Foundry type metal

[Bass Ackward]

Bass, that is even more complicated than where my thoughts were previously. I want to get a reasonable MV from my 20" 30-30, without torturing the rifle and with consistent and decent accuracy.

There are three ways to shoot cast. First is cast, like cast, at what are considered to be cast velocities using faster powders. The second method is to use cast pressures, but go to slow powders and allow lighter per caliber weight bullets to accelerate slowly using slower powders. The third method is to harden cast bullets and raise the pressure so that the base of the bullet can withstand higher pressure.

I always shoot using the second method so that I can keep my bullets soft. I shoot rifles with throats shaped to support a softer bullet. The advantages of using this method are a soft bullet for hunting and a less base expanding pressure to create bore friction. The less bore friction you have, the less barrel vibration you have. The less barrel vibration you create, the wider your accuracy nodes will be and you can usually achieve superior accuracy at this point.

There are two things that work against you when you want to shoot low pressure / high velocity loads:

1. First is bullet weight. This is because all weight is additive to increase inertia and thus pressure on the base.

2. The second negative is short barrel length because it removes options to achieve velocity without raising pressure.

There is one saving grace. Case volume. Increasing volume slows the expansion of powder gases until the bullet is moving in the bore where it is fully supported. ZThe larger the case, the farther the peak pressure is pushed down the bore. Thus the bullet is moving faster when it occurs and can handle more pressure before the base is changed.

So what you have is an under bore cartridge (30/30) normally described as efficient. You are trying to use a heavy for cartridge for caliber bullet. And you have a short barrel. Grumpy, you need to explore the third method of shooting cast and in my opinion are heading in the right direction by increasing hardness.

[charger 1]

think I'd make #3 the #1 choice, but you knew that

[9.3X62AL]

Bass--

You REALLY summed it up with that last post. Very succinct and direct, and much food for thought.

[454PB]

Right now I can't understand how you'd get 18 BHN from a 50-50 mix of lead (5 BHN) and lino (22 BHN). Sounds as if you've slipped in some of your foundry type.


Geoff

I went back and found my post expressing the same surprise at the hardness of 50/50 lead and linotype:

http://www.castboolits.gunloads.com/...ad.php?t=10835

It wasn't 18 BHN, it was 20 BHN! Yes, I could have a bunch of foundry type mixed in with linotype, which is just fine with me.

[charger 1]

what would the BHN of the foundry type be as it sits, and probably has been sitting for 20+ yrs judging by the dust

[grumpy one]

Bass, many thanks. It comes together for me now, and I think I can set up the next few stages of experimentation. In the end the objective will be to just barely achieve the required bullet strength, so I don't run unnecessary amounts of antimony through my barrel and wear it out faster than I have to.

Charger, unless the foundry type was heat treated, which seems unlikely, I expect it will be the same hardness now as a month after it was cast. If it really is foundry type, that should be about 33 BHN, for every individual piece of it. If you can conveniently do some on-site hardness testing you can find out what is going on. If this is coming from a really big printing works, their foundry type may really have come from a foundry, and been kept separate since, so it will be the real McCoy, 33 BHN. However I think many smaller print works did a lot of casting themselves and only sent out to a foundry for the tricky stuff, so they ended up with all shapes and sizes of printing blocks made out of whatever fell to hand when they cast it. If you find some linotype or monotype castings mixed in - which have a quite distinctive appearance - you'll know straight away that this is not pure foundry type. I don't see that it matters whether it is foundry type, linotype, monotype, or a mongrel bred from all three. The only real issue is whether it has copper in it. If it does, you have a hassle to get rid of it. If it doesn't, you just sort the stuff into two or three hardness grades and make ingots out of each grade-pile. One thing you shouldn't do, is mix the very hard stuff - the grade most likely to contain copper - with the softer grades, because that will just make copper removal more difficult.

FWIW, after my first couple of batches of foundry type I finally had the sense to sort out the linotype and smelt it separately, so I ended up with a few ingots of pure linotype. No printer in his right mind will have allowed mongrel alloy to find its way into his linotype machines.

[charger 1]

its only 16 bn,but if I drop it in water hot it goes 25 instantaneously

[grumpy one]

Charger, 16 BHN is well below linotype, let alone foundry type, so most of what you have is various soft alloys, not printers' alloys. So long as it isn't contaminated with something other than lead, tin and antimony (I'm ignoring trace amounts of arsenic) it's great stuff for bullet casting.

You may need to do some sorting, separating this into piles of soft, medium and hard. Once you alloy the stuff you can't ever go back to the original range of materials, and you will most likely find a use for a pile of specifically hard stuff.

[charger 1]

its all got print on it. And it all jumps to 25 if you quench. I dont mean its gotta cure. I mean bang a gain of 10 bn right away. The thin pieces break easy and very granular inside

[grumpy one]

Getting harder when you quench it only tells you that it contains antimony and arsenic. You can identify the alloy from whatever is the lowest BHN you can record, which means by air cooling it then waiting a month. Sounds to me as if that's 16 BHN.

Having print on it tells you that it has been used by a printer as typemetal. He could use anything he wanted - a printer having used it does not make it typemetal.

I'm not too sure about the brittleness, but the large grain size normally means it solidified over a long period, and large grains do sometimes cause brittleness because the material at the grain boundaries has a different composition from the centre of the grains.

And I'm not knocking your find here - if it made well filled-out type, its a good casting alloy and will make fine bullets.

