I have callouses developing on the insides of my thumbs by the knuckles from playing my whistle (low D, plastic). Is this normal, or is this the results of my callous playing? 
I didn’t think I was gripping too hard and it seems odd to be getting callouses from such a light smooth instrument. I’ve been playing with the instrument for a couple months, maybe 1/2 to 1 hour or so a day. Just wondering if others experience this. Thanks.
I’ve never gotten them, but people do vary in how sensitive their skin is, so it’s quite possible it’s normal for you. Have you had any irritation of the thumbs, or is it just callousing? The reason I ask is, it’s just barely possible you’re sensitive to the particular plastic.
Redwolf
I too have some callous on the inside/left-side of my left thumb. Its because I support my low whistles and flute with the side of my thumb instead of the pad. My hand reacts by adding more padding in the form of a callous to protect the skin rubbing up against the bone of the thumb knuckle. If it gets to thick you can just sand it down with a little sand paper. This is what I learned to do when I developed similar callouses from working the high bar in gymnastics (Junior High foolishness back in the 60’s).
Gee, if the calluses were on your FEET, I could help you! 
(when I’m not making whistles, I’m a Podiatrist)
I’m predisposed to calluses; I can grow 'em anywhere just like that. There are tough spots on my hands that reflect the instruments I play. How ARE your feet, JP? 
My feet are smiling, thank you.
Actually, since you mentioned it, and we have an expert on hand, they do seem to be getting flatter and longer as time goes by, and sometimes I get this little … oh never mind.
Haven’t noticed any other reaction to the plastic and I’m sure I’ll get used to the callouses but they feel a little strange right now. After 30 some years of guitar playing I’ve sometimes had to trim callouses with a razor if they start getting in the way. Sandpaper sounds like a better idea.
A much better idea!
Dr. Scholl sells a callus file which is basically a plastic paddle like thing with wet/dry sandpaper on each side (coarse and fine). If you wet the calluses and then work on them a bit each day, this should keep your hands pretty smooth.
BTW-- feet do often get flatter and longer with time. Nothing to worry about unless they start to bother you. It really cracks me up though-- I’ll tell an older person that their shoes are too small, and the reply is usually something like " But I’ve ALWAYS worn a size 9!". I ask them if they’ve ALWAYS worn the same size pants or skirt or shirt, etc. They are aware that every part of their body changes as life goes on, but expect their feet to remain the same forever. See, you got me started… :roll: