Inlays are high ... sand?

[Cullen G]

I have a fretless neck with scrolling inlays the entire length. I've noticed the inlays are now slightly raised. I'm guessing this isn't the most desirable on a fretless bass.

Is the answer to sand the entire neck flat again?

 

[ThomasTronics]

Radius block if you are going to sand the neck.
But make sure you match it to your existing radius.
220 grit?

Pictures?

 

[Cullen G]

Radius block if you are going to sand the neck.
But make sure you match it to your existing radius.
220 grit?

Pictures?

Thank you for responding. I haven't been happy with this fretboard from day one. The original roundwound strings scrathed the hell out of it with extremely minimal playing for one month.
As you can see, the inlays aren't sticking up visibly. But nothing feels smooth when you rub your hand over the fretboard. You can also tell this particular fretboard material scratched very easily. It's too soft. I want a smooth, harder fretboard. So I'm thinking CA glue. But I would want to sand it first, and need all the advice you're willing to share. Thanks again.

 

[Bruce Johnson]

I have a fretless neck with scrolling inlays the entire length. I've noticed the inlays are now slightly raised. I'm guessing this isn't the most desirable on a fretless bass.

Is the answer to sand the entire neck flat again?

Well, unfortunately, that's the reason why most of us Luthiers never put inlays on fretless fingerboards. There's too much difference between the materials. The wood shrinks a little bit, and the inlay doesn't. Then the inlay is sticking up.

The basic fix is to gently file the inlays down flush with the wood. A small flat #2 Swiss pattern file, filing lightly so it skips over the wood. Don't do this with sandpaper on a block; you'll end up with lumps and dips.

When you have the inlays flush with the wood, then it would be good to true up the whole fingerboard surface. This is done with a long straight flat bar with sandpaper on the bottom, following the string paths. Not a radius block.

Truing up a fretless fingerboard is more complicated than it first appears. But it's not that hard to do yourself, once you understand the geometry.

Here's a classic TalkBass thread all about truing up fretless fingerboards. In more detail than you ever want to know. But don't be intimidated by it. It's not that hard.

Even fretless fingerboard levelling tips

 

[Cullen G]

Aaaaaaaaaaaaauuuuughhh!!!

Sounds waaay more involved than I figured. I assume 8 or 10 coats of CA glue with light sanding between coats, won't level the fretboard out?
Thanks

 

[Bruce Johnson]

Aaaaaaaaaaaaauuuuughhh!!!

Sounds waaay more involved than I figured. I assume 8 or 10 coats of CA glue with light sanding between coats, won't level the fretboard out?
Thanks

You can coat the fingerboard with CA glue if you like......But only after you have filed the inlays down level and trued up the surface. The surface has to be trued up before you put on some external coating.

 

[Cullen G]

Oops ... I apologize. My eyes aren't what they were.

MY INLAYS ARE LOW. All of them. The wood is actually higher by .10 to .30 mm. What does this change?

 

[Bruce Johnson]

Oops ... I apologize. My eyes aren't what they were.

MY INLAYS ARE LOW. All of them. The wood is actually higher by .10 to .30 mm. What does this change?

In that case, you can either:

True up the surface of the fingerboard, trimming the wood down to the level of the inlays...

And/or build up some CA glue on top of the inlays, to bring them up slightly above the surface. Then file them flush, and true up the surface.

Probably both. Go over the surface with the long sanding blocks to get it approximately straight and true. Then see where you are. Any parts of the inlays that are still sunken, fill them up with CA glue.

 

[kgbeast]

Myself, I would have radius sanded the whole thing until the inlay and wood are even. But that needs to be done in a jig as free-handing that will probably produce bad results. I did successfully reradiused a strat neck in a home-made jig with the 8" radiused block from StewMac, so it is definitely possible, however the success of that will depend on your experience working with sandpaper and wood as well as overall handyman level so you can actually construct the jig. If you are more of a fighter than a lover, I would leave that alone.

Filling in with a clear goop is something that can potentially work... Because the neck is radiused and the inlay is so gigantic, you can not really fill in with resin or CA glue as that will run off the hi points and make a mess. You could try a knife grade crystal putty (like Tenax brand, but I think there are some options at Amazon). I have no idea how hard it will be to clean that off the wood. But basically you need something of vaseline consistency that dries out clear. You can possibly use the UV adhesive, It comes in as a very thick substance you can possibly build it up and hit it with UV before it collapses. Do not try to build it up flush, you will want to make the inlay higher. Once that done, you will need to level it with the wood. You can use a 1" wide rigid bar, like a 1/4" thick, 1" wide walnut hobby board from Home Depot. You adhere a piece of 220 sandpaper, then atop of sand paper put thing strips of masking tape. Tape will skip on the wood, while the sandpaper will grind down the resin or the cured putty (see attached image). It is important to check the sanding block like this on something perfectly flat but easily scratched like a sheet of acrylic. Basically when you try sanding it with this, it should not leave any marks at all. If the sandpaper still gets to the surface, you will want to add more masking take. With something like this, it is quite easy and safe to remove anything that is a little proud of the finished surface.

