153 replies to this topic

[Phoenix]

Thanks for the replies, Rhodri especially. I don't overfill my jar, and whilst I have sometimes milled a batch of BP straight after a batch of Tiger Tail without cleaning the jar, I am sure it has also affected batches in a clean jar. On the other hand, I think that all the charges that this affected were made from the same batch of willow charcoal, so I'll try fully wetting my next batch of barbeque BP, and see how that gets on.

[bobconan]

Im gonna do my first powder and im just gonna get 2 ball mills http://www.harborfre...temnumber=46376 Mill the charcoal/sulfur and the kno3 seperate take them out run them through 80 mesh seive 5 times and then do the water thing, make mush and then granulate it through 16 mesh screen.

Edited by bobconan, 22 April 2004 - 09:01 PM.

[chim-chim]

Im gonna do my first powder and im  just gonna get 2 ball mills http://www.harborfre...temnumber=46376 Mill the charcoal/sulfur and the kno3 seperate take them out run them through 80 mesh seive 5 times and then do the water thing, make mush and then granulate it through 16 mesh screen.

bobconan,
You could save a few dollars by just getting the double unit instead of two singles,
Dual Ball Mill
But, WOW, that's about a third what I paid for what appears to be the same brand.

At about $25 dollars shipped, anyone thinking of getting a Mill soon ought to check this out.

Wish you posted that a month or so ago, but thanks for posting the great deal. I might get a spare at the price.

It doesn't come w/ a remote switch but it's an easy modification off the bladed rocker it uses, or just use a switched outlet.

[bobconan]

You guys in the uk dont have access to the best materials do you? I see alot of chlorate being used. scary. I wanted the seperate ones so i could use them seperately. Turn one on or off without disturbing the other. Has anyone actually ever heard of a mill blowing up? Its common for people to have 2 or 3 pounds of bp just sitting around for mussle loaders. How much more dangerous is it in a mill?I wanna just put it in my attic. Especially if i mill them seperatly.I was thinking that a good way to avert static buildup would be to put gold leaf on the drum.

Edited by bobconan, 23 April 2004 - 12:20 AM.

[italteen3]

bobconan,
You could save a few dollars by just getting the double unit instead of two singles,
Dual Ball Mill
But, WOW, that's about a third what I paid for what appears to be the same brand.

At about $25 dollars shipped, anyone thinking of getting a Mill soon ought to check this out.

Wish you posted that a month or so ago, but thanks for posting the great deal. I might get a spare at the price.

It doesn't come w/ a remote switch but it's an easy modification off the bladed rocker it uses, or just use a switched outlet.

Please tell me if the one at harborfreight is the exact same thing as the one at United Nuclear found here for MUCH less? (Except without the UN stickers ofcourse) That saves me $100 almost THANKYOU!

Im sorry for my forgetfulness, but I browsed thread and cant seem to find where it was said but charcoal made from the wood of a tree near water makes much faster BP. Ive mentioned it before but I have access to my neighbors land upstate (150+ acres). He said I can chop any tree i want down. There is conveniently a river right behind his house and TONS of willow trees. Would a Willow right next to the stream produce the quickest BP, 3 feet away, 10 feet away, 20 feet, 50 feet, etc.?

Thanks!

[bobconan]

Ya i actully saw that. im pretty sure it is but with a different label. and besides a ball mill is a ball mill is a rock tumbler. They are all just tumblers except for the expencive ones (150 or up cheap) that do like 10 lb at a time using like all brass machinery. Btw I get all my chems from this site www.pyrotek.org I actually have a repore with the guy that runs it. I dont think they ship overseas tho. And even moreluckily its 40 mins from my house. But anyway. back to bp. my biggest concern is the rubber and static electricity. But it looks like even the one from pyrotek is rubber. Bp burns soooo much faster then i thought it would. i was using pyrodex to fool around with. Also, How safe is the cjlorate bp. i mean chlorate is detonable right? thats why you cant mill flash.

