first time 6 cavity mold learning curve

[oley55]

First time casting with a 6 cavity mold and struggling a bit. Brand new MP 452-200 FP NLG, (https://www.mp-molds.com/product/mp-...o-lube-groove/) cleaned and heat cycled in hotplate-oven a few times. Warmed to 400 degrees with sprue plate face down on aluminum block with drilled holes so the sprue plate would have full contact (pic). Alloy is COWW with 1.0% tin added. Lead temps 700-740 degrees (most at 740). As cast: .453" and 225.4gr. The weight is a little surprising, but I am OK with it since I was on the fence for choosing a 200gr vs 230gr.

Struggling to find the correct flow rate. Too fast and the sprue is running all over the mold, too slow and I get fine lines in the bullets. I like the slow trickle, but not with the lines (even with a fully up to temp mold). The sprue cutter handle worked it's self out and before I noticed it the wood handle split (sorta fixed now). I think I was squeezing it to hold the mold closed (I did have a couple pours where the mold was not fully closed). At any rate I stopped gripping the sprue cutter handle during a pour. One things for certain, if I do not have a hefty sprue puddle, the bases do not fully fill out.

Somehow I managed to get some lead splatters on the face of the mold and was getting finned bullet bases. Wiping it hot didn't work and had to stop until I could do a thorough cleaning. I think I may have gotten some splash splatters while cutting/dropping the sprue into the pot. I don't normally do that, but with those huge 6 cavity sprues it seemed like a good idea to instantly recycle them. I stopped doing that during my next session.

At various times, I had some trouble with the sprue adhering to the sprue plate and leaving behind residue surface lead, but could be wiped/rubbed off with a cotton rag. Not sure if that means the plate was getting too hot or what...?

I had a few occasions where for no apparent reason all or most of the bullets came out very rough (pic). Eventually I determined this only seemed to happen if or when I had left the bullets in the mold for a longer period while wiping off the top and sprue bottom. (I think...?) Over all most are a little rougher than I'd prefer. Wondering if I am waiting too long to cut the sprue, but I hate to see those sprue pull outs from cutting too early.

With the number of rejects I had, I suspect my production rate would have been far greater with a two cavity mold. I hope that's just the learning curve and not the norm for a 6 cavity.

Input and critical observations will be much appreciated.

[Dusty Bannister]

I operate my bottom pour pots at one flow setting, wide open. The operator has to learn when to shut off the flow at the correct time. It also helps to tilt the mold away from the empty cavities to avoid overflow accidentally spilling into the cavity. What did you lube the exterior of the mold and sprue plate with? The alloy might be a little too hot and the mold might like a couple more heat cycles to build up a patina so the wet lead does not stick to the mold.

[bangerjim]

Just takes practice. I have MANY (!) 6 cavity molds in Al and brass and once you figure out their unique characteristics, 100% quality boolits will rain down!

Nothing happens without practice. Just keep at it, tweaking your methods to find out what works. I now never use anything less than a 4 cavity brass mold. 1 and 2 cavities are a waste of time for me unless it is for some weird boolit design I need from the past. I rarely use those anyway.

good luck and keep up the practice! Nice thing - - - - bad ones remelt very easily!!!!!

[oley55]

What did you lube the exterior of the mold and sprue plate with?

Initially I had rubbed it down with a carpenter's pencil. After the stuck splatters on the mold top, I used a cotton rag with a whisper of the gray Permatex Never Seize on it.

[Targa]

Ill just add that if you are doing one continuous pour try pouring each cavity separately. Once you get the hang of it then pour a continuous sprue. As for flow rate, like mentioned previously, I want mine wide open especially with cavities as big as your mold.
Your bullets look pretty darn good to me, they will definitely do what they were cast to do.

[Bull-Moose]

Bullets look nice and consistent. Keep practicing and you will find a tempo that produces exactly what are are wanting.

[Conditor22]

" Warmed to 400 degrees with sprue plate face down on aluminum block with drilled holes so the sprue plate would have full contact (pic)."

aluminum block with drilled holes I like this and have thought of doing it several times. Many molds are going with thicker sprue plates that take longer to warm up/

Yes, MP makes nice mold BUT I feel they put the cavities too close together increasing the learning curve and ease of using the mold.

Unless your bottom pour pot has a small spout, I found that pouring wide open will blow lead back out of the cavity.

Struggling to find the correct flow rate. Too fast and the sprue is running all over the mold, too slow and I get fine lines in the bullets. I like the slow trickle, but not with the lines (even with a fully up to temp mold). The sprue cutter handle worked it's self out and before I noticed it the wood handle split (sorta fixed now). I think I was squeezing it to hold the mold closed (I did have a couple pours where the mold was not fully closed). At any rate I stopped gripping the sprue cutter handle during a pour. One things for certain, if I do not have a hefty sprue puddle, the bases do not fully fill out.

IF you put any pressure on the sprue plate handle it will force the mold cavities open.

When you find the right rate of flow for the mold and filling technique you'll be knocking out great boolits

[oley55]

reference any pressure on the sprue plate handle will force the mold open. I can not imagine mine is unique but it only opens the mold blocks when it is nudged or pushed away from the mold handles. When squeezed into the mold handle it has no effect on the mold blocks. at least that’s how mine works.

I am using a Lee 4/20 and yes when wide open the lead flow seems to shoot into the cavity with enough force to push the lead right back out. have been experimenting will directing the flow to the side of the cone opening but with little to no success.

[Dusty Bannister]

With the 4-20 it helps to adjust the mold guide for best location under the nozzle. If it shoots back up, you are not hitting the hole, but bouncing the stream off the cone of the sprue plate. Since you are having so much trouble, drain half the pot and start over with less head pressure. Also, maybe you are not keeping a consistent distance from the nozzle, I like about 3/8th inch to clear a sprue puddle as it becomes solid. Once you have figured out the right distance and position of the mold you can add more alloy to the pot.

It should be considered to place the pot at a convenient and stable height so you can see what you are doing and then make adjustments from there as you become familiar with the process. I would have expected that with the experience you have, this would not be a problem. Unless the nozzle has been altered.

[dannyd]

You going to shoot those at Gateway

[Wheelguns 1961]

I keep a rag dampened with 2 stroke oil near me when casting. After I cut my first sprue, and before I dump the bullets, I give the top of the mold and the bottom of the sprue plate with this rag. It stops any lead from sticking to either.

[oley55]

yep, it's a bit of a ride for me from far NE JAX (off the Nassau River), but I do enjoy shooting there.

[oley55]

I keep a rag dampened with 2 stroke oil near me when casting. After I cut my first sprue, and before I dump the bullets, I give the top of the mold and the bottom of the sprue plate with this rag. It stops any lead from sticking to either.

I'll give that a try.

[bruce381]

look fine powder coat and size