The following pics are for those not familiar with weights. Personally if I ever went blind (and I'm sure many of you with tons of WW experience would agree) I could bet any amount of money I could still accurately sort. Yes you can actually create a "feel".
Below is a set of weights-different metals.
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Below is "clip-on ww". I've seen these with AW, MC, P, FN marks.
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Below is "stick-on ww". All kinds of marks on these, basically if you pick them up, they'll be stiff as opposed to flopping around like steel. If in doubt nip the corner with dikes.
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Below is the aggravating "Zinc(Zn)" clip on ww. It's the one that disappoints me the most when I find a "fatty". (Not ALL Zinc weights will have Zn on it.)
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Below is "steel stick-on ww (Fe)". These will dangle around in your hand staying connected with adhesive on back.
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Below is another example of steel stick-on's.
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And then you have the steel (Fe) clip-on ww. I've learned that unless a weight has been altered, if it has totally flat ends or ends that look like a hammer, it's probably steel.
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After a few buckets, the novice will learn that all ww's are not created equal but will get faster with the sorting! If I missed anything, feel free to correct me or add something!