Best Metal used in Moulds ?

[smokepolehall]

I know the iron will rust unless its kept coated n moisture free. Does the brass or alum. have any problems ?

[RogerDat]

Aluminum is not as hard so a little more prone to damage. More likely to get a ding from bumping or gouge the top with the steel sprue plate with mold made from aluminum. But it is lighter weight so less fatigue to cast with. Bit more rapid in temperature changes, cools faster, heats faster than iron or brass.

Which sort of balances out to my way of thinking. The slower change of temperature means easier to hold a certain temperature, but it takes more heat and time to get up to proper temperature. Brass can stick to cast metal that has lead and tin the way solder can be used to solder brass. Not a huge issue from what I understand, but one to consider learning about if one wants to use brass molds.

[Harter66]

Well aluminum is soft . It doesn't look like I will get much over 8-10,000 pours out of these Lee 6c or the NOE moulds I passed a few 2 C Lee's on when I bought the 6c sisters I had about 2,500-3000 pours on the old style 452 255 RF .
All mocking aside the sprue plates , handle screws and guide pins are steel in the aluminum moulds and require a little up keep . So far for me the 2 stroke oil for the sprue hinge is meeting that need . The aluminum moulds are typically an aircraft grade and corrosion resistant . I don't think they would fair well on a steel bench top where the cars drip water every morning but they are reasonably low maintenance .

Brass
I have no idea where I've been 2 months trying to get a brass mould up to some minimal level of casting patina on purpose and so far I'm not doing well . Frankly this is the most humid summer I remember since 76' . Of course I'm looking at wet in the context of 4" of precipitation per yr .

An issue that I am looking toward is dissimilar metal electrolysis when I move in a yr or so to a place where drought means they had less than 12" of rain per month . My concern is probably unfounded or there would be more discussion about the various moulds being stored separately to prevent stuck screws and such.

[country gent]

Mehanite cast iron is stable dosnt warp easily and durable. It is heavy and may rust with out proper care. Longevity is very good, probably the best of the 3 materials. It has been used for many years and machines easily with consistant results. Not a lot of issues with dissimilar metals expansion.
Brass is a good material and holds heat well making casting easier. Brass machines easily with little problems. While brass dosnt rust the sprue plate and other steel parts still need protection. Brass may need to be seasoned some to cast its best. Brass over heated may warp also. It is in the middle of the three materials as to durability.
Aluminum depending on the grade used is softest of the 3 materials and the lightest. On smaller bullets keeping a mould at temp may be hard due to dissipation. With large bullets over heating and frosting may become a problem. Again the Steel parts need protection even though the aluminum dosnt. With proper care and handling an aluminum mould may never wear out but a little heavy handed operations may destroy it quickly.
To me I prefer brass mehanite and then aluminum in that order, but it also depends on what the manufacturer offers for the bullet I want. Lees desighns are all aluminum, others may ofer brass aluminum or steel or all 3 even. Lyman Saeco rcbs offer mehanite only so the bullet wanted may designate the material also.

[David2011]

I've only used one brass mold and it was for black powder balls but it was the easiest casting mold I've ever used. Loved it. Of the molds I have I like using the cast iron and steel molds best. My aluminum molds are all Lee so I can't speak for the high end aluminum molds. It takes much more work to get the Lee molds to drop boolits than the steel and cast iron molds.

Aircraft grade aluminum? All aluminum is aircraft grade; it just may not be suitable for some aircraft uses. The fuel tanks in many fabric covered aircraft are made from aircraft grade 1100 aluminum - dead soft and essentially pure aluminum. It's not much good for anything else but by golly it's aircraft grade.

[Harter66]

My error . I should have been more specific about 6061 T6 aluminum being a specifically called out marked and utilized for aircraft structural and load bearing members . I probably should also point out that aircraft billet aluminum is manufactured to standards established prior to 1939 under Mil Standards , MS and AN . In turn making aircraft grade billet inferior in terms of modern manufacture .

I've pulled some cast lead ballast and counter balance fittings that would hardly pass for a poor casting .

[MT Chambers]

1. cast iron
2. brass
3. aluminum
4. Lee

[mac60]

1. cast iron
2. brass
3. aluminum
4. Lee

Yea, we get it already.

[DerekP Houston]

If I'm ordering custom molds I go for brass, just for the heat distribution and the even heating. Otherwise I've had no issues with rcbs iron and lee aluminum, each have their own learning curve though.

[jmort]

If you want the opinion of the best mold maker, Tom, at accurate, he prefers aluminum
I prefer aluminum
Get what you want
Enjoy

[JonB_in_Glencoe]

If you want the opinion of the best mold maker, Tom, at accurate, he prefers aluminum
I prefer aluminum
Get what you want
Enjoy

I gotta agree.
I like my aluminum molds the best.

[dragon813gt]

It's personal preference. I don't buy iron because I live in the rust belt. I buy brass from Miha because that's what he offers. I like brass but I know it will be to heavy when I'm older. Said I would never use aluminum after selling off all my Lee molds. Then I bought one from NOE and it's my preference at this point. The aluminum the custom makers use is a different, better, type than Lee uses.

All of the materials cast differently. It's up to you to figure out how to cast w/ them. The reason they won't cast lies in the person using them, not the mold. Unless we are talking about Lee molds. Then the mold could be junk.

[cuzinbruce]

Has anyone tried nickel? I believe Belding & Mull used to make molds from that?

[trapper9260]

I use all three type of molds. Like stated it depend on the maker.If it is between brass and AL I will go with brass because of it works best for me.But if it is only AL i will go with it just like I will go with Iron. They all work for me and take care of them to last for me.

[Lloyd Smale]

I like steal. the just seem to heat more uniformly and hold up much better then aluminum. brass is another good one but heats up a bit faster and is heavy. Aluminum is at the bottom. Yes you can cast bullets out of an aluminum mold. that said aluminum heats up even faster then brass and cools quicker too so you get more variation in heat. that and it is fragile and you have to cast carefully to not damage molds. I like steal. If you don't agree id suggest you try casting with something like a ballistic cast/H&G mold. Nothing casts nicer. If your worried about them rusting keep the mold box in the house instead of in the barn or do like I do. When I'm done casting and mold has cooled to "warm" I spray it with kroil or something similar. About once or twice a year I take out all the molds that have been sitting in the drawers and wipe them down and give them a fresh spray of kroil. Never had one rust doing that.

[Randy C]

I own all, and they all work for me, I like brass the best Its humid in my reloading room, there's less up keep for me, I have to wipe my presses down to keep them from rusting,

[DocSavage]

I have a mix of molds made from iron,brass and aluminum and have to admit I prefer aluminum. All but one of my Almonds are from NOE the other is from Accurate. There lighter there for longer casting sessions less fatigue,heat quickly and though I'm not casting hundreds of pounds of lead the blocks are holding up nicely.
With proper care there's no reason why an Al mold won't last a long,long time

[MT Chambers]

Yea, we get it already.

No, it never grows old.

[ikarus1]

I prefer to use lead or lead alloy IN my molds

[mac60]

No, it never grows old.

That depends on one's perspective.