Hawnjigs
KISS
For tackle casting, "hard" lead generally refers to an alloy with antimony hardener like wheel weights, and "soft" is generally pure lead or nearly so. My personal guideline for "hard" is 2% or more antimony content, and "soft" 1/2% or less. Between the two values I would define as "medium soft" or "medium hard". Tin content of commercial lead alloys is usually small and effect on hardness is negligeable.
There are excellent articles published online listing typical metals composition of common lead alloys, but often we get mystery lead cast into forms, ingots, sinkers, etc. To determine hardness, I use several tests:
1. Scratch Test: fingernail pressure can scratch or even gouge soft lead, difficulty increases with hardness.
2. Appearance: soft lead will often form an even dark oxide coating over time, harder lead will often retain a grainy silvery surface appearance.
3. Drop Test: soft lead will have a dull sound dropped on a concrete surface, harder lead a higher pitched ringing sound.
4. Clink Test: tapping two same alloy pieces together will produce sound results similar to the drop test.
5. Melt Test: pure lead will melt transition directly from solid to liquid, hard lead will usually exhibit an in between sludge phase.
While the above tests are useful for a preliminary idea, its possible to better define the hardness of lead using a relative weight test. Needful equipment for this includes a scale accurate to 100th of an oz. or like my Ohaus beam balance 10th of a gram, and a mold capable of identical size castings, bigger the better within the capacity of the scale. Using 5 oz. sinkers, soft lead weighs 140.6 grams and hard wheel weight lead weighs 136 grams, & even these limited reference points can be useful in determining relative hardness of a mystery alloy.
Please feel free to correct or improve this posting.
There are excellent articles published online listing typical metals composition of common lead alloys, but often we get mystery lead cast into forms, ingots, sinkers, etc. To determine hardness, I use several tests:
1. Scratch Test: fingernail pressure can scratch or even gouge soft lead, difficulty increases with hardness.
2. Appearance: soft lead will often form an even dark oxide coating over time, harder lead will often retain a grainy silvery surface appearance.
3. Drop Test: soft lead will have a dull sound dropped on a concrete surface, harder lead a higher pitched ringing sound.
4. Clink Test: tapping two same alloy pieces together will produce sound results similar to the drop test.
5. Melt Test: pure lead will melt transition directly from solid to liquid, hard lead will usually exhibit an in between sludge phase.
While the above tests are useful for a preliminary idea, its possible to better define the hardness of lead using a relative weight test. Needful equipment for this includes a scale accurate to 100th of an oz. or like my Ohaus beam balance 10th of a gram, and a mold capable of identical size castings, bigger the better within the capacity of the scale. Using 5 oz. sinkers, soft lead weighs 140.6 grams and hard wheel weight lead weighs 136 grams, & even these limited reference points can be useful in determining relative hardness of a mystery alloy.
Please feel free to correct or improve this posting.