Ever wanted your thumb secure from slipping around inside the thumb strap-especially when the thumbstrap gets smooth worn on the inside or when you sweat? I find I play more confidently and accurately when my thumb does not slip around inside the thumb strap. Well, I have tried rosins and non-slip tacs, but none worked well and they were messy. I found a solution that acutally works and works well. Lightly coat the inside of the strap with liquid latex and let dry. I use a Q-tip to dab or swab it on. It sticks very well to the leather and provides you with a non-visible grip like you won't believe. I have been using it for the last month and it works under all situations. It is a very thin non-slip grip that lasts and can be pealed off if not satisfied or reapplied if needed. You can get liquid latex from various internet suppliers or can usually pick some up at Haloween stores during the season. I have been extremely happly with the results. Easy to apply,very thin, invisible from the outside, lasts, no mess, and really increases my playing confidence knowing my thumb won't be slipping around.
I drilled a couple of small holes side by side about half way in from the end of the thumbstrap, and tied a small loop of leather lace through the holes. Kind of hard to explain, but it makes a little tie on the underside of your thumb so it holds the loop tigher around your thumb. You can adjust the tightness of the thumbstrap by tightening or loosing the loop tie. Make any sense? Works great. Holds my thumb completely from slipping in the loop. I can put a picture up somewhere if anyone wants to see it
Just put a rubber band around the thumb loop to make the loop more snug. Position the rubber band so that the thumb loop fits snugly, and wrap the rubber band around the thumb loop enough times that the rubber band stays in place. Works great.