Terminator

Bernie,

I've just found a website that sells Ball Mills that use Neoprene rubber containers:

United Nuclear . com

(http://www.unitednuc...om/ballmill.htm - just in case the link doesn't work)

This is a site that sells laboratory equipment to schools and businesses.

The professional ball mills start from $69 - (follow the link).

FOR ANYONE WANTING TO BUILD THEIR OWN BALL MILL, go to the first page via the link as their are some excellent colour photos showing how to make a homemade mill.

PS If you decide to use a neoprene liner in your own mill, make sure you get "smoothskin" (bare) neoprene. Many neoprenes made for the wetsuit market have a nylon covering (static risk).

Might I suggest you also consider Butyl rubber. This is pond liner material and is sold by most good pond shops on the role by either the metre per set width, or by the square metre. If you're lucky you might be able to get an offcut at reduced cost or even free if it is too small for pond use.

I know of no interactions between Butyl rubber and BP but as I am not a chemist, please check this out first with your chemistry books / experts on site, as I can't be held responsible for anyone blowing themselves up on this one - the duty is on you to check.

Al.

Bernie mentioned they use Hickory as a substitute for Willow in Cricket Bats the US.

Has anyone tried Hickory in BP?

I only ask because it occured to me that this can be bought in chipped form from garden centres for adding to BBQ charcoal for flavour. Therefore it is easily available and I would think that being chipped it would turn to charcoal relatively quickly.

Al.

Interesting, I didn't know that. Presumably therefore this is another reason not to use a copper tube as a Ball Mill container.

But, what about brass bearings then could these be used instead of lead?

PS should beware "brassed" bearings as I'm sure most of you are aware that these are just coated steel (risk of coating wearing and then sparking).

Al.

Just had a thought from what Tomu said.....

Has anyone thought about using solid copper ball bearings as the ball media instead of lead?

Rather than having a copper tube, you could have a plastic / rubber tube and copper ball bearings.

Being harder I would expect them to make a better job of crushing the powder and unlike lead there will be no tendancy to contaminate the tube / powder with lead dust. (The amount of copper shed by the balls will be insignificant.) Also, their hardness will eliminate any tendancy for clumping (lead balls can in some applications, (I don't know about Ball Mills), have a tendancy to attach themselves to each other and clump together).

Al.

Tomu,

Don't know much about Ball Mills so can't comment too specifically on the point, but I believe you have missed one valuable safety point:

You say that if the copper pipe mill exploded it would just splay out the ends of the pipe as copper is soft.

However, what about the lead balls inside? It seems to me that any explosion in the pipe sufficient to splay the pipe, would burst these out like a crude shotgun with potentially horrific consequences for anyone within a short range.

From a safety point of view, I would have to say that one of the previous suggestions of MDPE (a soft tough plastic) with blow out tube ends sounds best. The soft nature of MDPE makes it agreeable to deformation.

(I believe that yellow Gas piping is MDPE if you need a large bore. I certainly know that the blue water piping is MDPE although this is usually only 1 inch diameter. Perhaps a friendly roadside workman would give you an off cut of the gas stuff?)

An even safer alternative to a sealed blow out cap would be to have a top cap made of fine mesh so that it vented some of the gas (pressure) rather than or before blowing out. I don't know how practical this would be for a Ball Mill though.

Remember, Black Powder is not a true explosive. It is a fast burning powder that produces a large volume of gas. It's not the powder that explodes but the vessel that contains it.

Therefore, whatever material you use for the mill, (non-sparking being obviously better!) if you provide the gas with an adequate means of escape in the event of accidental ignition, you will avoid an explosion. Just don't stand over the vent!

Al.