Fillout

[PuppetZ]

So I got this new C312=155-2R from Lee. I have a weird thing happens consitently. The rear(meaning the closest to the handle) cavity wont fill out properly. No wrinkle or hollow but rounded GC shank. It happens only with the rear cavity and not the front one. I thought maybe it was a venting problem due to the proximity of the sprue plate hinge and lossened the screw a bit but no luck there. I tried lowering alloy temp, raising temp, casting faster, slower, tried different pour speed. Nothing did the trick.

I wonder if anyone has a mold that does this thing and what do they do about it?

[DrCaveman]

Hmmm pretty much got me stumped. Not that I am an expert.

You didn't mention filling the rear cavity first as an option. That is something I have done to even things out from time to time. Seems to distribute heat differently within the mould.

Other than that, my guess wold be that your mould isn't up to temp. Try dipping it in the alloy for 10-15 seconds, see how your results differ.

[DrCaveman]

Bear in mnd that the GC shank will most likely be covered with a GC so rounded corners there shouldnt matter. My experience with this boolit (through CZ 527 in 7.62.39) has required GC to avoid leading the barrel. But I may improve yet, am still horsing around with cooling methods, lube, and sizing diameter.

[PuppetZ]

Tried that too. I literally immersed it in the alloy to make extra sure it was hot. Did not change one thing except the sprue took forever to solidify and boolits came out frosty like the great white north. Weird I tell ya.

Edit : now I come to think of it, the fisrt few after the lead bath looked much better fillout wise, but merely took a few cycle to start messing again.

[Cadillo]

As the Caveman said, try altering the order in which you fill the cavities. I figured this out when I got my first brass mould, which gave me problems similar to what you describe. I reversed my cavity fill order, and the problem ceased for me. I think it has something to do with mould heat distribution and retention.

I also found that using brass moulds, I have to run my melt quite a bit hotter, 700 degrees F, in order to keep my cavities filling properly. The brass moulds just seem to require a higher mould temp to maintain proper fillout.

[PuppetZ]

I'll try even more heat and change the fill order then.

This mold does not seem to heat up as much as my C309-180-R. That one does fillout properly but I have to keep it very hot or it wont work well. Perhaps the lighter 155gn cavity just does not hold enough heat to keep the mould to optimal temp. Will have to try that. Thanks for the ideas guys.

[runfiverun]

i swap on some of my steel molds for the opposite reason.

[220swiftfn]

If everything else is good, it's either a venting issue, or the sprue plate is cooling off too quick. As others have suggested, cast the rear cavity first, and maybe give it more of a sprue puddle to try and keep the plate temp up.


Dan

[geargnasher]

If you use the proper pour technique and temperatures, there's no need for the mould to vent at all.

Gear

[44man]

If you use the proper pour technique and temperatures, there's no need for the mould to vent at all.

Gear
That's right but the way I pour, I need some vents. I made vents too deep on one mold and if the mold gets too hot I get nice branches to hang lights on! :veryconfu A fingernail fixes the boolit.
I started cutting vent lines just .002" deep only on one block and it is working great.
I have never wanted a gang mold so all I made are two cavity. I make blocks large to hold heat.
I would alternate every pour if one cavity is a problem. Start by pouring a bunch in the offending cavity and then move to alternating.
I cast everything but pure lead at about 750* but I have a slow, even pace when I cast, even stepping out of the garage to water the grass without losing a boolit! :bigsmyl2: I have had as many as three double cavity molds running but it is a pain to get the third mold to temp. A propane torch speeds things up. I pre heat to 500* but my mold furnace is small.

[Shiloh]

I've engraved a couple of LEE molds in problem area. Now they run great.

Shiloh

[runfiverun]

you could open the part line at the top of the mold for a little more venting if nothing else works.
just a quick trip or two down one side with a stone or fine toothed file.

[gwpercle]

Did you make the proper sacrifical offerings and prayers to the casting gods ?

Sometimes prayer helps. Exorcising the demonic spirits that possess some moulds is at times required. I have had some success by cursing at it , and threating it with a lementing job using comet .

If all else fails send it back to Lee , they have excellent customer service.
Some times they just wont cast and it's so frustrating to keep trying to find out why and trying different everything you can think of to get it to work......
Life's too short for all that aggrivation.

[375RUGER]

If you don't ladle pour then ignore this.
try tipping the mould sideways press the ladle against the sprue, turn uprright, a dwell of 2-3 seconds is probably enough, tip the ladle away letting some pour out to make a sprue.
I've never cast from bottom pour pot so I don't even know if you can press the mould up against the spout.
This method fills out so well that I can't even use it on my 360-158 because it will leave a flash at the base of the boolit.

You could also try adding some venting on the top of the block at the problem cavity.

I've also swirl poured to help base fillout.

Or just do what gwpercle said and burn some ghost money.

[PuppetZ]

I switched cavity fill and raised the pot temp a bit too. I have kind of random temp control as I heat my pot over a camping stove. I then started casting as fast as I could and leaving very generous sprue to heat up the mould as much as I could. I had perfectly filled out boolits out of the 2nd pour with 20 defective out of about 400. I guess it's a characteristic of this aluminum mould. You gotta be in a hurry to cast well with it.

[Old Caster]

Yes you can pressure pour with a bottom pour pot by pressing the mold right up to the spout which is similar to ladle casting. Make sure if you do this that the spout isn't open too much where lead comes out too fast or lead will squirt out of the top like a faucet. This method will make bullets exactly like the mold so if the mold isn't top notch, it will give fins or a a flat on the base like you mentioned. I have a 358477 Lyman that will do this. -- Bill --

[PuppetZ]

If you don't ladle pour then ignore this.
try tipping the mould sideways press the ladle against the sprue, turn uprright, a dwell of 2-3 seconds is probably enough, tip the ladle away letting some pour out to make a sprue.


I might give that a try next time I'm playing with my new toy.

[220swiftfn]

I switched cavity fill and raised the pot temp a bit too. I have kind of random temp control as I heat my pot over a camping stove. I then started casting as fast as I could and leaving very generous sprue to heat up the mould as much as I could. I had perfectly filled out boolits out of the 2nd pour with 20 defective out of about 400. I guess it's a characteristic of this aluminum mould. You gotta be in a hurry to cast well with it.

Yeah, the blessing AND the curse of aluminum molds is the heat sinking of the material.


Dan