At Patrick Eggle Guitars we used Electrodag, a thick black paint which was excellent. Googling that product yielded the following result
ACHESON INDUSTRIES (EUROPE) LTD, (Process & Engineering Materials), Slough, Windsor Court, Petersfield Avenue, Slough, SL2 5DS, Tel: +44 (0)1753 501200, Fax: +44 (0)1753 879005, e-mail: paul.spackman@nstarch.com, ISO 9001:2000, Marketing Manager: Paul Spackman, UK Sales Manager: Tony Parry