a newbs progress and question thread

[Mumbles]

It might have been a little overloaded, but I could easily fit 1 kilo (2.2lbs, ~36 oz) in one of those Hobfir mills in 4 hr. The amount you can fit in a jar is definitely charcoal dependent though. I was using willow from custom charcoal as a point of reference, and it got fairly dense after milling. There has been a price increase since I got mine. At the current price, I'd probably go with the Rebel 17.

 

 

Yeah, put up some photos of the work mill.
Surely you could use a big container but still only mill small amounts in it, the noise might be a lot louder though.

Just make sure there is no chance anything can go wrong imagine if the BP was initiated inside at your work place and no one knew what you put in there. Not to mention if people were near it when it did.
That would be interesting to explain thats for sure

 

Just a point of clarification, but one should never severely under-load a mill jar. A proper load balances the amount of media and the amount of material. Too little material results in a lot of ball on ball contacts which is bad for the media, and may increase ignition risks. If you have a 5 gallon mill jar, you better be sure to have a proper amount of media and a milling charge in there.

 

Large mill jars have accounted for a majority of the ball milling accidents in recent past. Larger jars have increased forces, as well as a lot more explosive material. I would suggest against using something as large as you posted RiderX unless it's thousands of feet from anything, and you figure out a way to empty it remotely.

[RiderX]

It might have been a little overloaded, but I could easily fit 1 kilo (2.2lbs, ~36 oz) in one of those Hobfir mills in 4 hr. The amount you can fit in a jar is definitely charcoal dependent though. I was using willow from custom charcoal as a point of reference, and it got fairly dense after milling. There has been a price increase since I got mine. At the current price, I'd probably go with the Rebel 17.

 

 

 

Just a point of clarification, but one should never severely under-load a mill jar. A proper load balances the amount of media and the amount of material. Too little material results in a lot of ball on ball contacts which is bad for the media, and may increase ignition risks. If you have a 5 gallon mill jar, you better be sure to have a proper amount of media and a milling charge in there.

 

Large mill jars have accounted for a majority of the ball milling accidents in recent past. Larger jars have increased forces, as well as a lot more explosive material. I would suggest against using something as large as you posted RiderX unless it's thousands of feet from anything, and you figure out a way to empty it remotely.

cant i make a smaller jar for it?

[OldMarine]

Measure the distance between the rollers and if possible the speed of rotation of the driven roller. I suck at math but I think all the formulas for figuring such things are in Lloyd's book and we may be able to puzzle it out.

[RiderX]

Measure the distance between the rollers and if possible the speed of rotation of the driven roller. I suck at math but I think all the formulas for figuring such things are in Lloyd's book and we may be able to puzzle it out.

will do so when i go back to work tommorow , i can swap the drive ratios as needed on the motor , and i think also the roller shafts , ill grab my optical tachometer tomorrow and fire up the mill to see what speed its at now though

[chuckufarley]

I agree with Mumbles recommendations, I wouldn't recommend milling BP in that size jar. On the other hand it could be very useful for single component milling, seems like you could almost mill a bag at a time of kn03 in that thing. Edited August 8, 2017 by chuckufarley

[RiderX]

I agree with Mumbles recommendations, I wouldn't recommend milling BP in that size jar. On the other hand it could be very useful for single component milling, seems like you could almost mill a bag at a time of kn03 in that thing.

oh i didnt have any plans on using that jar , #1 its steel #2 it has paddles inside it #3 even if i could fill it i do not need that much comp laying around

Edited August 8, 2017 by RiderX

[Baldor]

cant i make a smaller jar for it?

Depends of the actual speed of the ball mill. If it's low enough, you can put an smaller jar inside the big jar. Of course, the small jar will turn faster than the big one, so you must make some calculations.

[Mumbles]

You can definitely make a smaller jar, but you're limited by the spacing of the rollers. I suppose you could add new rollers, but at that point, combined with the gearing changes it might make more sense just to build one purposely from scratch. The hobfir ones (~7" OD) will run Lortone/Harbor Freight jars (~4.5" OD) for instance, but you can't go much smaller. I'm sure you can find something that works.

