Monotype

[klw]

What is the chemical composition of monotype?

Are monotype and linotype the only two eutectic alloys containing lead, tin and antimony?

[cbrick]

klw, no, there is Foundry type, Monotype, Stereo type and Linotype.

Here's a link to an article that has a chart with the formulas.

http://www.lasc.us/CastBulletAlloy.htm

Hope this helps.

Rick

[klw]

klw, no, there is Foundry type, Monotype, Stereo type and Linotype.

Here's a link to an article that has a chart with the formulas.

http://www.lasc.us/CastBulletAlloy.htm

Hope this helps.

Rick

That is really helpful. Thanks!

[grumpy one]

What is the chemical composition of monotype?

Are monotype and linotype the only two eutectic alloys containing lead, tin and antimony?

There are several different versions of monotype. You can get some detail of 5 different typemetals sometimes called monotype on this site, though it seems to have been imperfectly translated from German:
http://www.chemie.de/lexikon/e/Type_metal
Note that only the 10/16 alloy is usually called monotype in other references. The rest are called by names ranging from stereotype, up to foundry type for the last one listed. Note also the site gives composition of some "top up" alloys commonly used for freshening up tired typemetals.

Monotype is not a eutectic alloy. Linotype is the only true eutectic of lead, tin and antimony, but there is also at least one pseudo-eutectic and a "eutectic trough" of alloys that exhibit some of the characteristics of a eutectic. Monotype however is just a high-strength alloy.

[klw]

Details on the pseudo-eutectic and the eutectic trough would be helpful.

I'm trying to identify lead and linotype by their cooling curves. That I know how to do. What I'm not so sure of is if there are any other compositions that would exhibit a similar cooling curve in alloys containing lead, tin and antimony. I'm talking about lead/tin, lead/antimony and lead/tin/antimony alloys.

[cbrick]

Interesting. keep in mind that if your using used type metals the actual percentages of metals can and do vary considerably. Tin is lost by repeated fluxing so how long it was in a print shop and used over and over will effect the percentages, tin effects the melt and freeze temps a bunch.

I hope you'll post the results of your testing. Curious minds want to know.

Rick

[Harry O]

I have about 350 lbs of monotype and did some research on it several years back. This is from memory.

There are 4 or 5 major types of monotype. Fortunately, two types account for approx 85% of all monotype that was produced. Even better, the difference between the two types of monotype is minor. I have used the average of 73.0%Pb, 17.5%Sb, and 9.5%Sn for many years in calculations, and it has worked well. I can probably dig out the exact specifications if I look hard enough or if you really, really need them.

Monotype does not have the same problem as Linotype. Monotype is cast in individual letters that are meant to be reused WITHOUT melting. That means that losing the tin every time they are remelted is not a problem with them. That also means that it is unimportant that the mixture be eutectic. What you get is exactly what the manufacturer put in them.

If you can get it, it is great for mixing with lesser metals to raise the hardness.

[grumpy one]

I posted something on this subject back on May 14:
http://castboolits.gunloads.com/showthread.php?t=16265

To partly answer your specific questions, the pseudo-binary eutectic (10% tin, 10% antimony) is called that because microscopic examination of its structure shows it to be lamellar: that is, its microstructure is in layers instead of crystals. Lamellar microstructure is characteristic of eutectics in the lead/tin/antimony alloy system. The eutectic trough consists of a continuous range of alloys on the boundary of the zone where actual lead crystals form; any alloy with higher tin or antimony will not contain any crystals of pure lead. The trough runs from the lead-tin eutectic (i.e. no antimony) at 61.9% tin (traditionally called radio solder) to the lead-antimony eutectic (i.e. no tin) at 11.2% antimony, running through the ternary eutectic (11.5% antimony, 3.5% tin, or linotype) along the way.

This probably raises as many questions as it answers, and I probably won't be able to answer them, but go ahead and pose them if you want - there may well be somebody on the list who is a serious practising metallurgist, or at least knows one.

[Harry O]

Here is the information I found when researching monotype.

Type 1, 79.0% Pb, 15.0% Sb, 6.0% Sn
Type 2, 74.0% Pb, 16.0% Sb, 10.0% Sn
Type 3, 72.0% Pb, 19.0% Sb, 9.0% Sn
Type 4, 64.0% Pb, 24.0% Sb, 12.0% Sn

The most common types are Type 2 and Type 3. Between them, they make up approx 85% of the total amount made. One had a little bit more than the other, but they each had pretty close to half of that 85%. Because they are so similar, I doubt very much that you could tell which one you have by melting/solidifying temperatures. That is also where I came up with the average of 73.0% Pb, 17.5% Sb, and 9.5% Sn. My understanding is that Type 1 and Type 4 were specialty items.