I want to try a mold made of something other than aluminum...so, iron or brass?

I have an aluminum mold made by Accurate. It's a very nice mold, but I have found that the needed casting pace is faster than I'm comfortable with.

I want to try a different material next time. Next mold I order is going to be a 147gr 9mm mold, and I'm trying to decide between brass and iron. Brass strikes me as fragile; it easily tins and warps. Iron/steel seems like a better choice, with the exception that they rust.

To mitigate rust issues, would I be OK storing an iron mold in an ammo can with dessicant in it? Aside from that, what kind of casting pace could I expect to need to maintain with a 4 cavity iron mold? I found that aluminum makes me go faster than I want; I suspect brass would about fit my pace, but there are too many horror stories of warpage and tinning for me to be excited about them, unless someone can convince me otherwise. A good 10 seconds between casts is my comfort zone, FWIW. I will probably get a 4 cavity mold...the weight should be good for me :bigsmyl2:

Getting it out up front, I do not have a hot plate for preheating molds, also no access to any metal coffee cans (which aren't made anymore) to create a makeshift preheating oven. I have no intention of buying one either, because I already can't keep all my tools organized nicely on my workbench, so no additions are going to be made. Any preheating I do is going to be done by dipping the corner of the mold in the melted lead, or not at all and just go straight to casting to get the mold up to temperature. My perception is that brass molds don't react well to this sort of treatment whereas Aluminum and Iron really don't care.

I have several Brass moulds all by old west moulds. Bernie Roweles does an excellent job on them. They cast like a dream come true. Brass heats very evenly and holds heat well. It runs good for me. Several things that help with reducing tinning Before casting heat cycle the clean blocks to 400* or so 3-4 times. This helps develop the patania that old moulds have. This patains aids bullet release and reduces tinning. The draw back in brass is large mould blocks are heavier. Brass is more durable than most aluminums, rust isn't a problem other than sprue plates and pins. I think as far as temps and cadence brass is the more forgiving material.

I use several aluminium molds and have no problem with a casting pace. I've 1 brass mold from Mihec and other than it being heavier than iron or aluminium no problems casting with it. As far as iron goes rust might be a problem but that can be eliminated by a light coat of oil on the mold when you put it away or get some small silica gel packs to place in the storage box. As far as preheating I just put the block on the top of my pot to heat it.

I never had the problem of casting faster with aluminum molds. I usually have to slow down because they get too hot.

I have all 3 types from .172 to .460. The .172 AL you can't cast fast enough with those as they loose their heat too fast to get total fill out so you need a hot plate or dipping every cast. I find that if you go too fast with the brass moulds they get too hot and you begin to get grainy frosting so either have to slow down (2 cycles/ min) or have a damp rag to keep them the right temp. Once I get 2 of them to temp I begin to use 2 moulds to keep them cooler. But I'll tell you don't case Mehi 410640's and Mehi 432640's cause sometimes it is very hard to push a 432 thru a 410 sizer. I love my old Lyman and RCBS iron single and double cavity moulds. They make pretty boolits every time and about 4 cycles per minuet will keep them happy.

I have some wonderful aluminum molds from NOE, Accurate, Arsenal and Lee I also have several Lyman molds that I've had for aver 50 years. In my opinion rust is is no more an issue with iron molds than letting your weapons rust.

Well try iron out, I think you need to find out the difference.

If I had to pick one mould material it would be iron. I have moulds made of all three materials and they all work just fine but I like iron the best.

I am not understanding why people worry about iron moulds rusting. I oil mine after use and have no problems simply wiping them down, pre-heating and casting next time.

Having said that aluminum and brass moulds both have steel sprue plates and a rusty sprue plate will ruin the tops of both brass or aluminum moulds so what's the difference? you have to protect iron and steel parts by oiling or storing in a dry place/with desiccant anyway if you don't want a rusty mould.

Longbow

I feel about the same way Longbow does. Iron has always been my favorite material.

Iron is easier to cast with but alum. works if you play with it. If you are having problems with heat loss try raising the pot temp. and casting in a warmer area (portable heater) it will help.

The biggest thing I have learned is every mold is different. One aluminum mold may cast great at one temperature and one with larger or more cavities may like another temperature. Same with iron. It is about finding a temperature and pace that each one likes. Write it down and store it with the mold for next use. My two favorite molds are a .314 SWC aluminum mold by Lee and an old 3118 iron mold by Ideal. Both cast perfect boolits every time. I just have to adjust my rhythm and temps to suite them.
SPJ

Iron kept in a controlled environment house (Heat/ac) have not rusted for me, and I don't do anything particular to prevent it, simply sitting on a bookshelf in the house. Her in Hampton Roads leaving them outside would guarantee rust!

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Originally Posted by DocSavage

I use several aluminium molds and have no problem with a casting pace. I've 1 brass mold from Mihec and other than it being heavier than iron or aluminium no problems casting with it. As far as iron goes rust might be a problem but that can be eliminated by a light coat of oil on the mold when you put it away or get some small silica gel packs to place in the storage box. As far as preheating I just put the block on the top of my pot to heat it.

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I'm sure aluminum makes for a fine casting pace for you, but I don't care for it.

I am not going to spend the time and aggravation oiling iron/steel molds after every use then scrubbing them before every use. It already takes long enough to get the whole casting setup up and running with the limited time I usually have, and I'm not adding more to that process...that's just more mickey mouse than I'm willing to put up with at this juncture. If there is a method to reliably store iron/steel molds without rusting that doesn't involve this level of maintenance, I'll be happy to use them, but this scrub then oil every single time business is not going to happen.

