Need some help with my 359640 mold

[boatswainsmate]

Hello All,
I'm at my breaking point with my 359640 mold. This is the only Miha mold I can't get to run correctly. I have cleaned the mold numerous times with denatured alcohol while the mold was hot & cold. I just can't get the mold to produce unwrinkled bullets no matter what temp I run the lead at. Please advise! Thanks in advance!

[BK7saum]

What alloy are you running? Maybe need some tin or a hotter mold. Sometimes it takes a while to burn the residual oil out of the mold cavities even If it's been well cleaned.

[BK7saum]

As you probably are aware a hotter alloy doesn't do much good if you can't get the mold preheated or temp up by running several pours in rapid succession.

[dragon813gt]

Your mold isn't hot enough. Preheat it on a hot plate. A good indicator that it's up to temp is when the sprue plate lube starts to smoke. Wrinkled bullets mean the mold isn't hot enough.

Depending in ambient conditions you may have to turn the lead temp initially. Cast as fast as you can and don't stop to inspect the bullets. Once it's up to temp it will hold there nicely.

If you're getting wrinkles on the noses w/ hollowpoints the pins aren't hot enough. I usually run the lead temp slightly higher until everything is up to temp.

[boatswainsmate]

I pre-heat on a hot plate, I have my PID set at 830 degrees and I run as fast as I can. This is the only mold I have issues with. My alloy is gives me great fill-out in my other Miha molds. My alloy is 1.29% Tin, 3.23% Antimony and 94.5% Lead. Lead calculator says 11.9 BHN.

[BK7saum]

Your doing all the right things, I'm stumped as to why it won't drop good Boolits. Still sounds like a cold mold but you should be good to go.

[rintinglen]

Stop looking at the boolits. Cast as fast as you can, fill and dump, fill and dump. Don't put the sprues back in, don't second guess the cast, don't check for wrinkles or voids, just fill and dump. Do it as fast as you can for at least 8 cycles. Then glance at the last 4 while you wait for the sprue to harden. I'm guessing they will be just fine. Repeat until pot is empty.

[gwpercle]

Forget the alcohol, for truely grease free cleaning , soak the blocks for a few hours in acetone, then scrub with new acetone and an old tooth brush. After that any problems will not be from a lack of degreasing .
Sometimes the oils from the cutting fluids seem to get down in the pores of the metal , the overnight soak will remove them !

Some moulds get possessed by an evil spirit...nothing short of an exorcism will help then . I get the local priest to help when this happens, one time the spirit was so strong I had to take it to a Voodoo Queen down in New Orleans to work her magic on it, but after that it was cured and bullets dropped like rain.
Gary

[boatswainsmate]

I finally got the mold making somewhat decent bullets! It still has sticky cavities. It took some Kroil applied with a q-tip and some heat cycling but it's getting there. Thanks for a the reply's! Boats
http://i306.photobucket.com/albums/nn271/ericlee1971/359640_zps3w3xlesk.jpg (http://s306.photobucket.com/user/ericlee1971/media/359640_zps3w3xlesk.jpg.html)

[paul h]

Try casting them with the hollow point pins. MP's tend not to drop so well with the flat pins.

[dragon813gt]

Try casting them with the hollow point pins. MP's tend not to drop so well with the flat pins.

I will disagree. I got over the hollow point fad quickly. If blank pins are available they are installed in all my molds. The bullets release just as easy. There is only one design where the hollow point pins are really needed.

[reed1911]

Interesting that adding oil helped them. Kroil is a thin penetrate oil close to kerosene.

[MT Chambers]

Pins are a pain, they cool off faster then the rest of the mold IMHO!

[runfiverun]

kroil in the cavity's has it's own sticky.

you just need some heat cycles on the mold so it will develop the nice brown patina in the cavity's.
in the mean time look over the venting capability's of the mold you might need to give them a hand by loosening the sprue plate or by breaking over the top corners of the mold a tiny bit.

[Dragonheart]

Instead of trying to figure what's wrong I will explain my process, which works well for me.

