Brass mould .........is it always like this ....

[Ian]

By the way, don't feel like the Lone Ranger. This was a run of dirty alloy, note the pinholes and trashy inclusions.

This session was run at the "light frosty" temperature, past the point that the first gnarly, ashy edges occur. Once the mould is hot enough, it all evens out again. Or you can cool it down and fight wrinkles. Another thing I've found that brass likes is for the alloy to be cooler, but mould run really hot. 675°F for the alloy and whatever it takes to keep that satin frost (about four pours per minute on average for a .30-cal) is what I do. I'd also pay close attention to those who can make perfect, shiny bullets from a 300° mould, they have their ducks in a row for sure.

 

[RBHarter]

"you got zero patina in those cavity's"

Yep , probably had it hot and cold 20 times mostly cooled open . I've never had to "rust" stuff on purpose . Especially brass . I have a TC Hawkins kit rifle , white barrel and brass fittings . The brass shows some staining in the unhandled places but the barrel is hardly grey after 15 yr of off/on shooting and setting in a closet wiped down in Hoppes every summer and post hunt cleaning .
Like I said ........dry desert .

 

[358156 hp]

I never considered smoking either mould, but it makes a lot of sense.

 

[fiver]

I understand dry.
anything over 45% humidity is noteworthy here.
you can try wiping some body oil in the cavity's, a little wet palm or some next to the nose, or forehead oil from a teenager can help things along.

 

[Ian]

I usually smoke them just for the break-in, maybe couple of times and they've built enough patina to not attract the alloy too much after that. I eventually wipe the smoke off with a Nylon toothbrush when they're "broke in".

 

[Brad]

That is also a huge cavity in those blocks:
Run the alloy cooler if you can. Tempo is your friend

 

[RBHarter]

Even with that huge lake just down the hill , 30% is soggy here . Fog is something we only see in the teens and single digits .

 

[S Mac]

Even with that huge lake just down the hill , 30% is soggy here . Fog is something we only see in the teens and single digits .

Wait till you move to Arkansas, be a whole nother world as far as humidity.

 

[RBHarter]

I've spent most of a summer and part of a winter there as well as September to April , the longest 5 yr of my life , in Wichita KS . I'm aware of the impending he..... velvety fine humidity vs the chunky heavy stuff we get out here . The bath water rain was fun vs possibly freezing to death out here .
Yep lots to get used to .

 

[JSH]

Well I thought I was cracking up. This is the first and only brass mold I have. May be the last. It is heavy and fickle of what it likes and doesn't like. I will revisit it at some point.
Tinning, I worried about that when I got frustrated and cranked the heat up. I should have as I created a mess that was a royal pita to clean up.
I try to keep notes on what a mold likes. This one had darn near a page of what NOT to do or what I tried and it didn't work.
Jeff

 

[RBHarter]

Well I thought I was cracking up. This is the first and only brass mold I have. May be the last. It is heavy and fickle of what it likes and doesn't like. I will revisit it at some point.
Tinning, I worried about that when I got frustrated and cranked the heat up. I should have as I created a mess that was a royal pita to clean up.
I try to keep notes on what a mold likes. This one had darn near a page of what NOT to do or what I tried and it didn't work.
Jeff

Nope it's not just you .
I always read about what a joy brass was to use . Nobody ever says "I love my brass moulds , they cast so easy and make beautiful bullets ..........,after you heat cycle , stain , fuss about , and find that perfect little nitch , 20° degree window of combined melt and mould temp ........
That's half the fun anyway .

 

[Rick]

Nope it's not just you .
I always read about what a joy brass was to use . Nobody ever says "I love my brass moulds , they cast so easy and make beautiful bullets ..........,after you heat cycle , stain , fuss about , and find that perfect little nitch , 20° degree window of combined melt and mould temp ........
That's half the fun anyway .

Yes . . . They do. I love my brass molds and they are easy to use and they do cast beautiful bullets. Have never heat cycled one other than using it. Have never tried to Stain one and in fact my most used brass mold has no "patina" to speak of. They have no "perfect little nitch" other than just as with any mold they need to be properly pre-heated. I use exactly the same cleaning on iron, aluminum or brass, pre-heat and cast.

Here a sample from MP 270 45 4 cavity brass.

 

[USSR]

Yes . . . They do. I love my brass molds and they are easy to use and they do cast beautiful bullets. Have never heat cycled one other than using it. Have never tried to Stain one and in fact my most used brass mold has no "patina" to speak of. They have no "perfect little nitch" other than just as with any mold they need to be properly pre-heated. I use exactly the same cleaning on iron, aluminum or brass, pre-heat and cast.

