Brass mold prep?

[emt1581]

Got my MP 147gr hp 9mm brass mold in this week. Can't wait to use it!! It's beautiful and VERY well made!

I've only ever used aluminum molds. Anything to know about brass as far as prep, use, and clean up?

Thanks!

[Mal Paso]

I took the sprue plate off, laid the blocks cavities up on the 1/4" steel plate on my hotplate, same setting (med) as my preheat for casting and let them roast for about 3 hours until golden. I've not cleaned the last 2 MP molds, the heat will drive off any oils. The key is to get some oxidation (Patina) going to keep boolit alloy from sticking to the mold.

Cleaning the mold won't hurt anything it just isn't necessary.

[Conditor22]

Your mold should come with seasoning instructions. IF not check the website.
I like to clean the mold cavities well then heat cycle them 4 times in my coating oven 400° let cool then 400° -----

[NyFirefighter357]

https://www.mp-molds.com/tipstricks/...-point-moulds/


Assembly, cleaning, prepping, lubing

"I start by cleaning the mould with brake cleaner, including the pins and the screws that hold the pins in. You can clean your new mould with warm water first but I don’t. Miha is generally doing a god job of removing any oils and debris from the moulds. I then assemble the mould, placing the HP pins I want to use in it, then backing the HP pin screws off about a 1/8 turn to prevent the pins binding in the mould.

Preparing a new brass mould: Heat cycle it on a hot plate. I put a bit over half power on my switch, not too high, and not too low, bringing mould to approx. casting temperature. I then switch off the hot plate and let the mould cool by itself. There is no need to take the mould apart when heat cycling. Keep everything together and make sure you have the pins inserted as well. Cycle three or four times, let it cool every time, when you’re done, everything will be set in. This starts the patina building. Just casting with it keeps the process going on too. Patina prevents sticking and bullets generally drop out."

[DAFzipper]

I use a toothbrush and acitone first. Polish the hollow point pins. Then preheat on a hot plate while the lead pot is heating up.

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[Three44s]

I do not use my MP brass molds, rather I just acquire them and admire them for their abject beauty!

Just kidding about not using them ..... LOL!

(Not kidding about just how handsome they are though!)

Three44s

[Thumbcocker]

I do not use my MP brass molds, rather I just acquire them and admire them for their abject beauty!

Just kidding about not using them ..... LOL!

(Not kidding about just how handsome they are though!)

Three44s

I went through the Chicago modern art museum once. Trust me a Mia brass mold beats anything I saw on the walls there.

[358429]

Got my MP 147gr hp 9mm brass mold in this week. Can't wait to use it!! It's beautiful and VERY well made!

I've only ever used aluminum molds. Anything to know about brass as far as prep, use, and clean up?

Thanks!

Hello emt1581, I found this for you, to read and mull, over a cup of coffee, or other suitable beverage. Enjoy!

https://castboolits.gunloads.com/sho...hlight=Casting

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[guy_with_boolits]

ive paid little to no attention to patina or other "release" methods and my MP452-200-HP drops boolits fine

have a selection of tools to clean the molds of lead debris, which they will slowly accumulate small amounts of:

-wood toothpick
-wood popsicle stick
-copper scour pad
-cotton pad soaked with 2 cycle oil (for oiling/cleaning the sprue plate bottom/top of FILLED & CLOSED mold)

[Mal Paso]

Beeswax is another good cleaner to get boolit alloy off brass molds. Best used on a hot mold.

[Super Sneaky Steve]

I used my MP 452-200 hollow point mould for the first time last night. I didn't do anything to it other than clean off the oil with a toothbrush and some Lava soap. Boolits fell right out.

The only real problem is the little C clips hang up on my mould handles in the back two cavities. The pin supports will also start to back out so be ready to tighten them up as you go.

The fitment of the block to the pins leaves a lot of daylight around them. I was worried about lead leaking through but it never did.

[358429]

Put the clipped pins in the lower holes.

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[emt1581]

Put the clipped pins in the lower holes.

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I clipped all the pins, upper and lower holes. Seems like having a pair of needle nosed pliers nearby would be helpful.

[emt1581]

Thanks fo all the replies!

I'll heat the mold up to temp and let cool for a few cycles. I can use my powder-coating toaster oven for that. Then I'll have some bees-wax handy.

Not really clear on the whole backing off of the pins an 1/8th of a turn to prevent adhesion to the mold body. I'd think I'd want those pins as tight as possible so they don't come lose of the HP core. Does steel routinely weld to brass in these molds?

Thanks

[358429]

I back the pins off 1/4 turn loosened from lightly torque tight. Ideally you want the pins to float in the mold blocks, prevent any galling. Materials experience changes in physical dimensions when you heat them several hundred degrees, above room temperature.


When my mold is up to casting temperature the blocks darken in color. It is a nice feeling when everything works right! The pins move freely from their own weight.


With the E clipped pins only in the lower holes, there is no interference between them and the handles during normal movement.

Synthetic two stroke oil (cheap oil is okay) dabbed onto a clean cotton rag, use this to periodically wipe the top and bottom of the sprue plate, and mold blocks, exterior part of pins.

When the mold is up to temp any excess oil burns off. Two to three casts will clean the cavities if you mistakenly put too much oil.

I use a propane torch to add heat as needed to the blocks, to the pins, and to the sprue.

Make bullets! They better be cool looking bullets!

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[Mal Paso]

Thanks fo all the replies!

I'll heat the mold up to temp and let cool for a few cycles. I can use my powder-coating toaster oven for that. Then I'll have some bees-wax handy.

Not really clear on the whole backing off of the pins an 1/8th of a turn to prevent adhesion to the mold body. I'd think I'd want those pins as tight as possible so they don't come lose of the HP core. Does steel routinely weld to brass in these molds?

Thanks

The HP pins float in and out easier if the cross pins are a tad loose. I have never had one come apart from the HP pin while casting.

I use a covered hot plate with a 1/4" steel plate on the coils to preheat or keep the mold hot if I pause casting. It gets the pins hot too.

I have the cross pins sticking out left, after I cut the sprues I turn the mold over and gently tap the sliding pins with a 6 oz mallet to push the boolits out and they drop off.

[Three44s]

I went through the Chicago modern art museum once. Trust me a Mia brass mold beats anything I saw on the walls there.

I take it you won’t be forking cash out for Hunters art anytime soon either? LOL!

Best regards

Three44s

[Drew P]

Soap and water with toothbrush and then long roast on hot plate for me too.

[44Blam]

Brass molds cast great at a lower temp. I tend to clean it with soap and water and then cycle it a few times.
Then I cast the first batch - usually it takes a little while before everything settles but once a brass mold starts dropping good boolits, it is consistent...
With a brass mold, I tend to keep the melt at about 675-700 and with an aluminum mold I keep the melt closer to 750 - 800...

[mattri]

What would happen if you didn't do a heat cycle, just smoked the mould and started casting?