272 replies to this topic

[fishy1]

what % of antimony is in hardened lead? just approximately, as i managed to get a fair bit of lead (soft) for free, and i can easily melt antimony and lead together.

[barra69]

what % of antimony is in hardened lead? just approximately, as i managed to get a fair bit of lead (soft) for free, and i can easily melt antimony and lead together.

If memory serves me correctly about 8 to 9% and about 3% tin to ensure a good pour. Thats what is used for casting hard lead bullets.

[Andrew]

4% Antomonial Lead is one of the standard alloys, this is suitable for milling media.

[pyrotrev]

I bought them anyway, and I will find some other use if not, but I am thinking of buying a rock tumbler to go with them from a place in Tideswell, Derbyshire

If you're thinking of the Beach tumbler, I would advise against it, I had to do a certain amount of modifications before the one I bought would mill stuff properly; maybe the little Evans one is better, the design looks more promising. Don at the Tideswell rock shop is a nice guy though, and very helpful.

[KNO3]

Hi, I am now planning on building my own ball mill and stop scrounging the use of one of my mates I just need a little bit of advice. I have some pure antimony and some pure tin, i just need some pure lead, would the best place to get that be roofing supplies and just pickup some lead sheet? I also would like to know what sort of sized media I should cast, and use what sort of tube/barrel and size, I only really want to mill 100g at a time, so would guttering drainpipes be suitable? or is that too small? And befor anybody questions how i am planning on doing this, i have access to a CAM Router (to make the moulds) a furnace, and a harth (with extractor) so I should be ok. Also, I have thought about trying brass media, and have decided that I want to try lead first, but i definetly will try brass next time I make any media, because if i just wanted to cut up some rod, i have access to various sizes of rod, and a hacksaw macine (pet named "Mr. Hacksaw" ) a lathe, and a CAD lathe (hmm parting tool) and if i want to make sperical brass media, i have the tools neccesarry to do that aswell, so I will definetly try brass, in due course. Thanks in advance for any advise you give

Edited by KNO3, 10 June 2006 - 05:32 PM.

[Mumbles]

A word of warning. You can't just add antimony to lead and expect them to alloy. You need to heat it up to a signifigantly higher temperature for them to alloy together.

[KNO3]

Thanks, I have done alloying before, tho am definetly no expert! I have a furness capable of 1000 degrees celsius, I assume that that would be acceptable? I also assume that the alloying process is the same with tin, I plan to break the metals up (antimony will just require some wacking with a hammer in a bag - very brittle) tins much more maleable so I think ill mealt it onlo a flat surface a then cut it up into pieces, same with lead. Then weigh them out, stick them in a large crucible, and stir them best i can, then stick them in the furness, what temp do you think I should go for? What I would also like to know is if guttering downpipes are suitable for a milling jar, and if so, what size media should be used in it? Thanks!

Edited by KNO3, 12 June 2006 - 08:44 PM.

[pyromaniac303]

If you're thinking of the Beach tumbler, I would advise against it, I had to do a certain amount of modifications before the one I bought would mill stuff properly; maybe the little Evans one is better, the design looks more promising. Don at the Tideswell rock shop is a nice guy though, and very helpful.

Sorry too late, already bought the Beach tumbler, but had not much trouble with it. The problem of the mill jar slipping against the rollers was fixed by just applying some large model aeroplane wing holding rubber bands to the mill jar, and have not had any other problems.

In 1 hour milling I got something much faster than I had ever got with a mortar and pestle. In 24 hours I had something that karl used as a break in a rocket header and he said it was ok. Also the break in the new payload rocket (worked this time!) video posted here was 3 hour milled balsa BP (very fast, and amazing stuff, would recommend anyone to try using balsa charcoal!).

I was just after a small mill to get me started and although it is low quality, it does the job well enough and seems to make a nice cheap mill for lazy people like me that would rather spend time making pyro than ball mills

Pictures from the shop are here . My free server has too many problems and is not even letting me log in now, so I couldn't upload the pictures I took onto it, going to have to just put up with the shop ones for now.

Even the lead fishing weights have had no problems, although I'm guessing there is a small amount of lead contamination in my BP. Does anyone know if this would cause much of a problem? Or is it just a case of me needing to replace them eventually?

[Mumbles]

I want to say it is around 700C for the antimony, but I am not sure. Tin is much easier to alloy. Another common practice is to mix the pure lead with 50/50 lead/tin solder. That alloys nearly instantly. You may need to flux the mixture though in order to clean it up. In fact, after you attempt to alloy it I suggest fluxing it to clean up anything that didn't alloy.

[KNO3]

I want to say it is around 700C for the antimony, but I am not sure. Tin is much easier to alloy. Another common practice is to mix the pure lead with 50/50 lead/tin solder. That alloys nearly instantly. You may need to flux the mixture though in order to clean it up. In fact, after you attempt to alloy it I suggest fluxing it to clean up anything that didn't alloy.

Sorry, i dont quite follow you, do you mean flux it to take away the impurities on the top, because i think that i can just skim it for that, otherwise i dont know what you mean, thanks!

[fishy1]

Sorry, i dont quite follow you, do you mean flux it to take away the impurities on the top, because i think that i can just skim it for that, otherwise i dont know what you mean, thanks!

Skimming it won't get them all out. For lead, I use beeswax. I drop a small piece on top, and it ignites. Stir it in (very important, you can use beeswax a few times to get it all out).

Skimming it without flux just gets some slag out, using flux makes it all collect and go to the top for easy skimming.

[KNO3]

Skimming it won't get them all out. For lead, I use beeswax. I drop a small piece on top, and it ignites. Stir it in (very important, you can use beeswax a few times to get it all out).

Skimming it without flux just gets some slag out, using flux makes it all collect and go to the top for easy skimming.

Ok, thaks, I will do that. Any impurities that are in there will come from the lead or any oxides that form, because my tin and antimony are 99.9+%. Cheers for the advice, although im starting to think that maybe i should just try brass rod first, and get my ball mill working befor trying more complex methds of making the media. I can get 110mm PVC tube, and i can get various sizes of brass rod, so what size rod would be acceptable?

Edited by KNO3, 17 June 2006 - 09:21 PM.

[Mumbles]

12mm ish would be good. I don't know the common sizes of rod in the UK, but something in the area.

[KNO3]

12mm ish would be good. I don't know the common sizes of rod in the UK, but something in the area.

Cheers!!! Ill get the closest to that. Cheers for the advice everybody!

[James P]

Just some advice.... I have been using 6 x 3/4" brass rods in a large rubber milling jar. The rods are just under the length on the jar so they just roll over each other. This has worked perfectly for me. PM if you want any more information.
Regards