UV-Cured Polyester Finishing Schedule

[Scott Sailors]

A number of luthiers and hobby-builders have asked me, recently, to post a suggested finishing schedule for use with the UV-cured polyester finish.  We use the products manufactured by Simtec Coatings, and following is our understanding of Simtec's recommended finishing schedule for use with their products.  (In addition to this information, you can go to our blog at www.ClearCreekGuitarFinishing.net to view posts on Equipment and Tools; Finishing Products; and Solvents, Viscosities, and Application Temperatures.)  Here's the schedule:

* Mix two-part insulator in a one-to-one ratio

* Spray insulator using a 1.0mm nozzle at psi recommended by sprayer manufacturer

* Allow insulator to cure overnight

* Thoroughly scuff insulator with a Scotch-Brite pad

* Apply first coat of pore filler

* UV cure

* Sand level being careful not to sand back into the wood

* Clean the surface

* Repeat the pore filling process until level

* Thin topcoat to original viscosity of new material (if necessary)

* Spray 3 coats of topcoat, 20 to 30 minutes apart, using a 1.2mm nozzle at psi recommended by sprayer manufacturer

* After third coat, allow to gas-off for 20 to 30 minutes before UV curing

* UV cure

* Scuff finish thoroughly for a mechanical bond with the next 3-coat application

* Spray 3 coats of topcoat, 20 minutes apart, using a 1.2mm nozzle at psi recommended by sprayer manufacturer

* After third coat, allow to gas-off for 20 to 30 minutes before UV curing

* UV cure

* Final sanding, buffing, and polishing:
*400, 600, 800, 1000, 1200, 1500, 2500, 3000 sandpapers

*Buff on 16” Domet wheel using the X-Fine polishing compound

*Polish using Perfect-It 3000 Swirl Mark Remover with foam buffing pad on a drill (moisten with water)



Final material thickness is 3 to 5 mils.