[RiderX]

You can definitely make a smaller jar, but you're limited by the spacing of the rollers. I suppose you could add new rollers, but at that point, combined with the gearing changes it might make more sense just to build one purposely from scratch. The hobfir ones (~7" OD) will run Lortone/Harbor Freight jars (~4.5" OD) for instance, but you can't go much smaller. I'm sure you can find something that works.

i can move the roller over no problem just unbolt the bearings move the roller were i want it and drill new mounting holes , id just have to buy a shorter drive belt which i think is nothing more then a fan belt on it. boss gave me the a ok to use it and mod it how i need it as long as they can put it back to its current config easily

 

i looked around th shop today i have 2x variable/adjustable drive pulleys and an assortment of pulley sizes .it raining again so i couldnt get the other measurements needed off the think

i think the first thing to do will be to build a jar for it though

 

the question is what do i build the jar out of , aluminum , plastic ( nervous about static with this ) stainless ?

 

edit we have some 6-810 inch plastic pipe ( not pvc laying around ) that ill have to see what it is

 

ill leave it to you guys to suggest what size jar i should build and how i should build it

Edited August 8, 2017 by RiderX

[NeighborJ]

There is no need to modify anything. I have a mill jar which is too large but rather than modifying it I chose to simply place a smaller jar inside the larger drum. The small drum turned faster as it rode along the wall of the large one but mine has a speed control to compensate.

[Mumbles]

For jars you can plan on 1.5-2lbs per gallon (200-250g per liter) of black powder. You'll often see a poundage rating on rock tumbling jars, but that bears little relevance to what we do. Both in terms of capacity and total load. It typically refers to the load of rocks it can handle. Figure out how much you really need. a 6" ID x 9-10" jar is around a gallon and can do around 750-1000g of BP at a time. Keep in mind that the mill you posted a picture of can definitely handle more than one jar as well.

 

I really can't stress this enough, but if you are going to use that mill, make sure it's well separated from any structures or things you or your boss care about.

[OldMarine]

Pvc pipe and fittings are the easiest, cheapest and durable way to go. The distance between the rollers well dictate the size of your drum.

[RiderX]

For jars you can plan on 1.5-2lbs per gallon (200-250g per liter) of black powder. You'll often see a poundage rating on rock tumbling jars, but that bears little relevance to what we do. Both in terms of capacity and total load. It typically refers to the load of rocks it can handle. Figure out how much you really need. a 6" ID x 9-10" jar is around a gallon and can do around 750-1000g of BP at a time. Keep in mind that the mill you posted a picture of can definitely handle more than one jar as well.

 

I really can't stress this enough, but if you are going to use that mill, make sure it's well separated from any structures or things you or your boss care about.

when screening it ive been making 11.1 ounce batches or 314g , so being able dbl or tripple that amount would be all i really need . and maybe just dbl will be enough since the bp will be much hotter then my screen mix so i wont be using nearly as much

 

i know just were to move the mill to for now , it will be surrounded by 3 empty shipping containers , hell i could even put it inside one of them

Pvc pipe and fittings are the easiest, cheapest and durable way to go. The distance between the rollers well dictate the size of your drum.

no static issues with pvc ?

[OldMarine]

No, charges are equalized in the jar and proper grounding when emptying will equalize it with the outer surface as well. I cannot find an instance of a mill jar igniting without some exterior source or improper handling as the cause. I still respect that much BP in my face but I don't fear it like flash and am comfortable I've negated as many of the risk factors as possible. This hobby is one big bag of acceptable risks, you choose those you're comfortable with and leave the rest in the bag.

[RiderX]

No, charges are equalized in the jar and proper grounding when emptying will equalize it with the outer surface as well. I cannot find an instance of a mill jar igniting without some exterior source or improper handling as the cause. I still respect that much BP in my face but I don't fear it like flash and am comfortable I've negated as many of the risk factors as possible. This hobby is one big bag of acceptable risks, you choose those you're comfortable with and leave the rest in the bag.

thanks ill see what i got laying around for pvc at the shop , i know for sure we have 4 inch not sure about 6 inch , i think i want to make a couple 6x10 jars since ill be able to put more then one at a time on it

[RiderX]

 

helps if u watch in 1080/60fps and full screeen a lil bit

 

looked great in person , camera did a shite job of capturing it , was definitely my best shell yet , this was a shell i made nesting hemis for not sure if the bright flash from the flash booster caused the camera to not pick it up , or if it was the camera settings i tried