Here a sample from MP 270 45 4 cavity brass.

View attachment 4856

+1.

Don

 

[RBHarter]

Maybe Im just working too hard at it .

 

[fiver]

I only have one brass mold.
it come to me as a 'here take this and see what you can do with it' deal.
I think everything that could be wrong with a mold was wrong with it right down to it being converted to a master caster and it's associated issues for setting up a new mold.
it probably cost the owner 225$ to get set up they way he had it so his frustrations were completely understandable.
I stripped it down to the bare blocks and started from scratch, it took me a good 8-9 hours of picking and poking to get it set up and working enough to try casting with it, then another couple of just trying different things to see what the casting issues were.
it still has a slight venting problem on the one cavity but i can knock out a good pile of bullets with it now.

 

[RicinYakima]

+2, I have a 100 year old New Yankee Specialty mould that still casts beautiful bullets. What is "staining", I keep mine polished like a mirror inside, turning a bullet with toothpaste.

 

[Rick]

Maybe Im just working too hard at it .

Or maybe . . . You've just listened to too many people that simply never learned to cast with a brass mold and of course had all sorts of problems, therefore all of the problems are that of the mold being brass. Horse pucky! Brass is a wonderful mold material that machines very well and gives cavities like that in my picture above.

All sorts of nonsense gets posted on what to do with a brass mold from etching it to spending a day heating and cooling it to brass loses heat rapidly so cast as fast as you can to . . . Well, you get the idea.

Here's the skinny on brass molds. It's a mold, cast with it. Brass warms to proper casting temperature slower than iron and far slower than aluminum. I use a hot plate with a digital thermometer and pre-heat to about 385 degrees, pot temp at 700 degrees, start casting and discard the first 4-5 fills (that's a weight issue). The heat in the mold will get more uniform throughout the mold. Once at a proper casting temp and good bullets are falling out all you need do is keep an eye on the bullets and adjust the casting pace to keep it at that temp. All that is exactly the same for iron, aluminum OR brass. It is also something that should be easily accomplished by anyone with just a bit of casting experience. It's simply basic casting and brass is no different. As a side note in addition to heating slower brass holds it's heat longer, better than iron and far longer than aluminum, simply adjust the casting pace to keep the mold happy just as with any other mold material.

Only other thing with MP or NOE aluminum molds is those wonderful thick sprue plates. They need to be kept HOT. Huge sprue puddles add heat to the plate and they need that heat to get good base fill out. Even if the mold is at proper casting temp that doesn't mean the sprue plate is. Again, basic casting regardless of mold material.

 

[Rick]

What is "staining",

A few years ago there were several discussions over on the other bullet site on how to (as near as I could figure) ruin a great mold. One was some kind of chemical solution to etch (stain) the mold. Not my molds thank you.

As a side question . . . How do old wives tales get started anyways.

 

[fiver]

the patina I spoke of is a browning of the mold.
it is the equivalent of a mehanite mold cavity turning blue or an aluminum mold getting it's haze.
basically an oxide coat.

 

[RBHarter]

Yep , I'm working too hard at it .
All of the non cartridge brass I've had has stained rather than tarnish .
I may have to resort to some polishing as this one has a little tool chatter in the hinge end cavity but not enough to delay the drop out if the mould it tilted 35-40° right . I'll have to reset the pot a little bit .

As I suspected , in lay terms , the mould will most likely have to heat soak/saturate before it throws good bullets .

I got pretty good at filtering out the good and great from ummmm NO on that other board . Most of what I've worked through this mould is from that . It just feels like I'm missing something really obvious with it , even more having made such a minor change as flipping a pin and changing the other . It was like starting all over again with a new woman .......errr,umm .....mould . I expect heat is the real culprit here . I have a little bit of learning to do with a 3 cavity 460-543 too . Too much cavity not enough metal ...... Odd that I just bang out the single 458193 just about a perfect bullet every time from the 3rd cast .

I got spoiled I guess . I poured 358s and 45s in pistol moulds like rain with 3-5% reject rate but rifle bullets gave me fits . I guess there's a threshold of sorts where a 45 cal bullet becomes a long skinny rifle bullet . Talking to myself here to apply a Cresent wrench solution to a 1 1/4" tubing wrench problem .
Best new trial will be sprue plate down in the hot plate box on top of the kettle plate while we wait for the pot to come up and turn the pot down to 710-720 vs 725-750 . ........maybe flip the mould from base to sprue when the pot starts to sweat on top of the melt .