I'm having trouble getting my molds to fill out completely

[m1garand_man]

I have been having trouble getting my molds to cast completely filled out bullets with out casting at temps above 700F. I experience the most trouble with large molds like for my 58 minie balls and long small diameter molds like for my 30 cals.

I use some aluminum block molds as well as the steel Lyman ones and have the same problems with both. Should I just turn up the heat or is there something I can add to the lead or spray in the mold that will help?

[ratboy]

are you preheating the molds?

[m1garand_man]

Yes I set the molds on the led pot to heat them for abotu 20 minutes first. After casting for about 15 minutes the problem stops but I thought any temp over 700F was way too hot.

[GRUMPA]

I typically cast at 750 or just slightly above from my bottom pour pot. I don't know what set up your using but since it cast all right after using it (same as me) everything works fine and I'm good to go. The one thing I noticed when I cast is when my nozzle from my bottom pour starts to plug up my boolits look funny. But I go at such a rapid rate that I don't notice anything till that happens.

[94Doug]

You probably need to speed up your cadence initially....your mould is probably cooling down between casts just enough to give you the problem. Once you're up to temp, you can adjust the speed a bit.

Doug

[Heavy lead]

Hotter moulds, same or a little less temp. with the lead.
You can always try pressure casting too, this may especially help with the long skinny boos.

[leadman]

Depending on the pot you are using the mold made not be up to temperature. I have an RCBS pot and my molds do not get hot enough by just setting them on the top edge of the pot. I usually dip a corner in the hot alloy before I start casting, even with the iron molds. Lee's instruction say to preheat using this method.

[462]

" After casting for about 15 minutes the problem stops..."

There's your answer...your mould is finally coming up to its optimum casting temperature. Try pre-heating your moulds on a hotplate, rather than setting them on the pot.

Your pot's temperature is okay.

[Gtek]

What composition are you using? WW, Stick ons, Certified, Range scrap? 700-750 should do anything required. Cadence, pour ,watch change in plate, cut, dump. I count in my head once the pattern of keepers starts. Every mold, alloy, day is different. Big=faster, smaller=slower, it is 90% mold temp with me. 1%-2% tin added on tough ones, depends on mix. One day it just gets easier, trust me. -Gtek

[jsizemore]

What alloy are you using?

About the time I ask somebody beats me to it.

[geargnasher]

I have been having trouble getting my molds to cast completely filled out bullets with out casting at temps above 700F. I experience the most trouble with large molds like for my 58 minie balls and long small diameter molds like for my 30 cals.

I use some aluminum block molds as well as the steel Lyman ones and have the same problems with both. Should I just turn up the heat or is there something I can add to the lead or spray in the mold that will help?

Ok, like the last two guys said, what are your alloys?

But first understand these two things:

Mould temperature is the determining factor for fillout, sharp edges, and no wrinkles.

Alloy temperature does NOT have anything to do with how well your boolits fill out, but it is important to maintain it at about 100 degrees over the point that the alloy is fully molten, no hotter unless using pure lead, then go to about 800 or so, or the point that the surface becomes a light straw color. Purple is too hot.

Pure or near-pure lead is the only boolit metal that you can gauge temperature by color, if you add any tin or antimony the surface oxidizes to a dull aluminum color.

To get the mould hot enough to cast, dip one corner in the melt for at least 30 seconds. dip the tip of the sprue plate also, then dip the corner again, then start casting FAST, like four pour cycles a minute until the wrinkles go away. Time it. Four pours a minute, don't look at them, don't pause with the mould hanging open, don't scratch behind your ear, just focus on pouring, cutting, and dumping as fast as you can until the mould heat becomes even and sufficient for fillout. You'll know when you finally get it hot enough, should take less than 20 pours at most, only three or four if you preheat properly.

Pure lead is a pain to cast unless you get it really hot. You can do this with pure lead because there aren't any other metals in there to harm or oxidize out of the melt through excessive heat. Wheel weight metal or any alloy containing a significant amount of tin (1% or more) shouldn't be over heated, meaning don't run it over 750 degrees ever, 700 is usually plenty.

Hope this helps.

Gear

[m1garand_man]

I've tried pressure casting and I usually have decent results in the small dia molds but get air pockets in the large ones.

This problem occures with all my alloys from roof flashing and recovered 22lr bullets to recovered centerfire bullets and WW lead.

I have a LEE pot that has a spout on the bottom. I think that model is the production pot.

I havent tried the hot plate method yet but I think what I really need to do is up my temps.

[Bret4207]

Mould temp and pot temp are apples and oranges. Pot temp you establish with the thermostat. Mould temp you control by your casting rhythm. Every second that mould is empty it's cooling down. Stop looking at the pretty boolits and pick up the casting pace till you start getting frosted boolits, then you can slow a bit. You'll figure it out pretty quick..

[44man]

Gear has it, pure lead needs to be hotter.
Bret also has it, casting speed.
You would do better with a ladle for the Minie' balls.

[docone31]

I put kitty litter on my melt. On this, I set my mold prior to starting my casting.
When I cast, I use the six second rule.
If the sprue freezes less then six seconds, it is too cool. Longer than six seconds, too hot.
Kitty litter also helps keep the tinsel fairy away when I put rejects in the melt.
You will get it down pat.

[918v]

What I do is I mate the ladle spout with the sprue plate hole and hold them together for three to five seconds. That way the melt in the ladle keeps the melt in the mold melted and hot. I get razor sharp bases that way. Pouring from above drops the temperature of the melt and requires both a higher starting temp and faster operation to maintain the temp of the mold. There's a reason the spout is pointed.

[williamwaco]

Yes I set the molds on the led pot to heat them for abotu 20 minutes first. After casting for about 15 minutes the problem stops but I thought any temp over 700F was way too hot.


You just answered your own question. Your mold is not hot enough.
Mold temprature is much more important than alloy temperature.

I am not a fan of preheating molds.
It probably would work ok with a separate hot plate but I get much better results ( more good bullets in less time ) if I just start casting with a cool ( back porch temprature ) mold.

I start casting and cast as fast as I can without being wreckless or careless. I fill and dump without even looking at the bullets. I don't even drop them on my drop pad. When the sprue puddle remains liquid for two or three seconds, I mover over and drop on the drop pad. I keep casting fast until bullets begin to frost. Then I slow down to a normal cadence. Cast, wait for sprue to harden, dump, leave mold open while inspecting the newest bullets, then close the mold and repeat. This procedure takes about fifteen to thirty fillings of the mold depending on whether it is aluminum or iron. ( oh yes, during this warm-up, pour as large a sprue puddle as possible, The large sprue puddle will transfer a lot of heat to the mold.

Depending on your mold and your natural body rythms, you may need to speed this up or slow it down.

Don't worry about your metal temprature. If your bullets frost, slow down or set your mold in front of a small fan. When your bullets begin to not fill out or wrinkle, speed up.

Another tip. If you are casting along fine, and suddenly for absolutely no reason one or two cavities begin to refuse to release their bullets, you mold is too hot. And yes, a single cavity of a six cavity mold can do this.