 

[Cullen G]

I thank both of you! I have been working with wood for 32 years. But speaker cabinets aren't nearly so complex.
I am green when it comes to this, so please help me understand where I may be thinking incorrectly.
I'd assume a long block with sandpaper would slowly sand the wood down to the level of the sunken inlays .... No? Wouldn't that be the only step short of the finishing process?
Assuming it was correctly sanded. In other words, why would i then need to add CA glue to the inlays, if the wood was sanded down to them?

 

[Cullen G]

And once the fretboard is properly flat, CA glue on everything evenly, light sanded between 7 coats?

 

[Cullen G]

I can construct a jig. I just need to look at some existing examples. Save me the engineering process if possible.

 

[Cullen G]

It seems to me, long radius blocks would make things simple. Or does the radius change as the neck narrows?
If not, it would only leave the string path sanding.

 

[Matt Liebenau]

The short version of the thread Bruce linked is to use a long, straight sanding block and sand along the strings paths then work the block side to side to blend the facets. The why is gone over in the thread. You can fill over the inlays, then sand then CA if you like. If the recesses are deep you’re probably better to fill in steps instead of all at once.

Once you’re done here’s one version of applying CA to a fingerboard that I’ve used with success. Five string single cut - oak content

 

[kgbeast]

I thank both of you! I have been working with wood for 32 years. But speaker cabinets aren't nearly so complex.
I am green when it comes to this, so please help me understand where I may be thinking incorrectly.
I'd assume a long block with sandpaper would slowly sand the wood down to the level of the sunken inlays .... No? Wouldn't that be the only step short of the finishing process?
Assuming it was correctly sanded. In other words, why would i then need to add CA glue to the inlays, if the wood was sanded down to them?

You do not need to use sanding and gluing at the same time. Filling up the inlay is to avoid whole neck sanding. So you pick one method and go for it. Sanding will produce the best result. I think radiused blocks come only in 8" unless you want to get the expensive aluminum one. Wooden blocks are great because you can attach to them the guides that will slide in the jig rails. The Jig I made was a pair of rails above the neck. The rails can be raised and lowered by nuts supporting them. Jig was to make sure that the block is not changing it's orientation and roll, as well as to support the block above the fretboard on rails so it can send only to a limited depth. So basically you dial in the jug so the block just touches the fret board all the way through the length. Then lower the rails say 1/16, and go hog-wild. After a couple minutes, the block will just glide over the board at which point you can see if any additional sanding is needed. You would cross hatch the fretboard with chalk or soap bar edge to make some marks to let you know what is sent and what is not if the board is not smooth. In my case there was a small warp as well as the desire to change the radius.

If you do not need to fix warps or change radius, you can make a jig which simply holds the block on the neck. That would be a pocket about the width of the sanding block with the neck leveled and attached at the bottom of the pocket

Obviously before any of that you need to make sure the truss rod is set so the fretboard is perfectly straight.

Beauty of the adjustable height jig is the the neck flex is not relevant as at the end it all will equalize as long as you start leveled and true.

Freehanding it or using the simple jig is an option as well, just more room to screw things up.

As with other things you can spend time to make a jig and do a fast accurate job, or you can just spend time slowly sanding and do multiple checks every step making sure that you are not cutting in hills and valleys. If you have patience you might prefer the free handing. Just put the chalk marks on the entire thing and they will guide you to sand even. Just make sure to really the chalk cross hatches once you send the off. You can do the same with narrower straight sanding beam like the one used for fret leveling. It is just will be harder to maintain the even radius. In principle some radius unevenness is not important, but it does look better if it is even.

 

[Cullen G]

You do not need to use sanding and gluing at the same time. Filling up the inlay is to avoid whole neck sanding. So you pick one method and go for it. Sanding will produce the best result. I think radiused blocks come only in 8" unless you want to get the expensive aluminum one. Wooden blocks are great because you can attach to them the guides that will slide in the jig rails. The Jig I made was a pair of rails above the neck. The rails can be raised and lowered by nuts supporting them. Jig was to make sure that the block is not changing it's orientation and roll, as well as to support the block above the fretboard on rails so it can send only to a limited depth. So basically you dial in the jug so the block just touches the fret board all the way through the length. Then lower the rails say 1/16, and go hog-wild. After a couple minutes, the block will just glide over the board at which point you can see if any additional sanding is needed. You would cross hatch the fretboard with chalk or soap bar edge to make some marks to let you know what is sent and what is not if the board is not smooth. In my case there was a small warp as well as the desire to change the radius.

