Inclusions.

[huntinlever]

Just finished quenching oven-treated bullets from a lengthy casting session today. Seeing them in the light of day leaves me pretty disappointed. I think they're riddled with inclusions but I can't figure out why. I've done nothing different - mold is on a hot plate, fluxed with sawdust, scraping pot down well and making sure it was thoroughly clean before ladling. Air-cooled on a thick cotton towel, sorted, oven-treated and quenched. Most came out this way. May be hard to see:

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Any ideas?

[BLAHUT]

Lead to hot ??
Shoot them and see ?
May not be a big deal ?

[Randy Bohannon]

What’s the point of quenching and oven baking ? All unnecessary steps for cast bullets since they will return to the alloys composition in a week or two. What did they look like before ?

[huntinlever]

What’s the point of quenching and oven baking ? All unnecessary steps for cast bullets since they will return to the alloys composition in a week or two. What did they look like before ?

I used to just water drop as I cast, and as Bigslug reminds me (a good thing), I'm probably worrying too much about a brush gun's accuracy needs, but have been trying casting, air-cooling, oven-heating then quenching in icewater. So that all bullets go into the drink at the same temp, in an icewater that is the same temp for the entire batch (as opposed to a water quench that heats up as the casting session progresses).

Here's a comparison. 46-425Q with Ben's Red, from 2015.

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I'm wondering if I'm just casting too hot?

[huntinlever]

Lead to hot ??
Shoot them and see ?
May not be a big deal ?

I'm wondering if I'm just casting too hot. The last photo I posted was from the 46-425Q, years ago - and the gun loved it. I need to go back and see what I was doing right, and what I'm doing wrong now, I think. Those bullets were much, much better.

[leadhead]

I don't think there's anything wrong with your bullets....
Size, lube, and shoot and see.

[Hannibal]

I don't know what you are using as a lead source but inclusions are contaminates such as dirt or perhaps even flux residue. You probably already know that so I apologize if I'm stating the obvious.

I had similar problems in the past and I learned that the best way to eliminate that was to make sure to keep the casting pot as clean as possible. I smelt all my alloy in a separate process to get it as clean as possible and cast it into small ingots. Only those ingots go into the casting pot. I also found that using wax for a flux in the casting pot caused inclusions so I switched to wood shavings and had much better results.

I'm not going to try to say wax causes this every time. All I know is it caused problems for me and when I switched to wood shavings there was immediate and obvious improvement. Perhaps it was the particular wax I have, I don't know about that.

[Winger Ed.]

If you can see dirt specs, it isn't fluxed enough.
I'm seeing just a hint of frosting from high heat--- I like mine like that. It usually leads to a nice crisp fill out.

Do your own research, but I'd shoot 'em and rock on.
Like they are, I don't think you'll lose any more than 1/2-3/4" group size at the most until you got on out past 100 yards or so.

[huntinlever]

I don't think there's anything wrong with your bullets....
Size, lube, and shoot and see.

Thanks. You and Blahut are probably right, as usual I'm overthinking it. My guess is that I may be starting out at 725 but either with overruns or not checking the temp better as the pot empties out, I'm climbing in temp. But I think you guys are right - I don't think it's due to dirty alloy, anyway.

Much appreciated guys. Off to make me some MILD 5744 loads. Wish me luck, 'cuz I ain't had any yet with anything but the teeth-rattle levels...

[huntinlever]

Whoops, crossed in the mail Hannibal and Ed. Thanks as well guys. Yep, I smelt in a cut-off propane tank, and work really hard to make clean alloy before even getting into the casting pot. Then I use sawdust only, scrape the pot and stir the carbonized dust in pretty rigorously, and try to make sure it's really clean of all contaminates before casting. I'm almost positive now it's exactly what you're thinking Ed. Have to shoot them. Bummer. :Fire: :mrgreen:

[Winger Ed.]

