Help needed with new MP brass mold . casting issues NOT molds fault

[Smoke4320]

Ok this is my first Brass mold so new territory being covered
308 160 mold... 2 hollow point and 2 Plain Pins in mold
Mold looks great ..Cleaned with dove dish soap and comet.. I seasoned it by putting in oven at 400 degrees for 20 minutes then letting it cool to room temp repeated 4 times (with pins installed)..

alloy is 98% COWW and 2% tin.. cast many many boolits with this alloy and at least 100 from this pot of lead with another mold.
cast about 40 boolits... at 680 degrees PID controlled all had issues, wrinkles, unfilled bands ect.. so I let mold cool to room temp and cleaned again
tried again set pot to 700 degrees..
Now heres the issue .. I have a small band on one side of the boolit just above the crimp ring that is hazed and shrunk in .. I have only seen this once and that was with a Lee 308 230 Long Boolit... cooled the mold and all was well ..
tried that here and I get unfilled bands .. so not sure what to do
any help would be appreciated
Thanks
Smoke4320

[dragon813gt]

Turn up the heat. They like to be run hot. The minimum I cast HPs w/ is 725. Do you preheat the molds on a hot plate. This helps a lot w/ his molds. For future there was no need for the comet. Spray w/ carb cleaner, heat cycle then lube and start casting. The molds have minimal oil on then when you receive them and require very little cleaning.

[Maximumbob54]

Agree with more heat. And preheat the mold. I'm casting from a cheap Lee pot and I just crank the dial to 10, melt everything down with the mold resting above, then as soon as they drop correct I reduce to 8 but usually go back to 9. I'm glad some people can cast in the 600's and low 700's but I need at least mid 700's for just about all of my molds to not drop lead raisins.

[Smoke4320]

yes I use a Hot plate and the mold was very hot .. will try running the melt temp up more and try again

Thanks
Smoke4320

[Rattlesnake Charlie]

Try pouring the alloy in faster, even causing some pressure. I think this may be an void where it is not venting before the alloy solidifys. Running at a higher temperature may solve it as more complete venting may occur before solidification begins. I have a couple of molds that seem to do better when filled under pressure. I use a ladle, so am pouring with the ladle about one inch above the mold. I keep a pour on until the sprue has been filled for a second or so. It makes a mess, but comes off in one large sprue chunk.

[Smoke4320]

Thanks Rattlesnake Charlie
Using a bottom pour pot and have at least a 1/2" between the spout and mold and pouring the cavities very quickly but I can try dropping the mold even further down for more pressure
Thanks

[mold maker]

The smaller and lighter a boolit is, the faster cycle, and hotter mold, it takes to produce quality. Also try tipping the mold slightly to create a swirling flow into the mold. The turbulence may eliminate the missing band.

[MtGun44]

Pressure comes from holding the spout against the sprue plate, forcing
lead alloy into the mold.

Cast faster.

Bill

[Smoke4320]

I should have stated before This is happening only on the third cavity (counting from front of mold) Also after careful study its only happening on the same side of cavity #3.
3 of the 4 cavities are casting fine with no more than 1 grain difference and most within 1/2 grain in the approx. 170 cast so far .. weighing approx. 143 HP and 147 solid
Tried upping temp to 725 and 730 ..tried pouring 5 casts per minute, 4 casts per minute .. even tried casting all other cavities for 6 to 10 times then only casting #3 once.. surprisingly this worked once then back to same issue ..
here are pics of the boolits .. When they come out of the mold the shrunken area is also frosted
77905
all help, ideas are appreciated ..

[Tatume]

Keep turning up the heat until your bullets frost. Frosted bullets are fine, but if you don't like them that way, now turn the heat down a tad. Run your pot at the highest temperature that will not frost, or a little more and let it frost.

