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Clumpy BP


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#1 Sparky

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Posted 12 September 2012 - 05:14 PM

Hi all

I've got a really simple small rock tumbler for making small batches of BP (<100g) and I'm already getting better results than I have managed by any other process but I keep having a problem.

I use about 700g of ceramic media that fills the jar about half way. I add in the 100g of comp which the components of have been stored in a nice dry shed in an airtight containers. The jar is under-speed (I am going to fix that) but my understanding is it should still work even if it's slow.

After about 4 hours of milling I find that the powder has clumped together into a grey ball in the middle of the mill. It's not sticking to anything else inside except forming this ball. When I break it up it readily turns back into a very fine, well integrated powder. I granulated some last night to test it and it's not bad. Still lots of room for improvement but still a load better than the CIA method!

I've tried drying the comp in a warm location but it clumped again. I'm going to try drying the components in a warm oven tonight and will try another run on Friday.

Aside from the possibility that my chemicals being a little damp could it be anything else? My storage area is pretty snug and not damp at all so I wasn't expecting this problem. The shed is usually in sun all day too so it's usually quite warm in there.

#2 Mortartube

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Posted 12 September 2012 - 05:50 PM

PM sent
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#3 Vic

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Posted 12 September 2012 - 07:17 PM

That's a new one on me, clumping in the corners yes, but a ball in the middle....
Freud. Artists, in this view, are people who may avoid neurosis and perversion by sublimating their impulses in their work.

#4 Sparky

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Posted 12 September 2012 - 07:28 PM

That's a new one on me, clumping in the corners yes, but a ball in the middle....


I know it's weird...it's a lovely grey ball. All the comp in one lump right in the middle with all the media going round it.

#5 Vic

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Posted 12 September 2012 - 07:42 PM

The only thing I can think of is the ceramic media is to light in weight compared to lead.
Freud. Artists, in this view, are people who may avoid neurosis and perversion by sublimating their impulses in their work.

#6 megabusa

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Posted 14 September 2012 - 08:14 PM

Sparky, get yourself a fishing sinker mould off eBay.

An hour spent melting lead + casting your own media will make a massive difference.

I used one to make 20mm balls, about 120 of them. A big improvement on ceramic media.




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