Shellac Problems

I'm running into some issues with French Polishing on the LP Junior. Everything seems to be working out fine on the top and back. The shellac is smoothing out nicely and I will be progressing to the alcohol only steps soon. 

But I'm running into two problems with the sides. 

The first is a dry spot, that just does not seem to be taking the shellac at all. I have been over it several times slowly rubbing the shellac in, but the dry spot only seems to grow.

The second problem is residual darkening from drips when I was working on the top and the back. I've tried sanding back and then reapplying shellac, but I can still make out some of the spots. This is worse in the area around the neck and next to the dry spot mentioned above.

So after a lot of internet searches with no luck, I ran up to Woodcraft for some advice. The clerk who has been an expert on finishes in the past made a few recommendations. The darks spots are actually caused by thinned out shellac from the drips that seeped deeper into the pores. Then when I tried to add more shellac while working on the sides, it was a heavier weight. The pores of the walnut was not able to absorb the thicker shellac as well.

I was worried I would have to sand the shellac all the way back. Instead the person at Woodcraft recommended using just pure denatured alcohol to remove the shellac instead of sanding. After a few minutes of rubbing the alcohol in it removed much of the shellac. Then I followed up with a quick light sanding using 400 grit paper coated in mineral oil. I was then able to start french polishing again, but this time I started with a heavily diluted coat of shellac. After that sealed the sides I started using the heavier 3 pound cut I was working with before to build the layers.

Now this just leaves the issue of the dry spots. For this the issue the internet did seem to help a little as did my friend at Woodcraft. Fixing this will be a slower issue. The online source recommended slowly working around the edges of the dry spots and building up there. I believe the quote was something along the lines, "you have to sneak up on the dry spots in order to fill them. My friend at Woodcraft reminded about using mineral oil to keep the polishing pad well lubricated. Without the lubrication the cotton rag will heat up while rubbing and cause friction on the wood, there by pulling the shellac up rather than applying it. This will cause the dry spot to grow. So this is where everything stands at this point. I am slowly building the shellac up on these dry edges.

LP Jr (Six) Final String Up Test and Grain Filler

So after leveling the frets, I decided to string Six up and test it out acoustically. Here's just a simple B minor chord progression.

And here is a little blues improv in E.

After taking of the strings and tuners it's time to fill the grain. I'm following the suggestion of one of the people at our local Woodcrafter. She suggested that because the grain is so fine that I could just use shellac. She recommended coating it on thickly. And then sand it back to the wood. I'll do the sanding tomorrow.

LP Jr (or Six) Fretwork

So I'm closing in on the end for the LP Jr project. I've decided to refer to her as Six now, since she will be the sixth guitar that I've completed.

I have a few more tasks to complete before I can begin finishing the body. I wanted to get the frets seated and level them first. I had to bend the frets to tighter radius than the fretboard. The fretboard is a 12 inch radius (matching the bridge.) I bent the frets to close to 10 inches.

I over bend the frets because I will be using a hammer to seat them.  As the hammer forces the frets into the slots it also flattens the radius.

With all the frets in place its time to clean things up.

First, I remove the overhanging edge pieces with a flat nose wire cutter.

Then I use a fine file, smooth the edges even with the side of the fret board. (I didn't take pictures of this portion of the process. I promise I will do that on my next build.) After the edges are smooth. I turn my file to a 30° angle and run it over the edges again, taking off more of the fret edges. This makes for a smoother playing neck.

Next, it's time to level the fretboard. First I tighten the truss rod slightly (maybe a quarter turn.) I take 320 grit sandpaper on my 12 inch radius fretboard leveling block and level the neck. This flattens the frets taking off any high spots. While doing this I will hold a straight edge to the frets looking for high spots that need more attention.

After I level the fret board it's time to put a crown back on the frets, or round their edges. First, I use a Sharpie marker on the flat edge of all of the frets, this helps me view my progress. (Yes, I did slip and mark up the fretboard at the 24th fret. I'll have to sand that mark off later.)

Next up, I use my fret file. It is a concave file that will round the tops of the flattened frets. By checking regularly I can watch the red marker slowly disappear leaving a round yet rough fret.

Next up I use 400 grit sand paper with a school eraser as a sanding block to take out some of the roughness. I use a metal fret guard to keep from scratching up the fretboard. I will polish the frets after I finish the body.

So now it's time to put everything together and see just what she's going to look like, and test how well she'll play.

I place al of the electronics in the rear cavity. This is a tight fit. On future builds I will route a larger electronics cavity.
  

















