272 replies to this topic

[Mumbles]

Just some advice.... I have been using 6 x 3/4" brass rods in a large rubber milling jar. The rods are just under the length on the jar so they just roll over each other. This has worked perfectly for me. PM if you want any more information.
Regards

Out of curiosity, is there any reason you decided to do this? There would be much less cascading of the media and I would imagine it would make it much less efficient of a milling design.

[James P]

The idea came from another pyro but it makes perfect logical sense. If you cut a rod into small pieces, the amount of surface area which could be used for grinding is quite small (edges). However if you take longer lengths then the whole length of the bar can be used for grinding.
Hope this helps,
James

[FrankRizzo]

That particular design is called a "rod mill".

Here's a good explanation of the industrial use:
http://66.113.204.26...ing/rodmill.htm

[portfire]

hi all. im in the process of making a ball mill so i can improve my bp (or make propper bp). im going to buy the jar/media (20mm diameter alumina (Al2O3) ceramic balls) from inoxia . they say they are inert and will not spark unless hit together with large force. my question is, will these ceramic balls be ok for making mealpowder. it's just on united nuclear it say's if your making bp then only use lead/antimony balls. i'd rather spend more and be safe than have an accident . thanx dean

Edited by portfire, 27 July 2006 - 04:30 PM.

[Creepin_pyro]

I've only ever used hardened lead for BP, and only use ceramic media for milling single chemicals, and there seems to be contrasting opinions on the safety of milling BP with ceramic, so I'll leave it to someone who has experience to awnser your question. However, I'd like to remind you to make sure that the mill is operated remotely, so that in case of an accidental ignition, there would be no chance of damage to people and/or property.

Hardened lead bullets suitable for milling can be bought from muzzleloading suppliers.

Stay green!

[portfire]

i agree with you 100% operating the mill remotely,safety is always No 1. i think i'll go for both ,as you say using hardened lead for bp an ceramic for single chemicals,seems the best way for me. cheers

Edited by portfire, 27 July 2006 - 07:19 PM.

[Andrew]

I might not be the "best" person to answer your question, but I have been milling bp with 20mm ceramic media for half a decade now, no missing house, or arm, or shed, or garden here!! I have had no problems at all.

You can get ceramic to spark under certain conditions. However, those conditions required are many orders of magnatude higher (in terms of momentum and energies), than those found in any ball mill. I'm sure there are some stories of ceramic being the cause bp mills blowing up; don't get me wrong it is posible in absolutly huge mills I'm sure, but comtamination is by far the biggest enemy here. Making sure you keep anything that even thinks it is a chlorate, well away form your mill is a far more important than choosing between lead and ceramic media.

At the end of the day, this one comes down to personal beliefs. It is so close to call, reason being, believe it or not you can get Hardened Lead to spark in just the same way as ceramic. However, in both cases the energies invloved in the sparks is so low.

It is also very important to get the correct meaning of the word spark! In pyro we often refer to a spark as a massive, (as in:- having a quantifiable mass) object that is glowing at a temperature high enough so that we can see it. This is totally the wrong ethos to have when thinking about sparks caused when two milling balls colide. Then ceramic (and hardened lead) balls colide with great force, the resultant sparks are like those caused by spark plugs. Super hot gasses that glow blue hot are the sparks found when milling balls colide. Although the temperature of the gas is well above 6000 degrees kelvin, the total energy contained as heat is very very small, certainly not enough to initiate bp. As a result, the sparks are very short lived and can only been seen in very low light conditions. As these sparks are in some part a direct result of the hardness of the material, I would hazard that the sparks caused by Hardened Lead (if it was as hard as ceramic) are just as mush of a risk as those caused by ceramic! There are of course many other factors to consider.

I hope this helps more than hinders!!!

[portfire]

thanx for that Andrew, it's definitely helped . i'll think i'll go for the ceramic . cheers

Edited by portfire, 24 January 2007 - 08:37 PM.

[rocket]

I find that good old fishing weight do the job fine, there cheap and very easy to get a hold of I?ve had a look for other media but its just to much trouble to get well for me it is.

[shadowpyro]

Well, just got some steel cylinders about 2cm in length(s) and 0.5 inch thick. I got it from the metal workshop, where i got this guy to cut a big steel pole up into the pieces. The pole was 1metre long, and i gave about a fiver to cut them up for me. I guess i'll just have to mill separate ingredients together with this media until i can find some brass.
Though there may be a problem with rusting if i'm using any moisture when milling...anyone else tried using stell cylinders before for milling? how efficient are they?

[fishy1]

Well, just got some steel cylinders about 2cm in length(s) and 0.5 inch thick. I got it from the metal workshop, where i got this guy to cut a big steel pole up into the pieces. The pole was 1metre long, and i gave about a fiver to cut them up for me. I guess i'll just have to mill separate ingredients together with this media until i can find some brass.
Though there may be a problem with rusting if i'm using any moisture when milling...anyone else tried using stell cylinders before for milling? how efficient are they?

Pretty efficient, steel's an awful lot harder than lead or even brass.

[shadowpyro]

So have you had any sorta static electricity problems with steel?

[karlfoxman]

Why use steel? Brass is tough enough and wont spark, if you suddenly change over to brass and dont clean your mill you will find steel would have been contaminated into your mill. Steel should not be used, I would never dream of using it. Go get brass instead.

[fishy1]

Why use steel? Brass is tough enough and wont spark, if you suddenly change over to brass and dont clean your mill you will find steel would have been contaminated into your mill. Steel should not be used, I would never dream of using it. Go get brass instead.

I don't see any reason not to use it for separate chemicals, and brass can be fairly expensive. Obviously use separate jars when switching media, and don't mill BP or any comps with it.

[karlfoxman]

Why add risk? What if someone uses the steel ones to mill a composition?? Brass is not as expensive as the damage caused if something went wrong.