Brass Mold Troubles

[Master_Mechanic]

Good morning everyone,
I have been casting for about 3 years now, most of my casting has been done with iron molds. Recently I ventured into the custom brass hp world and have picked up several mp molds. I took the advice in the stickies and cleaned, heat-cycled and lubed the molds. I preheat the molds on a hotplate, but i have trouble with proper fillout. If the mold is too cold the wrinkle or if there too hot the bases smear regardless of how long i wait to cut the sprue. Ive tried different temps from 650 to 700. I'm ladle casting with the lyman ladle. Any thoughts on what I should do?

[44man]

I had the same problem with a huge brass mold I borrowed. They are hard to keep at the right heat. It took me a while to get the hang of.

[dragon813gt]

Those lead temps have been to low for me to get everything to work right. I usually run it at 735. This allows for the mold and pins to stay hot and the sprue to harden in 5-8 seconds.

[Master_Mechanic]

if i run the lead and mold hotter it seems like i smear the base when the sprue cools.

[Jailer]

if i run the lead and mold hotter it seems like i smear the base when the sprue cools.

Pour a smaller sprue puddle.

[trixter]

With mine in 45 cal, I run the lead between 725º and 750º, and cast just as fast as the mold will let me; my cadence is about a 1001 - 1007 for the sprue, then another 1001-1010 to open and it works very well, just a light tap on the pins and they all fall out. I heat the mold on a hot plate while the lead is melting, and checked it with my thermometer one day, it was about 550º off the hot plate. I get perfect boolits from the first cast. My other MP mold in 45 SWC, a H&G 68 clone is another story and works very differently. {another story for another time}

[Master_Mechanic]

With mine in 45 cal, I run the lead between 725º and 750º, and cast just as fast as the mold will let me; my cadence is about a 1001 - 1007 for the sprue, then another 1001-1010 to open and it works very well, just a light tap on the pins and they all fall out. I heat the mold on a hot plate while the lead is melting, and checked it with my thermometer one day, it was about 550º off the hot plate. I get perfect boolits from the first cast. My other MP mold in 45 SWC, a H&G 68 clone is another story and works very differently. {another story for another time}

the 1001-1007 count, is that from pour or from puddle hardening?

[dragon813gt]

the 1001-1007 count, is that from pour or from puddle hardening?

Judging by what he wrote, yes. 7 seconds for sprue to harden, open plate, a 10 count, then open the blocks. If your sprue isn't hardening then you need to cool the sprue plate off. This is easily done by leaving it swung open for a bit or a moist towel. You can regulate the sprue plate temp by pouring a smaller or larger puddle.

[Master_Mechanic]

That might just be my issue, too cold and not waiting long enough after hardening to cut then not waiting that extra time before opening the mold. i have an aluminum noe mold that works very well, but it takes longer to cut the sprue being a 5 cavity. Thanks guys, i will keep trying.

[44man]

Like turning cold rolled into tool steel, maybe some metals are not good for molds. The huge mass of brass molds might not be the right way to go.

[dragon813gt]

Like turning cold rolled into tool steel, maybe some metals are not good for molds. The huge mass of brass molds might not be the right way to go.

Brass is perfectly acceptable it just requires a different technique. I prefer it because it holds heat and I can cast at a relaxed pace. Once they're up to temp they stay there easily. But I've found them to have a narrow operating band. I swore off aluminium because of Lee molds. I now have two aluminium NOE molds, two more on the way, that have restored my faith in that metal. Also have one from Accurate that's a joy to use as well.

[Love Life]

Cast hot and let the sprue harden up. My brass moulds make very nice boolits, but I much prefer iron moulds.

[paul h]

I find brass to me the most sensitive mold material for temperatures, kinda like Goldi Locks who doesn't like her porridge too hot or too cold, brass needs to be at just the right temp to make good boolits.

[Springfield]

Bulplate Sprue Lube will help with the smearing, and may eliminate all your problems. I can send you a small sample bottle if you like, I have a few from molds I have bought. Works wonders, it really does.

[Master_Mechanic]

Bulplate Sprue Lube will help with the smearing, and may eliminate all your problems. I can send you a small sample bottle if you like, I have a few from molds I have bought. Works wonders, it really does.

I have several bottles of the lube, i never had luck using it on the top of the molds/bottom of the plate without contaminateing the cavities.

[dragon813gt]

I have several bottles of the lube, i never had luck using it on the top of the molds/bottom of the plate without contaminateing the cavities.

You used to much if it got into the cavities. The lube that came w/ the mold works just fine. It's best to apply it when the plate is hot. A little bit goes a long way.

[Master_Mechanic]

fill the cavities with lead, put a dab of lube on a qtip and apply to the mold? seems to allways effect my boolits. i will try agian.

[44man]

Brass does have a narrow band, seems to give up heat fast or retain it. Just takes practice.
I hate lee aluminum but have no trouble casting. I made my molds from aircraft aluminum and it is as tough as iron molds. I find no difference at all.
Brass makes a mold like a jewel but the setting can lose the diamond.

[Smoke4320]

Like others have said Brass (for me ) seems to like higher than 725 degrees.. For mine its 735 as the sweet spot ..
for the mold lubing I just put some on a q-tip and make one swipe around the Sprew plate and a very quick light wipe between the holes. a little on the pivot pins and go about every 150-200 bullets I do it again

[quasi]

Brass does have a narrow band, seems to give up heat fast or retain it. Just takes practice.
I hate lee aluminum but have no trouble casting. I made my molds from aircraft aluminum and it is as tough as iron molds. I find no difference at all.
Brass makes a mold like a jewel but the setting can lose the diamond.

Aircraft Aluminum? What is that? Tough as Iron moulds? I think you are shoveling with both hands.