Poll: Best mould material

[LeadThrower]

Wow, Cap'n. Fantastic! I now must wipe the drool from my keyboard.

I really find my brass mold from Mountain Molds to be a joy to use. My iron lymans are great, and Lee's 6 cavities make fine boolits, too. I voted brass for the corrosion resistance of Al with enhanced durability.

[leftiye]

Carbon, or some other mold material that doesn't conduct heat. Problem is that the material - straight graphite, doesn't hold together too well. If someone has knowledge of a heat impervious binder, this might be a great mold material.

[Cap'n Morgan]

Carbon, or some other mold material that doesn't conduct heat. Problem is that the material - straight graphite, doesn't hold together too well. If someone has knowledge of a heat impervious binder, this might be a great mold material.

The dense micro-grain graphite used for EDM sinking could no doubt be used for mold material, but apart from the obvious strength problem I'm not sure if it would be an advantage with a poor heat conduction material, at all. On one hand the mold would take longer before becoming too hot, on the other hand the bullets would also take longer to solidify.

The best[TM] solution would probably be a mold made of a material like Beryllium copper, which has extremely good thermal conductivity, and then keep the mold at an even temperature by hooking it up to a circulation system.

[leftiye]

Capn, I was looking at it the other way - mold temp would not be an issue with a non conducting material because once you got your lead temp high enough (and I don't think this would be much if any higher than normal), then the problem would be with the boolit cooling (just a matter of time). Once it was hot enough to fill out, it would be all dun. The mold would not cool the lead.

[Cap'n Morgan]

leftiye,

You may be right here. It could be interesting to do the experiment. Perhaps a simple drilled mono-block mold for a patched bullet - wouldn't be quite as fragile as a "normal" mold.

[azcoyhunter]

I have only used AL, but I would be worried about "rusting" the steel molds.

Brass would be nice I think as it would be tougher than AL, and not rust.

Just my 2 cents

[Marine Sgt 2111]

I have been using iron for 40 years and while it can rust, thats not a problem if you have a dremel tool, a brass brush for it and enough intellegence to know how to use said tool.

I have a single original winchester brass mold and like it fine, and have a dozen or so alum molds and they are ok...but if I buy Saeco, RCBS or other well made iron molds I can convert them to use on my auto caster.....

for what it's worth.....

[jimofaz]

Hi Guys.
"Steel" as a single poll choice can maybe be a bit of a mis-nomer when it comes to bullet mould material. Meehanite (brand name of a dense, fine grained cast iron with very few occlusions), 12L14 steel (leaded for smooth machining characteriscs), 1008/1010 CRS (low carbon cold rolled steel-gummy and cuts like crap for me), malleable iron, tool steels, generic cast iron, etc. ad-nauseaum have been used for mould making. I have had my best results with either brass or 12L14 steel for making lathe-bored moulds. The lead content of the 12L14 allows it to cut with a burr and chatter free finish, just like naval brass which also contains lead (I think). For holding size over a wide range of applied heat, it was just as good as meehanite having a low coefficient of expansion factor. No, I did not look that last up, but my experiences with mould making & using suggests that it is so. 12L14 allows the male alignment pins to stay put, and the cavities to remain right where I cut them, unlike some of the aluminum moulds I have made. To be fair to the guys favoring the lighter weight aluminum, I only played around with what was available to me at the time (about 25 years ago), that being fixture-grade bars of some un-remembered alloy. LBT & NEI are reputed know how to make a good mould out of aluminum, but I have no idea what grade of Al. they use.

Having done a bunch of mods to existing moulds over the years, the worst alloy for me to work with was meehanite (cast iron). That may have been my fault, being a quasi self-trained machinist and by no means an expert, but the boring cast iron or any sort left chatter marks and a rough finish. I expect my boring tool (right angle grooving and nose profiling spoons) condition, set-up, or speeds & feeds may have had something to do with that. Never had the finish problems with the other alloys though. Cast iron also cuts "dirty" for me, with lots of nasty graphite-like dust & small chip particles.
YMMV...jimofaz

[JIMinPHX]

jimof az,
I had wondered about using 12L14 (leadloy) for a mold. The stuff cuts so nice & finishes so well that it would seem a natural choice for making nice cavities. My concern was that since the alloy already contains some lead, that it might attract molten lead & the lead you pour into it might want to stick. If you can tell me from experience that this does not happen, then I will try to find some flat bar stock in that grade & give it a whirl. In the past, I've only seen leadloy in round bar. I'll have to look around to see if I can find it in flat.

As for Navy brass (alloy C46400), that's basically a 60/40 copper/zinc formula with a small pinch of tin thrown in. It can have up to 0.2% lead or it can be lead free depending on the specific batch. It is nice stuff to work with as long as you don't use tools with too much positive clearance angle. More info on Navy Brass below -
http://www.nbmmetals.com/downloads/NBM_C46400.pdf
http://www.alibaba.com/product-tp/10...ead_Free_.html
http://www.anchorbronze.com/c46400.htm

As for cast iron, any grade of that stuff is always a mess to work with. That black powder that comes off of it is hell on the bed ways too. It's real abrasive. It also dulls up the tools real quick. I stay away from that stuff whenever possible. If you do have to cut it, keep the speeds down & keep the tool tip radius small. I also try to keep a a good strong vacuum cleaner right up against the cutting tool. If you have any cutting lube in the process, the powdered chips tend to pack up & cause trouble. Sometimes I even cut that stuff dry because of chip control problems. That's an extra special kind of mess though.

