Choosing Mold Material

[GregLaROCHE]

I’m getting ready to order a couple of custom molds and was wondering how to choose the material. What are the advantages, not counting costs? Does it make a difference with the size of boolits you will be casting? If it’s a single, double or six cavities? Anything else to consider like heating up time or staying at the same temperature?

Thanks

[gwpercle]

Each material has it's pro's and con's .
What I'm going to say is based on my personal experiences over the last 50 + years . Let me also qualify that I pressure cast with a ladle from an open top pot . No bottom pour and no 6 cavity moulds . How you cast also determines what you cast with...I'm a pressure caster .

Weight can be a factor , depending on your age and hand, wrist arm and shoulder condition.
Aluminum 2 - 3 - and 4 cavity moulds start looking good when the age factor is thrown in.

Starting out , cost can be a big factor , I bought what I could afford . Lee and Lyman 1 and 2 cavity moulds . You didn't say if cost was an object.

Steel . I like steel moulds because they retain heat and are tough to damage. They must be protected from rust however but I still like them .

Brass is heavy , costs a little more , retains heat , no rust . I own only one brass mould , a double cavity , but do not cast extensively with it ... no gun for it's boolit !

Aluminum is light weight , doesn't rust and usually less costly . But it can be damaged if not treated with kid gloves and care must be taken with them .

I've aged and at this point in life prefer 3 cavity NOE aluminum moulds . The size and weight allow me a decently long casting session , excellent choice of design's , no rusting problems and I enjoy dealing with Al Nelson...nice guy , USA made products .

I still like 2 cavity steel Lyman and 1 -2 cavity aluminum Lee moulds .

When I started casting there was but one choice , a single cavity Lyman ...that's all the shop carried and all we could afford. My first 2 cavity was used !
Then Lee came out with $9.99 moulds with handles.....Oh me oh my !
Times were so much simpler back then !
Gary

[country gent]

There are several posts on this issue that are very thorough.

Heres my take and in the order I prefer.
Brass: Holds heat the best once hot and up to temp it stays there. No rusting other than iron steel parts. Brass machines very nicely and is durable. It is the heaviest of the mould materials. Seasoning the blocks when new helps get the mould up and running faster. I believe you can run a brass mould hotter before frosting occurs also.

Steel: ( cast Iron) Probably the most durable of the materials. cast well with little special attention Will frost and over heat faster. Coos faster than brass slower than aluminum. on med size blocks big bullets pace or cadence may need to be faster to maintain consistency. Will rust with out protection

Aluminum: depending on alloy aluminum can be soft and the most delicate of the materials. Cools out the quickest. May require a fast cadence to keep going good. Frosts and gets to hot faster. May need to smoke to get good castings. Only the iron parts risk rusting. Doesn't stand up to heavy handed handling

[bmortell]

I don't really consider anything besides aluminum anymore.

Steel, greasing and degreasing and waiting for it to get hot then holding a heavy mold and costs more to machine, I don't see much advantage, you can beat it up more but i don't throw my 100 dollar molds around, and it holds heat but I consider that bad cause i want to cast quickly.

brass is kinda in-between but still has half the negatives of steel, does look pretty tho and only slightly more money than aluminum atleast on some places, but the extra weight and low thermal conductivity is a negative to me.

as for the other questions i guess the larger the cavity and larger number of them, the more it will show the thermal conductivity of the mold material. say in theory you had a stainless mold with 6 500s&w cavity's in it, that thing would stay hot for a very long time and boolits wouldn't be ready to drop for a while even if you set it on a heat sink stainless just wont transfer temp quickly, so i suppose as weight of lead in the mold rises youd want to raise thermal conductivity also to keep things even, to me atleast, even with my 300gr cavity's in aluminum i still wish it cooled faster cause it slows my pace by maybe 20% compared to lighter boolits and i cant have same cadence for all boolits.

[MT Chambers]

I'll take steel or brass over aluminum every time. Aluminum damages easier, wears quicker, and heats too fast, frosting boolits.

[GregLaROCHE]

Do they make moulds out of stainless steel?

[Animal]

Somenone pointed out that the pros/cons of aluminum can depend on the alloy. Is there a significant difference between the alloys used by Lee and custom makers like NOE?

[hermans]

I agree with country gent, love my brass molds, but they are heavy. Steel is great too, but brass makes the most beautiful boolits.
For my very high volume pistol shooting, I use aluminum 8 cavity molds from MP, they also make good boolits, but you have to be very careful not to damage these molds since they are pretty soft.

[country gent]

Im not sure what alloy Lee is using. They say Aluminum but that's a pretty broad term when you get down to it. ( 60 - 70 - 80 series and all the variations in each). Have had a few lees moulds to re work and I found them soft to the point of being "gummy" when machining them. I cant remember which but noe or accurate gives the actual material designations for the materials their blocks are machined from. I think Old west does also. Once you have the actual number designation (alum 6062 EX) then you can look up its individual properties and tensile strengths.

