A Finishing Problem Solved

I had the use of an unoccupied shop here in town for a few months in 2016 and was able to work on some instruments there until the owner asked that I vacate so he could begin renovations. I had recently sprayed lacquer on three guitar bodies and their necks at the time, and they hung inside a cupboard with a computer fan porting the fumes to the exterior of the building for a few weeks while I got on with other things. When it finally came time to pack up and move out, I placed the guitar bodies and necks in some cheap new cases, comfortable in the knowledge that they’d be protected throughout the move and beyond.

From that point on, construction of my workshop became a priority that occupied me for more than three years. When the dust had settled and I was ready to complete those guitars, I found that dye from the lining of the guitar cases had penetrated the lacquer on the soundboards to an unknown degree, although I figured it was likely that the staining extended to a significant depth. I pondered how best to remedy the situation for some time, often practicing avoidance behaviour for months at a time as I moved ahead with new instruments.

Scraping and sanding the lacquer off the soundboards and respraying was one option, but I worried that merging new lacquer into old may have given less than optimal results; I’d used a pre-catalysed lacquer that supposedly doesn’t melt into previous coats as effectively as nitrocellulose.

The alternative was to use a chemical stripper over the entire body which would essentially take me back to square one in the finishing process. The degree to which I’d be successful in neutralising the stripper before I applied new sealer and top coats gave me cause for concern though.

After weighing up the advice kindly offered by a couple of Facebook friends, I decided to strip the finish from the bodies entirely. While acetone softened the finish to the extent that it was at least sticky and could be removed with difficulty using steel wool or a single edged razor, it was a painfully slow process, and I concluded that removing all of the lacquer in this way was far too onerous a task. I opted for regular paint stripper which proved very effective in softening the lacquer, allowing it to be easily scraped off. I was careful to remove all traces of the stripper using generous quantities of denatured alcohol, and I'm ready - once again - to pore fill in readiness for spraying.

As I began work on these guitars up to twelve years ago, you'll no doubt appreciate how keen I am to complete them and resume work on other instruments I've commenced more recently.

Cheers

Pete

Manchinga/Engelmann Spruce OM Update

 With the top now attached, I now have four guitar bodies ready for binding. Something to look forward to (said nobody, ever!)

Cheers, Pete

Progress: Manchinga/Engelmann Spruce OM

I've made some progress with this guitar over the past few weeks; however, I was hampered by the manchinga sides that rippled badly across the grain in the process of bending them. This has been my first experience working with manchinga, and I suspect that a little less water applied to the sides prior to bending them may have contributed to a better result. I had partial success in flattening them by soaking them in Supersoft veneer softener and clamping them for a couple of days in the mold I use to laminate sides. The remaining inconsistencies were masked once the veneers were added to the interior of the sides, and sanding will flatten their outer surface without removing too much material.

Check out the grain in that amazing Engelmann top!

Cheers, Pete

Next Cab Off the Rank? A Manchinga OM.

This set of manchinga has been gathering dust in my modest tonewood stash for several years. From the time that I acquired it I resolved that wood this remarkable should be set aside for as long as possible in the hope that my skills would eventually grow to a point at which I'd consider myself able to do it justice.

Whether I'm at that point or not, the reality is that I'm not getting any younger, so while my eyesight is still in good shape I'm preparing to take the plunge and begin construction of a guitar using this beautiful wood, coupled with a drop-dead gorgeous Engelmann spruce soundboard I've also been saving for something special.

I'll post a progress report on the other three guitars I'm working on very soon.

Cheers, Pete

A Little Eye-Candy.

Here a progress shot of two of the three guitars I'm currently working on: an Australian blackwood/Engelmann spruce OM, and a Bubinga/Sitka spruce OM.

A Narra/Engelmann OM has been a late addition to the production line, the motivation being that I'd like to try a bevelled armrest for the first time.

More updates soon.

Cheers

Pete

What's on the Bench?

As many of my blog posts hereabouts will attest, construction of my workshop occupied me for the best part of four years; even now there are "finishing off" tasks that divert me from guitar building. More significantly, the list of jobs around the house expanded impressively while I was focused on the workshop, so I've made a point of addressing enough items on the list over the past few weeks that I've been able to increase my guilt-free time attending to a couple of new guitars, both of which are at a similar state of completion.

I added some inner laminations of cherry veneer to the sides on these guitars, the advantages being that:

• the potential for cracks in the sides is largely eliminated meaning that the application of bias tape or cross-grain wooden reinforcement is no longer required.
• the sides are dead flat across the grain once laminated; there's no cupping or rippling and therefore no requirement to sand them flat.
• a stiffer and more massive rim assembly means that the vibration of the top and back plates is absorbed by the sides to a lesser degree than would otherwise be the case.

There are many ways to laminate the sides, but I settled on using a jig modelled after the one pictured below, the idea for which I borrowed from guitar builder Ryan Gerber.

Side laminating jig

Australian blackwood/Engelmann spruce OM

Bubinga/Sitka spruce OM

Cheers

Pete

The Bubinga Lottery

The task of bending the sides gave some cause for concern when I decided to use my one and only set of Bubinga recently. I was already aware that bending this wood can pose challenges, and on researching the topic it became apparent that unhappy accidents are commonplace. To mitigate the potential for disaster, I took the cautious approach and doused the sides in Supersoft veneer softener and shrouded them in plastic for a couple of days before unwrapping them and allowing them to dry completely prior to bending them.

 

When I finally took the plunge and inserted them in my Fox bender, sandwiched between layers of damp craft paper and wrapped in aluminium foil, I cranked the temperature of the heating blanket up to around 320F and allowed them to cook at that temperature for a good ten minutes. When the sides had cooled to room temperature and I was able to remove them from the bender, I found that they'd survived the ordeal with no sign of the cracking or faceting that others have experienced.

What I've learned about this wood is that there are several Guibourtia species marketed as Bubinga, which perhaps explains the variety in appearance encountered between individual examples. With the sides successfully bent to shape, I've concluded that either the precautions I took contributed to my success or that the particular variety I'm working with tends to be less troublesome than other species. With Bubinga now listed on CITES and therefore no longer available in this country, I guess I should count my blessings as I forge ahead with this guitar, safe in the knowledge that I'll never have to deal with it again.

Cheers

Pete