[BigG]

You guys in the uk dont have access to the best materials do you? I see alot of chlorate being used. scary. I wanted the seperate ones so i could use them seperately. Turn one on or off without disturbing the other. Has anyone actually ever heard of a mill blowing up? Its common for people to have 2 or 3 pounds of bp just sitting around for mussle loaders. How much more dangerous is it in a mill?I wanna just put it in my attic. Especially if i mill them seperatly.I was thinking that a good way to avert static buildup would be to put gold leaf on the drum.

Have one heard of a mill blowing up? You must be joking. Yes ? hear quite often, and seen pictures of a site after a ball mill explosion some eight years back.

As for the post by italteen3 ? again, this subject was discussed so many times. Will people please search? When searching, please make sure you look for posts more then 90 days old (which is the default).

[Creepin_pyro]

Please make sure you look for posts more then 90 days old (which is the default).

Hehe..... took me a good while to work that one out . Would probably have less "search before posting" posts if the default was "in the beginning"

Why would gold leaf be useful for combatting static buildup - i'm interested because I've got a load, but can't think of a use for it... no good for sparks

[Kembang Api]

I like to know if anyone heard a mill blowup???

I mill my BP by milling the Kno3 with charcoal with the ratio of 20:1 for the reason when I set it a site it would not start caking. Than I mill the remaining charcoal and sulfur for the duration it need (2 to 3 Hours) depending how fine the meterial are.
Both milled powder is than mix by seiving it with 100 mesh for 2 times, when this done. I mix it hand using with hard paper board.

I believe they call this method double / double mix, I believe this method was found in the net, sorry I did not remember the website address.

[bobconan]

i know in the industry it happens but they do it like 360 days a year and on a large scale. do you have a site for the pictures?

[chim-chim]

Please tell me if the one at harborfreight is the exact same thing as the one at United Nuclear found here for MUCH less?  (Except without the UN stickers ofcourse)  That saves me $100 almost THANKYOU!

I got my ball mill from UN, and I am nearly certain that's the same one. I knew UN was relabeling when I got it, but at the time, I could only find it for a few dollars cheaper, so I just went with UN.


" I wanted the seperate ones so i could use them seperately. Turn one on or off without disturbing the other. "

Yeah, I would too, but I have too much Scot in me to not at least mention the cheapest workable option.

Attic?

I always assume a fire will start, whatever I'm doing, and decide where and how to do things based on that.
i.e.- a small shed out back could burn down unattended with little issue,
a fire started on your back porch might light the house, but the F.D. would likely put it out,
a fire in the attic.....

"i know in the industry it happens but they do it like 360 days a year and on a large scale"

We talk about reducing risks here quite a bit, which is great, but I like to reduce stakes as much as possible as well. Assuming few of us will drop the hobby anytime soon, thinking we don't have equivilant risks to industry may be dangerous. What we don't do in volume, we make up for in cheaper equipment, more experimenting, less control of chemical purity, etc.

Your ball mill will likely never explode, but it might. Given the option, put it someplace it wouldn't matter (mid-Sahara maybe), or at least where it would matter least of all your options.


P.S.-That 90 day default got me too. Just yesterday I found I have another couple hundred pages to read from before. (thankfully I hadn't asked the question yet)

Keep safe.

[Phoenix]

The static problem has recently been/is being discussed on rec.pyrotechnics. What I gather from there is that the inside of the ball mill does not need to be grounded, since the total charge inside the jar will remain the same (insulating jar - electrons can't get in or out). However, what can possibly happen is that different areas inside the jar become charged to different potentials (which is what happens to clouds to make lightning). However, since you have a conductive milling media, and the contents are being constantly mixed around, this will not be a problem. Therefore you won't get electrical sparks inside the jar whilst it is sealed.

The bigger danger is that the outside of the jar can become charged, as that is rubbing against the rollers which could carry charges away from the surface. Therfore when you come to open the jar it is possible that a spark could be created between the jar and something else (eg you).

