359 125grn flat based

[RedHawk357Mag]

Was kinda wondering what temps others are using with this mold. I fully understand that my temperature, Alloy, casting techniques will be different and even the personality of my mold. I normally get away with 700ish for alloy temps, lower with ladle being able to pour more heat. But I am trying to figure out how to bottom pour with this mold. I quit at 730 degrees,the other day. This is probably the highest temperature I have casted at to date. I bump up five degrees each "toe dipping". I use a pretty good hot plate with a saw blade with a big honking tin can for a mold oven. I am getting incomplete bases in the first or sometimes the second cavity. Sprue plate is free to swing. It came extremely snug. My plan is to keep bumping the heat up until the bases start doing better 50 percent. I am new to this smaller bullet I have casted 357 158s, on up, 40s, 44s. I casted with the Lee six cavity 125 RNFP and it pretty much rained great bullets no matter how I tried to stymie it [emoji1]

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[Southern Son]

What alloy are you using? Is it in the Lee alluminium mould or another? I have been casting 50/50 (WW with pure Pb, and a little tin) in a MP made mould for my 9mm. The boolits are 128grains and hollow points, and the mould is a 4 cavity brass. I have been running the pot at 750 degrees.

[RedHawk357Mag]

Alloy is bullet scrap with just a hair over 2 percent tin. The mold I am currently working on is the group buy mold that recently completed, brass. The only experience with this lite of bullet is a aluminum 6 cavity by Lee the 125 grain rnfp. Thanks for sharing your temp information. I suspect that I will find the sweet spot in a higher temp as well.

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[mnewcomb59]

That mold is very easy casting. Leave a large, continuous sprue across all the cavities. Like a half dollar sized sprue puddle should do well until the mold gets fully up to temp. If you don't leave a generous sprue puddle, there is no pressure forcing the lead into all the corners of the mold.

You may have a venting problem. Occasionally if I can't get a mold to cast, I will put a light 45 file cut along the top of the mold halves. Now when they meet up, there will be a small trough for air to rush out. I have also been known to use a triangle file across the inside of the mold halves to make a vent on the base driving band. Go slow when you are experimenting with adding vent lines. They just need to be big enough for air molecules, hardly even need to see light through them.

[runfiverun]

if it's a brass mold it needs a couple of things.
the first is heat.
the second is patina.
the little boolits don't add as much heat to the mold so you need to add it more often [cast faster] and more of it.
if it's the boolits bases cover more of the mold's top with more heat.

[RedHawk357Mag]

Thanks everyone for the information provided. I will definitely give the information a try I will say that I have been using nickel sized spru puddles. Thanks again.

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[farmerjim]

Is this the Lee 358-125-RF ? With this mold I use a Lyman MAG 25 set at 725. I use 2 alternating molds. I make sure the stream is going straight into the sprue hole, and fill in one large continuous pour. The lead will cool to 710 when I add preheated ingots, but still fill out fine. If I hit the side of the sprue hole I will often get a incomplete fill of the base. I cast these boolits by the many thousands for 9mm 38sp and 357 mag.

[RedHawk357Mag]

I am sorry wasn't clear about the mold. The one that is being obstinate is the recently completed group buy from Mihec. I am pretty sure it's me not the mould. This one is the only one I have been kinda slow to understand what it is trying to tell me. Definitely gonna go with a larger sprue puddle and maybe cast a few hundred with a ladle and see if that helps with seasoning.

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[reddog81]

I have found that you not only need to mold to be hot but also the sprue plate otherwise you will encounter this problem. If the sprue plate is not hot enough the lead at the very top of the mold will cool before getting complete fill out up there. Like others have suggested using larger sprue puddles on the top when first casting will typically alleviate this problem.

Making sure there is enough tin and a high enough temperature are also necessary, but will cause problems throughout the rest of the bullet and not just the base.

[RedHawk357Mag]

Well... Got to do some more work with this mould. Today I used a two and half quart cast iron Dutch oven it holds around 36 to 40 pounds of Alloy. Alloy is my own processed bullet scrap with just a touch over 2 percent tin. Has worked very well in the past for 9mm, 40, 357/38, and moderate 44 magnum. Mould preheated on very good hot plate with saw blade bottom with a big tin can to enclose it. Started with 600 to 650 degree alloy using a Lyman ladle. Absolutely would not work. The alloy would not flow into the cavities. Alloy was to cold and poured huge thick slabs for sprues. Tried the Rowell one pound ladle, this hummer can heat a mould up really well. All I could accomplish was first filled cavity the other three cavities had a small ball of lead in nose cavity of the molds. Changed to new tank of propane and kicked the fire up to just over 700 to 720. Skipped Lyman went straight to Rowell, extreme frosting, excellent bases. Too hot. Turned fire down to around 675 to 680, put mould back on the hotplate. Once I got my Temps started again with Rowell. Nice bases slight frost overall. Turned the fire down some keeping an eye on temp. Around 650ish fourth and third cavities started throwing incomplete bases. Timing... Each cavity was a five count pour, at 675 a ten count to solid sprue additional 5 to 7 count for proper cutting hardness. Less than five seconds in a pour resulted in incomplete fill in bases. Between pours a ten count with blocks apart and plate away from blocks. Normally I do five count between pours. Less than 10 would be heavy frost with bullets spot frosting almost appearing white instead of gray. Based on today's pours the Lyman nor the bottom pour can make decent pours on this mould. This mould is by far my most difficult mold and that's even before trying the hollow point pins. I am guessing with the extreme pour times and alloy flow I have venting issues? Key points, 675 degree alloy, five count pours, with 17 count cooling before cutting sprues, resulted in frosting but use able bullets. 700 degrees extreme frost. 650 results in one filled out first cavity three cavities of balled alloy in nose cavity. To get filled out bases requires a large amount of pour over in each cavity. Thanks if you made it this far.

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[RedHawk357Mag]

So today I. Worked with this mold again. Took a small jewler file and LIGHTLY filed the top edge of both mold halves. Scared the whole time so I was very light handed. The mold works flawlessly now. Turns out it just wasn't venting.

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[Bullwolf]

I've also experienced this with a couple of "fussy" moulds that just did not want to completely fill out the boolit bases no matter what I tried.

Filing a light bevel on the top edge of the mould blocks, just underneath the sprue plate made it go away. Remove just enough metal to allow air to escape from the boolit cavities.

You can do this with a jewelers file, an Arkansas stone, or even some wet/dry paper. File a LIGHT bevel only on the top of the blocks. It doesn't take much. Remember you can't easily put the metal back, if you go to far.

If you experience finned boolit bases after, then you've removed too much.

Ben has a real nice write up (with pictures) and results in the link below.
Base Fill out (http://www.artfulbullet.com/index.php?threads/base-fill-out.27/)

http://www.artfulbullet.com/index.php?threads/base-fill-out.27/

This picture from Ben, shows just how little of a bevel it takes.

http://i1155.photobucket.com/albums/p545/Ben35049/004_zpsb46866bc.jpg

What good boolit base fill out looks like.
http://i1155.photobucket.com/albums/p545/Ben35049/001_zps47daa585.jpg


http://img.photobucket.com/albums/v494/haysb/Lyman%20Mold%20Tune%20UP/025.jpg

Another excellent post Ben.



- Bullwolf

[RedHawk357Mag]

That's good information and pictures you linked to. I did less removal and it worked like gangbusters. Prior to filing little globs of lead would form in the cavity with alloy temps under 750. The globs would probably weigh about 50 to 75 grns. To get any useable bullets the mold had to be blazing hot, if I recall sprue times were like 12 to 15 seconds to cut and still have some lead adhere. To bottom of sprue plate. All good now and the bullet shoots really well. Life is good.

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