If you do not need to fix warps or change radius, you can make a jig which simply holds the block on the neck. That would be a pocket about the width of the sanding block with the neck leveled and attached at the bottom of the pocket

Obviously before any of that you need to make sure the truss rod is set so the fretboard is perfectly straight.

Beauty of the adjustable height jig is the the neck flex is not relevant as at the end it all will equalize as long as you start leveled and true.

Freehanding it or using the simple jig is an option as well, just more room to screw things up.

As with other things you can spend time to make a jig and do a fast accurate job, or you can just spend time slowly sanding and do multiple checks every step making sure that you are not cutting in hills and valleys. If you have patience you might prefer the free handing. Just put the chalk marks on the entire thing and they will guide you to sand even. Just make sure to really the chalk cross hatches once you send the off. You can do the same with narrower straight sanding beam like the one used for fret leveling. It is just will be harder to maintain the even radius. In principle some radius unevenness is not important, but it does look better if it is even.

Wow! Thank you. I already had recognized the need for a jig to clamp the bass in place, with the bottom of the bass and neck supported.
Leaving figuring out a sliding mechanism to level the fretboard. I'd LOVE to see how you designed the sliding mechanism without flex.
It's worth saving. I love the bass.
Filling and filing the inlays sounds crazily tedious! If this were easy, it would be the way for sure.

Sooo, if you get a block with the exact radius as your fretboard from the factory, I'm struggling to see how sanding could be that difficult. But that's probably my ignorance.
I'm not trying to change the radius. Just sand the existing radius down evenly.

 

[kgbeast]

You can buy radiused sanding block from Stewart-Macdonald. I also saw those on AliExpress for pretty cheap... Like a couple of dollars. Obviously you need to know what that radius is.
The sliding jig I had was put together with strut channel for base with 1/2" plywood top to screw the strat neck to , 3/8 threaded rod for the up/down adjustment and the to pails were made out of 3/4 square tubing found at work as scrap. The thing looked kind of like fish tank without the glass. To the radiused wooden block, I have added small L-brackets with 3/8 bolts threaded only about 1" so most of it smooth. Cut off the heads. Two on each side of the sanding block, sticking out like an airplane wings. That is what was sliding on the rails. That did not have any noticeable flex. However, the whole thing could have been made out of lighter materials, I just had what I had. It took me hours to put this together and make it straight enough. I think it took an hour to setup and dial in the height. The actual sanding job took probably 10 minutes if that. It was a rosewood neck. The only thing I had to buy was the radiused block from Stewart-Macdonald. I think it was $15 back then, about 10 years ago. I did not save the jig as it looked pretty crude and was constantly in the way. Warped necks that worth repairing are not a common thing.

 

[Bruce Johnson]

Wow! Thank you. I already had recognized the need for a jig to clamp the bass in place, with the bottom of the bass and neck supported.
Leaving figuring out a sliding mechanism to level the fretboard. I'd LOVE to see how you designed the sliding mechanism without flex.
It's worth saving. I love the bass.
Filling and filing the inlays sounds crazily tedious! If this were easy, it would be the way for sure.

Sooo, if you get a block with the exact radius as your fretboard from the factory, I'm struggling to see how sanding could be that difficult. But that's probably my ignorance.
I'm not trying to change the radius. Just sand the existing radius down evenly.

You are missing the main point: A trued up fretless fingerboard is not a straight radius, that you can sand with a radius block. If you simply sand it with a radius block, you will end up with high spots in the middle of the neck on the outboard strings. Why that happens is explained in that thread I linked to. The correct technique is to use a long narrow beam sanding block, following right on the string paths. Radius blocks are only for rough shaping, not final truing.

 

[kgbeast]

Yes, I should have mentioned that I have not ever held a fretless neck in my hands. So my radiused sanding was merely to bring the neck and the inlay in a common place and remove any high/low spots in general. Any fretless specific board tuning is not necessarily what all that was about and you should certainly refer to that thread mentioned once the inlay problem is dealt with .

 

[Cullen G]

You are missing the main point: A trued up fretless fingerboard is not a straight radius, that you can sand with a radius block. If you simply sand it with a radius block, you will end up with high spots in the middle of the neck on the outboard strings. Why that happens is explained in that thread I linked to. The correct technique is to use a long narrow beam sanding block, following right on the string paths. Radius blocks are only for rough shaping, not final truing.

Okay, now I understand better.
I have the heavy aluminum 24" level. I have to get stronger masking tape, as mine releases too easily. I have sandpaper, but will need to get some 24" long. I have thin plastic sheet for masking. No glue necessary until finish coats. Not changing radius or shape of fretboard. Only sanding to surface of inlays. Sanding with the string paths. Start with 180 - 220 grit.
Work one string path a few strokes, then the next, etc and back again until even with inlay tops.

I think, lol