordered some 2FG Goex for lift. That should work okay, right?

[TheSidewinder]

2Fg is fine for lift. I've used it and it worked great. I used 4Fg for the break.

 

And the only reason I did is because I had it left over from my muzzle-loading days. No sense letting it go to waste.

 

It's expensive, on a per-shell cost breakdown, but not obscenely so.

 

If you're making dozens of shells, though, then it becomes a major cost. As Swede said, making your own is the best way to go.

[TrueBluePyro]

yeah, if you started using it for breaking shells, that is where you would be paying alot, and making it your self (once you get it set up) isnt all the hard or intimerdating at all.