There is a big reason for using softer materials in manufacturing its not always material cost but more tooling life. The cutters, drills, saw blades, and taps are expensive to buy or produce. ( AT one time lee machined close then swaged to final form and finish with a hardened steel slug). Making this tooling last as long as possible is a big benefit. A simple Cherry may have $10.00 of material in it but $500-$600.00 of man hours making hardening and finishing. On these tools the is a limited number of times they can be sharpened so extending each time 200-400 parts is a big savings. Harder materials reduce tooling life and on some getting the needed finish may require a second cutter.

[Burnt Fingers]

I've got two MP 6 cavity brass molds for 9mm. I love them to death. The weight isn't bad, they are a lot lighter than my four cavity Arsenal .40 cal mold.

I'll take brass or iron over aluminum every chance I get.

[GregLaROCHE]

From what I’m hearing, I’m leaning towards brass. If you’re buying a mould other than from Lee, the additional cost of brass doesn’t to be that much. I’m planning on two cavities, so weight shouldn’t be too much of a problem, however, one of the boolits will be around 500 grains.

Thanks for the info.

[country gent]

Like I stated brass is a very good mould and casts very consistent bullets. I like all of mine 2 singe cavity Old West and 3 double cavity Old West. One thing is to make a small platform from sheet metal up. make it about 1" tall above the bench and open underneath. A simple c shape to set the mould on when cooling after use or when reloading pot. Brass takes a lot longer to cool out and can be an issue at times if you aren't prepared for it. I have set the moulds down fluxed and skimmed pot and continued to cast good bullets with out any reheat. When casting with 2 moulds the aluminum or steel is cooled out way before the brass are.

[bangerjim]

I own darn near every aluminum mold LEE makes/made due to being very inexpensive at the time. The cast good boolits but are VERY easily damage and dinged up with just normal usage.

Also several 1 & 2 banger steel ones I have picked up over the years. Not a fan of steel, even though rust is never a problem here in the desert SW.

I only buy BRASS molds now. I have 10 of them and use them regularly to cast perfect boolits! I love the 4 and 5 banger hollow point molds! They hold heat better and can be run hotter. but are heavy and hard on the wrists and arms during a very long casting session. Still, I will never buy another aluminum or steel mold again.

And BRASS is puuuuurddy to look at!

banger

[Crash_Corrigan]

I have about 100 molds. Most are aluminum. Some Lee, NOE and a lot of Mihec's Slovenian creations. Mihec's 8 cavity 130 gr mold for 9 MM is a real gem. With that in one hand and a Lee six banger in 230 gr .452 LRN I can really empty a 22 lb RCBS Pro-Melt furnace pretty fast and get some very decent boolits besides.

I really like the aluminum molds for their light weight and excellent castability.

The steel molds are good because of their durability and excellent heat retention.

The brass molds produce the best looking and most correct sized boolits but they are a bear to use because of the weight.

I think I am about to stop buying molds cuz I have what I need now. Having 30+ firearms to feed keeps me pretty busy and I am simply not going to buy another different caliber although I have a wild thought about getting a .243 Remington for Coyotes as my CZ 527FS in .223 does really not have the reach past 150 yds that I yearn for.

[Petander]

I've become a brass fan,too. I often cast in a cool weather like 40's,door open. Can keep a nice pace with brass molds.

But aluminum can give very good bullets,too. I just weighed a bunch of 50 cal 405 bullets from Veral Smith's four cavity aluminum mold, all are within +/- 0,5 grains,that's kind of crazy good. Diameter doesn't vary at all,as if they all came from a one cavity mold.

[country gent]

I have never seen Stainless Steel mould, either for bullets or industry not saying they haven't been made. Most die cast dies are different tool steel same with injection moulds. Te throttle body infection moulds at work were almost all d-2. For bullet moulds brass steel aluminum nd in the early times sand stone limestone and maybe granite were used for moulds. I could be interested in trying a mould made from granite. Very fine grained, stable, and weight would be acceptable. Draw back is every thread would need to be an insert fitted in place. Also di to the hardness the blocks would be easily chipped with rough handling. But I believe with the addition of release angles on grease grooves and the right finish they would cast very good bullets.

[lotech]

I've used them all. A quality mould is just that; the material it's made of doesn't matter.

[HATCH]

steel or iron molds will last the longest. They are also the quickest ones to have issues should you not keep the maintained (oiled down)
I really like my brass MP molds.
The lee alum molds are ok.

I do all of my casting with a master caster so its strictly steel or iron for me no days.

[kevin c]

...For my very high volume pistol shooting, I use aluminum 8 cavity molds from MP, they also make good boolits, but you have to be very careful not to damage these molds since they are pretty soft...

This is my take on it. The aluminum 8 cav MP molds are what I need for the large number of boolits I shoot, but it is also a fact that I've already (noncritically) beat one up.

[Burnt Fingers]

This is my take on it. The aluminum 8 cav MP molds are what I need for the large number of boolits I shoot, but it is also a fact that I've already (noncritically) beat one up.

That's why I went with the six cavity brass.