Saturday, June 24, 2018 -- New Foundry Metal
This is a broken Margach bar of new foundry metal, ordered as 12% Tin and 24% Antimony from Canada Metal a few years ago. Note that slow cooling of the metal has allowed many Tin-Antimony crystals to appear. If you really wanted to know the recipe of metal you are using, maybe melt some and allow it to cool slowly and inspect the quantity of crystals?
This particular alloy content is fussy to use, with a tricky "liquidus-solidus" transition. This makes sense as the eutectic formula for Tin-Antimony-Lead alloys is apparently 4%-12% (with a balance of Lead), so there is a lot of excess Tin and Antimony in foundry metal. (For example, literature recommends using eutectic alloy for Elrod operation, why make it more complicated than it already is?) As it starts to freeze, the Tin-Antimony crystals can form large grains which could distort a smooth type face, especially in fine detail areas.
For 18 point type with this metal, I run it up to about 750 degrees F and it produces a really beautiful face with strong kerns. However, if I order new metal again, it would probably be 10%-16%, recommended by Monotype in their literature to be a good 'all around' formula.
One final comment, the English Monotype handbook lists many combinations of Tin, Antimony and Lead to achieve different results; the highest content alloy recommended for their equipment is 12 percent Tin and 24 percent Antimony, used for forms like train schedules that required changes without visible variation; this is foundry type. So the significant use of hard foundry type from their perspective was to allow for invisible changes to an existing form, not to allow for thousands more of additional impressions; contrary to popular opinions on the subject of foundry type vs. Monotype or Linotype.
Saturday, June 24, 2018 -- New Foundry Metal
This is a broken Margach bar of new foundry metal, ordered as 12% Tin and 24% Antimony from Canada Metal a few years ago. Note that slow cooling of the metal has allowed many Tin-Antimony crystals to appear. If you really wanted to know the recipe of metal you are using, maybe melt some and allow it to cool slowly and inspect the quantity of crystals?
This particular alloy content is fussy to use, with a tricky "liquidus-solidus" transition. This makes sense as the eutectic formula for Tin-Antimony-Lead alloys is apparently 4%-12% (with a balance of Lead), so there is a lot of excess Tin and Antimony in foundry metal. (For example, literature recommends using eutectic alloy for Elrod operation, why make it more complicated than it already is?) As it starts to freeze, the Tin-Antimony crystals can form large grains which could distort a smooth type face, especially in fine detail areas.
For 18 point type with this metal, I run it up to about 750 degrees F and it produces a really beautiful face with strong kerns. However, if I order new metal again, it would probably be 10%-16%, recommended by Monotype in their literature to be a good 'all around' formula.
One final comment, the English Monotype handbook lists many combinations of Tin, Antimony and Lead to achieve different results; the highest content alloy recommended for their equipment is 12 percent Tin and 24 percent Antimony, used for forms like train schedules that required changes without visible variation; this is foundry type. So the significant use of hard foundry type from their perspective was to allow for invisible changes to an existing form, not to allow for thousands more of additional impressions; contrary to popular opinions on the subject of foundry type vs. Monotype or Linotype.