82 replies to this topic

[Robbie414]

No its a 6" diameter piece of drain pipe basically with plastic end caps. So Lead is the only option then? May be a stupid suggestion but how about good ole glass marbles???

[Rhodri]

Bernie's concerns are warranted - but I know the type of tumbler you're using.

I have tried marbles but I find that they don't have enough density to really "mash the molecules".

I still maintain that good lift BP will need a bigger and more powefull mill and that this type of mill is more suited to 'gerb' type powders.

TIP: Becuase you're not going to get a really good grind in a rock tumbler, try reducing the BP components to a fine powder first either in a clean coffee grinder or the old 'pestle and mortar' - then add these to the mill. I like to think of the tumbler as a 'mixer' rather than a 'grinder'.

[BigG]

Glass balls will work, but they have a few problems. First, they are significantly lighter then lead; therefore will take much longer time to grind the material into fine powder. Second, Marbles will grind themselves into the powder ? littering it with fine hard glass powder, and there are a few researches that show that this increase the powder sensitivity significantly.

You do have other options. The best (even better then lead) is brass. Brass balls are VERY expensive but have a much slower rate of wear and tear. They will last for years. Instead of brass balls you can use hollow brass rods ? the kind that is used for drainage pipe. Choose those who have quite a large wall thickness (those who sold in model shops for airplanes are NOT good as they have very thin walls) and cut them into 1-2 inch segments. They will require more time then ball shape but will work. Oh, do make sure you use BRASS and not Copper. The one you get at most DIY shops are copper ? you will need to look a little longer for brass.

BigG

[bernie]

I would'nt if I were you. Ball mills need to have a 6 sided wall design to maximize the the use of lets say, solid BRASS rod cut into short lengths.

[Robbie414]

So then....Lead it is! Lol

Large lead weights are expensive, but what about the shot type that are only a few quid a tin.....or how about .22 lead air gun pellets....or would these be far too small and iregular?...What sort of RPM speeds are we talking about for these mills then? Cus I could change the gearing ratio on the pulley fairly easily and the motor should cope well as the weight of the BP would be far less than that of rock, water and carborundum....just an idea

[BigG]

I will disagree bernie. We are not looking here for the most efficient ball mill, but for one that works fine ? and knowing the situation in the UK, the brass rob idea will probably be the simplest. As for .22 shots. They will not do as they are to light. You will need around .5 inch. Those are possible to buy from gunsmith who deals with black powder (.5 are used to fire old weaponry by enthusiastic (Musket and the such)). You do not need license to buy them. Cost about 20? for anything from 50-100 balls.

I can calculate the RPM for best efficacy as I have some book lying around that explain how to do this, but for this you need to supply some measurements for the milling jar and media. Safe bet is to aim for somewhere around the 60-100RPM. It would work fine for most sizes of jar and media ? although might take more time then the optimum configuration.

BigG

[Robbie414]

Thanks Big......will start experimenting!....it won't take much to increase the RPM to 60.

[smpip]

Hey Bernie, did you know that KNO3 is the next best thing to have around if you have run out of Bromide at the Old State Pen?
You've got one switched on wife.

[Edited on 31-5-2003 by smpip]

[zanes]

hi, i heard that garden direct sell kno3, what product is it, how expensive and pure is it?

[Matt]

I get my KNO3 from an agricultural place, 40 big ones for 25 kilo's. Thats aussy currency too, but our dollar is rising hooray! haha

-Matt

[adamw]

What product is KNO3? Potassium Nitrate I'd assume, unless things have drastically changed!! Why not have a look on their website and find out yourself!

[PanMaster]

farmers call it nitrate of potash
also known as 13-0-46 NPK fertilizer

[bernie]

The Mrs. is actually a pretty nifty gal. She is very fond of the club we belong to and everyone loves her cookies and brownies. It's probobly the only reason they let me stay in.
More proof she is great...... She really does like BIG bottom shots. No .....not that kind! The type the Italians stick in the multi breaks etc. The ones you can feel in your chest.

[smpip]

Big Bottom shots (but not them kind???), Italian multi breaks, that you feel in your chest? ??? Yep Iv'e read it but it still makes no sense to me.!
Your not refering to squibs in film use?
Please break it down for me.
I have either led a sheltered life or I am just too English for my own good!
The moment you said your wife puts a little KNO3 in your ice tea, that was all I needed to read to know that shes a great Lady.
Do you know that KNO3 is also used to preserve/cure dry sausages and salami, great stuff.


[Edited on 1-6-2003 by smpip]

[Pyromaster2003]

lol i am dieing to add what i think the 'big bottom shots' thing meens but il keep it to myself:-)

i got my KNO3 from a meat curing place pretty cheep.*i think. would this stuff be pure because its associated with food?