 

does slow flash still give off the flash of light? i dont have the right aluminum right now to make slow flash

 

 

that was a 2.5 inch shell , with a nesting hemi and 2 layers of gum tape just to be sure it was sealed , im out of bp again so it will be a few more days before i can try again

[Mumbles]

All flash, and really all burst for that matter gives off light. Mixing it in with the burst vs. keeping it centered can help mitigate that. I actually can't speak to whether the aluminum makes much of a difference. I don't notice it as much with shells using bright flake or a coarser dark flake (like 10890 or 809), but that might just be confirmation bias. Also, dim stars make the bright flash upon breaking more noticeable.

[RiderX]

All flash, and really all burst for that matter gives off light. Mixing it in with the burst vs. keeping it centered can help mitigate that. I actually can't speak to whether the aluminum makes much of a difference. I don't notice it as much with shells using bright flake or a coarser dark flake (like 10890 or 809), but that might just be confirmation bias. Also, dim stars make the bright flash upon breaking more noticeable.

ill just have to try it and see what happens. I know whistle mix doesnt flash but i dont even want to try making whistle mix yet.

i just noticed the camera went out of focus between the time the tail went out and the shell broke so maybe that has more to do with it then anything , really disappointed as it was a really nice shell

next time i will deff be using more the one camera

 

i really like using the nesting hemi's was so much faster to finish the shell , though it deff drives the cost up , i made the nesting hemi out of 3 inch hemis that i measured and cut in the right places to make it fit tighly around the 2.5 shell , so not as expensive as buying actual nesting hemis , but ill be buying them in the future for the 3's

[dynomike1]

What i would do is build 1 6x10 jar then build a smaller one to test comp with. Your biggest expense is going to be on the jar is reducing the neck from 6 to 4" and the cap. Looks like you can move the bearings down to a 2" spread or maybe 4".

Edited August 10, 2017 by dynomike1

[RiderX]

What i would do is build 1 6x10 jar then build a smaller one to test comp with. Your biggest expense is going to be on the jar is reducing the neck from 6 to 4" and the cap. Looks like you can move the bearings down to a 2" spread or maybe 4".

what caps are u guys using

made a batch of bp last night should be dry this afternoon if its not already , so ill prolly try out a nested shell tonight again, also built my first 3 inch can 3 x 7.5 long , waiting on a length of 3 inch hdpe to come in before i fire it though , i want a tube atleast 24 inch long to shoot it out of , im going to bury this one 1 ft in the ground just incase of an opps

 

speaking of which anyone got a picture of how to tie the time fuse into the quick match to ensure lighting , i have the time fuse ontop of this shell

i just slice the outer cover of the quick match and insert the strands of bm into the qm right

Edited August 10, 2017 by RiderX

[greenlight]

Have a look about halfway down this page. There are two pictures of a good example on how to ensure ignition and contact using a piece of blackmatch in a h configuration and a slice in the quickmatch casing:

 

http://www.skylighter.com/fireworks/how-to-make/tiger-willow-ball-shells-3.asp

[RiderX]

Have a look about halfway down this page. There are two pictures of a good example on how to ensure ignition and contact using a piece of blackmatch in a h configuration and a slice in the quickmatch casing:

 

http://www.skylighter.com/fireworks/how-to-make/tiger-willow-ball-shells-3.asp

awesome thank you there was another page on skylighter that had showed it as well and i couldnt find it again

[dynomike1]

I use a rubber cap with a clamp around it. You can get them at a plumbing store. Look at the picture on page 8. I dont use BM any more, i dip my time fuse in a slurry then pulverine. Haven't missed a lick yet.

Edited August 11, 2017 by dynomike1

[RiderX]

I use a rubber cap with a clamp around it. You can get them at a plumbing store. Look at the picture on page 8. I dont use BM any more, i dip my time fuse in a slurry then pulverine. Haven't missed a lick yet.

ive got 164ft of QM atm for cross matching time fuse so until i run out of it im just going to stick with it , i still prefer my 1 sec or 5 sec artillery fuse for the shells

 

maybe when i switch over to electronically firing ill start using the qm on the shells

Edited August 11, 2017 by RiderX

[RiderX]

how owuld u guys rate the veline color stars , are they decent? or should i just pick colors i want to do in other formulas