13 replies to this topic

[DrDerekDoctors]

Well, I just joined the ranks of serious amateurs as I splashed out on a CR2 tumbler from Manchester Minerals. Anyhoo, the lead media I have is plain old gun bullet's which are between 0.4" and 0.45" in size (two different lots - cleared out the gunstore). So I was wondering how long I'm likely to get out of them assuming fairly irregular use and <6 hour milling sessions. Is it something I need to start planning for now or could they last years and years?

[Andrew]

If it is hardend lead, you probably will never have to replace them, if it is not hardened then you probably will need to replace then after each milling run.

[RegimentalPyro]

I've used pure lead with no antimony [soft balls!] and they have lasted many milling runs, although they ARE getting smaller.

The main danger is contamination - There are two sorts.

1) Contamination of the comp by lead [I've had white Perc come out Blue/ Grey!]

2) Contamination of the comp by the previous comp which has become "pushed" into the balls.

I'm not so concerned about 1) but 2) is certainly a worry. To get round it I wash the media thoroughly , and then tumble it in soapy water in the milling jar [they're the waterproof rubber ones from Manchester minerals].

It's not ideal - If you can get hardened lead then that's the way to go. My way works, but that's about all you can say for it.

As a related aside, Brass bar sawn up does provide lots of nice hard non-sparking media. I've found it's not *quite* as efficient as good ol' lead shot, but it's jolly good nevertheless!

[Richard H]

I'm a strong advocate of brass, it pretty much lasts a lifetime and tumbles really well.

[Phoenix]

I used to use lead but now use brass. I used un-hardened lead and I never saw any significant reduction in its size, but the two varieties of the contamination problem were definately present. So far I've found the brass to be much better in this respect. Actually I find it mills materials quicker, but the jar (well, jars - I have two now) is fuller than it used to be when I used lead.

It needn't be expensive or a lot of work. I paid ?35 total (including postage) for enough 1/2" brass bar for two 1 litre jars, and ended up having a load spare (I think I got 6m. Id have needed about 4.5). Sawing it was no trouble at all. Took about an hour and a half per jar, by hand.

[sasman]

If i were starting from scratch and just bought a ball mill i would recomend (even though i havent got any?) Brass media..

I cast quite a few hardened lead balls and they show no signs of wear. but only use them for milling KNO3, C ,S mixtures.. I use steel media for milling other chemicals because the lead balls tend to discolour the chemical being milled which i dont like...

But if you already have the lead you may as well give em ago, and if there is any noticeable wear after a few milling sessions(dont forget to use the correct media to chemical ratio if you underfill you get more wear!) i would start looking for some other media..

[burningbush]

As other are saying go with brass! I used unhardend lead it worked well for some items BP but left small amounts of residue .
I used US coins "nickels and quarters" and they last along time too!
I think I read that the coins worked well from skylighter news letter,tried it and they worked as well as brass or better.

Bullets normally have small amounts of copper or tin and sometimes molybendium
alloy's.
I dont know if I'd use bullets ? maby round bullets made for old style bp gun would be ok but again wear down fast.
As above also stated never mix your media! I use seperate media for kclo4/ kclo3/bp/colr comps too...its not worth the risk of contamination for the small cost of brass, coins , etc..
Pc.

Edited by burningbush, 28 May 2005 - 05:43 PM.

[DrDerekDoctors]

Andrew: Blimey? That often! You must've had extra-extra-soft Mr Whippy-style lead or something. That sounds astounding. And would *significanly* increase the cost of making BP...

RegimentalPyro: I have the same jars as you, but until I start making stuff other than plain BP I'll have enough media not to worry about cross-contamination. I shall bare it in mind, though, thanks.

Richard H: I reckon you work for the Brass Sales Council of Great Britain or something. Well, if these suckers wind up like itty-bitty peas after one cycle I shall definitely be buying some brass.

Phoenix: Does it really saw that easily? I had this horrid feeling if I bought some brass bar (btw, where would I get it from?) I'd need a plasma torch to get through it or something.

sasman: I didn't realise that using the wrong ratio of media to chemical would increase wear! I'll make sure to remember that, ta'.

burningbush: These are old-style musket ball-bearing bullets. The nickels and quarters sounds intriguing, though. Seeing as I'm not millings complete comps they might be an idea (if I can easily source the correct coins - I'd guess that 10ps would do the trick, too). And I shall always and forever use separate media for separate chemicals/comps.

Still, I shan't find out tonight, as tonight I have a date with some instant-lighting charcoal, a biscuit tin and a load of wood (damned if I remember the name, but it's a good one - not willow or plum, but dead tall - curse my brain! EDIT: POPLAR, DAMMIT!) I liberated from the edges of the Curry's car park.

Edited by DrDerekDoctors, 29 May 2005 - 02:12 PM.

[seymour]

I too like liberating trees. I liberated a willow tree from the park . I got some rather odd looks But now I have willow to last me a long long time. ( willow is heavy the tree was like a Km from my house)

[newtoolsmith]

I use lead balls for BP and such explosive mixtures only. Of course to avoid sparks.

For all other millings I use steel cylinders (looking like barrels) out of ball bearings. They are from 1.3505 C-steel, are hardened and show no damage. These will last for ever and are very cheap (free) and available in dozens of kilos.

MfG
newtoolsmith

[fishy1]

I too like liberating trees. I liberated a willow tree from the park . I got some rather odd looks But now I have willow to last me a long long time. ( willow is heavy the tree was like a Km from my house)

i don't bother liberating trees anymore, i just wait until we get a nice strong wind (anything upwards of 100mph), and there's always 3 or 4 branches of good wood to be taken.

[seymour]

Yeah, we just had a Tropical Cyclone come through which gave me a few branches.

[al93535]

I use unhardened lead, I cast them myself. Sure there is some wear but I have been using them to mill BP, charcoal, and charcoal based star mixes for two years!! This is in a real mill, each milling session is 4 hours and I have been milling at least once a week, but sometimes almost straight for a week.

[Damp Squib]

While were on the subject I'd like to get a bearing of how hard other peoples lead media is,the cylinders I have cast are antimony hardened printers lead,I cant scratch them with my nail but they will write on a peice of paper this seems quite soft to me and has got me wondering how hard the alloy I have is.

So if anyone else has hardend lead media would you see if it will write on a peice of paper and let me know

cheers