Thursday, December 31, 2009

Beautiful Blackwood

Here are a couple of attempts to show the beauty of Australian Blackwood after I sprayed two coats of de-waxed white shellac this afternoon as a sealer and tie-coat.

Among the many significant milestones to be enjoyed during the building process, this must surely be one of the most satisfying - the ugly duckling is turning into a beautiful swan! There's still a long way to go before the transformation is complete, but it's at this point I tell myself I can see the light at the end of the tunnel and can look ahead eagerly to the end result of my latest collaboration with Mother Nature.

I visited Australia's south-east for the first time last year and was taken aback by just how common Australian blackwood (Acacia melanoxylon) is, however, trees yielding wood with the striking figure displayed here are altogether more unusual. The rippled appearance in the grain changes constantly depending on the direction of the light and the angle of view - no photograph can truly do this wood justice! There's little wonder it's become so highly prized in the guitar world both here and abroad for it's looks alone.

Just to demonstrate that its popularity extends beyond guitar enthusiasts, here's a shot of a brushtailed possum who had taken up residence in a blackwood tree next to our overnight camp in Victoria's Tarra-Bulga National Park.

Click on any of the photos for a larger view.


Saturday, December 26, 2009

Economies of Scale

As my current marathon effort building several instruments at the same time draws to a conclusion, I've sworn never to repeat the exercise when I finally have a clean slate and I'm ready to begin the next one. As a part-timer, the building process is slow enough as it is and I've found it a little frustrating having to wait so long to enjoy the fruits of my labour when my limited time is divided between so many instruments.

Nevertheless, it's sometimes more efficient to work on a production run of components like these mahogany neck blocks, when preparing bracing stock or dimensioning and slotting the mahogany strips to be used as kerfed linings. The additional time involved isn't hugely significant and it's easier to fabricate them mindlessly with consistent dimensions when jigs are in place or machinery is set up and adjusted appropriately. There's the pleasing illusion of rapid progress to be enjoyed later on too when there's a ready-made stock of components on hand!


Saturday, December 12, 2009

New Rosewood Back and Sides

Here's a recent acquisition which I hope to begin work on early next year, assuming I've managed to complete my current crop of guitars. As much as I've grown to love it, East Indian Rosewood can sometimes look a little bland and uninteresting, but in this case the colour variation is a little more pronounced than usual and I found myself unable to resist the urge to click the "Buy Now" button when I spied it on Allied Lutherie's web site! It should look terrific under a finish, and the tap-tone in its current raw state suggests that it has the potential to sound pretty impressive too.

East Indian Rosewood is something of a staple in the guitar-building world and, unlike some of the other rosewoods, is still reasonably priced and has a fairly secure future. I always smile when I see sets of this wood marked down to a lower grade when they're not exactly quarter-sawn or exhibit anything less than perfectly straight grain. Some of the other more coveted rosewood species are offered to instrument builders for astronomical prices even when they're flat-sawn or have been salvaged from stumps and have the wildest grain imaginable. The bar is obviously set pretty high for their Indian cousin!


Friday, December 11, 2009

U-Beaut Hard Shellac - Once Bitten, Twice Shy

I didn't want to die wondering whether U-Beaut's Hard Shellac could have been the answer to my finishing dreams and I experimented with it on this little Claro Walnut/Engelmann Spruce 12-fret double-0, destined for my own use. Having been distracted by other projects recently I've only just strung the guitar up and, although it's still a little tight and is yet to have its initial fret job and setup, it sounds very promising already. What's more, I love the way it looks - up to a point.

