AdmiralDonSnider Posted December 7, 2009 Posted December 7, 2009 This weekend I took a closer look at Fulcanelli again and wonder if his lift charge suggestions are somewhat contradictory. Take a 3" single break canister for example; Fulcanelli suggests using one ounce of 2FA in his table, but a few lines later he mentions a rule of thumb suggesting the use of one ounce of 2FA per pound of shell weight. However, my 3" single breaks weigh about 300 at max.: I wonder which suggestion yields the right lift amount?!
Bonny Posted December 7, 2009 Posted December 7, 2009 This weekend I took a closer look at Fulcanelli again and wonder if his lift charge suggestions are somewhat contradictory. Take a 3" single break canister for example; Fulcanelli suggests using one ounce of 2FA in his table, but a few lines later he mentions a rule of thumb suggesting the use of one ounce of 2FA per pound of shell weight. However, my 3" single breaks weigh about 300 at max.: I wonder which suggestion yields the right lift amount?! Many people use about 1/10 to 1/16 of the shell weight of 2FA, depending on the powder quality. Personally, I use 1/10 of my pressed and corned 2FA equivalent (-4 +10 mesh). I know for ball shells as large as 5", some will use a 3-4FA size, but it is hard on cannister shells, where the coarser 4FA gives a more gentle lift.
Mumbles Posted December 7, 2009 Posted December 7, 2009 Some people will round up to the next pound for lift. I often do this just to make sure the shells get up to an appropriate height. However, 2FA is generally kind of coarse and weak for single break 3" shells. I generally use a full ounce of 2FA, or a more traditional amount of 4FA. It's just something you learn from testing. With heavier shells, 2-3 lbs+, you can go with the ounce per pound rule of thumb more confidently. You may see that some will make additional mesh cuts on their 2FA. They separate it into -4+8 and -8. The coarser cut is used for big multibreaks, while the finer for insert breaks and lifting these smaller shells that can survive the slightly harsher lift.
dagabu Posted December 7, 2009 Posted December 7, 2009 Some people will round up to the next pound for lift. I often do this just to make sure the shells get up to an appropriate height. However, 2FA is generally kind of coarse and weak for single break 3" shells. I generally use a full ounce of 2FA, or a more traditional amount of 4FA. It's just something you learn from testing. With heavier shells, 2-3 lbs+, you can go with the ounce per pound rule of thumb more confidently. You may see that some will make additional mesh cuts on their 2FA. They separate it into -4+8 and -8. The coarser cut is used for big multibreaks, while the finer for insert breaks and lifting these smaller shells that can survive the slightly harsher lift. I agree with Mumbles, mesh out the grains for 3" cans, they can take a little more pressure then the larger shells. I also use 2FA for small plastic shells with no spiking. This may sound a little counter intuitive but it takes an ounce of 2FA to lift a 300 gram 3" shell due to the lighter weight and the slower burn of the powder, 4FA would provide the same lift but at a much more vigorous burn then the slower powder. I use 7FA (Mil Spec 7) to lift stars and 1.75" cans, the cans take only 10 grams and the stars only .5 grams. It's the speed of the burn that gets them out of the gun so fast. They are pretty quiet too. I have seen some huge grain blasting powder used at PGI last year on the 10" salamis to lift them since the weight was 170# plus for the shell. IMHO, your mileage may vary... D
TheSidewinder Posted December 7, 2009 Posted December 7, 2009 I use 22-25 grams of commercial 2Fg (muzzle-loader) lift for my 3" single-break cans, which weigh roughly a half-pound. That's inline with what Dave uses. I've been accused of over-lifting a bit, though.
Arthur Posted December 7, 2009 Posted December 7, 2009 Heavy canisters can benefit from a shock absorber of several discs of corrugated card. Really big shells can have two discs of particle (wood!) board with a big twist of newspaper between, used as a shock absorbing sabot and a piston ring, use very little lift too.
dagabu Posted December 7, 2009 Posted December 7, 2009 Heavy canisters can benefit from a shock absorber of several discs of corrugated card. Really big shells can have two discs of particle (wood!) board with a big twist of newspaper between, used as a shock absorbing sabot and a piston ring, use very little lift too. Little and slow! I like to lift my mines with corrugated card board too, the piston thing takes to much time and I don't like to use tubes for that. D
usatrapper Posted December 7, 2009 Posted December 7, 2009 People Commonly say to use 1/10 or 1/16 of the shells total weight(using 2FA) However everyones powder is differnt. Homemade Black Powder is done by hand , therefore you are not going to get the same exact thing every time. I like to take a "dummy shell" and see what works best. The way I make a dummy shell is by taking a 2 inch paper ball shell and filling it with dirt, then simply attach the lift cup and external fuse. I hope this helps.
