64 replies to this topic

[digger]

I persoanlly don see the point in milling anything prior to ball milling. Your mill should pulverise everything its self (its a mill).

I agree, my mill turns everything to a fine powder in a few minutes. A lot quicker than pre-preparing stuff.

Edited by digger, 30 August 2009 - 01:50 PM.

[cooperman435]

Out of stock Items now sorted sorry I didn't realise so much was set to "0"

[CCH Concepts]

any chance of you letting me know when you in stock. also any suggestions of things to add bearing in mind my experience. also hearing some thing i would recomend as something i currently use.

E-madeinchn

its a really cheap system and so far has worked well.

[pyromaniac303]

What basis do you have for this comment? Have you tried it?

I would say that powdered BBQ charcoal is the worst charcoal for lift from my experience.

Here is a video of meal powder made from activated charcoal Activated Charcoal BP. I think you will agree that it is perfectly acceptable for lift powder. It may not be quite as fast as willow based powder, but there is not a great deal in it.

I would personally say that most problems with BP are due to poor mill efficiencies.

P.S. Activated "Carbon" may be poor for BP especially if it has come from an oil based process rather than the hardwood route. This however this is very different stuff to activated charcoal.

I was impressed with the BP in that link, its many times faster than the result I had which used activated filter carbon. Maybe I got confused between activated carbon and activated charcoal as I assumed they were the same thing. The stuff I used was for aquarium filters. I tried this a couple of years ago, even when fully milled for several hours it burnt slowly and left a few smouldering blobs of oxidiser and ash.

[Mortartube]

I agree, my mill turns everything to a fine powder in a few minutes. A lot quicker than pre-preparing stuff.

Yours may, but out of the three mills I have made (none were very good and I had little or no money to invest in them), My purchased rock tumbler still turns out the best BP I have ever made. I admit it takes longer but it is a damn sight quieter too.

If CCH has a very inefficient mill, it may speed the milling time to give a quick blitz in a grinder even if not talc fine.

If I had a decent ball mill, I would chuck it in a bit lumpy too.

[digger]

I was impressed with the BP in that link, its many times faster than the result I had which used activated filter carbon. Maybe I got confused between activated carbon and activated charcoal as I assumed they were the same thing. The stuff I used was for aquarium filters. I tried this a couple of years ago, even when fully milled for several hours it burnt slowly and left a few smouldering blobs of oxidiser and ash.

Fair enough, there can be a difference between the two. The problem can arise as manufactures will label a product activated carbon from both wood and oil sources. The only way to find out is the manufacturers spec sheet. But activated charcoal should always be from a wood source, usually hardwood hence it being a little slower than the good old willow/alder/poplar (although balsa is hardwood and that apparently is the bees knees).

Yours may, but out of the three mills I have made (none were very good and I had little or no money to invest in them), My purchased rock tumbler still turns out the best BP I have ever made. I admit it takes longer but it is a damn sight quieter too.

If CCH has a very inefficient mill, it may speed the milling time to give a quick blitz in a grinder even if not talc fine.

If I had a decent ball mill, I would chuck it in a bit lumpy too.

Fair point. However a good mill does not have to cost the earth.

I built mine for about £40. The motor and speed controller came from ebay at about £25 including postage, they don't come up that often as a pair but be patient. The rollers were liberated from an old conveyor and the frame was welded up from some old angle iron but a wooden base would have been just as effective.

I have a 50 litre mill jar for milling big stuff like charcoal after making a drum of it. It has about 40Kg of media in it and it turns easily on the mill (my bp jar is 3 litre and will do the max 100g allowed in a few hours, I am sure it could do more). I have to say having a speed controller really makes all the difference as you can optimise the speed for any size of mill jar in a few seconds.

The most expensive part of my mill was the media as I bought a 25Kg sack (£210 ouch) of ceramic media so I could fill a few jars for milling things such as sodium benzoate. However this cost can be mitigated by making your own lead media by buying some scrap lead from the local scrap dealer for about 60p per kilo. It is easy enough to melt it down and pour it into a load of holes drilled into a plank of scrap hardwood (offcuts for free from the local timber yard). Ok they would be tubes and not spherical but they would work just fine. If you are feeling adventurous you could even alloy the lead with 4% - 8% antimony to harden it up a bit.