However, simply letting the jar sit around for a little while before you open it, and possibly wiping it with a damp cloth, should allow any charges on it to disperse, and allow any localised charges inside the jar to even out.

[chim-chim]

as that is rubbing against the rollers which could carry charges away from the surface.

Static can be predicted with the Triboelectric Series, the further the spread on this chart, the greater the static potential.

Dry human skin ( ++++++ )
Leather
Rabbit fur
Glass
Human hair
Nylon
Wool
Lead
Silk
Aluminum
Paper
Cotton ( + )

Steel(0)

Wood ( - )
Amber
Hard rubber
Nickel, Copper
Brass, Silver
Gold, Platinum
Polyester
Styrene (Styrofoam)
Saran Wrap
Polyurethane
Polyethylene (like Scotch Tape)
Polypropylene
Vinyl (PVC)
Silicon
Teflon ( - - - - - - )

A rubber drum on rubber rollers isn't going to generate static, a rubber drum on nylon rollers is probably a bad idea. Don't use a Teflon coated drum for your leather rollers

Most tumblers/mills are going to be some combination of rubber and plastic rollers, which are typically rather neutral combinations.

[Phoenix]

[EDIT] Wood on wood, so I'm OK

Following the discussion on moistening and granulating BP in the comet topic, I thought I might post a method of making BP that I quite like. I know that the standard precipitation method is fine, and "why try reinventing the wheel" etc, but this seems less messy and cheaper, and possibly safer.

1. Ball mill charcoal and sulphur together (15:10 ratio), with the addition of dextrin to taste. I was intending to make 100g of BP, and I added 1.5g of dextrin, so the resultant grains were quite fragile. (The final yield was ~130g. See below.)

2. Weigh out 75g of potassium nitrate for every 25g of the C/S/dextrin mixture. It does not need to be milled.

3. Prepare 40g of BP + dextrin for every 25g of C/S/dextrin (i.e. every 100g of BP you would end up with minus this extra bit). This is because the amount of potassium nitrate solution you add to the C/S/dextrin mix makes it too wet to granulate. I only found this after I had done it, so had to quickly mix up some green meal. However, pre-milled or otherwise processed powder would probably be better. For the time being, forget about this. (Don't forget where you left it though).

4. Put the potassium nitrate in a pan or beaker etc. Pour on enough water to dissolve most of it (I didn't measure the amount. Probably about 90ml)

5. Unload the C/S/dextrin mixture from the mill. Put it in a bowl. Work a little of the cold KNO3 solution into it. The purpose of this is to get it dampened so that it is easier to wet later.

6. Begin to heat the KNO3 solution. Allow it to boil until the KNO3 just starts to precipitate. Add a little more water to re-dissolve this and as soon as it has boiled again, pour it into the bowl of C/S/dextrin. Mix it together. It will now be too sticky to granulate. Add the previously prepared BP mix until it is the right consistency to granulate. In practice, I added three 10g portions to my 100g batch. I suggested preparing 40g, and I will next time, as it is quite likely that the amount required will vary slightly from batch to batch. I'm sure most people can find something creative to do with a few grams of spare green meal.

7. Now force the still warm ball of BP through a screen to granulate. I spread it on newspaper, and as there was no sun to put it in I set a fan to blow across it to speed up its drying.

I ball milled the ingredients with the exception of KNO3. However, this may not be necessary. If they are screened quite finely and mixed it should still work OK. Therefore it could be useful for people without mills. For me it is good, as I don't like milling large amounts of live composition. Like this, I can just mill a large amount of C and S and then prepare a larger batch of BP like this, if I need to.

It seems safer than the usual precipitation method as it does not involve heating a live mixture at all, and there are no flammable alcohol vapours given off. It is also cheaper as you do not need alcohol. Finally, filters full of black sludge never appealed to me, and this method does not require them. Just my opinion?

Edited by Phoenix, 23 April 2004 - 09:30 PM.

[bobconan]

My theory is that the gold leaf would conduct away any of the surface charge. Kinda like those metalized antistatic bags for electronics.