38 replies to this topic

[littlejohny]

The lead sinkers will cost a fortune It is going to cost me about $70 to correctly fill a 55mm ID pvc pipe thats about 3/4 foot long. I think it will be alot easyer to buy a mould and cast my own, I won't have to buy the lead I've got alot of huge deep sea sinkers wich will make about 7 lead balls each:)

[Damp Squib]

Unless the lead is antimony hardened you may end up wasting your time as it wont be hard enough for the mill without causing contamination of your comp,the lead I have aquired is antimony hardened printers lead from a friend,I can scratch the surface with my nail and it wont leave a mark,if I press down hard on a peice of paper though it will draw a line which gives me concern toward contamination

I'd love to know if other members antimony hardended lead will write on peice of paper?

you could try sourcing some antimony and harden the the lead yourself,half a pound of the alloy melted easily for me on an electric hob on 2\3 power so no special equipment is required,I also have a really simple way of casting perfect cylinders which I will go into once you get to that stage

[littlejohny]

Unless the lead is antimony hardened you may end up wasting your time as it wont be hard enough for the mill without causing contamination of your comp,the lead I have aquired is antimony hardened printers lead from a friend,I can scratch the surface with my nail and it wont leave a mark,if I press down hard on a peice of paper though it will draw a line which gives me concern toward contamination

whats so bad about BP having small amounts of lead in it

[Tim]

If sinkers cost too much then i found out today that our school manual arts store room has lots of brass rods. I am in an extention class because im good and we get to use whatever we want from there. So i'll design something that need brass rod and ill keep some and saw it down. I'm not 100% sure its brass rod.....but its gold coloured and im pretty sure copper is brownish.

But sinkers from crazy clarks would be like $1 for a pack of 8. And ive got a 3 inch OD jar. Hopefully wont be too much.

[Damp Squib]

whats so bad about BP having small amounts of lead in it

Its a personal preference really,the smoke from your BP will be have lead fumes in,the outside of my motors often get black from BP and therefore so do my hands,as I'm sure everyone has pulled the odd black bogie from their nose

Lead isnt like cyanide you wont foam at the mouth if poisoned,it acculmulates slowly in your bloodstream over time you may never know you have lead poising in your lifetime even though you may have some of the symptoms

http://www.nlm.nih.g...icle/002473.htm

heavy metals

http://www.lenntech....eavy-metals.htm

How long does it take for lead to leave the bloodstream?

http://www.mass.gov/...ead_hlthhaz.htm

So whatever lead you absorb through your fingers or worse as fumes from your BP or Airfloat meal will be in your teeth and bones for the next ten years poisoning you

Food for thought

[littlejohny]

Alright after reading all those I get your point

I went into big W today and was surprised at how cheap the sinkers where, for 64 1cm lead sinkers it costs $5 so its now only going to cost me about $10 for my media.

[littlejohny]

Yay I found a motor that is more than enough to power my mill.

specs
RPM: 935
HP: 1/3
Amps: 3.7
Rating: Continous
Size: bloody huge
Weight: 10kg

Should be more than enough for my small mill, while I am using my small mill I will slowly be building another mill that is bigger and better

Edited by littlejohny, 15 February 2006 - 09:12 AM.

[littlejohny]

this ball mill is really starting to irritate me . I was thinking I might have been able to get out of this reasonably cheap. My problem is the belts and pulleys I can only find the large type of belts and the really really small type, I need a pulley for a 5/16 inch shaft wich I have found for $20 RIP-OFF but my motor has a shaft wich is about 1.5cm wide which I can not find one to suit the pulley for the 5/16. does anyone know a website in aus that I could buy belts and pulleys from.

any help would be much appreciated, thanks

[Amleth]

Alright after reading all those I get your point

I went into big W today and was surprised at how cheap the sinkers where, for 64 1cm lead sinkers it costs $5 so its now only going to cost me about $10 for my media.

Yikes, how small is your mill? You need to be able to fill half the volume of your jar with media, and 128 1cm sinkers fills three-fifths of sod-all. 1cm media is pretty damn small, too. A puddle of those things rolling around in the bottom of a sensibly sized jar would mill ungodly slow, if at all. Have you read the ball mill construction thread?

Plus sinkers fill up with comp in their holes or splits and are a bitch to clean, not to mention re-introducing some of that (often unmilled) comp back into the milled stuff when you screen the media out...

Were you aware that you can get a pack of a hundred 0.499" or 0.575" black powder rifle balls for $10? That'll fill up a lot more volume than 128 piddly 1cm sinkers, for the same price, and be more efficient. Look up the Green River Rifle works in South Australia. They'll ship interstate.

You'll probably need several packs, though. About 350 of the 0.575" balls fill up a litre (and closer to 400 of the 0.499" ones, but the 0.575" ones are the better option since they're the same price, fill more volume, and will last longer, since lead media will shrink with wear over time). Sure, you can make 'em yourself a lot cheaper, but if you value your time at all, somewhere around the fiftieth casting you'll wish you'd just bought the damn things... IIRC, there's a 10% discount for orders over 500 balls, so getting enough for more than one jar is probably a good idea if you can afford it. I got 800 of the 0.575" ones for about $110, including shipping, and that was with a courier, too.