[CCH Concepts]

What basis do you have for this comment? Have you tried it?

I would say that powdered BBQ charcoal is the worst charcoal for lift from my experience.

Here is a video of meal powder made from activated charcoal Activated Charcoal BP. I think you will agree that it is perfectly acceptable for lift powder. It may not be quite as fast as willow based powder, but there is not a great deal in it.

I would personally say that most problems with BP are due to poor mill efficiencies.

P.S. Activated "Carbon" may be poor for BP especially if it has come from an oil based process rather than the hardwood route. This however this is very different stuff to activated charcoal.

ok thats alot quicker than mine. is that just esperience or should that be what i should be expecting from mine.

[digger]

ok thats alot quicker than mine. is that just esperience or should that be what i should be expecting from mine.

Well...... as others have said ensure your charcoal is good.

Some ebay sellers have very good charcoal, others do not. Be very careful about the description. If it just says air float pyro charcoal or something similar then the odds are it is just powdered up BBQ charcoal (keep this for your firedust/willow stars). Decent BP can be made from this but it is much much harder to do. You will probably have to mill it for ages and then press it into pucks on a hydraulic press and then corn it. However if you have willow or commercial charcoal powder then you should be able to make BP at least as good as that in the video just by ball milling for 4 - 8 hours. That was my very first batch of ball milled BP, my BP has improved since then.

I think that the first thing that you need to do is ensure that you have a good mill and jar with the correct amount of media which is set up to run at the optimal speed. It makes a huge difference having a well set up mill.

Do you have any photo's of your mill, jar and media? If so could you post them here so that people can help you correct any problems there may be with it.

[CCH Concepts]

I'll have to take some photos and load them up another time. I don't think it's the best. It was one I bought off of ebay and it doesn't turn particularly quickly.

[cooperman435]

Mill speed, volume, media and charge are all very important to a mills efficiency. If any are off then there is every chance your mill will be poor at producing BP at the least, too far from the accepted values and it may be essentially useless.

All these values are discussed elsewhere in the forum (many times) and I personally would advise sticking to them religiously or it may be a complete waste of time.

[CCH Concepts]

OK, ill do some searching and compare to my mill. i assume there are quantitative values i can compare against.

[digger]

There are. However there are some pretty simple ways of tuning a mill. You need it turning at around 2/3 to 3/4 of critical rotational speed. Critical speed is that at which all the balls/media stick to the outside of the jar. If you have a speed controller then it is a simple matter of slowly ramping up the speed until the mill goes quiet then backing it off a little until the noise returns.

Or you can calculate it from this formula: "Critical speed = 265/(Jar I.D. - Media O.D.)^0.5" the dimensions are in inches

As others have already said you will need to have your jar about half full of media and the maximum charge of powder should be no more than a quarter of the volume of the jar (less and the milling time will be shorter).

[CCH Concepts]

that makes a lot of sense, as mine isn't spinning fast enough to have enough centrifugal force to hold the balls to the side of the jar, at the moment they just bang around.

Edited by CCH Concepts, 31 August 2009 - 03:42 PM.

[digger]

that makes a lot of sense, as mine isn't spinning fast enough to have enough centrifugal force to hold the balls to the side of the jar, at the moment they just bang around.

They should bang around a lot. You need the mill turning at 2/3 of the critical speed, this makes sure that they bang around as much as possible.

Have you managed to get enough media to half fill your jar yet? IIRC you only had six shot in it before which will do next to nothing.

[CCH Concepts]

i brought some new balls, but they where quite big. my jar is only about 20 cm in diameter and these balls were maybe 2.5 cm and weighed about 100g each. the ball mill wasn't strong enough to turn turn them reliably it kept getting stuck, i settled with six 1 cm balls and three 2.5 cm. but i didn't let this mill over night, something like 16 hours.