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Originally Posted by Minerat

I have all 3 types from .172 to .460. The .172 AL you can't cast fast enough with those as they loose their heat too fast to get total fill out so you need a hot plate or dipping every cast. I find that if you go too fast with the brass moulds they get too hot and you begin to get grainy frosting so either have to slow down (2 cycles/ min) or have a damp rag to keep them the right temp. Once I get 2 of them to temp I begin to use 2 moulds to keep them cooler. But I'll tell you don't case Mehi 410640's and Mehi 432640's cause sometimes it is very hard to push a 432 thru a 410 sizer. I love my old Lyman and RCBS iron single and double cavity moulds. They make pretty boolits every time and about 4 cycles per minuet will keep them happy.

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4 cycles per minute is probably really close to my comfort zone. I'm thinking iron is going to be more my "speed."

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Originally Posted by longbow

If I had to pick one mould material it would be iron. I have moulds made of all three materials and they all work just fine but I like iron the best.

I am not understanding why people worry about iron moulds rusting. I oil mine after use and have no problems simply wiping them down, pre-heating and casting next time.

Having said that aluminum and brass moulds both have steel sprue plates and a rusty sprue plate will ruin the tops of both brass or aluminum moulds so what's the difference? you have to protect iron and steel parts by oiling or storing in a dry place/with desiccant anyway if you don't want a rusty mould.

Longbow

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That's actually a good point. None of my sprue plates have ever acquired a spec of rust on any of my aluminum NOE or Lee molds and I've never, ever, oiled a sprue plate for storage, not even once. My molds are stored indoors in my basement, but I run a dehumidifier down here pretty much 24/7. Relatively humidity never gets above 40% and usually stays between 30 and 35. My guns are down here and they never rust either, so maybe I'm worrying much over a non-issue.

Iron or steel, I live in Louisiana, heat and humidity capital. I coat the inside and out, all parts with Liquid Wrench Dry Lubricant, it does not have to be removed , it acts as a release agent, it protects them from rust. And does not contaminate the cavities. When I'm done casting, I coat all surfaces and put away. Next session...pre heat and cast away. They nearly jump out of the mould when opened.....try it one time.
My casting shed is an unheated unairconditioned uninsulated out building...non of my moulds have rusted , not one.
Gary

Aluminum is the superior mold material, according to my testing. And Tom at accurate agrees, so it must be true.

With no disrespect to your assertion, I am a firm believer that ALL moulds react from whatever "treatment" they're subjected to by the owner. A Number 1 "no-no" I was severely instructed in was to NEVER dip any part of the mould into the pot, under any circumstance. Perhaps there's nothing wrong with it, but I heeded said warning and have too much money and love in my wee mould collection to give it a try. I used iron (H&G, Lyman, & RCBS) moulds for years with no need for dipping, no inverted coffee-can, or any added gizmos to produce workable bullets. After getting a brass mould or two, I kind of fell in love with using moulds of this material -- but, it may possibly be due to the very highest quality of those I have, produced by NOE and MP. Imho, too. If moulds are not subjected to rapid changes in ambient storage temperature which may lead to condensation and rust -- no problem. Keeping your mould(s) in an air-tight plastic box with a few grains of rice added is all I've ever needed re rust prevention.
While production is quite high with a 4-cavity mould of brass or iron, it -- for me -- gets heavy enough after a couple hours casting that for the past year or two I have made the preference-switch to two-cavity moulds. An added "plus" is I often use two 2-cavity moulds in sequence -- one after another -- and if I didn't have to add replacement alloy to the pot as the bullets get cast -- probably exceed the production rate of just using one 4-cavity mould.
Good luck -- this IS a hobby. Richard Lee has quite a section on his casting, using Lee aluminum moulds; and, I suggest you read (it's free) the Glen Fryxell book at http://www.lasc.us/articlesfryxell.htm. Both will surely make anyone's casting less problematic.
BEST!
geo

I had no problems with the change over from aluminum to iron . The new and only brass has really tried my patience . True to form however about 2 minutes before I huck it across the shop it starts giving up the goods . What I need is a note that says go ahead and cast a couple of pots of something else while the brass heat soaks then go ahead and cast some with it .

I have 1 four cavity iron mould and it would probably be great if it had about half as much mould . It's a Lyman 25 cal 90 gr and it takes forever to get hot and it's a pita to keep hot . The hand full of doubles whether RCBS or Lyman are almost as quick to heat as aluminum and run nicely . I am concerned about rust with a pending move . As such I have amassed enough VCI paper to wrap each mould at least twice and purchased stock in Kano products . Kroil is said to be able to spray/store/heat/cast I will soon find out . I will likely start this week packing up for long term storage . I dread the safe .

As far as aluminum the moulds under 30 cal keep me moving , but I have no trouble pacing a 5C 225-55 , I actually have to slow down with the 454424 copy 5c and the 3c 460-543 makes me wait . A 45-200 in 2c RCBS and 30 cal over 155 gr in a Lyman 2c are just about perfect , the 6c 35 cals are very well balanced too . From those as a reference base line you can count on running smaller cal faster and larger cal slower regardless of cavity count . I would say that a 6c AL runs about 7-8/10s of a 2 cavity iron pour for pour and that a 2c brass pours at about 80% of the iron . So if you're getting 10 pours/min in an Iron mould you'll get 8/ min with brass in a comparable mould but with an aluminum 4-6 c you'll get 7-8 but 3x the drop .

Cast iron is the king of engineering materials......just make sure supposed "iron" blocks arent actually freecutting mild steel....then rust is a problem.