Also, think about editing existing posts to add new info where you haven't had a reply rather than creating a whole new post (or three in this case)...

[littlejohny]

Also, think about editing existing posts to add new info where you haven't had a reply rather than creating a whole new post (or three in this case)...

I did that, except no one would know that I have posted something new so I went back and made another post.

Yikes, how small is your mill? You need to be able to fill half the volume of your jar with media, and 128 1cm sinkers fills three-fifths of sod-all. 1cm media is pretty damn small, too. A puddle of those things rolling around in the bottom of a sensibly sized jar would mill ungodly slow, if at all. Have you read the ball mill construction thread?

the size of my mill is 3inch PVC pipe thats about 3/4 of a foot long, yes I know its small but I 'm only experimenting to start with, as for the size of the sinkers I thought that was an allright size I figured going to big they wouldn't tumble as well in the mill, about the ball mill construction thread I was kinda detered by having to read through about 25 pages of info.

Plus sinkers fill up with comp in their holes or splits and are a bitch to clean, not to mention re-introducing some of that (often unmilled) comp back into the milled stuff when you screen the media out...

the sinkers I am/was going to get had very small holes throught the centre,

well thanks for your reply

[Amleth]

I did that, except no one would know that I have posted something new so I went back and made another post.

People will notice. You don't need to bump the thread every few days until someone replies.

the size of my mill is 3inch PVC pipe thats about 3/4 of a foot long, yes I know its small but I 'm only experimenting to start with, as for the size of the sinkers I thought that was an allright size I figured going to big they wouldn't tumble as well in the mill,

So your jar is pretty damn close to a litre in volume, and you need roughly 500ml of media for it. Even if we naively assume the 128 1cm ball sinkers are stacked in a perfect cubic grid arrangement (in which they take up the maximum volume possible), they'll still only fill 128cm^3, or 128ml. So, even in the case of a perfect balancing-act arrangment you'd still need at least four times as many to hit the approximate 500ml mark (i.e, $40 worth). In reality they'd collapse into a somewhat smaller volume so you'd need even more still.

Spheres filling a given volume contain about 1/5 empty space, IIRC, so work out how many 1cm balls take up 400ml and you have a good estimate to buy. (I'll save you the time; it's about 764, so 12 packets = $60 worth)

And then they'd be crap anyway. The small size would impact you milling efficiency due to the smaller mass (especially in such a small jar), and the holes would fill up with crap and cross-contaminate batches of comp.

$20AU + shipping'd get you 200 0.575" rifle balls that should do fine for your jar...

about the ball mill construction thread I was kinda detered by having to read through about 25 pages of info.

It's better to sift through all that info and get a good mill than find out you've wasted your time building the wrong thing. Plus, people tend to get annoyed when you ask the same questions that've been already been asked (and answered) a thousand times before, especially when you self-admittedly didn't want to read through a thread that contains all the answers to those questions (often several times over), because it was "too long"...

Plus, this thread has was meant to be about motor electronics, but has degenerated into ball mill construction anyway. Rather than reinventing the wheel, just go read the ball-mill thread. It's packed with good information.

the sinkers I am/was going to get had very small holes throught the centre,

well thanks for your reply

So, still getting sinkers?

[littlejohny]

Allright I see your point i'll go and read the thread sighs ,

And then they'd be crap anyway. The small size would impact you milling efficiency due to the smaller mass (especially in such a small jar), and the holes would fill up with crap and cross-contaminate batches of comp.

I read somewhere "I think" that smaller milling media will give you finer powder than larger media but it will take alot longer to mill, is this true.

Plus, people tend to get annoyed when you ask the same questions that've been already been asked (and answered) a thousand times before, especially when you self-admittedly didn't want to read through a thread that contains all the answers to those questions (often several times over), because it was "too long"...

Ouch sorry!!

EDIT

Allright after skimming throught the ball mill construction thread I found some usefull infomation,

for media I was thinking of using copper pipe with lead cast down the centre, do you think this would be allright, although I think there is a very low chance of it sparking .

I also managed to work out the right gearing from burlhouses post well atleast I think I did

The motor shaft is 1/2 inch, the speed of the motor is 935 rpm i'm reducing this down to 75 rpm, In the end the roller shaft has to spin at 288 rpm meaning a 3.22 reduction.
So I need to get a 1.6 inch pulley, not to good at maths so can some one tell me if thats correct

Edited by littlejohny, 17 February 2006 - 12:14 PM.

[Damp Squib]

I read somewhere "I think" that smaller milling media will give you finer powder than larger media but it will take alot longer to mill, is this true.

