The U.S. aircraft register, updated daily
Parts

Polyurethane Varnish

No failure report names the polyurethane varnish. 2 FAA approvals let 1 company make a replacement polyurethane varnish, Randolph Products CO holding the most (2).

Approved replacement parts 2 parts manufacturer approvals

A parts manufacturer approval (PMA) lets a company other than the aircraft's maker make a polyurethane varnish and sell it as an approved part for the models named. These are the companies holding such approvals for a polyurethane varnish:

MakerPartReplacesFitsGrantedStatus
Randolph Products COPolyurethane Varnish Component B URC0509??CBURC0509Miscellaneous Aircraft Make(s) as listed on Sealed...2003-03-27current
Randolph Products COPolyurethane Varnish Component B URC0509--CBMiscellaneous Aircraft Make(s) as listed on Sealed...2001-02-06current

Sources: the FAA's service difficulty reports since 1995 (a report is a part that failed and was fixed, as filed by an airline, repair station or owner; the count shows reporting as much as reliability) and the parts manufacturer approvals in the FAA's Dynamic Regulatory System. The part name is the reporters' and the approval holders' own words, reduced to the first plain words so that spellings meet.