45-70 brass hp mold bullets sticking and poor fillout

[Strtspdlx]

I preheat the mold on a hot plate on high while the lee pot is warming up, once the pot is good and hot and it doesn't cycle on for a long time I flux the melt. once I'm done fluxing and cleaning I grab the mold from the hot plate and start pouring, I usually load up the sprue plate with lead the plate takes a ton of heat, I do this until the sprue doesn't cool in under 3 seconds, then I run the mold to the point the bullets while "release" from the mold with light taps verse beating the **** out of the handles. This sometimes takes 15-20 pours depending how hot the pot is. I have noticed that I have to crank the pot up about 2 settings verse what my 6 cavity lee likes. But my noe brass mold works about the same but I don't have fillout or sticking issues. So what I'm getting is rounded edges and the grey hue around the edges with very frosted bullets. The alloy is straight coww and I don't know temp of alloy. ive tried all different nozzle settings and found it seems to have better fillout with a hot pot and a flow that doesn't overflow the sprue funnel. more or less if I hit the hole dead on and not the funnel part I usually get decent fillout, but not always. Even when filled out I'm having issues getting the bullets to release from the cavity unless I run it to what id call ridiculously hot, but this is my first brass mold and the noe mold I have that's brass never gave me a single issue, the hp pins always release. once the bullets separate from the cavity they slide right off the pins, the pins are free as they slide super smooth once the mold is warm. and its a 300gn bullet for 45-70. I don't know if I'm missing something or if theres something I don't know, but I'm hoping someone can help me out. I'm tired of beating on the handles. I'm waiting for them to break one day, also I did go over the cavities (its a 2 cavity) and didn't see any burrs or anything that I would think could cause a sticking issue. The mold is from a very reputable maker so I think its something I may be doing verse the mold, or maybe its the design because It is a gas check design with square lube grooves.

[Chill Wills]

1)Add a minimum 3 oz of tin to a max of 6oz in your 20 lb pot.
2)You need some way to know the temp. (Get it?:p) Or your casting in the dark.
3)A dip ladle will really change your game - then you can pressure cast stubborn mold designs.

[Strtspdlx]

I tried pressure casting with my bottom pour and it gave me tiny little fins around the hp pins. I'm assuming a ladle would likely do less because it isn't 20lbs of lead. im trying to stay away from adding tin if at all possible. I only have 3-4lbs of it. But Atleast now I may try to make
my own ladle and give it a try.

[Chill Wills]

you have 3 lbs of tin in your supply = 48oz - ...maybe more.
Try 3oz in the pot (that is 1%)
You will see a big improvement
Hollow points need to be ductile to open and hold together.
Don't be stingy with the tin <G> you will find more.

Good luck.

[Smk SHoe]

Rorometals sell tin that looks like slag run off or messed up popcorn. When i have a full pot going i just grab two pieces and throw it in. I use mostly range recovered lead so it already has some tin in it. Just the little extra really does help. Have to clean some lead off the face of one of my mold because flow was so good and I must not have had it closed with tight pressure and got some flow into the vents at the bottom of the mold. Just a little bit, but it does gum up the operation till fixed.

[725]

That's when I add linotype and wipe a whisper of Kroil around the mold.

[Strtspdlx]

I did try adding some tin. It helped slightly but I wasn't getting the results I had hoped for. So I took a good hard look at the mold under magnification. Some of the vent lines where clogged up with lead. After I carefully cleaned them out I smoked the faces to try and prevent future deposits and now I can cast about 5lbs before they clog back up enough to cast bad bullets. I'm thinking I may be running the melt too hot? It's a brass two cavity hp mp mold. I'm not sure what else could cause lead buildup that quickly. It's not on the face of the halves at all. Just nicely filled out in the vent lines.

[Harter66]

Clean brass and lead tin .......

I just had a go around with a second hand mould that has a brass handle screw in it I had a devil of a time getting it in unscrewed to change handles .
I've heard of tinning on brass , the vent lines will be the most protected faces on the mould and most likely the last to patina , nonstick oxidizing .
So I've read anyway.

[Strtspdlx]

Harter66: with that said would you recommend throughly cleaning the mold and heat cycling it more to try and oxidize the vent lines?

[Soundguy]

frosted = too hot. get a thermometer. I prefer the rcbs, but there are a few out there in affordable range.

[Strtspdlx]

Rorometals sell tin that looks like slag run off or messed up popcorn. When i have a full pot going i just grab two pieces and throw it in. I use mostly range recovered lead so it already has some tin in it. Just the little extra really does help. Have to clean some lead off the face of one of my mold because flow was so good and I must not have had it closed with tight pressure and got some flow into the vents at the bottom of the mold. Just a little bit, but it does gum up the operation till fixed.

sorry I just read this after I had posted. But yes I think my primary issue is the vent lines clogging up. Now I need to figure out a permanent fix. I can clean them but doing it every 5lbs or so is a pain in the rear.

[Strtspdlx]

frosted = too hot. get a thermometer. I prefer the rcbs, but there are a few out there in affordable range.

i did just hook up a pid. I had it running about 750 and poor fillout with clogged vents. Then I ran it up to 800 and if I was quick enough it would fill out. Then I realized the vent line clogging issue and cleaned them and ran it back to 750 and it was fine but still clogging. So I went to 780 and still the same issue.

[Harter66]

I don't have any brass moulds and I'm just a lowly mechanic .
I have a iron mould that grows whiskers down the vent lines .

The stick and flow will go away with use , I believe that " a good cleaning" would have the opposite effect . I would try several things if it were mine . The sprue plate/mould face NOE lube instructions applied to the vent line faces would probably do the trick . I've smoked a couple over the wax smoke a time or two to encourage patina in a fussy AL mould .

Pure mechanic speculation based thoughts .

[Strtspdlx]

I'm a technician also. I get where you're coming from. That's why I smoked the faces to try and minimize any sticking. It was a lot less to clean out. I suppose I'll try the noe mold instructions. I did just recently purchase one of their molds.