aluminum, brass or iron for molds

[Libraryhound]

I am looking at an custom 20ga slug mold and the maker gives you a choice of aluminum, brass or iron for the mold. I will be using only wheel weights what would be the best mold material? based on the size being 20ga and wheel weights as the load?
Thanks
libraryhound

[Lloyd Smale]

aluminum is light and thats its best property. It allows you to cast longer without fatique and disapates heat fast so you can cast a bit faster. Alum molds are fragile though and dont hold up as long . Brass is HEAVY and holds its heat longer then any material. Its easier to machine then steel so its usually a bit less expensive. It holds up much better then alum but not as well as steel. My favorite is steal. A little lighter then brass and much more durable then either brass or aluminum. Disipates heat better then brass but not as well as aluminum. A good steel mold is a lifetime investment if taken care of. Now theres some leyway in what im saying. personaly i dont think a lyman steel mold is a whole lot better then a cheap lee aluminum mold. I think ive tore up as many lyman molds as i have lee.

[jhalcott]

Depending on intended use there are some differences. For production of quantities(ie casting for profit) steel is best. If casting for a hobby with limited shooting brass would be my choice. If shooting a lot and casting a bunch at a time , go with the aluminum. Taken care of ALL three metals will out last most of us.You CAN beat a steel mold to death almost as easily as an aluminum one!

[Libraryhound]

Thanks for the replies. I am leaning toward the brass mold as it will be for hobby. I might make 20 slugs a batch maybe 100 slugs a year, after I get the right load recipe. I was leaning toward the iron but it is a good amount more in cost.
Thanks
Libraryhound

[Lloyd Smale]

with brass id stick with a single cav mold. It will be to heavy as a 2 cav in something as big as a 20gu. slug and will no more quicker to cast with then a single cav because its going to get hot fast.

[Ranch13]

If all you're going to cast is a 100 or so a year, I'ld go with the aluminum. At that rate those blocks will/should last forever.
I have aluminum moulds from Accurate and brass from Old West, and they've all been used pretty heavy, and are holding up well.

[RIF]

Lyman makes a 350 grain 20 gauge slug mold that works with regular shot components. 

[Drilling Man]

  I have to admit, i like steel moulds best, they just seem to make better bullets "longer" for me, and I like the way they hold heat more evenly...
 
  All of them work though, i do have several Al. moulds too, just like steel better.
 
  DM

[Libraryhound]

Accurate 20ga 360 grain slug brass mold. I got it in early. Won't get to use it till next month.
Libraryhound

[Jason F]

Did you slug your barrel before you ordered that mold. I ordered about the same design in a 450 grain but at. 628 diameter for my h&r 20 ush. I noticed yours was made at. 620 diameter.