Build #3 DHB-4 fretless

[Simon Barden]

You've done a great job on the side dot removal.

Once you've settled on the actual scale length you'll be using (which with it being a fretless really depends on where you decide to initially put the saddles to measure to), you can use the StewMac fret position calculator to determine where the virtual frets should be.

https://www.stewmac.com/FretCalculator

[FaustoB]

Thank you so much Simon!
I wasn't aware of that online tool, very interesting and super helpful, bookmarked!

usually I find the side dots position by giving the instrument a ballpark set up (bridge height etc..), based on what feels right on that instrument, with bridge saddles sort of halfway their range; then I put some masking tape on the side of the fretboard, and find the side dots positions by playing on the instrument a combination of harmonics and actual notes, checking with a tuner and open strings.
Then gradually I start drawing lines in pencil on the masking tape.
I make an effort to not hurry this process, I like to leave the instrument overnight, continuing to fine tune the following day. Usually I set aside at least a week for this step to allow for several passes; I keep going until I feel the instrument reaches very stable side references, feels natural, and I can play it "without thinking too much".

I am not sure if this is the way to go, but instinctively it feels right to me. I really like the idea that the instrument itself is "doing the speaking", letting me know what is right and where the notes are. I wonder if my ears tend to feel more familiar with just intonation on an unlined instrument?
Switching between just and equal intonation, correcting the intonation in a musical way based on other musicians parts is part of the fretless charm.

However, the web site you mentioned provides great reference and for sure some mathematical and precise numbers to check against it before drilling the new side dots in!

Thank you!

[Simon Barden]

Unless you’re doing a side dot per fret, they are only going to be general indicators. Most of the fret positions won’t have dots, so a lot of your playing will be intuitive anyway and you’ll be making adjustments to your finger positions by ear as you play. I expect the more fretless you play, the less you actually need the dots. But what you don’t want are dots in the wrong position to put you off.

[FaustoB]

I am working on this project, sanded the body and neck, stained with an black interior stain and then applied a clear glossy varnish but I am encountering a potential problem.

I might have got my research mixed up because I was under the impression that after two coats of varnish I was going to start alternating sanding with finer grits and reapplying diluted coats of varnish, until a smooth surface is achieved, similarly to the Tru Oil procedure.

However, I have (thankfully!) did a quick test on a piece of scrap plywood wood that I stained and varnished with the same products, and when I sand (400) an opaque, whitish colour comes up... it looks like I am making it worst. The surface doesn't feel that smooth either.

After some research, it looks like I need to buff the timber using super fine 3M rubbing pad with an orbital sander....
is this the way to go? I don't have an orbital sander but perhaps I could ask around and borrow one.
This is the video and blog post I watched suggesting this workflow.

The bass looks good but the finish is not smooth, there are minor paint brush lines, and occasional drops of thicker varnish here and there.

[FaustoB]

Ok, quick update.

After a bit more research, this evening I decided to sand lightly by hand, and apply a thin coat of varnish slightly diluted (1 to 10) using a cloth instead of a paintbrush.

I'm much happier now, the surface starts to appear much nicer, definitely smoother, and the whitish patina goes away after the coat.

I'll proceed this way tomorrow again with finer sand paper.

[Simon Barden]

Any clear finish, be it poly, acrylic, or nitro is going to go white and opaque if you sand it with P400. You've creating lots of scratches in the surface and these diffuse the light falling on it, reflecting it back in all directions. Apply more varnish and this will fill in the scratches and create a clear layer once again.

Personally I'd just apply several coats of poly and wouldn't bother with intermediate sanding. With just a couple of coats and sinkage into the wood, there's always the risk of sanding through into the stain layer, especially on corners. So unless you've got a particularly large drip (which needs to be left to dry for several days before spot sanding away as the interior of the drop will remain wet for a while), then I'd just go for layer application for depth, certainly if unused to the process. As you get more proficient and experienced, than you can start light intermediate sanding, but you need to get a feel for it.

Ultimately you need to get the finish flat and smooth. That's all the video you linked to showed. And that's one way to go about it but there are many ways and the chap stopped short of the final polishing process using cutting compounds for a proper shiny finish.

You need to sand the surface flat using wet and dry on a backing block. The bigger the block, the flatter the overall surface will be, but obviously on curves it's either a small block or hand sanding. Once the varnish is on, I'd be using it wet. The first task is to get the surface flat and free of pits in the finish. If it's very uneven, then I'd start with P400, otherwise I'd use P600 as there's less chance of sanding through by over-enthusiasm. Once the surface is flat, then you can move on to finer grits - P800, P1200, P2000 and P2500 if you want. Once you've gone the hard work with the P400 or P600, then the rest is a lot easier as you are just trying to remove the scratch marks the previous grade grit made.

Just make sure that you add a drop of detergent to the wetting water for the wet and dry, as it reduces surface tension and helps keep the paper clog-free. Check the paper often as you don't want balls of finish clogging the paper as this can scratch the finish with coarser scratches than the grit you're using.