dagabu Posted December 7, 2009 Posted December 7, 2009 People Commonly say to use 1/10 or 1/16 of the shells total weight(using 2FA) However everyones powder is differnt. Homemade Black Powder is done by hand , therefore you are not going to get the same exact thing every time. I like to take a "dummy shell" and see what works best. The way I make a dummy shell is by taking a 2 inch paper ball shell and filling it with dirt, then simply attach the lift cup and external fuse. I hope this helps. A while ago it was recommended that I fill my brand new 3" ball shells with sand to test them. Uh, don't do that! It stressed my mortar and the resulting BOOM! was quite a bit more than I really wanted. I found that kitty litter is really close to a fully loaded shell weight and it doesn't add anything bad to the earth when it comes down... in the day time, no night shots with this one. Your dirt shell is probably pretty darn close to thew kitty litter in weight. D
homebrewed77 Posted December 7, 2009 Posted December 7, 2009 People Commonly say to use 1/10 or 1/16 of the shells total weight(using 2FA) However everyones powder is differnt. Homemade Black Powder is done by hand , therefore you are not going to get the same exact thing every time. I like to take a "dummy shell" and see what works best. The way I make a dummy shell is by taking a 2 inch paper ball shell and filling it with dirt, then simply attach the lift cup and external fuse. I hope this helps. My BP the same everytime...And I have a standard way of making it..And yes..It is pretty much the same EVERY time..As is just about everyone here's BP...I use the same wood everytime..same milling time..ect...ect,,the only time anything changes for me..Is when I try a different wood..But that is a givin...One peice of advice I could give someone like you just dipping there toe into this hobbie is....Make large batch's of charcoal at a time..Use the same wood that works best for you..I use cotton wood...But you do have a good point with the dummy shell though...Dirt is way to heavy though..I would say..Go to one of the very info filled threads on BP and start reading..
AdmiralDonSnider Posted December 8, 2009 Author Posted December 8, 2009 (edited) Thanks for the advices. In my recent 3" cans I used the full ounce of FFA, and they seemed to come out overlifted. I´d like to save BP if possible, so I´ll probably also give 4FA a try in case of the small calibres. I´ve got a small additional question concerning "intentional underlifting" of shells. I usually shoot hand-fired backyard displays with both bombettes and shells, where the audience isn´t too far away from the mortar racks. Many people have pointed out that shells require the right view distance to be fully admired, so instead of extending the distance audience-mortars one could also vary the lift heights. I once accidentially underlifted one of my 3" cans; it was an impressive sight although - or better - because it bursted at 50m height only. Do some of you intentionally underlift shells, and if so, what is a safe percentage to cut off the charge? Edited December 8, 2009 by AdmiralDonSnider
dagabu Posted December 8, 2009 Posted December 8, 2009 (edited) Do some of you intentionally underlift shells, and if so, what is a safe percentage to cut off the charge? Um, intentionally? Hey sidewinder, what did you think of my un-intentional 3" ball shells this fall? Please don't take this as being a smart ass, I have to think safety over substance on this. What is the shell filled with? 1/4" stars? Lifting the shell to 50, might be OK but if the stars hit the ground then you are to low. I don't think you are going to get any but the fastest charcoal streamers to extinguish before hitting ground and that is always a concern. Another thing to ponder is the timing mechanism. Time fuse would have to be around 1/2", no way to cross match it that short. I used half a charge to lift my 3" shells, major brain fart, I use that for lifting 2" cans. They round-tripped and made nice ground flowers. D Changed to meters, timing stays the same. Edited December 8, 2009 by dagabu
Mumbles Posted December 8, 2009 Posted December 8, 2009 He did say 50 meters, not 50 feet. 150' is on the low side of things but high enough to probably be safe if you are careful with effects. It's not uncommon for some salutes to be under lifted to give more of an effect, but that comes with years of experience. I'd never do it with effects.
Arthur Posted December 8, 2009 Posted December 8, 2009 Trouble with underlifted shells is that the burst radius can get close to the audience. Take care
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