casting with a brass mold

[Hogtamer]

I'm in on a group buy for and Mp double cavity Lyman type brass mold, should be here soon. I've not cast with a brass mold before, anything special I should know before I dive in? Thanks, HT

[Sig]

A quick search brought more results than I can type. There are varying opinions regarding what is necessary. I did the cleaning & heat cycling thing with mine. Others say heat it up & cast away.

brass mold prep site:castboolits.gunloads.com

[Hogtamer]

Oh yeah, search, thanks Sig!

[longbow]

Hogtamer:

I have not even bothered to prep my brass moulds as most do. I wipe them off with a paper towel to make sure there isn't any liquid oil or cutting fluid left on, lube sprue plate and pins with sprue plate lube, set on my hot plate while my alloy is getting up to temperature and pre-heat the mould until the sprue plate lube JUST STARTS TO SMOKE and I mean just starts to smoke. You want the mould well pre-heated and that is actually a bit hot but works for me. You do not want to overheat a brass mould as rumour has it they are prone to warping. I have not warped one and don't want to.

Having said that there is nothing wrong with cleaning with dish soap, spraying with brake cleaner, soaking in mineral spirits or whatever turns your crank. I'm lazy and just cast.

I oil all my moulds when I am finished casting too. Yes, even the brass and aluminum moulds because they have steel sprue plates, alignment pins and Cramer HP pins. I don't like rust!

I have three Mihec brass moulds and one Accurate brass mould and all cast beautifully but like to be pre-heated and run fast with fairly hot alloy.

I wish I had gotten in on this Lyman clone group buy but I was out of work for a few months this year so toy money is tight and I really don't need it especially since all I have are smoothbores and the Lyman design is best in rifled guns I understand.

I may pick one up eventually as I am sure they will be popular and Miha will be doing another group buy or stocking them. I drooled just looking at the photos.

Anyway, brass moulds are great but:

- watch you do not over heat it
- cast fast and steady to keep mould and pins hot
- alloy... I use the term alloy loosely because I cast mostly range scrap or wheelweights and seldom add tin or solder. Some have reported soldering and there have been reports of tin oxide building up and that can be hard to remove. I have not experienced that at all but a search will turn up several threads on lead/tin build up in brass moulds. Some go as far as inducing a patina on the mould to avoid the build up. If you add tin be watchful of soldering/build up.

treat that mould well and it will treat you well. it will cast excellent slugs I am sure.

Enjoy!

Longbow

[gtgeorge]

I have a shelf full of Miha's brass molds and have settled on just heat cycling them a couple times and the cast until the wrinkles stop. I used to wash them and/or boil them in dawn/water but didn't seem to speed up the process.

Seems Longbow above gave very useful advice.

[Beagle333]

I scrub em down with Dawn and a toothbrush, then preheat and cast away. They do work better on or about the third time using them, but I get great boolits the first and second time too. The boolits just jump out better after 3± uses. Have fun!

[longbow]

I should have added:

http://castboolits.gunloads.com/showthread.php?173350-Seasoning-a-Brass-Mold&highlight=patina
http://castboolits.gunloads.com/showthread.php?169575-Brass-Patina-Recipe&highlight=patina

Might be something there that is useful.

As I said, I have not bothered and not had a problem yet.

Longbow

[PbHurler]

I have a several brass Mihec & NOE molds. I have found that a patina on the molds really helps to drop the bullets. When new, I disassemble, scrub with a toothbrush Dawn dish soap & HOT water. Rinse in HOT water then blow 'em off with compresses air.

I heat cycled the molds 3 times, then commenced to casting with them. I was getting a little "tinning" at the parting line(s).
I cleaned that up as is discussed in a sticky here. http://castboolits.gunloads.com/showthread.php?213156-Lead-Adhearing-to-Mould

I re-heat cycled these molds 5 to 6 more times and they acquired a "patina" on their own, no chemicals were used. Now the molds are less cantankerous & drop from the cavities MUCH better.

Seems a shame to "discolor" such beautiful craftsmanship; but the molds are tools and are meant to be used.

Hope this helps

[plainsman456]

I hit them with carb spray then warm them up.

When safe i pour for about 20 minutes to get them up to temp.Then stop and do it again the next day.

When doing the second pour they usually put out some pretty boolits.

Thanks to AL at N.O.E i have another brass mold and in a few minutes will be doing some 44 mag.hollow points,might do about 20 pounds or so.
They are almost to nice to use.

They do seem to like the heat more than other types but when warmed up in their sweet spot put out nice ones.