[prs]

I agree with the statement by MTGUN44, hold closer to up pressure. It probably IS the mold's fault, since your screw-ups would show in all or random cavities. Use a dental pick to gently trace the vent lines at that cavity. Not trying to modify the mold or to etch the brass, but rather making sure there is no blockage there from the diatoms in the Comet. Using comet on molds? Why? I use Dawn to scrub with soft toothbrush, then a good hot rinse with water, then brake clean, and finally 90% isopropyl. Even at that a brand spanky new mold may need a few heat cycles to come around to my way of think'n. With the vents assured to be clear, use a shorter drop and good steady rate of flow with a good generous spru puddle. Angle pour does often help and "ratteling" the mold a bit can help it breath too. Good luck!

prs

[mold maker]

A problem that happens to only one side of one cavity consistently, indicates the problem is with something amiss with the mold, surface. I'd give it another serious cleaning and inspect it under high magnification. You may find there is distorted brass at that point on the mold.
What the picture shows is a minor imperfection, that likely wont effect performance.

[Buzz64]

MP mold ? - try 755 degrees -

[hunter74]

Had the same problem with my 140 gr 9mm mould. The problem cavity had burrs in it. When i got the cavity smooth the problem went away when operated at 730 F. And abowe

[tward]

+1 on the heat. Ran my 4 cavity 180 gr 38 mold at 770 yesterday, brass loves heat add Cramer pins = more heat. Tim

[popper]

casting all other cavities for 6 to 10 times then only casting #3 once.. surprisingly this worked once then back to same issue .. Mould problem. As the flat is perpendicular to the mould half, it could be venting problem. Could be an actual flat in that cavity that disappeared when handle pressure is less. Could be a hot spot in the mould as you state it's frosted there. That problem would most likely be a return. If a deep HP I'd say that is going to be a weak point, especially in that long nose bore-rider.

[Smoke4320]

MP mold ? - try 755 degrees -
don't you start losing tin at about 750 degrees?

"If a deep HP I'd say that is going to be a weak point, especially in that long nose bore-rider."

its on the Flat Point bullet ..I have it setup to do front 2 as HP and back 2 as solids

[Smoke4320]

Ok I upped lead temp to 750.. let everything settle.. mold on hotplate ..
second pour I am getting good boolits .. even cavity 3 just has small frosted spot in the normally indented area.. after 6 pours problem returned on cavity 3 .. the hotter it got the worse the indention is and always in the same spot

[Buzz64]

Two things I'd check. Casting speed - are you keeping up with the mold cooling? Second is as stated above, check the vent lines and make sure they are clear. After that - I'd suggest sending a pic to MiHa and see what he says.

[dragon813gt]

It's odd that the frosting is only in one spot. This is leading me to think it's a problem w/ the brass itself. I've always seen an entire frosted bullet.

[freebullet]

Clean the cavities with a solvent soaked q-tip.

[freebullet]

Also try adjusting the alloy. I have a mp 200-45 its very alloy sensitive, what normally works for other molds just won't make good boolits in that mold. Add a trace of lino.

[Smoke4320]

"Casting speed - are you keeping up with the mold cooling"
Thanks for the reply but it gets worse as the mold gets hotter so don't think its not casting speed.. if I slow down and let the mold cool or skip that cavity for 6 to 8 pours the problem lessens..

"Clean the cavities with a solvent soaked q-tip."
cleaned with dawn and comet twice cast at least 200 bullets then cleaned with dawn again
then tried Carb cleaner cold and twice hot.. done that at least 4 times now
even tried smoking the mold
I am at a loss on this one

[freebullet]

Sounds like its plenty clean. If a few alloy adjustments don't make the difference I would contact Mihec. Post a pic of the offending block if you can. Maybe some folks here that could spot an issue for you. I got the same mold but haven't had a chance to break it in yet.

[dragon813gt]

Also try adjusting the alloy. I have a mp 200-45 its very alloy sensitive, what normally works for other molds just won't make good boolits in that mold. Add a trace of lino.

Really? That is the easiest casting mold I have. It rains bullets no matter the alloy once the mold is up to temp. The alloy really shouldn't be an issue w/ the mold unless you have some really weird percentages outside the norm.

[44man]

I recently had occasion to use one of his brass molds and found there IS a heat problem. I had to run the Lee pot at 800* and work fast. The brass seems to cool quick and more in spots. There are hot spots too. This was my first experience with brass and I don't like it.
I got at least 25% rejects with one cavity not filling the base and a hot spot at a GG.
Holding my ladle the right amount of time had the sprue harden on the ladle.
The mold is a work of precision but now I don't like brass.