casting problems, .309 170g

S

Shadow9mm

New member
Got a new mold in today, a Lee C309-170F, and I am struggling to cast clean bullets.

I put lead in the pot and the mold on top to warm up for about 30min.

Started casting at 700F, super wrinkly.

Worked my way up in temps in 50F increments.

Stopped at 950F as I did not feel comfortable continuing up in the temps.

At 950F the bullets all have a frosty appearance. many do not have good fill out on the grooves. Of the 100 or so I cast I only got 4 total that were clean.

What am I doing wrong? Is the mold not hot enough? I have several lee pistol bullet molds for handgun bullets that cast well at 750-800 F. I kept the mold on the pot to keep it warm between casting while letting the pot heat. I let the first couple castings at each temp sit in the mold a few extra seconds to help make sure the mold was at a good temp. Or with the long skinny rifle bulles do I just have to push the temps up?
 
Clean the mold before casting. New molds have some kind of oil on them. Carb spray, Brake cleaner, etc. all work. Wrinkled bullets is de facto evidence of oil present.
 
All molds should be cleaned, but the older style 'butter aluminum' Lee molds are notorious for having oil in that porous alloy.
Clean clean clean. Degrease as well as possible.
And even then you might have to run a couple hundred bullets through the mold before they drop clean and crisp.
 
FrankenMauser said:
All molds should be cleaned, but the older style 'butter aluminum' Lee molds are notorious for having oil in that porous alloy.
Clean clean clean. Degrease as well as possible.
And even then you might have to run a couple hundred bullets through the mold before they drop clean and crisp.
Click to expand...
well, I have close to 100 bullets through it now. Its been sprayed down and scrubbed out with brake cleaner. Got the pot and mold heating up now! We shall see how it goes! hopefully I will be able to cast at lower temps.

Update, cast about 100 bullet, still had a tiny bit of wrinkles, but it cleared up about half way through. got about 42 useable bullets from the session, not a bad start
 
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What happens ... and this happens with all aluminum moulds cut on CNC machines ... is the cutting oil molecules are forced into the pores of the aluminum ... think of the blocks as a sponge ... they soak in the cutting oil .
Heat will drive oil to the surface of a cleaned mould cavity . Clean and heat / cast about three cycles to get all the oil out .
A shortcut is to soak the blocks in a jar of acetone . I stand the blocks in a small jar , fill to cover the blocks with acetone and let them soak for 24 - 48 hours ... the acetone sucks the oil out if left ... I take alumn. foil and wrap around the jar top to get a seal ... acetone evaporates easily .
Gary
 
I have no experience casting bullets. I'm just curious.

Cutting oil has boiling point of about 600F. Casting temperature is way above that. Is it possible to heat up the mould to, say, 700F to drive the oil out of the "pores" and evaporate it? Keep cleaning with solvent doesn't sound very efficient or even effective.

-TL

P.S. I don't cast but I do own a mould, for making hot glue bullets. For that I need to oil the mould, which is opposite to casting lead bullets.

Sent from my SM-N960U using Tapatalk
 
tangolima said:
I have no experience casting bullets. I'm just curious.

Cutting oil has boiling point of about 600F. Casting temperature is way above that. Is it possible to heat up the mould to, say, 700F to drive the oil out of the "pores" and evaporate it? Keep cleaning with solvent doesn't sound very efficient or even effective.

-TL

P.S. I don't cast but I do own a mould, for making hot glue bullets. For that I need to oil the mould, which is opposite to casting lead bullets.

Sent from my SM-N960U using Tapatalk
Click to expand...
It is possible that casting bullets in an oil contaminated mold will produce an ash/burned-on stuff instead of cleanly evaporating... I will not swear to it though. Nevertheless, I have found no problems with Lee Aluminum molds that have had the oil removed with Brake or Carb cleaner.
 
I usually disassemble new molds then grab an old plastic bowl and put them under the faucet in the sink. I'll run the hot water on them till it is good and steaming. Dose it with some Dawn deterergent and let it soak till the water cools.

Bigger six cavity molds usually get this a couple of times before taking an old toothbrush and doing a good scrub with a bit more Dawn. Once done, I'll rinse while scrubbing then another soak in more hot water. Once the halves have heated back up, I set them on a paper towel and let the heat evaporate the water.

Then I reassemble using a cotton swab to apply a tiny bit if anti seize to all of the screws. Once I'm up to casting temp I'll just touch the hinges with some lube and go for it.

Usually it takes a half dozen or so throws to get the remaining oil out, and sometimes several cycles of heating and cooling off. Each mold is an intinty unto itself.
 
I find that Lee molds are a crapshoot. Some work great and other not so much. I'm not down on Lee products but this is just my observation and I have several Lee molds and I love about 60% of them and I'm indifferent on the rest... Some have a very high reject rate and others constantly drop beautiful bullets.

Tony
 
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