It's a question most of us have asked and many of us have tried to answer: How do you turn a fretted bass into a fretless? The mechanics are simple enough, you pull out the frets and fill the slots with something. In practice, it can be a bit more daunting. Here's my attempt to answer the question... in photo-essay form.
But first a disclaimer. I don't claim to be a luthier (I doubt many of us do, really), I just have a lot of fun with all facets of the bass guitar. Refinishing, repairs, building, playing, I like it all. Most of the things I know about these topics I learned from reading forums just like this one, so thanks to everyone out there. That being said, I can't possibly claim that the way I do things is the right way. In fact, most of the time I do things in distinctly wrong ways, but they're effective for me. I encourage everyone to do what works for you, regardless of whether or not it's how the pros do it. I mean, if we could all do it just like the pros, we'd all be doin' it for a living.
And now, on to the defret.
The first step in the process is to find a victim. Mine happened to come from a friend who wanted to try fretless. The bass is what any coinesseur would call "crap". The bridge is off center, the tuners all pull to the bass side (making for some distinct nut problems that I had to deal with a while ago), and the electronics are shakey at best. On the other hand, she plays well enough and didn't require a whole lot of monetary investment.
As you can see, she's a p-bass knock off with "GK" on the headstock. I don't know who these GK folks are, but I'll bet Fender isn't too scared of 'em.
Taking a closer look at the fretboard we see quite a lot of wear. There was either a very thin finish or no finish at all on the fretboard to begin with, so all the nice grime from playing has worked right in there. Other than the grime some of the frets are starting to come up and a few of the dot markers have sunk, telling me that it's high time this girl had some lovin'.
Before starting on pulling the frets I wanted to be sure that I minimized the clean up work I'd have to do. This means masking off the fingerboard. I used wide masking tape and simply covered the board, frets and all. Then I went along each side of each fret with a utility knife and pulled the tape away, leaving the frets exposed. This prevents any slip of the tools from scarring the fretboard and making more sanding work later on.
To actually pull the frets there are a couple different methods available. One is to use a good pliers / end cutter to get under the fret and pull it straight out of the fretboard. In this case I'm using a needle nose pliers to grab a hold of one end of the fret and pull it free. An end cutter has sharp edges that help to get under the fret and is therefore more ideal, but I didn't have one lying around.
I found that a glazing bar could be used to get under the end of the fret easier than a plier. By slipping the end of the bar under the fret and gently twisting, the frets could be levered out quite easily. Any method is acceptable so long as it doesn't do much damage to the fretboard and the fret slots are left in tact (as little tearing along the edges as possible).
Once all of the frets were removed it was time to clean up the slots. I decided I needed a new tool for this, so it was off to the bench grinder with an old screwdriver. I thinned the blade so that it could reach the entire way into the slot and then made a small hook in one face to allow me to scrape out the slots thoroughly.
Before cleaning the slots still had filler in the ends. By dragging the slot cleaning tool through the slots these filler plugs were easily removed. A few more passes and the bottoms of the slots were scraped clean and ready to go.
When all of the slots were cleaned out and the masking was removed it was time to fill the slots. My customer wanted some clear fretlines that would match the existing dots, so I looked around for something black and thin. As luck would have it, I found a crazy carpet in the garbage that would work fine (if you don't know what a crazy carpet is, ask a Canadian). I cut off a 3" wide strip of the plastic and set about fitting it to the slots. I had to thin it out quite a bit by using two sided tape to stick it to a block and running it on the belt sander. Once it was approximately the right thickness I would sand it with a block as needed for fine tuning.
The actual slot filling process went like this. First I would cut a curve into the edge of the plastic to match the fingerboard. This forced the visible edges of the material to hit the bottom of the slot, leaving no gaps.
Next I would sand the plastic to thickness as required using two blocks, one for backing and one with sandpaper attached. This usually didn't take long since I had already done my rough thicknessing on the belt sander.
Finally I would fit the marker into the slot and cut off the excess. This just happened to leave a curve pretty close to the fretboard radius for the next marker, giving me a jump on the next cycle of the process.
When all of the markers were in place I used some cyanoacrylate to make them permanent. I poured some CA into a dish and used a scrap of wood to drip some along each side of each marker. Thin CA is perfect for this application because it penetrates into the space between the marker and the fretboard, making an excellent bond.
With the markers in place and trimmed down, it was time to begin the sanding. Because there was so much work to do on this particular fretboard I started with 60 grit sandpaper on a radiused sanding block. After a bit of elbow grease the fret and dot markers were all levelled out. Then I stepped up to 220 grit to get a nice flat surface for finishing. Note that I masked off the body during sanding. I probably could have removed the neck and skipped the masking, but having the neck on the body made for a nice sturdy support while sanding. I pulled the neck once it was time to do the finish because I didn't want to risk getting epoxy into the gap between the neck and body and making the bolt on into a set neck.
The finish I decided to use was epoxy. My local Windsor Plywood had 51-Cure available and I wanted to give it a try. I bought the medium set of bottles and the pumps to go with them. If you're considering epoxy, definitely look at the pumps. They make measuring out ratios incredibly easy (one pump of each, then mix) and speed up the whole process considerably.
I spread the epoxy using a 2" foam brush. The main things to look for are bubble formation and cratering. Cratering occurs when one part of the surface refuses to "wet" with epoxy, leaving a small dry spot. It's easily solved by simply going over that area again with the brush, making sure to get the epoxy worked in good. Bubbles will generally find their way to the surface on their own, but another pass with the brush can help them on their way.
I ended up putting down three coats of epoxy with quite a lot of wet sanding at 400 grit in between. Before sanding the epoxy has a very high gloss finish. After it is incredibly smooth and satin feeling. Each coat was allowed to dry for a few hours before sanding and a day or so before recoating. This made sure that the previous coat was cured before a new coat was put on. Here are the three coats as they appeared before sanding.
Note the incredible gloss of the unsanded coats. In the third picture you see a prototype fingerboard that I coated with tinted epoxy. The epoxy was tinted with some dye mixed with isopropanol. I think it opens up some neat avenues of exploration, but that's for another thread.
With the final coat of epoxy applied, I gave the back of the neck a quick once over with some satin polyurethane (more for feel than anything else) and sanded the entire neck out to 800 grit. I then went over it with some fine steel wool just for good measure. I also deepened the slots in the nut until each one was about a credit card thickness away from the fretboard (or should I say fingerboard now?). A new set of flats (Dean Markley, I believe) and a quick setup (I took the action right to the bottom and redid the intonation) and she was ready to roll.
And there you have it, my adventures with defretting. The bass goes back to her rightful owner tomorrow, but I think I'll get some playing time in tonight. The satin finish with flats just feels so smooth, and there's plenty of mwah to play with.
I'd be more than happy to answer questions or take abuse regarding my methods. Remember though, while you may think it's hack work (and you'd be right) the results are good enough for me to be happy, and I've got a bit of a perfectionist under all the layers of slacker.
PS: Ok Wilser, who's up next on the "How To" list?