Liquid Electrical Tape - details
Liquid Electrical Tape (LET) is a rubber-fluid compound which can be painted onto surfaces to give a solid rubber-like finish when dry. It's mainly used in electrical applications to help insulate wires or joints, or in marine environments to protect against corrosion (eg. bolt threads etc.)
Of interest to Leica users is that it can also be used for repairing vulcanite, repairing holes in cloth shutter curtains or painting around the metal eye-piece of older Leica Ms to prevent them from scratching your spectacles.
LET is available in 4 oz (118 ml) and 32 oz bottles in black or red or green. It is made by Star Brite and can be easily purchased from electronics suppliers or marine equipment dealers (eg, see this link).
In Australia you can buy the black Performix 118ml product from Jaycar Electronics - search for item #NM2832.
Like paint, LET must be thoroughly stirred or shaken prior to use.
LET cures very quickly when exposed to air, so don't muck about when painting it on!
Looking at the data sheet, 30% of this stuff by weight is comprised of Hexene, Xylene and Ethyl Benzene solvents. This of course is Hindenburg-in-a-bottle, so beware! Use in a very ventilated place and keep well away from flames or sparks or even (gulp) static electricity.