crystalized lead - what's this about?

[Skip62]

I'm new, need help. Why is the lead like this?

Thanks

79832

[btroj]

Looks like high Sb alloy that cooled pretty slowly.

[geargnasher]

I agree with Btroj. Depending on what you want for alloy, you can try adding about as much pure lead as you have alloy in the pot, put in a pinch of tin (1-2%) to give the antimony something to mix with, flux it with some sawdust, and have another go.

Gear

[Skip62]

Great, I thought it was going to be bad....lol Will do.
Thanks.

[Defcon-One]

Exactly! It looks like normal Lead Alloy with 3% or higher Antimony content. You know, like clip-on wheel weights

[btroj]

The slower it cools the bigger the crystals can grow.

[Skip62]

hmm, so this leads me to another question. Ever since using this batch of lead I get small voids in the bottom of my bullets where the sprue is cut. Since you are saying it's cuz it is cooling slow, if I WD, will that stop that from happening? It's 100° here in Texas and cast in the garage, so cooling slow doesn't surprise me.

[btroj]

Nope. That void is from either the sprue breaking instead of cutting or from shrinkage due to a too small sprue.

Try cutting the sprue a bit sooner and see if that void goes away. Sprue plate lube will be your friends here, it keeps lead from sticking to the plate and mould. If it is from shrinkage a slightly larger sprue will help.

[Skip62]

hmm, the void isn't there when I cut the sprue, only later after it's cooled. I cut pretty soon, and use 2 cycle lube. Pretty good size sprue, and I've even cast sprue from 1 hole to the next. It's not on every bullet, maybe 1 of 30 or 40.

[btroj]

Then try waiting just a touch longer before cutting the sprue. Bullet metal is instill shrinking and pulling from the sprue.

You don't see the hole right away as the metal covering the void may be very thin, it shows up later if that metal is disturbed.

This is all part of the "art" of casting.

[Skip62]

Ahh, gotcha, thanks. I believe it is an art. Some days, great results, and everything is easy, other days.....not so much...

[btroj]

Time, give it time. After a ton or two it all gets easier.....

[Skip62]

LOL, well I've only done a couple hundred, now I don't feel so bad...lol

[geargnasher]

The little "goat arses" hurt nothing as long as they're consistent and centered in the base. Bubble voids near the edge of the bases can blow out into the first lube groove and create a bit of leading and spoil the shot, so I tend to cull anything that is a true void but don't worry about a puckered crater from shrinkage directly under the sprue hole. If it bothers you or the puckers are inconsistent due to technique, try pouring a bigger sprue to keep the sprue plate hotter and waiting a couple seconds longer to cut it like Brad said, that will continue to "feed" molten metal to the base while it cools and shrinks. Extending the time it takes to freeze the sprue/boolit will give that extra dab of metal time to flow. Sounds like you're well on your way to getting the hang of this, enjoy! PS, whereabouts in our republic are you located?

Gear

[williamwaco]

When the mold is full and you have a sprue puddle on the top of the sprue plate . . .

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.

.

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The mold is not yet full.

As the bullet hardens, it shrinks and pulls in more melt from the sprue puddle - if it can.

If the sprue is too small or not hot enough, this doesn't happen and you can get anything from a slight dish to a pin hole to a larger void and even worse you can have a void that is hidden by a thin base cover and is not visible until you poke it with a sharp object.

Note that these voids are not related to the void you get when the sprue plate rips out part of the base during the cut leaving a ragged hole.

[Skip62]

"goat arses"....BLAHAHAHAHAHAHA that's a good one. There aren't many, 10 out 500, and I just dump them back in, but it's good to know not worry about them. Not sure it happened at all in the batch yesterday, lest not that I've run across yet, so maybe I am getting the hang of it. I watch the puddle dimple, then it frosts over, then it turns almost white, that's when I cut the sprue.

Thanks guys, I couldn't get through this without y'all.

oh yeah gearnasher, Carrollton, just north of dallas. I tried to look up you coordinates, but google maps didn't like it

[geargnasher]

One of my coordinate numbers is bogus to protect the innocent (only 60 minutes in a degree, you know), but I'm about an hour's drive NW of San Antonio. I used to work for Boeing at Corinth just across Lewisville Lake from you, but haven't been back up there in many years.

Williamwaco hit another home run with his post above, he described what's going on with voids and keeping the mould hot enough for the sprue to remain a fluid reservoir for adequate base density better than I did.

Gear

[John Boy]

Then try waiting just a touch longer before cutting the sprue. Bullet metal is instill shrinking and pulling from the sprue.A simple cure for voids in the bullet bases is pour for 5 seconds and based on the melt temperature, cut the sprue when the puddle frosts in 5 seconds

[Magana559]

Keep the mold and sprue plate hot so you get clean cuts.

[Larry Gibson]

I agree with Btroj. Depending on what you want for alloy, you can try adding about as much pure lead as you have alloy in the pot, put in a pinch of tin (1-2%) to give the antimony something to mix with, flux it with some sawdust, and have another go.

Gear

Gear better watch out, you're soundi g like me......might ruin your reputation. .....LOL....

Larry Gibson