Cast bullet imperfections

S

south.texas.dead.I

New member
Ive been hanging around the forums here for a bit and am noticing some really good looking casts and had to wonder how they became so. Here are some of my bullets from a normal casting session. I know the wronkles are caused by not having enough heat but what would y'all suggest these imperfections are result of?
These are .401 165grn lee swc with a lee pot set at 7.75/10


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Kinda hard to tell, look frosty to me. Fill-out looks good but sometimes the Lee moulds like to run hot and get frosty. My RD 460-350 bullets look like that when my mould is happy.
 
I know they look fine, it's just that I've always been so competitive and wanting to be the best or have the best cast bullets at least ;)


Living another day
To bust another clay
 
Look good to me, will be hard to tell with a couple of coats of LLA anyway. I cast some nice purty bullets now and then but it seems some alloys and moulds are better off frosty. I think a finely machined and polished custom mould will drop a shinier bullet but for now I'll make do with Lee and Lyman. I have a Lyman or two that might get polished, then maybe I can cast purty bullets too. ;)
But seriously, proof's in the pudding...on the target.:D
 
Shiny finish doesn't shoot any better than frost ones. Shoot 'em!

If you really want to get OCD about them, then lap the cavities with a very fine polishing compound, run your alloy at just over melt and your mold at just under melt, then don't worry about water dropping. But keep in mind the moment you tumble lube them it won't make a squat bit of difference anyway--they'll all look the same and won't shoot any better.
 
From what I can see from those lousy cell phone pics, they're just fine. The TL lee boolits always look like that. You're never going to get them shiny.

To be called imperfect, they would have to have major voids, wrinkles, and poorly filled out bases. Lube and shoot them, they're fine.
 
Get a thermometer & monitor ya temp , frosty is OK but if temp gets in the 800f range & the mold gets too hot the tin will start to "cook" & voids such as this
102_0417.jpg


Will start hapening, these 2 were cast seconds apart . I had to start alternating first pour & slow my pace ,the temp of the alloy was 755f.
 
GP100man said:
Get a thermometer & monitor ya temp , frosty is OK but if temp gets in the 800f range & the mold gets too hot the tin will start to "cook" & voids such as this
102_0417.jpg


Will start hapening, these 2 were cast seconds apart . I had to start alternating first pour & slow my pace ,the temp of the alloy was 755f.
Click to expand...

I'll try turning the temp down a bit thanks for the pics


Living another day
To bust another clay
 
Those bullets look pretty good. Watch your temps and make sure that you've got enough tin in the alloy. It doesn't take much tin, but a little always helps. Don't let your mold get too hot. One trick I've learned is to get a small pan with shallow sides and put a water-soaked cloth in it. When the mold starts getting too hot, I'll simply put the bottom of the mold on that wet cloth and the heat will flash the water into steam. The escaping steam uses BTUs quickly and the mold will cool off.

Frosty bullets don't bother me. I've always believed that the frosty ones hold LLA better than the shiny ones. As long as the bullets are showing good fill-out, without voids and wrinkles, then you're good to go.
 
The top bullet of that pair looks like one from a cool melt where tin has separated, or a cold mold, to me.
I don't think I've ever had rounded edges from having bullets too hot.
My only problems casting hot are that Lee aluminum molds start experiencing dimensional problems (finning, bad venting, sprue plate scraping on the mold body,etc). I just cool the mold with a cloth if that starts happening
 
Ps.

They were poured into the Lyman 2 cavity 314299 seconds apart, the top bullet is from the cavity I always filled first thus giving the mold longer to absorb heat & getting too hot.

They don`t gotta be shiney , I strive to see a parting line that`s when ya know ya alloy is hunting every nick & scratch to get into !
 
Something else to look at as a cause for wrinkles and poor fill-out is oil in the mold, or clogged vent lines.
Wrinkles are not always caused by low temp.
 
The top bullet of that pair looks like one from a cool melt where tin has separated, or a cold mold, to me.
Click to expand...

Tin does not separate from an alloy. Tin and lead and antimony are true solutions, meaning they're not easily separated. Tin will "cook out" if the alloy is heated much over 750 degrees, the tin-lead-antimony mixture is exposed to the atmosphere at the surface of the melt. Tin oxidizes much easier than lead or antimony. Therefore it forms a scum on the surface of the melted lead faster than the other two metals.

A fine point I know, but the old myth that lead, tin, and antimony separate is just that, a myth. The theory that because tin is lighter than lead, it separates into a layer on top of the lead.

Now about the cleanliness of the mold, oil or some other contaminate can make for wrinkles and poor fillout. But they always do it until they are either removed, or burn off. They just don't do it now and then.

I take a new mold, or one that I've stored for a long time with preservative grease on it, Boil it in very soapy water,(Dawn), for ten - fifteen minutes. Then a rinse in very hot water. This will remove darn near anything that would otherwise cause wrinkles, or poor fill-out.

Another cause of poor fill-out is pouring technique. Some molds must have the stream of lead go straight down the sprue hole. Some demand the lead be poured on the taper of the sprue plate to swirl the lead into the cavity. Some molds demand to be pressure poured, the ladle in contact with the sprue plate with the weight of the lead creating pressure on the cavity.

I find pressure pouring important with big boolits like for my 45/70. Most others work well with my bottom pour lee 20 pounder with a mold guide. The guide helps make the location of the stream consistent from one to the next.
 
Tin does not separate from an alloy. Tin and lead and antimony are true solutions, meaning they're not easily separated. Tin will "cook out" if the alloy is heated much over 750 degrees,
Click to expand...
I know that tin and lead (and antimony if present) form a eutectic mixture and stay together to reach a lower solidus than pure lead, but the "separate" vs "cook out" is a little too fine of a distinction for my brain, snuffy. :) I'm still seeing liquid piled on liquid and not dissolved in it.
So how does that define its behavior well above the much lower liquidus/solidus temp, which is what we're talking about above 750F? Or are you saying that a eutectic solution like PbSn or PbSnSb can only be separated into its constituent part by oxidizing/reducing?
 
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