Hardness testing procedure questions

[knotbrush]

It was simpler when I was dealing with only one alloy. Now I have accumulated a number of batches of wheel weight, range lead, soft lead and Linotype. I feel I need to get a handle on the hardness of each batch both air cooled and water dropped. Typically I cast 18 boolits each of air and water cooled, wait a day or so and test the hardness with the Lee Tester Kit on three boolits and average the numbers.

One of my molds is a Lee 6-hole .358 TL DEWC. It has a nice nose that has a very slight radius. Can I use this nose for testing? It sure saves a lot of time filing and polishing to get a testing surface on the side. I've heard (not tested) that water dropped boolits only get a hard coating, like case hardening, and I've heard that they harden through. I've heard you can't test from the nose of a boolit or the base. I understand not using the base but why not the nose? I cast a bit hot and the 18 that I keep are only after a half dozen pours that go back in the pot to make sure the mold is up to temp.

What if I made a mold that has a square profile by milling 3/8" wide x 3/16" deep by 1/2" long slots in a 2-hole mold blank? Would those slugs be better for testing? I'm trying to avoid the filing and polishing of a testing surface. (Besides, I'd love to make some square boolits to give to my reloading buddies!)

[Bret4207]

I would combine everything but the linotype and mix it all up together. Then see what you have. If you really, really need a harder alloy (which you may not) I'd juice each pot with some linotype.

Bhn reading is just a relative number, it doesn't mean a harder alloy will shoot better.

[Bass Ackward]

Two ways to look at this and it depends on your personality.

You can mix it all together and get one consistent batch that once you figure it out that you won't have to make any adjustments.

Or, you can use it to experiment. What you will find out is that different designs work better at different hardness's and diameters. Bad news here is that your test results will be valid in THAT gun with THAT design, with THAT lube, shot around the temperature of the gun itself.

Contrary to board doctrine, AC or WD will continue to harden at different rates for 30 days. As they get harder, they will grow. Or not. So shoot your bullets when they are the hardness you want and don't wait for "complete" hardness.

[Charlie Two Tracks]

I don't know how much of each type you have. If it's a couple hundred pounds of each, then I would test each batch. If not, then I would go Brret's route. As Bret says, BHN can vary quite easily. What is the temperature that you cast at, what is the outside temperature that the boolits are exposed to while casting? These guys told me that FIT is king. That sure seems to be a very accurate statement for me. As an example, I had some Missoure Bullet .358's that were a BHN of 18 (before I started casting) and I would put 7 grains of Unique behind them. I cast some WW that had a BHN of 14 (with tin added) and they shot the same. I had some lead that was BHN 11 and they still shot the same. All were sized to the same diameter. I do like the square boolit idea.
Bass Ackward posted as I was typing this. There does not seem to be any hard and steadfast rules in casting. About the only thing that will stay the same for each caster is: THAT LEAD IS HOT AND WILL BURN YOU BAD IF YOU MESS UP. I may be wrong but that's about the only rule applying to casting that is the same for everyone. Great hobby and sure is fun

[btroj]

I have three main piles of ingots. Pure, range scrap, and lino. I just put in the pot what I think will work for whatever I am going to cast. No weighing or measuring, just a couple ingot of this and a couple of that. If I want harder than I normally get from water dropping I might add a half pound or so of magnum shot.
That is about as scientific as I get. My bullets may harden, and grow, over time like Bass said. I can't say for sure as I don't measure either. I just cast em, lube and size em, and go shoot em.
Don't g et too wrapped up on a specific BHN. It is a number. It gives you a relative measure of hardness but it does not mean a whole lot. Let the gun tell you what hardness you need. It will be the final judge anyway.

Brad

[Bass Ackward]

I think I misread. Are you talking about making a slug to do hardness testing itself?

IF so, then it would depend on your testing method. I do have an LBT tester that if you get off to the side of the nose, will give you a softer reading than if you do it dead center sometimes. I just don't worry about hardness to that extent. I am more concerned about consistency from slug to slug myself.

[Shuz]

knotbrush--I've been using a Saeco hardness tester for over 25 years and have found it to be very reliable and consistent. What works for me is to use a Lee 44-200RNFP as a test slug.
Like you describe, I get the mould hot and then pour a few samples with this mould and let them air cool. If my alloy is going to be heat treated eventually, I will then water quench a few and mark the bases and noses with a black magic marker. Both samples are then stored in small medicine bottles with alloy composition as best determined by what I used to make up the alloy. These bottles are then stored in the same coffee cans as the ingots for future reference.

[mpmarty]

I cast straight WW and if I'm feeling generous I'll throw in a few monotype pieces. I have a LEE hardness tester that I seldom use at all.

[fecmech]

Why not just test the ingots, they've usually aged out and are air cooled, at least mine are. I don't have a tester so I just squeeze a ball bearing between a pure lead ingot and the test ingot and do the math. I may be wrong but I would think a month after you cast your bullets they would be pretty darn close to an air cooled ingot. Obviously this doesn't work with water dropping and heat treating but it does give you IMO a very good idea of the base metal hardness you're working with.

[lwknight]

The ingots will not give you the same hardness as the actual boolits because of the larger mass of the ingot , the coolig rate is much slower.

[geargnasher]

Two ways to look at this and it depends on your personality.

You can mix it all together and get one consistent batch that once you figure it out that you won't have to make any adjustments.

Or, you can use it to experiment. What you will find out is that different designs work better at different hardness's and diameters. Bad news here is that your test results will be valid in THAT gun with THAT design, with THAT lube, shot around the temperature of the gun itself.

Contrary to board doctrine, AC or WD will continue to harden at different rates for 30 days. As they get harder, they will grow. Or not. So shoot your bullets when they are the hardness you want and don't wait for "complete" hardness.

That was part of the question, too, the way I read it.

FWIW, I make huge batches of "working metal" which does general duty, this is where all the accumulated odds and ends get thrown together every year or two and re-alloyed in a new batch to be used for 90% of all my shooting. Loads are adjusted accordingly for each caliber each time the master batch is redone.

I keep a few hundred pounds of certified alloys of various compositions and some pure stuff on hand for making some specific alloys when needed.

That's just how I do it.

Gear

[fecmech]

The ingots will not give you the same hardness as the actual boolits because of the larger mass of the ingot , the coolig rate is much slower.

I would certainly agree with that but after a period of time say a month or so when alloys have aged would they not be the same? My ingots for clip on wts usually measure 9-10 when first poured and a couple month's later 13-14(I always add 2% tin).

[geargnasher]

I would certainly agree with that but after a period of time say a month or so when alloys have aged would they not be the same? My ingots for clip on wts usually measure 9-10 when first poured and a couple month's later 13-14(I always add 2% tin).

No, they will not be the same. If cooled at different rates, or heated to different molten temperatures before cooling, two samples of the same alloy will have different hardness readings for years. Heat-treat lasts a long time. This assumes, of course, that the alloy had the ingredients necessary to heat-treat to begin with, mainly antimony and arsenic. The difference in hardness is due to how the crystalline structure of the antimony forms when cooling. Obviously pure lead and lead/tin binary alloy isn't subject to heat-related hardness differences.

Gear

[fecmech]

So Gear would the bullets cast and air cooled with my ingot alloy of clip on wts +2% tin be harder or softer than the ingot.?? They are both heated to about 750-800, cast, and then allowed to cool to ambient.