Type hardness

[kevin c]

So I got some type in an on line purchase. What I got was single letters in three or four font sizes and spacers. All have a rounded groove in the back. Ah, thinks I, foundry type! But some doubt remains, based on comments from wiser heads than me here, plus other reading I've done.

Talking it over with some members here, I try my LBT hardness tester on the type. The readings I get are all over the place, including different parts of the same piece of type, and none of the readings are close to the BHN for mono or foundry, and many are below 10. This is on multiple pieces for each of the fonts.

I will send samples out for XRF, but has anybody else had this experience?

[Grmps]

You need to smelt the type into ingots (mixing all the miscellaneous types together and see what the hardness is, it will get harder over time. A picture of the type would help us identify it.

This is what mine looks like it is a cross between Monotype and foundry

http://i.imgur.com/SO0mFi9.jpg?1 (https://imgur.com/SO0mFi9)

I had it tested
Sample #1
Pb = 72.0%
Sb = 17.6%
Sn = 9.4%
Cu = 1.0%
with a hardness around 27

Check http://castboolits.gunloads.com/showthread.php?204515-Lead-ID-Question-Monotype-Linotype

And search linotype ID

[lightman]

I've got 3 buckets of the stuff, all mixed up. The hardness is all over the place! Grmps has a good suggestion if you plan to use this. If you ever plan to sell it, most buyers want it in the original form.

[kevin c]

Thanks for your replies. I am just surprised that I couldn't get a reading anywhere that was over 16 for something that is supposed to be in the high 20's on any of the samples I tested. I am aware that ingot hardness will vary from cast bullet hardness, related to different cooling due to different mass and shape, and it seems a natural extension that the type hardness would vary as well, but I was getting down to 7 on slugs (I think that is the right typesetting term) no bigger than a 30 cal rifle boolit.

I will melt a representative mix to cast some boolits and to send off for analysis.

[lightman]

Its great stuff and mine tested much harder than what you were getting, but nothing was consistent. It kinda surprised me as that kind of type supposably was not remelted and recast very often. Your analysis will be interesting to see.

[JonB_in_Glencoe]

try casting some boolits, then measuring the boolits with your LBT tester.
waiting 24 hours should be enough to give you a pretty good idea what the hardness will be, but waiting 2 weeks is better.

[beemer]

I have bucket of hand set type, I guess its mono type. It's only used to harden WW as it's too hard for boolits. the ones I poured for my 303 Brit would sometimes break off at the case mouth when they hit the feed ramp.

I poured some 357's with a 140 gr. mold that ended up at 125 grs. I hope yours is more usefull.

[PBaholic]

I have bucket of hand set type, I poured some 357's with a 140 gr. mold that ended up at 125 grs. I hope yours is more usefull.

Hard alloy has less lead in it, so it weighs less.

[Hardcast416taylor]

I do as Beemer does, use the Monotype I have (a 5 gal. pail full) sparingly to sweeten a melt pot of alloy. I was given the full pail when a hospital print shop was phased out and the mono letters came my way.Robert

[lightman]

How do you measure the amount that you use as a sweetener? Mine are still in the original letter form and all mixed up. Mono, foundry and maybe some lino. I understand that if you ever sell any that the buyer usually wants it in the original form. I don't plan to ever sell and I'm considering smelting it into ingots and maybe having one tested.

[PBaholic]

How do you measure the amount that you use as a sweetener? Mine are still in the original letter form and all mixed up. Mono, foundry and maybe some lino. I understand that if you ever sell any that the buyer usually wants it in the original form. I don't plan to ever sell and I'm considering smelting it into ingots and maybe having one tested.

I smelt all my alloy into a standard size. I use a mold that makes 2.5 lb ingots that fit well into the 2 x 4 wall of my shed:

204391

Then I measure the BHN or Brinell Hardness of each batch:

204392

P.S. This is how Brinell himself measured hardness, except he used a ball bearing.

Once I have known alloys, I mix and match to get the BHN 10 alloy I want. The hardness mix is fairly linear between BHN 5 and 25, so you can use simple math to figure out the hardness of your alloy.

1 # of BHN 5 and 1 # of BHN 25 = 2 # of BHN 15 (5 + 25 = 30, 30 / 2 = 15)

This works with 3 alloys as well:

2# of BHN 5 and 1 # of BHN 20 = 3 # of BHN 10 (5 + 5 + 20 = 30, 30 / 3 = 10)

I have an Excel calculator that I use for more complex mixtures. Message me directly if you want it.

[kevin c]

Sent a sample to BNE (thanks, Barry!). This was a mix of all the fonts and spacers. The bullets are still aging (and I'm out of town shooting the USPSA Iron Sight National) so no hardness measurements yet, but the analysis came back:

Pb 79 % Sb 14 % Sn 7 %

Too rich for Lino but too thin for foundry or mono. Close to stereotype composition, but what I read about stereotyping for printing is that the printing was in whole page not individual letter format. Perhaps salvaged depleted mono or foundry, but again I thought these slugs were seldom remelted.

Will hardness test the bullets with my LBT in a week or so.

[kevin c]

BHN is 22 to 23 on my LBT. It was suggested to me that the spacers may be of more depleted alloy than the type, so that the analysis I got might be on the low side. The percentage of spacers is no more than a few percent by weight per my estimate, but I could be way off. I might have some individual pieces tested.