Bohn Designs: August 2015

A photo blog of replica 59 Les Paul build #2. I will caption the pics, and add comments where they are not redundant from the first build.

Here we go...

Pretty close to the target of 2.500. For my code, the maple cap should not be any thinner than .700".

Raw body blank with maple cap attached. Plug the hold down holes when gluing on the cap!

Prep the acetone/binding glue for later in the day. The shavings are scrapings from the last guitar.

Back cavities done in about 10 minutes.

Flipped over and ready for machining.

Rough outline to make clearance for 3d machining.

Binding channel depth just into the mahogany body.

Completed carving and cutout. Total time: 3hrs.

Binding ready for install.

Binding installed.

A note about the way that I did all the binding on this guitar. First off, I would use the binding glue made from acetone/binding scraps and a small acid brush to put a liberal amount of the goop around the entire binding channel. The glue is mixed thin enough to flow into the wood and leave a bit of the plastic residue on the surface of the wood. I would let this dry, which happens pretty much as you brush it on. The binding was then set in place, and strait acetone was brushed on the gluing side. Before this was allowed to flash off, I would press the binding in place in the channel and tape as shown in the above pic. I could work about 12" at a time. After this was in place, I would go around the perimeter and flow some more acetone between the binding and wood. If done right, the you could see the binding melt into the body. The adhesion is perfect.

Sanded to 320.

Nice curves.

Perfect binding.

Body building time: One saturday from glued rough blank to finish sanded.

Fretboard blank ready for machining.

On the first guitar, I used a pre-slotted fretboad from Stew-Mac. After I got the inlays slightly off center on each of the frets, I vowed to never use a preslotted fretboard again. For this board, I created code to first radius the entire length to 12" radius using a 1/2" router bit, then cut the fret slots with a 0.023" 3 flute cutter. I got the board a bit thin when radiusing (about .20" thick at the center of the board) Slotting went fine, but the end mill for slotting is a bit too short for the depth required. I ran it deeper than it's made for, but it worked out OK anyways. The slots ended up being closer to .027" wide which made the fret pressing easy and didn't curve the fretboard.

Afternote: The frets were not glued in, and now that they have been leveled and crowned, I see no reason why they would have to be glued in.

All fretboad machining done in a single setup means no errors!

Inlays glued in and leveled. Note the sharp corners on the crown inlays. I hate when these corners are rounded off just because the maker was too lazy to use a chisel to sharpen them for the inlays.

Something like that... The neck blank was made at the same time as the first guitar.

Fretted and ready for leveling the frets to the side of the board.

A few minutes with the file and these will be gone.

Added a few thickensses of tape to the back of the fretboad before binding the sides.

Clamp one side of the binding at a time. Use a strait edge for this.

Fretboard building time: One lazy Sunday.

Nice tight neck joint.

Good fit.

Gluing the fretboad to the neck blank. Do this before shaping the neck.

Notice that I now have made a radius clamping caul. This was worth the time and effort. The glueup was easy and perfect. I will reuse the caul when it comes time to level the frets.

Need to use a few little wedges at the nut end of the fretboard.

Use a backer plate when shaping the headstock to ensure no chip out.

Working the sides of the neck down to the exact width required at the nut and end of the board.

Work the neck with the body to ensure a seamless neck transition.

Something like that.

Glamour shot of the back!

Nice neck joint.

Burst colors. Lemon yellow. Georgian Brown on the left, brown mahogany on the right.

headstock logo cut and inlayed using epoxy tinted black with charcoal.

Staining the headstock veneer with black dye. It takes several applications to get it jet black.

Grain filling

This turned out to be one of the worst jobs to do on the last les paul, so this time I was careful about the procedure. I did alot of reading on the internet about different grain filling strategies, and tried several of them out. I was looking for something easy, quick, and effective. Quite a tall order! Below is a summary of my tests.

Egg Whites - I was a bit skeptical about this process at first but decided to give it a fair try. The theory is that you fill the pores with a slurry of sawdust and egg whites. You basically wet sand the work using wet/dry paper and egg whites for the wet medium. Believe it or not, it worked remarkably well! On both samples, it took 2 applications to completely fill the pores. The slurry dries rock hard and it's pretty easy to get a fine slurry going when using 320g wet/dry paper. The downside is that it take quite a bit of time and is a bit messy. It also changes the color of the wood, in this case, gave it a bit of a pinkish cast. If the egg whites were left on the wood surface longer, the color intensified.

Testing grain filling with egg whites.

More egg white testing.

