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I have a brand new brass 4 cavity MP mold that I set up with the round hollow point pins. I cannot get the boolits to drop off at all. The first two rounds dropped ok. The third was tough and the 4th are still stuck on the pins while I let the mold cool off to see how stuck they are. I need some ideas.
I am not new to casting.
My pot is 670 degrees digitally maintained. (Lyman Mag 25 pot)
Alloy is an approximation of Lyman #2.
The mold and melt needs to be significantly hotter. I cast hollow points at 800-850°F melt temp verified from rotometals thermometer. I wipe the mold with a 2 cycle oily cotton rag, it needs to be hot enough to steam -aprox. 400-450ish°F mold temp.
I cast at 750 but adjust the timing to keep the boolits in the mold longer to keep the mold hot.
Synthetic 2 cycle oil is your friend
I absolutely agree! I have several MP brass molds, and they like to be very hot, and like HATCH said, that small bottle of synthetic 2 stroke oil that comes with the molds, is a must on the underside of the sprue cutter as well as the top of the mold, just a little goes a long way!Quote:
Originally Posted by HATCH
Like everyone else said, you are not hot enough. I cast these molds at 750-800 degrees. Are you preheating your mold? This is important because it seems that your pins are not hot enough. It takes some trial and error to get your hotplate set at the proper temp. A brass mold needs a higher setting.
When it comes to oiling your mold, a little goes a long way. Don’t use any oil until your mold is up to temp. A tiny drop on the male alignment pins, and a tiny bit on the parts that slide the hp pins is needed. I also keep a rag with a small amount of oil handy when casting. When you fill the mold for the first time, wipe this rag across the top of the mold (while the bullets are still in the cavities) and bottom of the sprue plate. This will stop lead from sticking on top of the mold.
There are some good suggestions on the MP website that have been very helpful to me in the past. One other thing, never beat on the mold with your mallet. Only tap on the handle hinge point. Tapping on the mold is a good way to ruin it. Good luck. Be patient! It will come around.
This is not my first MP brass hollow point mold and 670-680 degrees has always worked fine for every Lee, NOE and MP mold I own. Yes, the mold is fully preheated. Please help me to understand how lubing the spruce plate and mold alignment pins affect the castings releasing from the hollow point pins? That is the only issue.
FYI, you guys casting at above 750 degrees are into the temperature where lead vaporizes and causes poisonous fumes. 800-850 degrees F is just crazy in my book.
I was just trying to help. I have no idea of your casting experience. Maybe this will help .[URL="http://https://www.mp-molds.com/tipstricks/tip-on-easier-release-of-hp-pins/"]http://https://www.mp-molds.com/tipstricks/tip-on-easier-release-of-hp-pins/[/URL]
I could not get the round hollow point pins to release their casting no matter what I did. I swapped them out for the pentastar pins and life is good. Back to 670 degree F pot temperature, normal mold temperature and no sticking boolits. I'll go with these for now.
I have spun the round pins in drill and light polished with flitz or worn out fine emory cloth. Coat with a pencil (graphite) and reinstall. Usually the polish does the trick. The graphite coating doesn't hurt. They stick when pins are cold/cool.
Use a graphite pencil to color the tips of the pins. I also use some 400 grit sand paper to polish the pit tips too if they look rough.
BK beat me.
I get impatient sometimes and if the graphite doesn't release the lead bullet, the next time I take a propane torch and make sure the hp pin is heated.
It sounds like there are some tiny machining burrs on the round pins. Even a burr that's almost microscopic can cause a bullet to stick in the mold. I'd suggest that you buff those pins lightly with some Scotchbrite or fine sandpaper (400 grit) to smooth the surface. On all my new molds, before I use them I rub any sharp edges with an ink eraser to remove any machining burrs. An ink eraser doesn't damage the mold cavities, but you have to thoroughly clean the molds afterwards because any eraser crumbs left in the cavities will create a defect on the cast bullet.
Both brass and iron mold blocks loose heat much more slowly than aluminum molds. You can work at a more leisurely pace with with either brass or iron. Under some circumstances people might need a hotter temperature melt when using aluminum molds, especially when casting smaller diameter bullets. I agree with 6622729 that 800 to 850 deg. is excessive. There's casting them "hot", and then there's "way too hot".
