Casting lead milling media: mould material and media shape

[deer]

Hi. I was hoping someone could give more specific directions exactly on the mould material and casting process.

 

Currently I’ve toyed around with plaster and concrete. It seems that plaster degrades quite quickly (1..2 casts), so I either need to prepare multiple moulds or one with many media slots. Both options have significant drawbacks (lack of reproducibility or large liquid lead volume).

Haven't heat tested concrete, but I hear it might do better - instead of disintegrating, just crack (which can be alleviated with some fine armature). But..

 

The thing is, I've considered both balls and cylpebs, but leaning towards cylpebs, because they could be cast in size, which if desired would fit and be pressed in copper tube for more durability. Now, while it's difficult to get smooth, round balls in concrete, getting cylplebs is a complete nightmare.

 

I was thinking, maybe you know a better mould material (less bubbling, heat resistance, no sand texture, no calcium residue etc) or should I just go with balls altogether. I was wondering if casting a long cylinder and then using e.g. heavy duty bolt cutters to make cylpebs would work?

 

P.S. I gathered several kilos of ~2..3mm lead shot I was thinking of melting into milling media. But reading some milling topics in here I learned that optimal media size is best for fast crushing to certain size after which it just sticks the powder back together and smaller media is needed to further refine the powder. Is it worth keeping these shot as very fine milling media or with lead and BP this size is not relevant?

[Arthur]

Sand is certainly the cheapest, the ball from roll on deodorants can make an ideal pattern. Probably the method used to make musket balls was a large, long set of pliers with a ball shaped hollow in the far end from the handles.

[Mumbles]

Cylpebs or cylinders are the easiest to make your own molds for. Most people using round balls, tend to just use commercial musket or buckshot molds. I have seen a couple made from plaster though.

 

There are some common, cheap solutions to this. In his book, Ball Milling Theory and Practice, Lloyd Sponenburgh uses little "cups" formed from aluminum foil rolled around a wooden dowel. These are placed into a tray of sand and filled with molten lead. After it's cooled a bit, he remelts the top to make a smooth surface. I've seen media made this way, and it comes out a little wrinkled occasionally, but quickly smooths itself out in the mill.

 

Alternatively, if you want a more permenant mold, you can drill holes into aluminum stock. Put a removable bottom on the mold, and you're good to go. Fill them, let them solidify and let them fall out or press them out. Lead doesn't bond to aluminum.

 

If you're going to put them into copper tubing anyway, you may want to consider just pouring the lead directly in. Once cool, pressing the overhanging lead will seal it in permanently.

 

I've tried casting long cylinders and cutting them to length. It's hard to cut lead than you might think, just because it's so soft. Bolt cutters may work, but I'd think it'd drastically deform the shape. I tried using a hack saw, and it sucked. The lead just smeared. There are probably better blades to use to make quicker work of it on a hacksaw or a bandsaw of some sort.

 

I've read some of the claims about needing small media to get extremely fine particles. Honestly, I don't know how true they are in practice. 1/2" or 3/4" media has worked great for everyone I know. I've used a smaller media (000 buckshot, about 8-9mm), and it does work great for making fine powders at a rapid pace. The problem is that as the media gets smaller, you lose crushing power for larger material since the media is lighter. I don't know that it was worth it since I had to pre-grind all of my materials. I'm not sure that 2.3mm media would be good for anything.

[calebkessinger]

I use a 12 hole .490 round ball mold right now. If you don't get your lead too hard they wear alright.. If you are trying to use straight linotype or the equivalent it's very hard on them.. I have a stack of worn out two hole molds and one pretty well destroyed 12 hole, Just broke out a nice shiny new one last week.. If you have a decent pot and get going good you can do a decent amount in a day.

[deer]

I'm trying to cheap out here, so no bulk metal stocks or commercial shot moulds. In the meanwhile I have 25kg of cement, lots of sand and few kg of plaster to experiment with as well as some wire I can use as improvised armature. ..now that I think of it I should try sieving sand to get better detail. Mould only needs to be enough permanent to do a test cast and a small batch. With multiple moulds every cast would be like a test.

 

Plasticine gives perfect ball templates (although fragile), but I'm having trouble with cylpebs - wood soaks up water, sheds lacquer and has other issues. Any idea for good and cheap cylpeb templates? My next option would be filling a 20mm PVC pieces with plasticine.

 

Also, not sure what to do with that darned calcium foam on top of concrete. Only option I see is casting both moulds as "top side", so bubbles and foam rise away from templates, like so:

Only problem, it would be much more difficult to produce such template and while ensuring alignment. Casting other side over first ensurer proper hole alignment, flush mating surfaces, compensation of any offset from ball center. Thus without paired moulds the template must be perfect. Also with cylpebs i'd need two of them and perfectly mirror-matched:

[MrB]

Fishing sinker molds. Costs peanuts, (I'd guess less then the cement approach would cost you, if you got to buy the stuff) but are a bit more cumbersome to work with then "real" ball molds. You get 3 sprouts of each ball, and you have to plug the ends, as well as clamp it together. On the upside, you get a few with every casting. But that does leave you with balls, and not the cylindrical stuff.

