I am trying to find out,what used in those WW II military radios that had all the curcuitry and wiring covered with a greenish/yellowish varnish to treat against fungus and moisture.---Was it a varnish,shellac,lacquer,or what?What gave it the greenish /yellowish colour?---I am sure the stuff is no longer available,but may be some ''old timer''still knows what it was.----Thanks,Olaf---

Hi Olaf

The material was called Humi-Seal. It could be bought in spray cans and had different grades or types. The material smelled like varnish but can't be sure.

Norm

: I am trying to find out,what used in those WW II military radios that had all the curcuitry and wiring covered with a greenish/yellowish varnish to treat against fungus and moisture.---Was it a varnish,shellac,lacquer,or what?What gave it the greenish /yellowish colour?---I am sure the stuff is no longer available,but may be some ''old timer''still knows what it was.----Thanks,Olaf---

I would guess it was a varnish (cured by cross-linking, rather than just solvent evaporation). I believe the fungicide was copper naphthenate, nasty stuff, and the fluorescent color was added to allow inspection under ultraviolet light.

: I would guess it was a varnish (cured by cross-linking, rather than just solvent evaporation). I believe the fungicide was copper naphthenate, nasty stuff, and the fluorescent color was added to allow inspection under ultraviolet light.

Any chance this stuff is a health hazard? Should we be exercising any special cautions with it?