Pumice/shellac - This method is similar to above, but instead of using sand paper to make the wood dust slurry, the pumice grinds the wood fiber, the wood fiber and pumice fill the pores and the shellac locks it in. You make a cloth ball soaked with shellac, add a tiny amount of pumice and rub this in with moderate pressure. You can see when the pores are filled. This also worked well and after one session on the test piece, the pores were completely filled. The fill was also darker than the wood, so if this was the effect that one was aiming for, it accomplishes it well. Down side is that it's labour intensive and fills the pores with a dark filler. (need picture of result)

Water based Grain Filler - This stuff looks a lot like drywall mud. It is a very fine texture. I used this on the first build, but for this test, I first sealed the mahogany with water based sanding sealer, sanded flat, applied another coat of sanding sealer, then applied the grain filler. I also thinned it out so that it was very runny. This allowed it to be worked into the wood surface without drying out instantly. I rubbed the filler into the pores using my fingers and as it was setting up, I used an old credit card to scrape the excess off the surface, scraping at about 45deg to the grain direction. This left very little on the surface. After drying for a few hours, I very gently sanded off the excess using 320g. The grain was filled pretty much on the first try. The entire guitar took about 1 tablespoon of the filler.

I opted for this process since it was the least invasive out of the 3 options. Sealing the wood first is the real key to success. Sanding the excess filler off was a breeze with the armor coats of sanding sealer applied.

Thinned out grain filler.

Grain fill body and neck separately to make sanding and handling easier.

Grain filled mahogany vs non grain filled ledge in the control cavity.

After grain filling, I applied one more coat of sanding sealer to lock it all in.

Strain the mixed aniline dye through coffee filters. Do it a second time if you can still see particles on the side of the container when you shake it up, do it a third time if you can still see particles, ect.....

The mahogany has been colored with brown mahogany dye mixed about 1/2 and 1/2 with lacquer. I hate how this turned out. Considering stripping this off and going with the burgundy used on the first build.

The problem I had with tinting this body comes from a few sources. Firstly, the lacquer/dye should be a homogeneous color with no color specs in it, just a glassy transparent tint. Secondly, the mixture should be mixed so that when a wet coat is applied, it's the tint color you are looking for. I mixed the dye too strong, and was forced to dry spray it on to get the tinting I wanted. I had the gun set slightly wrong, and it was spitting largish splats of color rather than a foggy haze of color. I didn't really notice this until it was done. It was clear to see on the exposed binding. Had I applied a wet coat, it would be much darker than I wanted. I did a test spray on a sample piece of mahogany and it looked ok, but I guess I didn't notice how crappy it looked. All in all, it looks alright and it's a nice even color, but the speckling will be noticeable through the clear coat. The back has a thin coat of clear applied to lock the color in, but I'm really considering stripping it back to the sanding sealer and doing it again with the reddish color used on the first axe.

Afternote: Yes, indeed, I stripped back the entire guitar and finished with the dark red color. I'm very glad that I did this, I would have never been happy with the first mess that I made. Stripping went pretty well. About 1/2 liter of acetone and a few rags and about an hour and it was cleanly stripped back to the sanding sealer. I didn't need to pickup the sanding block before spraying again. This did not affect the grain filling either.

Front ready for colors!

Lemon yellow applied to bare wood. this pic does not show how saturated the yellow really is. It's almost flourescent!

Burst of "Georgian Brown" applied and a single coat of clear lacquer to seal it all in. This pic is much more red than it really is. Stupid cell phone white balance!

Scotch brite scuffed the top to remove dust lumps. This is a true representation of the real color. Bindings are also scraped. It's ready for clear coats to begin. I'm very happy with the burst, color, shape, and width.

14 Sept 2015

It's been several weeks since my last post on this guitar, but I have been making progress. Since last posting, I have clear coated the guitar and let it cure for about 2 weeks. At this point, there was barely any smell coming from the finish, so over the weekend, I took to the task of wet sanding and buffing it out.

Plugged the headstock holes with absorbent towel

I don't know if anyone else has had this problem, but for the second time, these tuner holes have given me grief when wet sanding. The water seems to wick into the maple veneer and expand. It's just temporary until it evaporates, but it's a bit of a PITA. I tried plugging the holes with paper towel, but this just seemed to keep the holes wet. These got bad enough that the lacquer actually turned hazy white around the holes as well as swelling. I think from now on, these holes will get drilled after final buff out. Any other way to deal with this? The body holes don't seem to have this problem.

Typical wet sanding - Use nitrile gloves to save your hands

Horrible result - scratches from the 320g starting paper were not properly sanded out.

I thought I would save some time sanding the baby out by starting with 320G rather than 400. Well, I was wrong. Maybe I would have saved some time if I were a bit more diligent at removing the scratches through the subsequent grits. I was tired and didn't feel like really doing this job, and after a few hours, I was no more alert or enthused about it.

Sunday morning I started back at 600g and was sure to get rid of the deep scratch marks. Through to 2000g, I sanded at different angles for each grit and only moved to the next grit when the previous scratches were gone. Basic woodworking.

New scratches on the left, previous grit on the right

Nice even sheen of 2000g

After buffing with Maguires #2 then Maguires #3 on a 3" foam pad

Gloss-tastic!

After re-wet sanding this guitar, there was not a single divot, chip, or sink anywhere on the entire guitar. Very happy with the result. The finish is a bit thinner than the first les paul, but is still quite adequate. That tiger stripe maple just GLOWS! It's like a natural reflector.