B!

[calebkessinger]

candlestick.... pour in, tap out..

doesn't get any cheaper than that.

[Arthur]

I've drilled holes in a piece of timber before now, it's a one shot mould because it chars with hot lead but it produces cylinders for the effort of drilling the holes.

[Arthur]

http://www.ebay.co.uk/itm/BALL-LEAD-SINKER-MOULD-FISHING-WEIGHT-MOULDS-/330828892935

 

Find these in your locality! Chose one that makes several of the same size of balls.

 

http://www.ebay.co.uk/itm/Antique-Lead-Musket-Ball-Mould-12mm-Diameter-marked-50-/161737088616

[deer]

That's the first thing I looked for - the demand is so low that shops just stock few retarded shapes and that's it.

Has anyone tried clay? IMHO it's meant to be heat resistant and allows quite fine detail and smoothness too.

[FrankRizzo]

 

I've tried casting long cylinders and cutting them to length. It's hard to cut lead than you might think, just because it's so soft. Bolt cutters may work, but I'd think it'd drastically deform the shape. I tried using a hack saw, and it sucked. The lead just smeared. There are probably better blades to use to make quicker work of it on a hacksaw or a bandsaw of some sort.

 

Fiskers loppers work very well to cut lead cylinders from a cast "rod". I've used this particular one with no problems.

 

http://www.amazon.com/Fiskars-PowerGear-Bypass-Lopper-96256935J/dp/B0000950Q2/

 

Edited June 23, 2015 by FrankRizzo

[Arthur]

If you want cylinders then just drill 100 1/2" holes in a piece of timber and pour them all full of lead. If you want balls then keep looking for a mould that makes spheres for fishing weights.

 

Quite seriously fine greensand is best for casting, make a pattern for say 10 balls then cast it several times til you have enough (and some over)!

[deer]

Is there something like a guide for the wood-cylinder casting method (wood type, hole depth vs actual cylpeb length, tips for smoother finish etc)? Because googling for one didn't gave me anything. Or that's basically there is - drill, pour, quench?

 

P.S. Just tried making mould with clay. I don't know what and how the sculptors use but the powdered one at home depot for chimney masonry doesn’t work. Basically it shrinks and cracks while drying - either the plasticine ball gets squeezed outwards, or breaks it's slot apart. Also without burning, it's quite fragile when simply dried.

Edited July 5, 2015 by deer

[schroedinger]

I've used gypsum some years ago for making fishing sinkers. It worked like a charm and even after 10 casts i had no cracking. Just make sure that you dry it proper and before the first use heat it in the oven for about 1 hour at 100 ºC and 1 hour at 200. Now cast into the preheated mould

 

For making the mould just cast the gypsum in a plastick container and add your template until it is half inside the mass. Let dry and cover with vasoline, and add more gypsum.

 

During the first step it is good to take two sticks and insert them to form alignment points. If your make a ball shaped form, do not forget about a venting hole.

 

But after all i wouldn't do it again, specially since i pay about 8 $ for a 12 mm 8 ball fishing sinker mould at a local store.

[FlaMtnBkr]

As Caleb said, a candlestick holder works great. It's what I used many years ago when I couldn't find anything and didn't want to invest in a mold.

 

It is slightly tapered and about as long as it is wide which is about perfect. I filled it, let it harden, and then turned it over into a big bucket of ice water. You will have to change the ice water quite often if you want to cool it as fast as possible as it heats up fast. I was able to do 30# one at a time in just a few hours one afternoon.

 

I also got a brass candle stick holder for 50 cents at a goodwill store and they had tons of different sizes to choose from.

 

Also, when they harden they usually pull in a little simple because the metal contracts as it cools and it pulls a little molten metal in to fill that space. If you take a torch and make a few passes it will melt the end and fill the dimple and sort of round the whole end. If you want to minimize warming the lead back up stand the cylinder up in a tray of water with just the very end exposed.

 

Or buy some already made lead spheres from Caleb which will likely be much harder and a higher end product than what you and I are able to make.

[deer]

Now it seems that the best option would be going with wood drilled cast cylinders.

 

Since I’m trying to cheap out and don't have exactly 1/2" (12mm) drill, what would be better, going smaller or bigger?

Closest options I have are the following:

10mm round wood drill (A) - nice hole with small centering pin, would fit 12mm copper tube with 1mm walls. Might need mould patching or media finishing.

16mm flat wood drill ( - very big centering pin and rough end surface, that would probably need some patching in each drill hole, would fit 18mm pipe with 1mm walls.

18mm forstner drill © - very smooth hole with minimal centring pin depression, doesn't fit any of the standard copper pipes, but the size would ensure longer life on it's own.

