Hollow Balls

[A Nimrod]

What would cause me to have air pockets where I cut the spur off when I am making .490 RB at 14.3 BHN ? And one more thing when I am making my 535 Lyman Postel 45 bullets I have a wide range of bullet weights like from 534 to 558 ? Too hot too cold what ?

TIA a Nimrod

[mooman76]

The wide range you are getting is from the air pockets! I don't know your methods of pouring so I can't tell how you are getting air pockets! I would say too cold if anything. Try cranking the heat up and make sure you are pouring the lead smoothly as to not trap air!

[MT Gianni]

Dipper or bottom pour, Are the moulds vented well, do you do the same pouring technique every time? Lots of unanswered ?'s out there. Gianni.

[A Nimrod]

I use a dipper and bring the dipper up to the mold and stick the spout into the pore hole on the mold and I use a 15 and 20 count. Could sticking the spout of the dipper in the mold trap some air in there ? I don't have a way to check temp of lead is there a way to judge (guess) the temp, if it is bubbling is it too hot ?

a Nimrod

[Old Ironsights]

Increase the temp of both your lead and the mould.

Your lead is solidifying too fast for complete fillout.

Contrary to popular belief the "frosted" balls you get from having your lead "too hot" is of no consequence for 99% of RB shooting.

OTOH, having badly wrinkled of balls with voids will totally wreck your accuracy.

More Heat.

[jh45gun]

Contrary to popular belief the "frosted" balls you get from having your lead "too hot" is of no consequence for 99% of RB shooting.

Would'nt that tend to frost your balls

[versifier]

I agree with the others on the heat issue. At the very least, the mould is too cold. You have to run pure lead hotter than the alloys. You don't say what you are melting it in, might be a lead thermometer can help you. Up close to 800*F is what you need for the pure stuff. That is the most common reason for voids in your boolits. Make sure you put the bottom of the mould into the molten lead to heat it up before you start casting.
Like Gianni said, check to make sure the vent lines in your mould are not blocked. That often causes incomplete fillout and is easy to overlook.
Get a Lyman dipper, if you don't have one already - the little spout on them makes everything much easier and none of the other brands I have seen have one. Try not putting the dipper directly in contact with the sprue plate. Hold the mould level and let the molten lead drop 1/2" or so when filling it. I have found that most of my large boolit moulds do not work well with the dipper in direct contact, though some of the smaller ones do. With some moulds you need to hit just off center with the stream so that it swirls in. I get voids in .54 MaxiBalls if I don't swirl it in, even with a bottom pour pot.
Consistant technique makes for more uniform boolits.

[Old Ironsights]

14.5bhn is also decidedly too hard for a ML - unless you are undersize for your bore and are using a thick patch.

And forget about using them in a C&B gun.

Why are you using alloy for RB anyway?

[Bent Ramrod]

Also, make sure you have a good puddle of excess lead in the sprue. Big bullets shrink as they cool, and can draw a surprising amount of bullet metal down from the sprue puddle. If the puddle is too small, they will pull a bubble of air down into the center of the bullet.

[44man]

I guess I am different in that all of my best balls and boolits come from tipping the blocks and ladle up together. I keep them tight together so there is no lead leakage past the ladle snout. I then hold it there for quit a while before tipping off. I will see the lead in the ladle go down, stop and then it goes down more. By keeping them together, the molten lead in the ladle keeps the lead in the mould molten longer. When my sprue hardens, it hardly shrinks at all. I figure if the sprue gets a big shrink hole in it, the mould was not filled enough. I don't want the mould to suck a bunch of lead in from the sprue.
The larger the boolit, the longer I hold them together, works for me! I also cast very hot and it takes a while for the sprue to set. I never get larger shrinkage then about 1/64" in the center of the sprue, most times less.
As you can tell, I work slow and with my mould preheated, boolit no. one is perfect and is the same as boolit no. 100. I absolutely HATE rejects!

[fiberoptik]

Hollow balls.... Sounds painful! =8:^)

[powderburnerr]

I am with 44 man here tipping the mould slowly while married to the ladel makes a lot of difference. also drilling out the dipper spout helps a lot pouring big bullets my ladels are all drilled out as big as possible ... I mostly cast pure lead 45 s up to around 565 to 570 gn wt, and have very few rejects . when I get real anal and want long range bullets I cast using a clock keeping each step the same time ... doing this I can keep a 1/2 gn spread all day.........Dean

[redbear705]

Mostly a vent problem.

Atmosphere has to have a way to get out of the way when the lead comes in the mold cavity.

Try holding the dipper/ladel a little way from the sprue when filling and tipping the mold slightly while filling will let there air out...just tip the mold up straight when done pouring.

And a small puddle on top of the sprue will also help stop the voids.

JR

[d.thomson]

I agree with what I have read, and in my limited knowlage I find getting the mold hot in the melt so that lead dosn't stick, leaving a puddel on top of the sprue helps to get full fillout. I have also found that if I pore fast ( abit slopy) I also avoid getting rinkels. I have found a slow pore no matter how hot the mold or lead I was getting wrikled balls. I pore just off the sprue hole and let it swerl in. Just my 2 cents Dave T.

[R.M.]

44Man

You say" I don't want the mould to suck a bunch of lead in from the sprue."
I think most here would agree with me in saying that you do want to see the sprue sucking down into the ball. This is where you get rid of the air pocket.
Also, it seems to me that you're running things on the cool side.

Just my 2 cents worth.
R.M.

[MT Gianni]

Rm I think 44 man means he wants voids filled in his casting process so that he doesn't see a lot of sprue shrinkage. In essence solving the problem before it occurs. Gianni.

[Dale53]

It is also helpful to let some lead run over the sprue plate (and drop down into the lead pot if you are using a dipper). This keeps the sprue plate hot and the metal is kept liquid just longer enough to "fill that hollow". I bottom pour and even with this method I run extra metal onto the sprue plate keeping it hot.

Dale53