[charger 1]

Getting harder when you quench it only tells you that it contains antimony and arsenic. You can identify the alloy from whatever is the lowest BHN you can record, which means by air cooling it then waiting a month. Sounds to me as if that's 16 BHN.

Having print on it tells you that it has been used by a printer as typemetal. He could use anything he wanted - a printer having used it does not make it typemetal.

I'm not too sure about the brittleness, but the large grain size normally means it solidified over a long period, and large grains do sometimes cause brittleness because the material at the grain boundaries has a different composition from the centre of the grains.

And I'm not knocking your find here - if it made well filled-out type, its a good casting alloy and will make fine bullets.

Well I guess we're getting to the same place but using different methods...Cause really I dont care what the hardness is now. What I care about is what the hardness is after molding and water dropping if its mixed with wheel weights. And it does appear to me as though a limited quantity of it in the wheel weight mix will bump the boolit hardness the few bn I'm looking for. The other thing I noticed different about it is the same thing you notice when machining stainless as opposed to other steels. People often think a given stainless is harder when in fact its tougher (more resiliant to grain seperation) Thats what I notice about this stuff. If I take a piece of this and a piece of anything else around the same bn or even a bit harder, this stuff is more difficult to scrape with a knife...I certainly notice its melting point higher than wheel weights

[grumpy one]

There are a couple of points that are really refinements - otherwise we seem to be in pretty much the same place. First, all of the printing alloys are pretty sure to contain considerably more tin than WW does, so they will produce high-definition castings of the type. That is going to make bullet casting easier or better, or maybe both. Second, be careful with that water-dropping trick since it is difficult to achieve consistent hardness. I won't say it can't be done, but I will say I can't do it, and have stopped trying at least for now. Lastly the melting point of pure lead is higher than any of the alloys until you get up to the eutectic (linotype), which has the lowest possible melting point, then melting points rise again as you go to higher than eutectic alloy levels. So, if your alloy has a higher melting point than WW, it would have to be way above the linotype alloy levels (4% tin, 12% antimony). That would be valid for foundry type - it is around 10% tin, and at least 20% antimony. However it doesn't explain your low BHN results from your alloy.

Most of this doesn't matter much - you just need an alloy that works better than WW, and you now have the ingredients to make it.

[Ricochet]

be careful with that water-dropping trick since it is difficult to achieve consistent hardness. I won't say it can't be done, but I will say I can't do it, and have stopped trying at least for now.

I still water drop because it's easier to cast that way, but now after I make a big batch of boolits I let 'em bake at 475°F for an hour and quench 'em in cold water so they'll all end up consistently hard. My nearly pure soft lead that I can easily dent with my thumbnail in the annealed state has enough stuff in it to end up about as hard as air cooled wheelweights when treated this way. That's really nice to know. I can use the scrap as is for most things and save my wheelweights for when I need the extra hardness.

[charger 1]

I dont know bout the water dropping variances. Not to be rude, but I run quality not quantity when I'm at the pot. If I make 50-60 boolits in a two hour session,fine. They've never varied by more than .5 bn after curring...Oh back to the orig post if we might

[Bass Ackward]

I dont know bout the water dropping variances. Not to be rude, but I run quality not quantity when I'm at the pot. If I make 50-60 boolits in a two hour session,fine. They've never varied by more than .5 bn after curring...Oh back to the orig post if we might

The problem with putting all that love into a few bullets is that you don't want to launch them which I see is true here.

Why am I not reading about any results here? That new throat probably has surface rust by now.

[9.3X62AL]

I've been adding one part foundry type to 8 parts WW metal, and arriving at about BHN 14--something like Taracorp 92/6/2. I run the pot wide open (850*) to blend the alloys, and let it sit for about 10 minutes--stir, and cool to 675*. So far, no copper or other foreign metal has showed itself. It sounds like my lot of foundry type is a fairly good one.

Antimony = rock. Now I'll have nightmares--thanks loads.

[MT Gianni]

I've been adding one part foundry type to 8 parts WW metal, and arriving at about BHN 14--something like Taracorp 92/6/2. I run the pot wide open (850*) to blend the alloys, and let it sit for about 10 minutes--stir, and cool to 675*. So far, no copper or other foreign metal has showed itself. It sounds like my lot of foundry type is a fairly good one.

Antimony = rock. Now I'll have nightmares--thanks loads.

Al, are you using that as a universal alloy or auto pistol only? Gianni.

[9.3X62AL]

Not quite "universal", John--but close. Autopistol, rifle, and mag revolver get this blend, while standard pressure revolvers get ACWW.

[charger 1]

The problem with putting all that love into a few bullets is that you don't want to launch them which I see is true here.

Why am I not reading about any results here? That new throat probably has surface rust by now.

Awaiting the darned mold

[leftiye]

Lino that we obtain (as we can) is often oxidized heavily by the printers, and thus varies widely in composition. Printers must have had some way of assessing this deterioration prior to reconstituting the linotype as they had special alloying ingots with high tin/ antimony (or else they just guessed) to add periodically as type became soft or wouldn't cast.

Foundry metal according to Harrison was unacceptable because it required special equipment and techniques to make it cast well. I've never had none, so I can't say from personal experience. Probably best to make a linotype composition out of it.

.5% tin (1/2 of 1%), and 5% Antimony will harden to a BHN of 42 (Forty-two! -not to be misread as 22)!!! This when heated to as high a temp as can be maintained without slumping for one hour, and then dumped into cold water. Not much tin / antimony there. I'd guess that any desireable hardness could be obtained by experimenting with temps, and times.