 

 

I'm kinda thinking if I can crush and coffee grind everything to rough powder, smaller size would be better for finer end result, but I'm afraid pouring in 10mm wood holes might make very inconsistent and many defective results.

 

Also, are wood moulds totally single use or I can maybe get 2..3 pours out of one plank? How close should I space the holes so that they don’t burn trough or otherwise degrade due to lack of structure? One hole distance apart or can they be closer?

 

TL;DR; Will do wood cylinder mould. Don't have 12mm drill. What's better alternative, 10 or 18mm? How much space should I leave between holes?

Edited July 11, 2015 by deer

[carbonhalo]

I stick 1m lengths of copper or aluminium tubing in a bucket of sand and fill them. Cut with hacksaw and file the ends smooth.

Ideally the lead has to be very hot or the tubing heated to prevent it setting 1/2 way down the tube.

With the aluminium tubing some of the lead slugs may drift off centre before the tumbling acting crimps them in, leaving a cup at one end.

[Mumbles]

What size of mill are you making the media for?

[deer]

Small one - 12cm diameter and 14cm length = ~4.7x5.5 inches (largest gray PVC connection piece with matching caps - D110):

http://www.tet.lv/ProductImages/28882.JPG + http://santehnikasparadize.lv/veikals/image/cache/data/big/big/19172732112930-228x228.jpg

If everything works as expected, I might get something like this later: http://www.inoxia.co.uk/products/ball-mill/jars/ball-mill-jar-1-3-litre (the biggest one).

 

carbonhalo - the copper is just an option if I find my lead too soft (e.g. it starts embedding too much material and wears, staining the material). Only then I'll buy the piping and simply press the cylpebs in it. This way 14mm would be perfect, to provide some margin for wear down to 13.6mm pipe I.D. With 10 and 16 I have to make prolonged cylinders, so that compressing them fills up the pipe.

[Arthur]

Ebay will find you a mould for multiple lead fishing weights. Some are mixed sizes but I'd rather have one mould with several holes all the same size. Melt lead and pour into mould, wait 2 minutes than use pliers to immerse in water, when cool remove lead balls and start again. Treat the mould as if it's HOT at all times, make sure that molten metal cannot spill on you, it's HOT and burned skin stinks horrid.

 

http://www.ebay.co.uk/itm/BALL-LEAD-SINKER-MOULD-FISHING-WEIGHT-MOULDS-/330828892935?

 

Find these on ebay in your country. One mould makes several balls of the same size.

Edited July 12, 2015 by Arthur

[chuckufarley]

Hi,

I found this thread while reasearching how to cast my own milling media. I'm going to try Portland cement or castable refractory mortor for a multiple cavity mold (12-24 1\2" balls). I plan on useing linotype, or 3-5% antimony lead alloy for the media. My question is, do i have to worry about fluxing the lead during the melting process to reincorperate the alloying metals (tin, antimony)as they oxidize? Has anyone had an issue with excessive oxides forming, possibly removing the alloying metals from the lead by skimming them off? or am im over thinking this?

 

Thank you.

[MrB]

It is supposedly a common problem for bullet casters, so i guess it depends on how many times you intend to collect, and melt the media to cast it again. I read a bunch on the topic, and it seams that sawdust is actually one of the better "fluxes" one can use, but what really makes a difference is using a melting pot with a bottom spout. It lets you leave what ever flux you use floating on top, not disturbing the surface while you cast, and as such limits the formation of new oxide.

 

Good luck.

B!

[schroedinger]

A good mold is made out aluminium or iron. A mold out of cement won't hold up many casts.

 

Also it doesn't save you anything, visit your next fishing store and ask for casting moulds, you only need the cheap ball sinker mould, they start at 10 bucks for mould with 6-8 cavitys (depending on the size you need).

 

Also with lead you want round shape or to fill brass/copper tubing cut offs. Anything else wears to fast.

 

For melting a lee melting station is the best and cleanest to work with.

[calebkessinger]

I use a 12 hole aluminum mold now. I made a couple thousand pounds with 2 hole molds before switching to one of these.

I just use a bottom pour pot, and do a lot of pre-mixing of the mixture so fluxing isn't much of an issue by the time I get it in that pot.

Lot's of wax on the molds during use helps them last, 2 hole molds lasted me a couple hundred lbs of lead before being worn out. One of those will do 1000 lbs before it has to be replaced. If you are truly using a linotype mixture of good hardness molds wear way faster than just soft lead.

 

 

Check out the store @

woodysrocks.com

[chuckufarley]

Thanks for the replys,

I've read a bunch on the bullet casting posts as well. There seems to be a divide on flux or not flux.

 

I do plan on using a bottom pour ladle. Also the lead im using will be (should be) clean. Maybe having the flux layer on top would help oxides from forming? It's a good thought.

 

I know the molds may not hold up very long but I do a lot of mold making (fiberglass mostly) so i wanted to give it a try (thanks for the advice though). I also have looked at those pouring stations. They look sweet i might have to try one of those.