Tape Flame Retardant 19mm x 30m . japan 570F Acetare Colth Tape.

Description Power Transformer Insulating tape, type 570F Laminated Acetate cloth and rubber tape used for inter-layer electrical insulation in toroidal transformers. 10 mil thickness (0.25mm) 3.7KV breakdown voltage per layer. UL510 Flame retardant (File ? E56086) 0.75 #34; wide 100ft long (30m) Strong acetate cloth will not stretch under heat or load, but soft enough to mold around small bumps. Made in Japan by Teraoka Tape ( retails for $13 / roll ) Can also be used as a base coat over the core, before applying the wire. The adhesive on this tape is not strong, however it safe for use enamelled wire - will not introduce moisture or decompose into weakly acidic or alkaline products which can etch the insulation and corrode copper. Note consummer tapes --including electrical tape-- are NOT suitable for use in transformer insulation. They have adhesives which either contain moisture ( to be gummy) or are slightly alkaline or acidic, or can with time and heat, decompose into products that are alkaline or acidic. These products can etch and corrote both the wire and the iron core. The ONLY place any consummer tape might be used in a transformer is as an outer wrapping, to cover the completed transformer , not directly over bare wire, but over a previous layer of transformer tape.