[Walter Laich]

on a size note: I have backed off used brass molds not because of any issue with them other than weight. At 71 I don't have the arm/shoulder strength for long casting sessions.
Wife says I should put them up for sale here and let someone else get a good deal while she gets the money of them ;-)

[dverna]

on a size note: I have backed off used brass molds not because of any issue with them other than weight. At 71 I don't have the arm/shoulder strength for long casting sessions.
Wife says I should put them up for sale here and let someone else get a good deal while she gets the money of them ;-)

Walter, I have a compressed nerve that affects my ability to cast for very long as well. Surgery maybe by the end of the year. Anyway, one option I am looking at is the Master Caster. It only uses dual cavity molds, but it will still produce about 500-600 9mm/.38 bullets an hour. jroc has/had an automated one for sale but the price is too high for me.

Old age sucks.

[country gent]

I clean them good with dish soap and water scrub good with a soft toothbrush a couple times really working up a lather to raise oils and dirt up and off. Dry well, oil sprue plate, pins and handles with 2 cycle oil. I also have been known to shim handles to blocks to cut down rock on the handles some. It helps keep the pins pre alighned a little better. I then pre heat and cast as I normally do. I also set the moulds on the edge of the paint roller pan to hel pre alighn then when closing them. One plus to the brass moulds is you can set them down or pause for a few minutes and they hold the heat not haveing to rewarm them.The draw back is when done they also hold heat forever. Ounce up to temp and casting good bullets they hold the heat evenly and better than aluminum or steel. One thing to remeber is they are softer than a set of steel mould blocks so care should be used when running them.

[Loudy13]

I got my first brass mold about 2 months ago and was a little apprehensive about using such a nice mold for the first time. I followed the Instructions that came with the mold from AL (NOE) and it worked great. Basically I cleaned the mold with a toothbrush and soapy water. I heat treated the mold by warming it up on my version of a hotplate til it was about the temp I would cast at then let cool slowly. I heated it up 3 times and overall and then once more before I started casting. I also smoked the mold with a butane lighter which I know is a crutch until the mold is good and seasoned but it worked really well for me (and it was in the directions). I have used this mold 3 or 4 times now and it keeps getting better and better.

Be prepared for quite a bit more weight than you have used in the past, I had to find something to rest the mold on in between filling and emptying.

[Dragonheart]

I use several brass molds and they cast beautiful bullets, hardly a mold line, but they are heavy. The standard break-in procedure is heating and cooling your mold several time before casting to build up a very light patina.

I personally take a shortcut and get a very dark patina on a new brass mold in just a few minutes. I found a compound available on Amazon called Liver of Sulfur - Extended Life, for about $10. The compound is used to quickly patina copper , but has little effect on brass. However, I made it work by using a Q-Tip to apply a coating of Liver of Sulfur to the brass first, it only takes a few drops to do a mold. Then go back over the Liver of Sulfur with a 50-50 mix of Hydrogen Peroxide and White Vinegar using a Q-Tip. The brass will patina quickly. If you decide to give this a try I would suggest you try it on some brass scrap to practice and see if you obtain the desired result. Once my mold has a patina finish I wash it in soap and water the either use it or lube it down and store it. When I bring a mold out of storage I wash it with a degreaser, then a water rinse, then a rinse in acetone to remove any remaining oil before using.

If you do get some lead spots stuck to the mold, most likely at the edge of the cavity, heating and wiping might work. But if it doesn't, just dip a pencil eraser into your 50-50 mix of Peroxide & Vinegar and rub the spot. It will turn black and after a bit of rubbing the spot the mix will dissolve the lead.

If you have any sticking bullets using the lead from a #2 pencil to coat the cavity usually eliminates the problem. Sharpen the pencil to a point to get into the corners of the bands.

Brass molds like to run hot. Preheating with a hot plate helps or just dip a corner of the mold into your melt. I run my melt around 800 degrees and run two molds instantaneously. Some heat their melt to the point the bullets frost then back off a little, this works well and will give you a run of perfect bullets.

[floydboy]

I had never used a hot plate to pre heat molds until after I tried casting with my first brass mold. Do your self huge favor and go ahead and get one and use it. Clean the mold however you want and get it hot and keep it hot. You will be surprised how well they work.

[Smk SHoe]

Was thinking of getting a brass mold to solve one of my problems. I like to cast fast. I usually rotate between three different six gang molds during a casting session. They get to the point where the spur takes more than a few seconds to harden and the spur still crumbles when cut. Doesn't help with consistency rotating three molds. too cool, then just right, then to hot, then set it down and grab another and do it again.