my new ball mill lortone 33B

[superspike23]

Hello everyone.

After a break in this hobby, I bought a new ballmill.

Lortone 33B.

 

 

 

I want to work now safer.

I have a few questions before starting production of BP.

 

I measured the speed of the barrel, 44 rpm.

Do you think this is enough?

 

I noticed that the inside of the barrel is not round.

 

 

 

And as media I use ceramic balls purchased from pyrogarage.pl.

 

 

 

Am I ready to start?,

[Shadowcat1969]

I would use some rubber hosing to increase the diameter of the driving shaft. That will increase the rpms of the jar, you want to be more in the range of 75 rpms if you can get that high. The milling is much more efficient that way. There are directions on doing this somewhere on the forums here, I will search a little later when I have the time.

 

The lifter "bars" in the jar shouldn't be an issue, I have seen claims that they actually help.

 

Another thing to consider is building a cabinet for it. I used to not have one, I just set it on a board outside. Then I built a simple plywood cabinet with legs and a lid. I now find that the jar and contents are noticeably warmer and I have better BP, partially because of this. It also helps deaden the sound during the mill run, quite a bit.

 

If you check Skylighter's Projects, Ned Gorski discusses temperature of your milling environment affecting your powder in one of his projects on building a box for your mill.

Edited October 1, 2013 by Shadowcat1969

[mabuse00]

Welcome to the 33b owners club

 

You are european right? 230V?

 

I measured the speed of the barrel, 44 rpm.

Do you think this is enough?

No. I think 80 or even a little more would be ideal. There is many information on the "Harbor Freight" models around, these seem to be faster out of the box, like 60rpm or so. I was a little disappointed when I found the lortone is turning that slow. I use 10mm/20mm id/od vacuum hose (lab stuff) on the drive roller.

 

Unfortunately the jar is almost scratching at the sheet metal on the return roller side, I allready have shrinking tube over the return roller the alleviate this a little...

Even with that modification I only get about 66rpm (not sure, I wrote that down somewhere, cant find it now...).

 

The machine does a good job overall, with 12mm leadballs that last astonishingly well my BP does not improove much after 3h of milling, despite the low rpm.

But considering the high price, the overall low quality (plastic bearings, thin sheet metal, extreme belt wear) I won't exactly recommend it.

 

I feel the contruction is at it's limits with the leadballs (4Kg+Jar+120-140gBP) and that even if you change the reduction ratio either by cutting the already to weak sheet body down and enlarge the drive roller even more or just change the belt pulleys ratios, it won't turn much faster. The motors is lacking torque, it will just get hotter, that's all.

If you really adress the machines problems properly, you're better off building a new one

 

I would advise to secure the jars lid with tape.

Edited October 1, 2013 by mabuse00

[superspike23]

Yes, it's 230v european model.

 

I use these ceramic media :

 

 

diameter 20 mm.

 

I use tape to increase the diameter of the shaft.

 

what do you think of these ceramic media?

Edited October 1, 2013 by superspike23

[mabuse00]

I use tape to increase the diameter of the shaft.

I wouldnt like that.

The tape might become loose somehow. Also the tapes glue might mess around after some time, if you know what i mean.

 

what do you think of these ceramic media?

I don't know PGs stuff, but I have a set of similar 20mm ceramic balls. I don't use them for BP so I cannot directly compare them, but I feel that they are inferior to my leadballs. Not heavy enough, not enough momentum to crush particles.

Also i have no idea if they're safe for BP (as far as you can call safe ) .

Edited October 1, 2013 by mabuse00

[Mumbles]

They're far too large in my opinion for that jar. If they sell something in the vicinity of 10-12mm, it will probably work much better.

[JayDee2]

I have increased the diameter of the drive shaft on mine to get 80 RPM. Also had to slightly increase the other shaft with heatshrink to stop the barrel scraping on the body. Motor seems to handle it well. Done about 200 hrs so far. I am now using 12mm Zirconia media after giving up on hardened lead due to experiencing very high wear rate. The Zirconia was not cheap but so far wear rate seems to be negligible after 60 hrs.

