I remember in the book Images Below about cave photography there was a section about weatherproofing flashguns. After taking off the cover of the gun they sprayed something onto the circuitboard being careful NOT to spray a certain component. If anyone has this book or has done this before can tell me what the spray was (silicone?) and what component NOT to spray was. I no longer have my copy. Thanks.
Also, has anyone ever tried tooldipping a flashgun, not the controls on the back or the lens of course, but the body? For dust, moisture, and general cave trauma protection? These are Sunpack 333 and Vivitar 3700 flashguns.