Casting lessons, I guess...

[stubbicatt]

So I traded a bunch of 223 brass which I will never use for a 50 cal ammo can full of ingots. Some of the ingots say Linotype on them, but had a suspiciously dull finish. None rings when I drop it on concrete, causing me to wonder whether there is any lino in them.

So I load up my new RCBS bottom pour pot with lead, and add "lino" ingots to arrive at an approximate #2 alloy. After some initial teething issues with the pot, I got a good rhythm going and cast a bunch of really pretty boolits.

Let them cool.

Next day started lubing some of them, and for kicks, ran my thumbnail across some. Dent. Noticeable dent. Tested some I had cast before, very small nick, but quite obviously harder than those more recently cast.

I'm pretty sure that those ingots which said linotype on them, weren't.

Next purchase will be a BHN testing tool of some sort... I'm leaning towards the Lee tool.

But until then, and perhaps it is the eternal optimist in me, I'm really tempted to run a few of these boolits through my 357 mag rifle, rather than toss the lot back in the pot and add verified linotype to increase the hardness. I loaned my Cast Bullet Lyman book out some years ago, and I don't remember who I loaned it to, but I suspect that if the thumbnail scratches them, these softer boolits will probably lead my bore to kingdom come.

What say ye, fellows?

 

[Axelwik]

Slugging your bore and sizing one or two thousandths bigger is far more effective at preventing leading than bullet hardness.

At slower velocities softer alloy is preferable.

 

[stubbicatt]

Thanks Axelwik. Bore size is .356, bullets .358. Should work then?

 

[dahermit]

So I load up my new RCBS bottom pour pot with lead, and add "lino" ingots to arrive at an approximate #2 alloy.

There is no way you can approximate Lyman #2 Alloy by mixing an unknown alloy ("marked Linotype"). It could actually be any lead alloy. There used to be informative pamphlets by Lyman as to which and how much of what to add to your pot to get #2 Alloy. But, in today's situation with lead alloys, one may not be able to get the components as easily as it used to be. It seems that bullet casting is on the decline from its heyday due to shrinking supplies of lead alloys and the caster just has to do his best to get the alloy he has obtained to shoot regardless of what the constituent parts in his alloy are. A note: Compounding the problem with formulating a specific alloy, there were several different alloys used for different printing processes (three different "foundry types", "monotype", "electro type","rules", etc.) and the layman has a tendency to be ignorant of that fact and refers to any and all of them as "Linotype."

 

[mehavey]

Next purchase will be a BHN testing tool of some sort...
I'm leaning towards the Lee tool.

The Lee Hardness Tester is a good one, and allows actual Brinell readings by diameter of the
impression left by an exact force. Just put it in your press and run the ram with the sample up into it.

The key is using a simple stand for the calibrated microscope:

 

[stubbicatt]

Da Hermit. Respectfully, I think we are saying the same thing. The ingots themselves were casted in a mould that had the manufacturer (local) and Linotype casted into them, in raised letters. Not like someone took a sharpie or something and scrawled "lino" on a generic ingot.

As I said, I don't think lino is what alloy was cast up in that mould. Without a hardness tester, which at present I lack, there is no way to know what any given ingot is composed of.

And yes, if actual lino, in equal parts with pure lead, one can approximate #2 alloy.

Thank you.

Mehavey, as always you do have ingenious methods to arrive at just the right tools for the job! From your posting I take it that you find the Lee hardness tester to be a good tool?

 

[mehavey]

The tester/little microscope arrangement above measured an impression 0.059" -- which calculates
directly to a BHN of 14.9. Since this bullet was cast from a RotoMetals alloy I got directly from
them as Lyman#2, it was spot on.

I them measured the same impression using the Celestron Digital Microscope I picked up after another
poster here mentioned using it for parts inpection, and found it measured exactly what the Lee
microscope was able to resolve.

So the Lee tester performs as advertised (as long as the microscope is given a stable fixture when reading.)

 

[snuffy]

One of the problems with Linotype alloy,(well there's more than one), is the alloy would get depleted of tin and antimony as it was run through the type casting machine. If it was not "sweetened" by adding tin and antimony periodically, it may not be full-boat as hard as it should be.

Another problem is the spacers used in some machines were soft lead. If someone was cleaning up/junking an old Linotype machine, they may have combined the soft spacers in with cast type sticks. That results in a variable mix much softer than pure Linotype.

The Lino ingots that were hung in the lead pot for the machine had hooks on the end and were 20+ pounds. Here's one I still have;

The one that's cut up and shinier I got off fleabay, advertised as pure lino. It was close but a bit softer.

The other type casting alloys mentioned by dahermit are also still to be found. Stereo type, foundry type and a couple of others are harder than Lino.

I built a wooden stand to hold the alloy being tested with the Lee hardness tester, I can't claim that kind of ingenuity just copied it. Looks like a wooden microscope. I'll take a pic of it later and post it.

Yes, the Lee works well IF you can hold the microscope steady enough to see the tiny grid inside the scope. AND get enough light on the indentation. I was told to use a driving band of the bullet, but first take a file to remove some of the surface to provide a flat for the indent-er . Theory is the surface of the lead is a bit harder than just under the surface, and you need a flat surface anyway. Some just use the nose or base, it works too.