[jimofaz]

Hi Jim in Phx.....I have had zero problems with either lead migration, pitting or sticky bullets when using 12L14. I believe I got my rectangular bar stock from McMaster-Carr, although it's been about 10 years. One caveat on 12-L14 however. I've mostly cut larger caliber moulds used for for BPCR. Why, I've even cut a mould very much like Cap/n Morgans .458-550, except mine was definitely not too pretty to use . These BPCR bullets are usually made with anywhere from 16-1, up to 40-1, lead to tin mix. I can only remember cutting one smokeless powder mould using 12L14, a 300 grain gas check number for a .35 Brown-Whelen. No problems casting with it using either wheel weights with a bit of tin adder, or linotype.

Thanks for the heads-up on naval brass. I have no idea what the pedigree was on the bar I scrounged from the shop where I worked about 25 years ago. Made for some very nice moulds howover.

I second your emotion on making moulds from cast iron of any sort. I too learned to slow the 4-jaw RPM's way down for best results. I cut it dry and also covered the ways with paper towels to keep that nasty dust from getting into where it was not wanted. Not being a trained machinist, I did not know about the small radius thing, so thanks for enlightening me. I was borrowing unused time after working hours or on Saturday's from our shop's Hardinge Toolroom lathe. Wish I had one in my garage now! The outfit I've been with for the last three years has lathes available, but they are huge production machines and not so user friendly.

BTW....that 3' bar of 12L14 set me back over $50 quite a few years ago. I've probably got a few sets of roughed out mould block halves left over in my tool chest you can have to play with before buyin' your own supply. I live in Chandler & work in Tempe if you want to hook up.

I'll also readily admit to having gotten very lazy with the whole business of making moulds from scratch. I've found it a whole lot easier to scrounge used Saeco or RCBS blocks (don't care to use any of the Lyman stuff at all!) in a smaller caliber and just re-cut those puppies in an hour or two per cavity. Beats spending approx. 10 hours of my un-trained labor to make 'em from raw bar stock!
Maybe someday I'll get back to it, but probably not until after I retire and get some chip-makin' machines of my very own to play with.
jimofaz

[JIMinPHX]

That's a mighty generous offer there Jim. I would like to grab just enough stock to make up one set of blocks to try out, but I'd feel much better about it if you would let me pay you the going rate for the material.

I think that I can get the production time on a set of blocks down below 10 hours. I was expecting more like 2 or maybe 3. I've got pretty good work habits & a few reasonably handy little fixtures to help me along. I have a bad habit of underestimating jobs, but I think that I can still keep it under 10 hours.

I do agree about the advantages of having a shot-out old mold in a smaller caliber to use as a starting point. That certainly is the best way to go. If someone like Lee would just sell me blank blocks with no cavities or handle pin holes in them, I'd never even consider making my own blocks from scratch.

I'll try to PM you towards the end of the week to see if we can set up some time for me to stop over & grab some of that leadloy off you.

Regards,
Jim

[JIMinPHX]

I see that Mr. Morgan has some of that fancy lettering software for his CNC machine. I also see that he does pretty nice looking stuff with brass.

My compliments to the Captain.

[405]

Of course I could go into all sorts of scientific and technical jargon about the absolute superiority of the iron mold but that'd just be a bunch of horse feathers

Reality is it's the only type I've ever used so don't confuse me

[Cap'n Morgan]

If someone like Lee would just sell me blank blocks with no cavities or handle pin holes in them, I'd never even consider making my own blocks from scratch.

Amen to that!

Sadly, a set of RCBS blanks is more than a hundred bucks at Midway.

[Old Ironsights]

I like my brass 2cav best, though I probably use my Iron Lyman 358156 more than any other.

The Lee's are OK, but there is just somthing about Brass...

[atr]

I like iron !!!!
my lyman molds have never failed me...
and Iron has a much lower rate of expansion / contraction (i.e. less prone to distortion) when compared to brass or aluminum

[JIMinPHX]

I've never noticed one to distort.

[shdwlkr]

most of my moulds are alum because of the cost but if I could i would have brass

[MakeMineA10mm]

Sorry to hijack Cat's thread, but can someone with some metalurgy knowledge shed some light on the following for me please??

1. Which type of aluminum is easy to machine (for custom-cut cavities), but "harder than Lee" - or more to the point - resilient enough to resist permanent damage if dropped?

2. Same question as #1, but about brass?

3. What is the commercial price difference between said type of aluminum and said type of brass (raw blocks - still need external machining and the bullet cavities cut)?


As an aside - I bought a bunch of Lee 6-cavity handles from Midway when they were on-sale, and I've been fitting them to all of my moulds. I had to drill-out the holes to fit them to my Saeco 315 4-cavity, and I noticed while doing so that the material those handles are made out of is incredibly soft. (Why should I have been surprised; they're cheap?!?) Anyone see this as a problem that needs fixed?

[Catshooter]

MM,

You have my official permission to hijack.

"resist permanent damage if dropped" Well, dropped is a pretty vaiable term, but, while no metalurgist, I can tell you from personal experience that the only thing will really resist damage well is hardened steel. All forms of brass & aluminum are very soft, and so is iron & steel. Even hardened steel will suffer from droping it on concrete.

Not sure what sort of answer you're looking for in question #3, but I can tell you that most brass is roughly three times the price of most aluminum. Brass machines easier than most aluminum. Brass chips are very small and don't tend to stick the cutter. Most aluminum, the chips are sort of sticky or gummy, sort of like lead but not that bad.

Aluminum likes to stick to the cutter, and that is particulary bad when you're trying to machine something like a boolit cavity, small, tight and with complex shapes needing high tolerances.

The reason I started this thread/poll was I'm sorta thinking of cutting some moulds. I like iron too, but I'm having a tough time finding some in a precision form. I don't want to spend alot of machine time truing the outside of the blocks. Brass is easy to find already trued and machines much nicer than aluminum, so I'm going with brass.


Cat