POLYURTHRENE & EPOXY FINISHES PART. 2

 
(561) 706-6011

View Larger Map

One of our articles titled: Lacquer vs. Polymer Finishes talked about the differences between an "epoxy" guitar finish versus a lacquer finish. This article discusses a remedy option for repair or re-doing a guitar finish when the "poly/epoxy" finish is no long presentable or desirable.
 
First, to keep the terms simple, "poly" will be the term used to describe an instrument finish by way of a polyurthrene or expoy formula. Lacquer remains "lacquer."
 
Recently one of our "newsletters" talked about two remedies for damaged poly finished guitars. Remedy one is to try and color clear cyanoacrylate (super-glue) to match a guitar color then do a fill-in to a chip or crack. Then after hardening (24 hours recommended) level the fill and buff to a gloss. However, this process may have to be repeated several times to level up to the existing finish.
 
Although this quick fix is a method, usually the outcome is a low 4 or 5 on a scale of 1-10 where ten (10) would be perfect. Problamatic is matching a color, curing time, and labor to level and buff. Our shop has not been successful in this method, thus, we now decline any "quick fix" cosmetic work of poly finished instruments as the outcome is poor.
 
We've come to understand that poly finishes are a poly/plastic/epoxy that is sprayed on an instrument that is either stained before hand or color mixed into the product. It hardens timely and buffs to a glossy mirror like shine. Poly finishes are cost effective, productive, and have an appealing gloss mirror like reflection that is appealing. However, if the poly chips or cracks then the problems begin. Simply, one lives with the dings, dents, and chips, or tries the quick fix method, or opts for a do-over.
 
The do-over means removing the entire poly finish by heat and exposing the raw wood of the instrument. Then sealing the wood, apply new color/stain, then refinishing the instrument with lacquer (recommended.)
 
There is no question in our mind that lacquer still remains the staple in finishes for an instrument. Not only for sound, but lacquer is forgiving (unlike poly finishes). That is lacquer can be sanded and buffed or even re-sprayed where the new lacquer will adhere to the old. That doesn't work for poly finishes meaning a new application will not adhere to an existing finish.
 
So in sum, either lacquer or French Polish finishes remains the most friendly and sound (no pun intended) product to apply to an instrument. However, its not that cost effective and requires curing time and appropriate climate conditions to apply.
Unless one is willing to live with the dings and dents of a poly instrument finish then the only correct fix is total removal and re-application of color and lacquer.