Sunday, April 27, 2008

Finishing Experiments

Ash has very porous grain which must be filled before coating in order to quickly obtain a smooth surface. Without filling the grain, the top coats will just soak into the grain making it difficult to get a glassy finish. I'm using Bartley's Wood Paste Filler and blue dye powder purchased from the Guitar ReRanch.

During the past week I've done some finishing experiments. I managed to get grain filler on the scraps, and some stain and sanding sealer as well. The short version is that I've decided not to stain the wood blue as I attempted in these experiments. Instead, I''ll use dark grain filler to get the high contrast effect and spray a translucent blue color coat after applying the sanding sealer.

Here are the scraps with various stages of grain filler applied.

The two outside pieces on the far left and right have the natural grain filler applied-- it dries translucent so the pieces look very close to the natural wood. The middle three were treated with darkened grain filler -- a mixture of one spoonful natural grain filler to 15 drops of Minwax ebony stain, which produced a very dark gray, almost black filler. The two pieces on the left did not get a wash coat, while the three on the right did (four passes of Deft clear gloss lacquer aerosol). The piece second from the right has been sanded after a single application of grain filler. It exhibits the desired high-contrast grain effect. You can see some blue splotches it -- some of the stain jumped out of the container as I mixed it.

I mixed the blue dye power in lacquer thinner and applied it directly to some of the wood after grain filling and sanding. The three right most pieces below also have a few coats of sanding sealer applied.

Staining the wood after grain filling and sanding didn't work out as well as I had hoped. It appears that the washcoat, the grain filler, or both, interferes with the stain even though the wood was sanded back. The color is uneven next to the grain filled areas - there is a very thin area of natural wood color that follows the grain pattern. I may try this technique with a piece that didn't get a washcoat to see how it works out. The use of lacquer thinner as the solvent also appears to be a problem. Even after several coats of sanding sealer I can see the grain pattern in the surface when viewed at a low angle. The lacquer-thinned staining step appears to have affected the integrity of the grain filler. On the piece that was not stained, the sanding sealer appears perfectly flat.

I might be able to get better results if I had mixed the dye with alcohol instead of lacquer thinner. This is an experiment I will probably try in the future, but for now I've changed my plan to include spraying a blue translucent color coat over the sanding sealer rather than staining the wood directly. The piece above does show the look I'm after, but I want a darker blue and a more even application of color. I could mix and spray the color using the dye powder I have on hand but I'd have to buy a spray gun and a can of regular lacquer (I've got lots of aerosol at the moment). So I opted to order a can of blue translucent aerosol from the ReRanch instead.

My next step will be to apply the darkened grain filler to the body... Check back soon.


Saturday, April 12, 2008

Drilling the neck

I love my neighborhood -- everyone is so friendly and helpful. I don't have a drill press, so I enlisted the help of a neighbor who has one and we drilled the holes in the neck this weekend following the instructions for installing a bolt-on neck at the StewMac website.

The first step was to clamp the neck into position and align the neck to the tremolo screw holes near the bride. We center punched the hole locations on the neck through the holes in the body.

Here we have the screws set through the neck plate and body so we can measure the depth required for the holes in the neck.

Next we set up the drill press so it will only drill to the required depth in the neck, and carefully aligned the bit over the center punch mark. We also spent some time ensuring the drill bit was perpendicular to the plane of the neck.

With the holes drilled, I bolted the neck on and re-checked the alignment. I find that I have to "work" the neck against the body as the screws are tightened to get it into alignment. So far so good.

My neighbor also has a table saw. We used it to cut a piece of scrap ash into small pieces for practicing the finish. We also attempted to cut a thin piece of ash from the board. With the think piece I'd like to replace the truss rod cover (finished just like the body). The thin pieces are still too thick, so I'll have to work them with a plane and sandpaper. Here are the practice pieces mounted to a board for easier handling...

Each of these pieces will be finished using a different technique -- i.e., different combinations of grain filler tints, wash coat (or not), etc. Based on the experiences of finishing these pieces I'll decide on the strategy for finishing the guitar body.

Friday, April 11, 2008


I've begun the process of finishing and assembling a Stratocaster style guitar. Most of the parts have been purchased from Carvin, except for the pickups which are a matched set of Seymour Duncan "Vintage for Strat" flat SSL-2's. The body is swamp ash and I'm considering a finish which involves applying dark grain filler, sanding back, and staining blue prior to the sanding and clear coats. This should give it a "Blue Zebra" look because the grain will become even darker due to the grain filler, while the light areas remain blue due to the subsequent sanding and staining.

The following artist rendition of the final product was created using the virtual guitar application at the USA Custom Guitars web-site.

The parts list also includes a maple neck with a 12" radius ebony fretboard, locking Sperzel tuners,Wilkinson tremolo, white perloid pickguard, black pickup covers and knobs, strap locks, and chrome jack. I plan on a standard Strat wiring stetup.

Here is the body just after it arrived from Carvin:

One of the first challenges will be to drill the holes in the neck. Normally Carvin ships the neck with the holes pre-drilled when you buy a kit. But I originally ordered the neck for another guitar so it doesn't have the holes yet.

I'd like to point out the web sites that have proved helpful so far. The most important is This site not only sells products for finishing guitars, but has great 'how to' instructions and an excellent user forum. The free information section at Stewart MacDonald is also very good.

Check back every so often and follow my progress.