Gibson Measures Guitar Coatings Using Ultrasonic Technology
Before using the PosiTector 100, measuring the coating on their world-famous wooden guitars was a challenge for Gibson Guitar. Conventional magnetic and eddy-current-type coating thickness gages measure coatings only on metal substrates. Out of necessity, Gibson began testing their coating thickness destructively, as they were unaware of any better solution at that time.
Gibson Process Engineer Dan Falck said they attempted to evaluate the coating thickness by pulling the lacquer off the wood and measuring it with a micrometer. Using flood lamps and razor blades, the lacquer was heated and a small rectangular piece was cut into the surface. Then, while it was still hot, the rectangular piece was stripped from the wood by hand and measured with the micrometer. This method often tore and distorted the coating, making it difficult — if not impossible — to measure accurately with the micrometer. The guitars used for testing were then scrapped because the testing process damaged them beyond usable condition. Destructive testing proved to be expensive, time-consuming and inaccurate. A better solution had to exist.