The grey pad in the video is equivalent to 00 grade steel wool and the white one 0000 grade steel wool. If the surface is already very flat, then you could go straight to using something like that (I thing there must have been some unseen surface preparation in that video) and P2500 grit wet and dry will get you to somewhere in-between the two finish levels. But you don't need to go finer than that with sandpaper as your cutting/polishing compound will take over from there.

I generally use T-cut (a medium cutting compound for cars available in the UK, but Meguiars Ultimate Compound is an equivalent) followed by Meguiars Scratch X2, which is a finer cutting compound. You can rub by hand or use some foam polishing pads on a battery drill (or a mains drill set to a pretty slow speed). It's very easy to build up heat from friction, so not too fast a rotation speed and keep the pad moving across the surface at all times. Heat softens the finish and you won't get a good shine. You should immediately change from a slight white opaqueness to clarity and shine.

So the video and the standard method normally proposed for guitar finishes are equivalent, but if you start with a rough surface, unlike the flat one the chap in the video had, then its going to take a very long time indeed with a grey 3M pad. And you can get a glossier surface than he did using a cutting/polishing compound.

The general sanding rule I use is that if it's taking a very long time, then go a grade coarser and see if that improves things, and keep going coarser if necessary. But even on finish bumps, I wouldn't go coarser than P240 used wet. And just work on those locally.

[Simon Barden]

And you seem to be using a very mixed application method. Normally you'd either use poly as it is (ideally spraying it) or mixing it 50/50 with turps to make a thin mixture you can wipe-on from the start rather than spray (or brush). Wiping-on from the start will probably get you the smoothest finish if you can't spray it on.

It's not TruOil, so you can't wipe-on un-thinned poly in the same way to start with and hope to get the same results.

Ultimately you just want to get enough of a finish coat on so that its deep enough to sand flat without sanding through to the wood and stain below. How deed it needs to be depends on how flat you can get the surface. Some people do it via very careful preparation of the surface and then applying the finish coats very evenly, so that only a few coats are required and little sanding is needed before polishing. Others take time to build up many thin layers. Others put a few thick layers on. A rough thick coat may take longer to sand flat, but it often takes less overall time than applying lots of layers.

Many ways to skin a cat, many ways to finish a guitar and end up with a similar end result. A lot depends on your level of expertise in the different finishing methods and the amount of time you have available. But it helps to understand just what you are trying to achieve. Some of the intermediate steps people take don't seem to make much sense to me, but if they are happy doing it that way it won't do any damage, though it might extend the process a bit.

To get TruOil or Poly to fill up undulations in the finish, rather than just form another layer that follows the contours (due to surface tension), you need to thin the finish significantly. And I'm never quite sure how well a very thinned finish would dry and adhere to the surface below. Obviously the more thinners there are, the thinner the final finish will be, so the more applications you need. A few thick layers and sanding back can end up taking far less time, even if the intermediate steps don't look as nice.

[FaustoB]

Thank you so much Simon for your help and for sharing your expertise. I really appreciate it!

All your tips and comments are on point.

The finish is looking gradually heaps better past that first shock of seeing the finish going so white the first time. I will definitely follow your advice.

Diluting 1/10 is something that I've read somewhere and instinctively made sense to me looking at the product I am using.
I tried it yesterday. I just needed the varnish to be a little bit less dense. The way it was it made it difficult to apply evenly without having heavy drops appearing and gathering everywhere.
I used a brush for the first 2x coats, as per tin instructions, but ultimately wasn't happy with it and used a cloth yesterday and I am much happier with the control I have.
All this is 20% experience and 80% guts feeling to be honest, but I am learning a lot and it seems to be working fine.

Thanks again for all the suggestions Simon, you shared a lot useful info!

[FaustoB]

the finish is proceeding, a bit painful but it's getting there...

In the meantime I'm getting my head around the wiring for this kit.

According to PitBull Guitars website and the electronics that came with this kit, my understanding is that this is the wiring diagram



I am considering not having the switch in this build, just keeping 4x knobs (2x volume, 2x tone).

I am wondering if this wiring diagram will work for my kit? (although I am a bit confused as it says "stereo jack" and I am not sure why, would a normal jack work?)



Another question I have is about the wires coming out of the pick up. One black, a pair twisted together white and red, and another pair twisted together white and green. What are these wires? Which one is ground and which one is hot?
Photo





On a different note: for this kit the bridge is made of timber and I was a bit worried about not having a ground connection going from the electronics to the bridge, and therefore to the strings.
After a closer inspection, I noticed there's a predrilled hole between the electronics cavity and the ferrules for the string through body. This is good news, it looks like I will have to feed a wire through each ferrule predrilled hole, making sure that it touches the ferrules. Still not 100% sure on how make sure that this wire will touch each ferrule but will come up with something. At this point I am thinking or soldering a bare wire to the ferrules.
Will take some better photos when I'll get there with the build.
I've check with a multimeter and the ferrules are conductive.

[Trevor Davies]

Hi FaustoB,
I can help with the pickup wires.

The black is hot,
the white and red (soldered together) wires join the 2 coils in the humbuckers - they do not go anywhere (unless you are coil splitting) just put some insulation tape around the ends so they cannot touch any conductors in the control cavity.
The green (with bare shielding wire) are the ground.