You’ll generally find the shrink wrap tubing in the electrical section of Lowes and Menards. If you go to an electronics store or auto parts store you can ask an employee. I have one that I used black cloth duct tape on that works great and soaking in a sink full of water hasn’t made it come off yet.
Really you just need to keep your shaving hand free of soap. I know that the stuff you make is slick as can be. Just keep your hand and razor rinsed off.
O rings can do wonders with razor handles. You can just place them in the places for best grip and they don't get sticky over time and a good row has staying power.
I bought some textured rubber, to replace a worn-out camera grip. It has an adhesive that is heat-set with a blow-dryer on low. I had some left, so I am trying that on the razor. It feels just right. Now I have to see how it stands up to water.
Hear! Hear! 15-20 should do the trick. Even if the handle isn't slippery, the grip is very comfortable.
Update- I put the textured rubber on the handle and used it this morning, in the shower. It felt very good and the rubber shows no signs of coming loose. Here is a link to the product, in case anyone is curious. https://www.amazon.com/gp/product/B01FLQO5IU/?tag=thshde-20
I have a Ming Shi razor and I really never had any issues if the hand is reasonable dry, just use a little alum and the problem is usually resolved. I do not shave in the shower so using alum no issue. I thought the handle was a dud at first but quickly realized the handle was doable and not a issue! Most owners do not complain about the handle and the razor is a good one IMO.