 

I also think that 20mm media is probably a bit large for a 4 inch barrel. I have both 12mm cylindrical and 12mm round Zirconia but so far haven't been able to tell any difference in performance. I generally mill BP for 4hrs. Have tried 6 and 8 hours but can't notice much difference.

[mabuse00]

They're far too large in my opinion for that jar. If they sell something in the vicinity of 10-12mm, it will probably work much better.

Imho one needs a certein weight for effective milling, especially in a such a small drum, where the media cannot gain much speed during "falling back" from the wall. If your jar has a large diameter, light balls might work better.

In fact the mill is to small...

 

I have increased the diameter of the drive shaft on mine to get 80 RPM. Also had to slightly increase the other shaft with heatshrink to stop the barrel scraping on the body.

Must be a lot of heatshrink?

 

I am now using 12mm Zirconia media

In my opinion this stuff has the same problem as the aluminium oxide based - to light.

But anyway, do you have a european source for that stuff? What did you pay?

 

I generally mill BP for 4hrs. Have tried 6 and 8 hours but can't notice much difference.

Have you tried less? I know it's hard to compare but I dare to say my leadballs are faster, and my drum is much slower.

edit: for how much BP do the 4h apply?

Edited October 3, 2013 by mabuse00

[JayDee2]

Hi mabuse,

 

I have tried 1/2 inch lead, and Zirconia 12mm round, 12mm cylindrical, and 20mm cylindrical media in this ball mill barrel for milling BP. . I took the following video of Zirconia media some months ago using a clear acrylic window on the barrel because I was interested to know exactly what was happening inside.

 

The first part of the video, shows 12mm round, then 12mm cylindrical, both of which appeared to give good grinding action. The third part of the video used 20mm cylindrical, and it to me it looks like it just isn't "working" well. The barrel is too small. Maybe 20mm round media would be a bit better, but I don't have any. I see both the 12mm round and cylindrical working well - not much difference really , but not the 20mm cylindrical, so I am not convinced that 20mm round would be a good choice for this 4 inch barrel.

 

I increased the diameter of the drive shaft using oil pressure hose line. Sorry, I should have mentioned that. It was only the lay shaft that I used heatshrink on to increase the diameter slightly.

 

Certainly lead is the heaviest media. I have tried lead, alumina ceramic. and Zirconia.

For the recommend approx half full volume of media barrel, the weights of the media were :-

Lead 2340gms

Alumina ceramic 760 gms

Zirconia 1330 gms (either 12mm round or cylindrical)

So yes, lead is still far heavier, but Zirconia is much heavier than alumina ceramic.

 

What is interesting is that my original harded lead 1/2 inch balls from PyroCreations (and a subsequent order of the same media) shrunk from 11.7gm to 8.6 gms per ball in about 70 hours of milling. i.e the weight of the media (200 balls) went from 2340gms to 1720gms in 70 hours. This wear rate seems to be higher than others have experienced "in general" , but so far no one has told me has what wear rate they are getting for the same 4 inch barrel lead media running at 80 RPM?

 

Whilst I have only done 60 hrs so far with the Zirc, there has been negligible wear or reduction in weight of the media, which I am really happy about. Also some environmental advantages with Zirconia compared with lead, to those who are interested (like my wife!)

 

Yes, the Zirconia was not cheap. About $35.00 per lb from Inframat Advanced Materials in USA. http://www.advancedmaterials.us/zirconia.htm I found one European manufacturer but they never responded to my inquiries.

 

I run 150gms BP in the barrel. I have not tried less that 4hrs

[mabuse00]

Thank you for sharing your experience, JayDee2.

 

Did your leadballs contain antimony? Mine do, but only 1%.

I have now run them for 65h and the weight went from 2056g to 2024g. Less than 2 percent.

After what I read in this and other forums that's almost to good to be true, but it is.

 

Ever changed a belt? How long did it last?

 

Alumina ceramic 760 gms

Zirconia 1330 gms (either 12mm round or cylindrical)

No wonder they are superior to aluminium. I'll think about that solution when my leadballs are used up.

 

 

Maybe Dagabu's copperpipe method is of interest to - if one can scrounge the raw materials somewhere...