Iron vs. aluminum molds and hot plates

[brewer12345]

So far I have exclusively used iron 2 banger molds from Lyman and RCBS. I have put the mold on top of the pot while it is heating and run several casts of rejects to get the mold up to heat. Maybe not the quickest way to get good boolits, but it worked and I got practice casting. I just ordered a 2 banger Lee 30 caliber soup can mold and I am in the group buy for an 8 banger H&G 50 wadcutter mold, so I will be learning to use aluminum shortly. Is it a lot harder to heat up aluminum molds? Anything significantly different than using iron molds?

I am guessing that with the 8 banger in particular I will pretty much have to use a hot plate. So you just turn the plate on and put the mold in contact with the heating element? Anything special I should be doing? Is it possible to damage the mold?

[MyFlatline]

All my molds are aluminum, with the largest being a 4 holer. I put it on the hot plate when I turn on the pot. When the pot is ready, I only pour 1 or maybe two test runs and it is ready to roll.
Sorry, I can't compare it to iron, have never used one.

[farmerjim]

I have both. I started with iron then went to Al. It took me a while to get use to Al, but now I like the Al 6 bangers better than the iron 4. It is easier to destroy an Al mold, so be sure to keep it properly lubed to prevent galling.

[oldblinddog]

In either case, put the mold on a hot plate (you can get a single burner from Walmart) when you turn the pot on to melt the lead. By the time you are ready to pour lead, the mold will be up to temp and you will have NO rejects. I prefer not to practice pouring as it is just as easy to pour shooters as rejects.

[brewer12345]

In either case, put the mold on a hot plate (you can get a single burner from Walmart) when you turn the pot on to melt the lead. By the time you are ready to pour lead, the mold will be up to temp and you will have NO rejects. I prefer not to practice pouring as it is just as easy to pour shooters as rejects.

Much obliged.

[runfiverun]

putting something like an old saw blade on the coils will even out the heat better.

aluminum is softer than steel and you have to take care not to gall the top of the mold,
and how you close the mold, slamming it around will tear it up pretty quick.

[gwpercle]

Aluminum is soft, treat it gently. They must be lubricated, the steel top plat wants to gall and damage the aluminum. They must be properly heat cycled and broken in. Follow the makers instructions or read stickies on proper way.
Lee moulds need to be deburred and have all sharp edges removed before doing anything...read stickies.

I also started with iron, never heat cycled, never broke them in , never lubed ...you can't do this with aluminum. You can sit them on top of the pot to pre-heat....I'm still doing it that way. 6 and 8 cavity moulds can benefit from a hot plate preheating because they are so large.
Lee 2 cavity blocks are small , they gain and loose heat quickly. Custom moulds , like NOE , have blocks that are much larger therefore heat loss is really not much of an issue.
There is a difference in casting, a little learning curve but by and large I now like aluminum moulds.
They don't rust.
Gary

[Geezer in NH]

Heat is heat watch and control the temps and you will be fine

[john.k]

I have cast iron molds from before you could get ally,and now buy Lee moulds exclusively.My biggest disappointment has been with current Lyman molds,steel is no good.The last Lee I got,I just took it out of the box,didnt bother cleaning,after the fourth or fifth bullet,was casting ok.Theres no way i would pay a custom price for an ally mold,for that money,cast iron.The only issue I have ever had with iron is the slow going with the old single cavity.

[murf205]

Either will make some really nice boolits if you do your part. Just remember to put a concentrated effort into NOT dropping either one on a concrete floor. I, now have a thick rubber mat to stand on when I'm at the bench because I have dropped one. Thanks to arthritis in my paws!

[Rick Hodges]

I have a piece of 1/4"steel plate I put on the hot plate, I use it for both aluminum and steel molds.

[S.B.]

I own brass iron and aluminum molds and just put the mold in the pot while lead is melting?
Steve

[robg]

Started with cast iron now use ally as well ,both work well but ally is easier on my wrists.

[Grmps]

Hotplates can get REALLY HOT. Like Geezer said, know the heat of the hotplate before you put a mold on it. Mine hits 350° set a little below MED.
Turned up I could smelt with it.

[S.B.]

Lead melts at 800+- degrees?
Steve

[Grmps]

Lead melts @ 621°

http://www.lasc.us/CastBulletNotes.htm

https://i.imgur.com/MC7A7sj.jpg

[RogerDat]

I think even heating matters more to an aluminum mold, hence the circular saw blade or solid surface hot plate. You want to avoid heating unevenly. I have a block of wood cut to support the handles so the mold sits flat on the hot surface. I also borrowed an idea from another member to cut a "door" on the open end of a stewed tomato can, the can becomes a dog house when turned bottom side up on the hot plate. Handles stick out the notched "door". Traps heat around the mold and helps it be even temperature like an oven.

Watch for the Lee 2 cavity mold hinge screw backing out or getting tighter. Doesn't have a locking set screw. Really like the 4 cavity aluminum NOE molds. Productive without being too heavy, and as someone else mentioned a bit more mass so a bit more even in the temperature fluctuations.

Have meant to try the Lee 6's for a while but can't find the caliber and bullet where it makes sense. I like having different weights and profiles so would rather have 3 @ 2 cavity than 1 @ 6 cavity so I have more variety for same cost. Maybe if I have to replace a Lee SWC 2 cavity I'll buy a 6 cavity. My 3 and 4 cavity are NOE.

[lightman]

I have a piece of 1/4"steel plate I put on the hot plate, I use it for both aluminum and steel molds.

I cut a piece of steel plate for mine too! I think its either 1-8th or 3-16's. It evens out the heat better than just putting the mold on the bare coils.

I run the control knob about half way and set the mold on it when I turn the pot on. I usually get good bullets after the first few cast.

[Lloyd Smale]

Me too. Ive never had a brass or steal mold damaged like this. Aluminum? well there a last resort for me. I only buy them if its the only way I can aquire a bullet that doesn't come in a mold made out of steal or brass.
I own brass iron and aluminum molds and just put the mold in the pot while lead is melting?
Steve

[elmacgyver0]

Nice thing about the Lee molds.
If you screw one up they are not that expensive to replace.

[brewer12345]

Nice thing about the Lee molds.
If you screw one up they are not that expensive to replace.

To read many of the posts here, many of them arrive pre screwed up from the factory.

Appreciate all the pointers. My mold will arrive tomorrow, so as soon as I can get my hands on a hot plate and find a few hours, I will give it a go.

[David2011]

Brewer,

A hot plate is invaluable in the casting room. I have one with the coil on top and put a saw blade on it. It's OK but if it ever burns out I'll buy one that has the solid surface and I would recommend the solid topped one to you.

[Harter66]

I got by without a hot plate also . While rooting through some junk piles actually it was a heap of abandoned cast iron pans an corn muffin pans I found a kettle plate it actually stands just off the coils on my current hot plate that only shows up about 600° max if every btu is trapped . The casting bench lights , pots and hot plate are on a single buss box power on to all of off to all , saves me from leaving a pot on over night again .....

The small caliber long bullets in the Lee doubles are probably going to make you feel like you're having to run them way hotter than you should , you will feel like you're wrestling between keeping the sprue plate hot an not over heating the mould . You will be . Forget about the mould temp rest it on the edge of your pot ....... presuming you're ladeling , while the sprue sets . Pour fast generally if you're more than a 5-6 count between sprue cut and ready to pour again you're going to be loosing ground against the mould temp .

I may be biased , but , yeah NOE and Mountain Moulds are worth the money especially when it's only a few dollars more for a 4-5C mould than a 2C RCBS or Lyman .