New Mihec mold..advice?

[Bagdadjoe]

I just got a new Mihec mold and wow..it's a piece of art. I almost hate to dirty it up! I have LBT moulds and of course they are aluminum..I haven't had a brass one before and it's a tank compared to the LBT's.
I saw somewhere on here that someone uses a hot plate to heat the mold prior to use? Since this thing has so much mass, I'm thinking that might be a good idea (it's a 4 cavity 358 180gr with the hp pins).
Any suggestions before I venture into uncharted ( for me) territory?

[GRid.1569]

My experience of Brass up-holds the pre heat method... trying to get it hot enough by pouring lead is near impossible (for me any way)... takes ages... get the hot plate....

When it's working though Boolits look great... :-)

[Balta]

And there like to run hot...For hp boolits polish the pins,and smoke em...
Mihec"s mold ar indeed piece of art
Happy casting :=)

[dnmccoy]

How do you polish the pins? Mine just arrived today!

[sh00ter787]

i wouldn't do anything to the pins or cavity's.

from what i learnt with my first hp mihec mold....
use a hotplate, get that baby hot, use the lube that came with it.

then cast! if it isnt going the way u had hoped, then heat it some more lol!

it is to be expected that the pins may stick a little at first, tbh once hot enough mine just fell or did so with a gentle tap on handles, i was concerned with mine as i had only had aluminium ones before, my concerns were really unfounded though - excellent molds!

[dnmccoy]

Im not home to open the package, but the molds dont come with handles correct? I got one of the 4 cavity 359-125 molds for 156$

[white eagle]

Just use a hot plate to heat your mold
they do not need to be hot let your boolits tell you what the mold likes
it may take a time or two to season the mold but all a hot mold gets you is frosty boolits
once your mold does reach temp it is easier to maintain good boolits once you get the rhythm
no cool off's like with aluminum
I personally like brass better than aluminum
you also don't need to polish anything Miha is a good enough machinist not to leave any tool marks or any surfaces that need smoothing out
get your timing and get your boolits loaded
have fun

[HATCH]

Correct no handles unless you paid extra for them.

I put the corner of the mold in the melt and let it get hot. Once the sprue plate starts smoking its good to go. Only takes two mins.

sent from my mobile.

[41 mag fan]

Just use a hot plate to heat your mold
they do not need to be hot let your boolits tell you what the mold likes
it may take a time or two to season the mold but all a hot mold gets you is frosty boolits
once your mold does reach temp it is easier to maintain good boolits once you get the rhythm
no cool off's like with aluminum
I personally like brass better than aluminum
you also don't need to polish anything Miha is a good enough machinist not to leave any tool marks or any surfaces that need smoothing out
get your timing and get your boolits loaded
have fun

What white eagle said.

I've got a couple Miha brass molds. what I do is put my heat on my hotplate at med/low and let it heat up while my pot heats up. About the last 100* before my pot is to temp, I turn the heat up a smidge higher on my hotplate..just a little like a smidge below med heat.
I then cast my first two and let them set extra long in the mold. Of course I cut my sprue when it's frosted up so it's not a PIA to open when hardened fully.
By letting the heat transfer, from my casts to the mold a little longer it brings my brass up to perfect temp.

One note about brass though, when it gets hot it stays hot, you can cast slower, and might need to take a few seconds break inbetween so it don't get too hot.

[41 mag fan]

Im not home to open the package, but the molds dont come with handles correct? I got one of the 4 cavity 359-125 molds for 156$

Lee handles will work on Mihas molds.

[Mal Paso]

I would heat cycle the brass mold 3-4 times by heating to 400F in an oven and allowing to cool to room temp. Do it with the blocks apart to allow oxygen to get to the cavities. It will darken the brass but the oxidation will prevent Alloy from sticking.

I am taking the process a little further, using chemicals to create a patina on my molds. http://castboolits.gunloads.com/showthread.php?t=169575

[Wots]

Just got done casting a few hundred mp 452-200. As was said above plus I was running the lead @ 820 deg. The were flying outta of the mold.

[MikeS]

There's no need to heat the lead to 820F and in fact you're actually doing harm (to your alloy) at that temp! Much past 750F and the benefits of tin go away. If you heat the lead to 100F over the full liquid temp (end of the slush phase) is about optimum. I normally cast at around 650F even with brass moulds, and have yet to have a problem. If you're casting HP boolits, you might need some more heat, say going up to 675 or so, but there's no reason to overheat your alloy. The thing you want to do is keep your mould hot, and you do that by varying the speed at which you're casting. Casting faster will make the mould hotter, and casting slower will make the mould cooler. The only time heating the lead to 800 or more is when casting with pure lead, without any tin, then you need to extra heat to aid in the fillout of the mould (which is normally done by adding tin when casting with a lead alloy). Generally speaking you would only use pure lead for muzzleloading projectiles.

[Bagdadjoe]

Wow, step away from the computer for awhile and when you come back you've got a treasure trove of information. I love this site. Thanks everyone for all the help! I'll be trying this baby out tomorrow.

[Balta]

How do you polish the pins? Mine just arrived today!

I use a dremell but sand paper can do the job..

[cbrick]

Not on any of my Miha molds have I needed to polish anything. Pre-heat the mold, including the pins and when it's at proper temp including the pins bullets will fall out.

The mold does need to be cleaned of mfg oils before use. I use denatured alcohol and a tooth brush.

675-700 degrees is well over proper mold casting temp and 675-700 is more than enough heat to get your mold up to casting temp and keep it there. More heat than this is a waste of tin.

A Dremmel on a Miha brass masterpiece? The thought sends shivers down my back.

A Dremmel? Yikes, think I'll start drinking again.

Rick

[Hamish]

Drop the Dremel and step away and no one will get hurt!!

Oof, the very thought!

Back when I started getting serious about sharpening the blades in my hand planes, I knew from my auto body shop days that the auto supply store carries sandpaper all the way to 2000 grit.

Chucked up in your drill you can do some serious polishing jumping about 400 grit at a time.

[Dannix]

Balta may have been referring to a dremel with a polishing tip. Please bear in mind English is not his native tongue.

I personally had to use a bit of 800 or 1200 wet/dry sandpaper on a few of my 125grn 9mm HP pins. I also needed to unscrew the pins a bit from the HP shafts so they would slide freely. Does it make me think less of my mould? Not one bit.


Bagdadjoe, do make sure you heed Mal Paso's advice and heat cycle the mould to get a layer of oxidation before your first casting session. I've learned the hard way the pains of tinning.

[Balta]

OK,guys.....Dremmel but with COTTON polishing pin......!!!
It just Clean the mold !!!!

[dragon813gt]

I know people say don't run the lead really hot. But it's the only way I've found to get the bullets to drop freely with the Cramer molds. I can only cast so fast. I run mine at 750 to keep the pins hot. Mold fill out is still good and the alloy I'm using only has 1% tin to begin with. The brass Cramer molds need to be hot to drop bullets consistently.


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[quasi]

lots of people cast hot, check out the Bruce B speed casting method.