Stary,
I just finished using this product on the soldered joints under my layout. Some had multiple wire taps into them and regular tape just kept coming unraveled.
It's called Liquid Electrical Tape. The brand I got over the Internet was Star brite. It works great, but you have to watch for dripping off of the applicator. Not good to do on a carpeted floor. Directions say you can apply a second coat, which I did, after 5 minutes or so. It comes in multiple colors in a 4 oz. can.