In my experience it depends what your milling,larger media has less chance of repeatedly milling the same parts of the compound but the force acting upon the compound when milled is much greater-good for milling metals,smaller media will have much more active milling area but less force acting on the given area good for pure soft chemicals such as nitrate,the first mill I made over five years ago used some 11cm drain pipe with small light marble pebble media,it did quite a good job of milling charcoal to airfloat,I didnt mill BP in it though so I cant say how good small light media is for blending compounds

for media I was thinking of using copper pipe with lead cast down the centre, do you think this would be allright, although I think there is a very low chance of it sparking .

I guess you really dont wanna buy those lead balls ,I aint tried it but you will have copper edges rubbing against the lead centres which will grind the lead out,the lead can also fall out from the centre after repeated hits in the mill,when I tried using copper for BP the media reacted with the BP and discoloured after only one run

If you wanna cast your own lead cylinders just get a peice of thin mild steel tube "like on a cheap deckchair"the length and width of the lead cylinder you would like mine were about 1\2 inch by 1\2 inch which gave a roughly a 25gram lead cylinder,sandpaper the weld ridge from the inside or dremel it out as I did,take the mould and press it down into some soft wood,I used balsa,you wanna press it down so the bottom of the tube cuts a groove in the wood this will stop the lead leaking out the bottom,twisting also helps the mould cut into the wood

pour the melted lead into the mould almost to the top,if you over fill the mould and the surface tension of the lead is bulging out the top, push a screwdriver into the lead so it spills over the edge onto the wood,once cooled the spilt lead can be thrown back into the pot,the wood after a few runs may start to blacken with the heat so just press the mold into a different part of the wood,

note the wood or mould musnt be wet at all or the lead gets spat everywhere

Next step is to make the edge of the cast smooth I did this by heating the top up with a blowtorch "I use my gas soldering iron with the tip removed",the surface tension as the lead is melted will give the end a perfect smooth finish,leave for a few secs until the lead has set but not fully cooled flip the mold and cast over with a pair of pliers the-bottom will be flat and rough due to being in contact with the wood and blowtorch the other side again the surface tension as the lead is melted will pull the lead into a perfect semi sphere

let it cool for 20 secs or so and dump it into some ice cold water this will also slightly temper harden the lead the cast should then just pop out of the mold easily with your finger,dry it with some tissue and press the mold back down into the wood ready for the next run,if you get two molds on the go you can have 100 'perfect'cylinders cast in a couple of hours

I used this method as I had antimony hardened printers lead on hand for free justa suggestion

[littlejohny]

I guess you really dont wanna buy those lead balls ,I aint tried it but you will have copper edges rubbing against the lead centres which will grind the lead out,the lead can also fall out from the centre after repeated hits in the mill,when I tried using copper for BP the media reacted with the BP and discoloured after only one run

I can't win

If you wanna cast your own lead cylinders just get a peice of thin mild steel tube "like on a cheap deckchair"the length and width of the lead cylinder you would like mine were about 1\2 inch by 1\2 inch which gave a roughly a 25gram lead cylinder,sandpaper the weld ridge from the inside or dremel it out as I did,take the mould and press it down into some soft wood,I used balsa,you wanna press it down so the bottom of the tube cuts a groove in the wood this will stop the lead leaking out the bottom,twisting also helps the mould cut into the wood

pour the melted lead into the mould almost to the top,if you over fill the mould and the surface tension of the lead is bulging out the top, push a screwdriver into the lead so it spills over the edge onto the wood,once cooled the spilt lead can be thrown back into the pot,the wood after a few runs may start to blacken with the heat so just press the mold into a different part of the wood,

note the wood or mould musnt be wet at all or the lead gets spat everywhere

Next step is to make the edge of the cast smooth I did this by heating the top up with a blowtorch "I use my gas soldering iron with the tip removed",the surface tension as the lead is melted will give the end a perfect smooth finish,leave for a few secs until the lead has set but not fully cooled flip the mold and cast over with a pair of pliers the-bottom will be flat and rough due to being in contact with the wood and blowtorch the other side again the surface tension as the lead is melted will pull the lead into a perfect semi sphere

let it cool for 20 secs or so and dump it into some ice cold water this will also slightly temper harden the lead the cast should then just pop out of the mold easily with your finger,dry it with some tissue and press the mold back down into the wood ready for the next run,if you get two molds on the go you can have 100 'perfect'cylinders cast in a couple of hours

I used this method as I had antimony hardened printers lead on hand for free justa suggestion

that would take along time, Hmm, My mother has some lead printing plates, Although I don't think there is anyway I'm going to get them, "she likes to collect old things" Thanks for that anyway.

Edited by littlejohny, 18 February 2006 - 03:45 AM.

[Damp Squib]

Other members have used copper tube filled with lead with some success the afore mentioned probs still occurred though,go with the lead balls I was prolly being a little over paranoid with the lead poisoning sorry ,its what most other members use

I find one of the fun things in pyro is finding ways round problems with what resources you have,its also the most frustrating