Casting problem

[Possum]

I am casting some 429244 & 429421's as well as multiple 44 cal Lee bullets. I am noticing I am getting a little tear on the top of the driving bands when I look at the bullet from the nose down. It is like a little crack on one side of the bullet driving band.

At first I thougt it was the molds, but it has happened in most of the molds I have cast. I am guessing it is happening when I rap the mold handles to drop the bullet? I do put some solder in the mix and then cast from straight WW. Has anyone had this problem and what did you do to solve it. Maybe I am casting too fast?

[44man]

Try waiting for the sprue to set longer. Most guys don't realize how soft the boolit is when they cut too soon and how much it can be distorted, even twisted. Even opening the blocks with a dead soft boolit can damage it. Think what would happen to engine blocks and cast gun parts if molds were opened when the metal was still molten.
There seems to be a contest about how many boolits can be turned out in the shortest time. Use Bull plate lube and you can cut while pouring!!!! Makes little sense to me.
Use Bull plate lube, slow down, make great boolits and be a lot happier.
Blocks can get too hot also and bleed lead into the air vents causing what you are getting. Check to see if they are blocked.
If you are bottom pouring, check the hole in the pot and clean it out. Watch the flow from the bottom, any change in it and you will get bad boolits. A bit of slag in it can direct the lead stream crooked. That hole is such a pain, I stay with a ladle but remember that the ladle hole must be kept clean too.

[Buckshot]

"Try waiting for the sprue to set longer. Most guys don't realize how soft the boolit is when they cut too soon and how much it can be distorted, even twisted. Even opening the blocks with a dead soft boolit can damage it."

.............Yup, the boolit's are still too soft (hot) and not competely set up yet. The smooth nose prolly tips away from the blocks and the drive bands crack down close to the body (at the bottom corner of the lube grooves. Been there, done that. Got frosty boolits too?

..............Buckshot

[9.3X62AL]

This same problem was one I had with a couple molds I use regularly, and about a year ago I lowered casting temp for my alloy (92/6/2, mostly) from 800* to about 675*. The disappearance of these cracks--a gain of about .001" to .0015" in diameter--and more consistent weights were among the results.

The chief offender during the earlier time was the 45 caliber Lee 405 plain base FN, and lowering the melt temp turned it into a real enjoyable tool to use. I have noted positive results from aluminum, steel, and iron molds by lowering the melt temp with lead/tin/antimony alloys. I still heat things up past 800* with unalloyed lead, though--and wait to cut sprues and open the blocks.

Use of 2-3 molds in serial sequence might be an answer to folks bottom-pouring their metal, and concerned about lack of production or "time-wasting" while waiting on castings to "freeze" properly. When using the 92/6/2 alloy, I almost always cast with 2 molds at a time.......and in concert with the lowered temps, my casting quality is a 90% to 95% "keeper rate" with most pistol boolits once things are up to temperature.

[Dale53]

I have a clock near my casting set up. Long ago, I determined that waiting six seconds after the sprue "changed color" insured that the bullet was "set" and safe to drop onto the padded bench. I cast ww's + 2% tin for pistol bullets and cast from 750-800 degrees (mostly around 750). I use a good thermometer.

Dale53

[44man]

Dale, remember my post where as soon as my sprue sets, I swing my arm 3 times? I timed it and it is 6 seconds. Works like a charm and I don't have to watch a clock. Yeah, guys made fun of me!

[26Charlie]

Possum - particularly with those 44 bullets, if the blocks are just opened by the handles, the blocks pry open first at the bottom and that puts a torque in the vertical direction on the bullet, which can crack the driving bands as you described, when the bullets and blocks are hot.
I put a little opening pressure on the handles, not so much that they actually open, then rap the side of the block at the bottom with the sprue cutoff stick (a broken hammer handle, in my case) - it seems to pop them open straight and avoid your problem cracks. Its really not too tricky to do this - try it to see what I mean.
Other answers are valid too - I like to use two or three moulds at the same time and get ten castings with each - typically twenty bullets with a two cavity mould - before going to the next in rotation.

[Ricochet]

I cast a whole bunch of hollow points once that ended up with eccentric nose cavities, from not letting the boolits harden enough before removing the pin and opening the mould.

[Possum]

Just got back from the range/farm. Yep, you guys are correct, I do hurry when I cast and that is probably the problem. Just read a few casting books on the way home and they said the same thing.

And yes, Buckshot, the bullets are frosty - how did you guess:-D

I'll try slowing down this week and see what happens. It seems like I have to get the mold really hot to start casting filled out bullets. Maybe I will crank the heat, then lower it down for the rest of the casting session. Thanks for all the responses. I knew there would be a good answer when I got home.

[Dale53]

Dale, remember my post where as soon as my sprue sets, I swing my arm 3 times? I timed it and it is 6 seconds. Works like a charm and I don't have to watch a clock. Yeah, guys made fun of me!

44man;
I actually only watch the clock to set my "inner clock" - what I do is to count "1000, 1;
1000, 2...

Besides, I go to the gym three times a week for a workout:mrgreen:

Hey! Whatever works, right?:Fire:

Dale53

[44man]

COUNT???? I done did forget how! My mind is somewhere else when I cast, can't fill it with numbers. I would lose track after 1000-2.

[MT Gianni]

I hate to give away another mans secrets but when Bullshop was in MT I bought some ww & lino from him so he didn't have to move it to AK. He had a large old school clock next to his casting bench that had a very audible tick, usful to keep on a rythm in casting. Gianni.