The switches and knobs are a little closer than I would have liked. This would have worked out fine, except that I wanted to add two there-way coil tap switches for the pickups. I used two on/off/on DPDT switches for a Series/Single/Parallel wiring for each pickup.

Finally, it's time to string her up and see just how she plays. While most people might find the neck to be a little thick at the nut, I find that I like it that way.
I'll upload a video of me playing the guitar acoustically in a couple of days. It sounds and plays great, even at this rough stage.

I'll upload a video of me playing the guitar acoustically in a couple of days. It sounds and plays great, even at this rough stage. 

Next up, I will block sand the body flat, and seal the walnut pores with shellac. I mixed up a nice thick  4 lb. cut of shellac tonight. I had to go back and re-read this post in order to make sure that I had the correct ration of flakes to alcohol - 4 oz of shellac flakes mixed with 8 oz of alcohol. 

LP Jr. - Neck Pickup Route

This is a rough mock-up after today's work. I placed the chrome hardware in order to see how this will eventually look.

Now for today's work - routing the neck pickup cavity. This route on the Jr. presented a special problem. Because this is a set neck with a 4° tilt, the standard Stewart McDonald humbucker routing template would not easily fit over the top of the body. There were a couple different possible work arounds. The one that I chose was to build a custom template out of scrap wood. 

First, here are some photos showing the nature of the problem.

As you can see, in order to use the StewMac template, I would have had to cut it to fit around the neck. But that still would not solve the problem with the thickness of the template. The fretboard sits almost 3 mm higher than the template. 

So the solution would be to use a scrap piece of wood and cut a custom template.

The scrap wood sits a safe 4 mm higher than the fretboard. I then use the StewMac template to cut my own template.

I drilled two large holes before routing the template.

I then measured off width of the base of the fretboard.

I then cut into the template, so that I could fit it around the fretboard. I cut a center piece to help with deep routes for the pickup screws, brackets and springs.

One of the other obstacles for the neck pickup route was the overall depth. The neck tendon under the the curly walnut top is about 1 inch thick. I wanted to leave as much of this tendon in tack as possible. The top is about 1/4 inch thick. The screws and brackets need a depth of about 1 inch, but the pickups will only need about a half inch. So the wood block is placed in the center to control the amount of routing I do on the edges. After routing those two areas to slight deeper than 1 inch. I removed the bock and routed the rest of the pickup cavity to about 1/2 inch.

After today's work, I have roughly just under 40 hours in this project.

LP jr - sanding, bridge and pickup route

So I've gotten quite a bit done in the last couple of weeks. First I sanded the body and neck to 220 grit. The details are really showing up nicely. The pin-stripe maple veneer really jumps out on the body.

Yes, I used two pieces of veneer on the neck laminates. In addition to the maple veneer, I used walnut veneer to accentuate the the lighter center curly walnut piece.

Then I positioned the bridge. In order to do this I strung-up both E-strings with dental floss. I lined up the floss with the sides of the neck. Because this isn't rocket science the center of the bridge position needed to be nudged about 1 mm above the center line. This movement of the bridge will not be visably noticeable to the naked eye. I also used a shim to check the overall string height of the bridge.

And finally, on Sunday, I routed the first of two pickup cavities. The cavity for the bridge pickup was a straight forward route. I just need to line the template up with the bridge. The neck pickup route will be more complicated as I will need to cut a template to fit around the base of the neck and it will have to sit higher for me to execute the route without damaging the neck. I will take plenty of photos in order to document this process.

LP Jr - Removing Dents

When I glued the top to the body, I made the mistake of placing the clamp directly on to the wood on the lower cut out. This caused a dent in the walnut. In order to fix this, I could have just sanded the top. But that would have taken a great deal of work and turned a great deal of the top into saw dust in the process.

I decided to try something that I read about somewhere on the internet. It involves using steam to raise the grain grain in the dent.

The first step is to apply water directly to the dent.

Then lay a cotton cloth over the water, and apply an hot iron creating steam.

The steam raises the grain of the wood.

Then follow up with a light sanding with 180 grit sandpaper. repeat this process a couple of times, and the dent will slowly disappear.

The completed Lap Steel

After about one year, I've finally completed the Lap Steel for my friend, Sven. I delivered it Sunday. He plugged it in for a test drive. The hard maple body offers a warm yet bright sound. The 250K tone pot combined with the .022uF capacitor provides a long smooth range.  

Here are a view more photos of the completed guitar after my final setup.