Have to shoot them. Bummer. :Fire: :mrgreen:

They look OK to me.
Weighing some will be the real test of their initial quality. Even then, keep the same weight ones together.
They'll impact differently if the weights vary....... What they look like,,, not so much.

At any rate--- I wouldn't just jump up and re-melt them.
I used to tell the young kids I worked with:
'Don't make extra work for yourself..... Plenty of other people are more than glad to do that for you'.

[huntinlever]

They look OK to me.
Weighing some will be the real test of their initial quality. Even then, keep the same weight ones together.
They'll impact differently if the weights vary....... What they look like,,, not so much.

At any rate--- I wouldn't just jump up and re-melt them.
I used to tell the young kids I worked with:
'Don't make extra work for yourself..... Plenty of other people are more than glad to do that for you'.

Thanks Ed, always good advice. If they're good visually, I accept 390.0-391.9 and remelt the culls. I know that's probably too tight, but...I'm uptight, I guess. :roll:

[huntinlever]

Guys, side query and apologies as I've looked but can't find it, but I seem to recall Larry Gibson and at least one other member giving recommendations on how long to let cast bullets "rest" after cooling/quenching/drying, whatever method, based on the alloy composition - in particular, antimony, before sizing. Something along the lines "3% antimony, let it go X hours before sizing," "6% antimony, let it go [longer] before sizing," on the idea the bullets will continue to expand for a period and if you size a bullet containing X% antimony too soon, you'll find it's not truly sized but will be larger after all is said and done.

Any thoughts on a 94-3-3? Rest 24 hours, then size/gas-check? (I size 0.460", but lube in the lubrisizer at 0.461", so no more work softening at that point).

[justindad]

I reject boolits with inclusions on the driving bands, because I have an unproven concern of barrel leading. Inclusions could also cause a bullet to fracture when you want it to expand. Probably the most practical concern is an imbalanced rifle boolit going 300 yards, but I just do pistols.

[dverna]

Maintaining pot temperature is important and I believe it is important to maintain level in a bottom pour pot.

The best way to control temperature is to use a PID controller and they are not too expensive.

Anothe option is to buy a thermometer.

Here is one I bought years ago similar to what I have:
https://www.rotometals.com/lead-bullet-casting-thermometer-6/

Good advice to shoot a few groups and see how the bullets perform.

[Bird]

If the driving and lube bands are well defined there should not be a problem. If you are ladle casting stop using sawdust. Bottom pour don't matter too much, as junk will float to surface.
Weigh a few and see if there are any inclusions or voids.

[huntinlever]

I reject boolits with inclusions on the driving bands, because I have an unproven concern of barrel leading. Inclusions could also cause a bullet to fracture when you want it to expand. Probably the most practical concern is an imbalanced rifle boolit going 300 yards, but I just do pistols.

Yep, I do too, the bands issue. It's been hard for me to accept minor imperfections on the nose, but if the bands are clean and it's within weight specs, and just a very (very, can't stand it otherwise) minor imperfection on the nose and....ogive, is that what it's called?...I'll at least take them once load development is complete.

Thanks on the fracture note, wouldn't have thought of that. Thankfully about 125 is my likely limit with this 45-70, for me. Hats off to guys like Blahut who can shoot a wing off a fly at 500 yards with their shoulder artillery!

[huntinlever]

Maintaining pot temperature is important and I believe it is important to maintain level in a bottom pour pot.

The best way to control temperature is to use a PID controller and they are not too expensive.

Anothe option is to buy a thermometer.

Here is one I bought years ago similar to what I have:
https://www.rotometals.com/lead-bullet-casting-thermometer-6/

Good advice to shoot a few groups and see how the bullets perform.

I might need to go bottom pour again - started off casting years ago with the Lee unit but got pretty frustrated with the dripping (or stuck open) spout and at some point went to ladle casting. More and more reading you guys, I can see I was probably complacent - wanted to load up a bunch of bullets so I went through 2X near emptying of the Lee furnace - so not only was I drawing down the level but my method of "how long does it take for the sprue to frost" method of parsing the temp dial is a pretty lousy way to do it.