Reports from those who had used an earlier formulation of this finish were encouraging, but there were occasional angry mutterings about serious crazing which sometimes materialised weeks or even months after application. In response to criticism, the manufacturer added a plasticiser to the recipe and re-released the product, advertising the fact that it was now suitable for musical instruments. I certainly found it a dream to spray after reducing it 50/50 with denatured alcohol to a 2lb cut and, after waiting three weeks or so for it to fully cross-link and harden, I was able to rub it out to an impressive shine. I was an instant but cautious convert! My optimism was tempered by the recognition that any finish - particularly a shellac variant - has to prove its resistance to use and abuse over time before it can be declared commercially viable. With neither use nor abuse to blame in this instance, my hopes have been dashed already however and, after six months, the finish on the neck of this guitar shows the first barely discernible but unmistakeable signs of the same crazing which so frustrated (some) users of the earlier formulation. There's an equally faint suggestion of the same thing happening at the waist on one side and there's no telling if it will worsen or appear elsewhere over time. I must say, I'm not too upset though; it was a risk I was willing to take and at least it's answered the questions I had once and for all - in my mind anyway.

Interestingly, this Australian product has recently been added to the inventory of one of the leading U.S. lutherie suppliers and there's been a good deal of excited chatter about it on one of the on-line guitar building forums. Based on my very limited experience, I can only urge caution; either the additional plasticiser hasn't been entirely successful in curing the crazing problem, or skilful application is absolutely critical to success. Although I was at pains to spray thin coats, waiting an hour or so between them (it was a hot day), it just may be that the ambient conditions at the time weren't ideal, or that my rudimentary skills with the spray gun weren't up to the task. Perhaps those applying it as a french-polished finish will have better luck, but after this experience, I'm fearful that the results are likely to be unpredictable at best - not a recipe for good customer relations. For the time being at least, I'm inclined to stick with the water-based KTM-SV I discussed in my previous post.


Thursday, December 10, 2009

KTM-SV - The Bee's Knees

As I'd hoped, the top coats of Grafted Coatings' KTM-SV went onto my OM beautifully, particularly after I'd added some distilled water to the finish prior to spraying. The advice I'd read suggested adding 1 ounce of distilled water to a quart of finish which equates to around 30ml for us metric types. I used approximately half of my quart tin which should leave enough for the Australian Blackwood/Sitka Spruce triple-0 waiting in the finishing queue.

Other than it being an opportunity to become better acquainted with my spray equipment, I learned that acceptable results are probably more likely when the temperature is lower and the humidity higher than it was on my first day of spraying. With the temperature climbing to around 35C through the day and the relative humidity sitting on 20%, I was probably foolish to have proceeded and it was difficult to achieve the wet coats I wanted. I'm sure my inexperience played a large part in the less than perfect results I had with the initial coats too. Although it didn't dry with the gritty appearance that suggests that the finish has dried en-route, between the spray nozzle and the guitar, I suspect it was dry very shortly thereafter, before it had a chance to self-level completely. As a result, some "orange peel" was evident after the first couple of coats. With more practice, the addition of the distilled water and cooler, more humid weather on the second day of spraying, however, I was pretty happy with the appearance of the later coats straight off the gun.

I waited a couple of days to level sand and a few more days before attempting to polish out the finish. Without a buffing wheel at my disposal I use a random orbital sander and Surbuf polishing pads purchased from Lee Valley Tools in the U.S. The polishing compounds I used are made by Autoglym and are branded 03B Fine Abrasive and 02B Ultrafine Renovator. They replace the Meguiar's products I used previously which I found unsatisfactory for my purposes. After a week, the finish on this guitar is HARD, and it's a slow but satisfying process sanding through the grits then rubbing out to a high gloss with the polishing compounds. Perhaps as I hone my skills I'll think about building a buffing wheel, but I feel there's less chance of buffing through to the wood with my current method, which is certainly slower but much less prone to burn-through.

Having progressed this far, I'm increasingly confident that the KTM-SV is the safe, environmentally-friendly finish I've been looking for. Those who've used it for some time and have had instruments out in the real world for two or three years have reported no issues with it which strengthens my belief that this is the ultimate finish for the the health-conscious amateur luthier with limited resources and a less than ideal working environment. For an even more low-tech approach, I understand it can be brushed on which makes this product suitable for even the rawest of beginners.

I'll post glamour shots soon - minus the scantily-clad model - when the guitar is strung up and ready for delivery!