I have 4, 4 cavity brass molds and they all cast great looking bullets. When I first got the molds I gave them a good scrubbing with liquid soap hot water and nylon brush. I then heated the molds to 400 degrees for 20 minutes and let cool, three times. They took on a light gold appearance. To increase the patina used a Q-tip to wipe on a thin coat of Liver of Sulfur then wiped on a mix of 50% hydrogen & 50% white vinegar. This quickly turns the brass surface to a light brown patina like aged brass. I then washed the mold in a soda & water to neutralize.

To start casting I set my RCBS Pro Melt to 800 degrees, giving it time to come up to temperature. I flux with Brownells Marvelflux. I lube my sprue plate & mold top with NOE Sprue Lube, then preheat the molds on an induction hot plate and bring them up to just under 450 degrees. I adjust the sprue cutter if needed. When I start casting I run two molds simultaneously and discard the first couple of pours. By the third or fourth pour I am getting keepers. The bullets drop out with a couple of taps on the handle's knuckle into a water bucket with a towel on the bottom to cool.

The big thing I have found about brass molds is they like to be hot. Once they start dropping good bullets almost everything from then on is a keeper. Running two molds I am either pouring or dropping bullets, I don't spend time waiting for the lead to set and I am turning out a lot of bullets.

[dragon813gt]

Two people have mentioned a pot temperature of 800. This is really excessive. And if you have any tin in your alloy there is the potential for it to oxidize out.

I cast in an unconditioned garage year round. It's been in the teens at times when I'm casting. Even at these low temps I haven't had to turn the pot temperature above 750 when using a HP mold.

Don't let me stop you from doing what works best for you. But there is chemistry involved when your alloy has tin in it.

[Dragonheart]

I do appreciate your concern and have heard this numerous times, but the end result just doesn't show me this is a problem. Using a hardness tester, which I admit is a subjective device and known for inaccuracy, I still get a 9-11 BHN using range lead at 800 degrees. If I only ran one mold I might be able to get by at 750, but running two molds simultaneously if I want consistent good bullets, this is what it takes for my brass molds. I did check the temp on my pot using a digital probe and it actually was running a little over 800. Obviously, my steel molds don't need this high heat.
I also think the Marvelflux makes a big difference as this is the best flux I have ever used. The flux cleans my pot and leaves the metal with a smoothness hard to describe. You end up with the contaminates mixed into a foamy liquid on top of the lead, when skimmed off it is apparent this residue does not contain any heavy metal.
Since I am powder coating I am creating a jacket on the bullet, which is similar in the hardness of copper plate (35 BHN), just not quite as thick. Some think the PC is just a lubricant, but it is more than that. I test my loads using a Ransom Rest and chronograph, which is not subjective, and the accuracy I am getting speaks for itself. In my posts I try to describe what I do and what works for me to help those just starting out or someone with a problem. If someone comes up with a better idea I am certainly willing to give it a try as I know there are other roads that will get you to the same place, I just look for the shortest and easiest path.

[dragon813gt]

I suggest you read up on Marvelux as well. It does take out the contaminants. But it also takes out the desirable elements in the alloy as well. Not to mention the rust. There are many threads about Marvelux on this site.

W/out an XRF analysis you don't know if you lost any tin due to oxidization. It's the only way you will truly know.

[Dragonheart]

Yes, I have read the Marvelflux posts and like anything on the net you have to take comments with a grain of salt because you haven't a clue where it's coming from or what they did. I personally like the product, consider it safer and better than anything else I have tried over the past 50 years. It is easy to get caught up in a subject and overthink it, that is why I judge by the end result, which posts on a target 25 yards away for all to see. If I can get 1-1/2" groups at 25 yards and have no leading in my barrels I must be doing something right.

As far as my XRF, it is no longer supported by the manufacturer since the company changed hands, so like many other XRF units it just got too old; my radiation source expired earlier this year and with no provisions remaining to renew the source it's a $30K paperweight. At this point in my life I can't see me purchasing another, so it I ever feel the need to run an assay I will have to rely on the kindness of an associate.