Only rigged up a PID one time before, for a cheese vat using a hotel-pan warmer. Good project. Thanks for the tip.

[huntinlever]

If the driving and lube bands are well defined there should not be a problem. If you are ladle casting stop using sawdust. Bottom pour don't matter too much, as junk will float to surface.
Weigh a few and see if there are any inclusions or voids.

Thanks Bird. I moved to ladle casting almost as soon as I began years ago, and have almost always used sawdust (v. beeswax - only a few times). I scrape really hard and am religious about getting the alloy clean. Is there something about the sawdust I might be missing?

[Dusty Bannister]

What’s the point of quenching and oven baking ? All unnecessary steps for cast bullets since they will return to the alloys composition in a week or two. What did they look like before ?

Heat treating and quenching does not have any affect on the alloy composition. Perhaps the post was intended to suggest that the alloy hardness age soften very rapidly. That is also incorrect as shown in the information from the LASC site.

We have all heard that heat treated bullet alloy will age soften over time but how much and how fast does this occur? While cleaning out the cabinet under my loading bench I came across a couple of box's of 35 caliber, RCBS 200 gr. heat treated bullet's properly labeled with the alloy (clip-on weights + 2% tin), the date and a BHN of 30. They were over 10 years old so I figured they would be putty by now but they tested at 26 BHN. 10 years, how is this possible? Taking from the "Key To Metals" article the antimony content of at least 4% and a low tin content controls the age strengthening and age softening of the alloy. It seems that if the percentage of tin had been higher or the percentage of antimony lower (or both) age softening would have been faster. With the box of heat treated bullets was a box of 7mm bullets of the same alloy and with the same date but not heat treated, the label said 11 BHN. In 10 years they also age softened and now test at 10 BHN.

[Hannibal]

Heat treating and quenching does not have any affect on the alloy composition. Perhaps the post was intended to suggest that the alloy hardness age soften very rapidly. That is also incorrect as shown in the information from the LASC site.

We have all heard that heat treated bullet alloy will age soften over time but how much and how fast does this occur? While cleaning out the cabinet under my loading bench I came across a couple of box's of 35 caliber, RCBS 200 gr. heat treated bullet's properly labeled with the alloy (clip-on weights + 2% tin), the date and a BHN of 30. They were over 10 years old so I figured they would be putty by now but they tested at 26 BHN. 10 years, how is this possible? Taking from the "Key To Metals" article the antimony content of at least 4% and a low tin content controls the age strengthening and age softening of the alloy. It seems that if the percentage of tin had been higher or the percentage of antimony lower (or both) age softening would have been faster. With the box of heat treated bullets was a box of 7mm bullets of the same alloy and with the same date but not heat treated, the label said 11 BHN. In 10 years they also age softened and now test at 10 BHN.

My understanding is that lead alloy will age harden over time, not soften. Pure lead does not have this property. I'm no metallurgist so I won't attempt to dispute others but the alloy I have used displayed hardening. All I can speak to is what I've personally observed.

[huntinlever]

Well, couldn't be more night and day. For the above photos, I'd started casting at 725 but didn't account for overrun - I saw this morning that where I'd set the Lee brought this alloy to 750+, not 725. I do believe at least for this alloy, with whatever I'm doing for process, it is too hot.

725. Never let the pot empty to less than roughly 3/8 original volume. Rest the ladle on the sprue plate and poured smoothly but moderately. 15 seconds set, cut sprue, wait 5 seconds, drop onto towel. Several hundred cast, and unlike yesterday with much more than what I thought were "inclusions" to worry about (many were finning, etc.), not one bullet lost to visual inspection. Weight sorting, treating, sizing, lubing and loading after maturation.

316057

Thanks again all.

[justindad]

Them is some good looking boolits.

[huntinlever]

Them is some good looking boolits.

Thanks much!