Monday, September 22, 2014

DIY Guitar Finishing

Living in Australia, I don’t share the luxury of access to a specialist finisher such as Joe White or Addam Stark, and I can’t avoid the time-consuming job of pore-filling, sealing and applying finish top-coats myself. Would I farm my finishing out if that option was available to me? I have to say, I’m really not sure.

As a hobby builder, I don't impose deadlines on myself, nor do I have impatient customers eagerly awaiting progress updates; the time I spend finishing my instruments therefore doesn't weigh too heavily on me. As the standard of my finishes has improved over time, my enjoyment of this part of the process has increased significantly; what was once an onerous task has now become just another series of steps along the way to completing a guitar. The final result relies less and less on chance as my tally of completed guitars grows. In fact, there’s a great sense of satisfaction at having done the hard yards, and in acknowledging that I've gone a long way towards negotiating the learning curve inherent in producing a professional standard of finish.

KTM-SV over Sitka Spruce
Those of you who have followed my blog will know that I've been pretty happy finishing recent guitars with Grafted Coatings’ KTM-SV, a water-based oil-modified urethane. While I’m more than satisfied with the end results I've been able to achieve, I'm deterred by the horrendous shipping charges from the U.S., and the fact that its adhesion over shellac is less than satisfactory. The Ilva two-pack sealer I'm forced to use is nasty stuff, which largely defeats the purpose of using a safe, environmentally-friendly water-based finish, and adds to the already prohibitive cost. As a result, I’m forever on the look out for new products, knowing that what’s on the market is constantly evolving and improving, particularly where water-based products are concerned. Grafted Coatings' recently developed water-based finish material, Ten!, has received great reviews from the few who have trialed it, and I'm keen to hear further reports when it's eventually in widespread use. As the release date is unknown, I'm about to experiment with another product that's new to me. 

Bona Mega is a water-based polyurethane interior floor finish recommended to me by a well known and very well-regarded U.S. luthier, who is himself an ex-KTM-SV user. In case there's a negative bias towards using a floor finish on a guitar, I won't name him. Suffice to say that the standard of his finishes has drawn glowing praise from those attending guitar shows in which he's been a participant. The advantage of Bona Mega for me is that it's readily available locally, and supposedly demonstrates excellent adhesion over a simple shellac seal coat, something that can't be said for KTM-SV. Bona Mega is expensive, but I'll avoid the shock of the shipping charges I pay when I purchase products from the U.S., and benefit from the fact that it bonds well with shellac.

I’m comforted by the fact that some of our more experienced and admired U.S.-based luthiers have also chosen the DIY route, despite the fact that they have access to the aforementioned specialist finishers, and I'm pleased to note that a growing number of them are prepared to use alternatives to the traditional nitrocellulose lacquers and the modern, more robust polyesters. Most importantly, it seems that the players willing to outlay large wads of their hard-earned cash on a hand-made instrument are becoming more knowledgeable and less bound by convention, and are slowly accepting these alternatives even if it means that their prized instruments are slightly more susceptible to damage because of it.

How about you, fellow builders? Do you undertake finishing work yourself? If so, what's your finish product of choice?

Product links:
Bona Mega
Grafted Coatings Ten!



Michael J King said...

I am finishing with French polish currently but even after it hardens it is still quite delicate, I found your post looking to see other alternatives for some of my instruments, I have tried a Nitrocellulose-Melamine spray finish that Sobell guitars use and its a hard wearing quick frying finish but the fumes make it not very practical in my small workshop. How long Does Bona Mega take to hard before you can buff it? Is it applied with a brush or spray?

Wood With Strings said...

Michael, I'm afraid I can't speak from personal experience as I have not yet used Bona Mega. The luthier who recommended it didn't mention his schedule for buffing, but if it's anything like the KTM-SV I've been using, it can be wet-sanded after two or three days, and buffed after seven. He sprays it over a shellac seal coat, as will I. With a decent brush and good technique, I suspect that it can be brushed, but again, I'm not speaking from experience.

Michael J King said...

will keep reading your blog for updates!

Kevin said...

Any updates on this topic since the last posts??

Wood With Strings said...

Hi Kevin. Progress has been pretty slow, and I've been waiting until I have all my current guitars ready for finishing before I take time off from my day job and commit to completing the spraying. It's frustrating not having as much spare time as I'd like, but I'll certainly post when I have something worthwhile to report. Thanks for stopping by.

JohnJ said...

Hi Peter

Very keen to hear progress with Bona Mega. Have you managed to put it to the test, and do you spray it it on?