19 replies to this topic

[Karl Mitchell-Shead]

Planning on making some 50mm, 75mm and 100mm bag / canister mines.

There is a lot of reading material and references when it comes to the amount of lift to use in a shell, however when it comes to mines no such ruidelines seem to exist, so to lift a good amount of stars to a reasonable height how much 2FA should i use for each of the above calibre's in your opinion?

Thanks Karl

[Vic]

Finding the sweet spot for your lift can only can only be achieved by trial and error and before that your bp needs to be absolutely constant in quality. I don't mean super fast willow bp save that for your burst in shells. Spruce bp is fine for the job.

The key to it all is your charcoal, you have to make your own and the timber you select is most important for the job in hand in this case lift. I would use spruce white wood, crap for joinery but good for lift.

All this doesn't answer your question, and there is no definitive answer but here is a 4” mine with 35g of spruce lift the same amount as used for lifting a 4” shell to optimum height mine. The only thing I would add that it was made using a Plásticos Gamón mine casing which confines the lift in a small cup compared to say a bag mine so at a guess I would say up it to between 40 and 45g and work from there.

I'm sure others here can give some clues.
Vic

[starseeker]

Planning on making some 50mm, 75mm and 100mm bag / canister mines.

There is a lot of reading material and references when it comes to the amount of lift to use in a shell, however when it comes to mines no such ruidelines seem to exist, so to lift a good amount of stars to a reasonable height how much 2FA should i use for each of the above calibre's in your opinion?

Thanks Karl

I find that 25g is about right for my 75mm mines,using about 100g of stars,(charcoal based stars so fairly light}

[Karl Mitchell-Shead]

Well as a trial i have filmed the manufacture of 3 50mm mines as a tutorial, not sure if i should post it, may get me into trouble.

I used 12.5g of VERY fast 2FA, yet to fire them but from what i have seen in the construction of commercial mines this is not too dissimilar.

[Karl Mitchell-Shead]

Where do you purchase Plásticos Gamón goods? I have sourced some 3" shells but struggle to find anything else

[pyrotechnist]

I have made some nice loud 2" mines that go to a great height using just crap quality meal bp with 2 wads of yellow book paper shoved down the motor tube creating a good amount of confinement. I tell you these babies sure do make a bang as they leave the motor.

[Sambo]

I've heard you should use a 1/4 of the total weight of the stars for lift. I can’t remember where this came from though; it seems to work fine for me and Starseeker anyway. It depends what effect you’re after as well. You may want to use a stubby mortar and less lift to get a "spray" of stars or a conventional mortar and 1/4 lift to get a narrower column of stars that droop at the apex.

[Karl Mitchell-Shead]

Shall i post the video or am i likely to receive a barrage of criticism?

[Bonny]

Shall i post the video or am i likely to receive a barrage of criticism?

Constructive criticism is a good thing in this field, one of the best ways to learn.
When making mines the lift will vary depending on powder quality, grain size as well as whether or not lift disks or pistons are used and how much wadding is added. 1/4 weight can be pretty heavy if using good BP,wadding and lift pisons.

[Arthur Brown]

A link to youtube could bring some comment, some of which may be constructive!

[Karl Mitchell-Shead]

A bit 'youtuberised' and a basic device using basic materials, nevertheless.....

2" Bag Mine

[Karl Mitchell-Shead]

Did i accidently post this thread in pyro formula or was it moved?

[Atom Fireworks]

Hey chief,

good too see people are still having fun ofter the crazy season. I make my mines very similar to you with the toilet roll tube and so on, i only make them when i have left over stars from other projects, one point i would like to mention is is it possible that the lift ignites and throws the full cannister out of the mortar without lighting all the stars?? The reason i ask this is because i have made multiple mines and sometimes only 10-20% of the stars light i guessed it maybe due to the idea above, i have been having trouble with stars not lighting so this may be the reason mine dont all light but its just food for thought, i have seen a freind of mine make a couple of whats called bag mines, and it is what it says, a moulded paper bag ( round somthing the internal id of the mortar) with lift placed at the bottom and strars placed on the lift and then the q.m placed in the centre and then the top of the bag tied shut, as simple as that and these worked extremely well, maybe you could do some experimenting??

Dumper

[Karl Mitchell-Shead]

Yes i see a valid point there, little reinforcement in the base of the mine may result in it being lifted like a shell, i am going to fire these tonight and film them to see how they perform, then i will try a few different techniques.

[starseeker]

Constructive criticism is a good thing in this field, one of the best ways to learn.
When making mines the lift will vary depending on powder quality, grain size as well as whether or not lift disks or pistons are used and how much wadding is added. 1/4 weight can be pretty heavy if using good BP,wadding and lift pisons.

Quite agree,
the mines that i make are the simple bag method,using pistons,wadding etc you would need to cut your b.p right back,maybe to 15 to 20 grams,(for a 75mm mine).

Edited by starseeker, 03 February 2010 - 05:57 PM.