Jump to content


Photo
- - - - -

Safety of Rebel/Thumblers tumbler ball mill


  • Please log in to reply
6 replies to this topic

#1 PyroCat

PyroCat

    Smelt the smoke

  • Full Member
  • Pip
  • 9 posts

Posted 11 September 2020 - 02:38 PM

Hello, I am wondering what other Pyros think about the safety of the Rebel 17 pound ball mill. It seems like it would be a deadly explosion if something were to go wrong while handling the drum before emptying it out, since it is sealed with 6 threaded posts and nuts. I know it is a must to wear PPE while emptying the mill but I don't think any amount of PPE would save you from the explosion if it blew up before unscrewing all the nuts from the lid. After hearing about the accidents when handling ball mills full of BP on here, I am concerned about the safety of the Rebel mill. Does anyone have any ideas on how to modify the drum to close the lid without using the threaded posts and nuts? Something that would fail and blow the top off, if it were to explode instead of the whole drum exploding violently? I noticed it does not have a grounded plug so I don't know if that's an issue or not? I'm sorry if this has already been discussed on here but I couldn't find anything about this, and I just want to be as safe as possible. Sorry if this is hard to understand. Thank You for any input.  :)   



#2 justvisiting

justvisiting

    Pyromaniac

  • Full Member
  • PipPipPip
  • 186 posts

Posted 11 September 2020 - 04:44 PM

PyroCat, milling black powder is inherently dangerous, but there are many ways to minimize risk of accident. I think your concern is valid, but it's just one of many things that can go wrong. Sometimes it has been suggested that if a mill jar of BP clumps, whack it with as stick to break it up. I would NEVER do that! Don't let contaminants like rocks and sand get into your mill. Potassium nitrate COMMONLY has hard gritty stuff in it. Don't use glass marbles or regular steel as milling media. Don't drop the closed jar. Don't pour the contents out roughly, and don't pour them onto a screen that can spark. Most importantly, always mill away from the possibility of human exposure of any kind. 

 

All that said: if you look at the sides of your Rebel 17 jar, the metal sleeve is only spot-welded together. I think it would fail at that point before the lid came off, not that things wouldn't be just as bad.

 

There's also single component milling, but that isn't totally risk free either. There are very few milling accidents, because people observe safe practices, for the most part. 



#3 Carbon796

Carbon796

    Pyrotechnician

  • Donator
  • PipPipPipPip
  • 350 posts
  • Gender:Male
  • Location:Colorado U.S.A.
  • Interests:Vintage tube radios, Jet Boats, Custom painting.

Posted 12 September 2020 - 01:05 PM

It's probably about as safe as your going to get, using hardened lead media ONLY.
The rebel/thumblers tumblers/polishers, stock. Do not make an ideal mill out of the box. They need increased speed and power, you can add the grounded plug when you swap out the motor, if you feel the need. A good majority of people, probably build there own mill. But, use the thumblers/reblel drums. You also need to realize that since it is sealed, it is sealing out, potential accidents/incidents from getting in.

ALSO, NONE OF THE INCIDENTS YOUR REFERENCING INVOLVED, USING HARDENED LEAD MEDIA AND THE HEX TYPE, RUBBER LINED DRUMS.

Edited by Carbon796, 12 September 2020 - 01:19 PM.


#4 BetICouldMake1

BetICouldMake1

    Pyromaniac

  • HE Qualified
  • PipPipPip
  • 153 posts
  • Gender:Male

Posted 14 September 2020 - 08:34 AM

I love my rebel jars. Yes, they are made of metal which would be very bad if they exploded, but a pvc jar blowing up wouldn't be pretty either. The jars seal extremely well so as long as you take the proper precautions to not allow sparking material in and to not have sparking sources present when emptying you should be fine. I'd be more concerned about using some makeshift jar that could pop open while the mill is running. 



#5 justvisiting

justvisiting

    Pyromaniac

  • Full Member
  • PipPipPip
  • 186 posts

Posted 14 September 2020 - 12:30 PM

I love my Rebel jars too, mostly ;) The noise produced compared to Sponenjars is night and day. One thing that I don't like is the flared mouth of the rubber boot liner. In the initial stages of milling, material packs into that area, where it is protected from further milling. When the jar is opened, the material falls down into the milled material. This normally wouldn't be a big issue. When milling charcoal-based comps, it can be problematic. The small amounts of mostly unmilled material that falls into the batch can be quite ugly in the sky. Perfect-looking crossettes can end up having small returning embers that diminish the beauty of the effect. To prevent this problem, I stop the mill halfway through the cycle, clean the flared area out, and start again.



#6 BetICouldMake1

BetICouldMake1

    Pyromaniac

  • HE Qualified
  • PipPipPip
  • 153 posts
  • Gender:Male

Posted 15 September 2020 - 09:52 AM

I've had that happen too but the amount of material is so small I've not noticed a visible effect in finished devices. But if I'm milling star comp I'm usually doing multiple 1000g batches so that probably helps. My biggest gripe is that the sides of the barrel that contact the rollers are slightly flared out so there's less contact on the rollers.

#7 PyroCat

PyroCat

    Smelt the smoke

  • Full Member
  • Pip
  • 9 posts

Posted 17 September 2020 - 07:13 PM

Thank you for the reassurance that the rebel jars are ok to use. I've personally had no issues using the rebel mill and jar combo to make evenly milled, fast BP doing 1000 gram batches. I did however switch from using commercial airfloat charcoal to paulownia charcoal for BP which made a big difference. 






0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users