Yes, I would say I need to polish the round pins. There are definitely machining marks on them you can feel with a fingernail. In the meantime the penta pins are working perfectly.
Attachment 324792
Attachment 324793
Wow, those are very pretty[smilie=w:Quote:
Originally Posted by 6622729
Another great pin release agent is Liquid Wrench Dry Lube #L512 ...
I use the liquid and apply with a Q-Tip ... also a great boolit release agent in general as it doesn't contaminat / wrinkle the cast boolit .
Polishing the round pins is probably all you need ... but as strange as it seems the Liquid Wrench Dry Lube is a good release agent and prevents rust on steel mould parts .
Those Penta-Pointed Boolits are freaking Awesome !
Gary
Another for graphite is your friend as a pin release. I have some powdered graphite that I used to tumble buckshot that I now apply with a Q Tip, I have used a pencil before and both forms of graphite make a significant difference. My guess is Liquid Wrench dry lube is graphite based.
Although I doubt any release agent will overcome a burr or rough surface.
Thank you for the kind comments about the boolits. I've now cast more than 500 with the penta pins. They shoot very accurately loaded to 1.125" OAL and 4gr HP-38 in my KKM barreled Glock. I'm using those recently available small pistol primers from Argentina. As always, work up your own load. Do not blindly do what I do. I am only sharing what I am doing, not telling you what you should do.
I might never mess with the round pins again but if I do I'll chuck them in the drill press and polish them a bit. Red Scotchbrite you think?
My 432-640 large pins were like that, but a quick touch with some 800 grit sand paper while they were spinning made them slick and smooth. Conversely, I have not been very successful in getting good boolits with the Penta point pins.
No, not until about 1,200 degrees or more. My several MP hollow point molds run best at around 850 degrees. Much below that and I have problems like you are. I can assure you that members here are not crazy.Quote:
Originally Posted by 6622729
Good Luck,
Rick
This is the first thing that comes up when I typed in "Lead vaporization temperature":Quote:
Originally Posted by RickinTN
752 degrees F
The problem is that lead starts to vaporize when heated over 752 degrees F, and you can end up breathing in the poisonous fumes.
I would find another reference besides "thisoldhouse.com" Don't believe everything you read on the internet.Quote:
Originally Posted by 6622729
According to some scientific references, the vaporization rate of lead is approximately zero at 600 degrees C, which is 1112 degrees Farenheit.
That reference from thisoldhouse.com is referring to lead in paint, which is likely a lead compound with different physical properties, not metallic lead.
Lead carbonate, previously used in paint decomposes in pure form at 315C/599F releasing toxic fumes.
Lead carbonate is not metallic lead, either.
Attachment 325396
I polish the pins on pretty much all my HP & HB molds due to release issues. The pentas can benefit from it as well but you'll need a steady hand. I haven't found it necessary to remove every machining mark, just smooth out the peaks. Some of them come rough as a cobb. I don't know the current state of affairs but for a long time but my understanding is that MP had been farming out the pins to a subcontractor so not much he could do for QC. Some of the longer round pins also suffered from tool deflection issues causing the tips to bow out and create a mechanical interlock. You can see some of that in the longer pin partly cut in the pic above. Some times I'll round off the end as you see to eliminate the needle point. Doesn't meaningfully effect expansion and helps eliminate some of the air bubble and fill out problems. Graphite or other release agent on the pin tips as everyone else has mentioned helps as well.
I believe that BK addressed your mis-direction pretty well.Quote:
Originally Posted by 6622729
Take care, and good luck,
Rick
I run my penta pins about 750° and the round at 720°. With both I cast fast to keep the mold temp up to frosting level.
As to the 752° level we all have to weigh the level of risk we each are willing to accept and act accordingly.
I choose to run hot and fast. But for my Big .45-90 535gr boolits I'll go as high as 800° on my PID.
KVO, that’s beautiful!
RickinTN. Misdirection? That feels like I should take that comment personally. I wasn’t trying to misdirect anyone. I was only sharing what I read.
I guess I probably took it personally when you called me out in bold print. I rarely say or type anything which I have no idea what I'm talking about. My apologies if necessary.Quote:
Originally Posted by 6622729
Take care,
Rick