Build thread: walnut, maple, buckeye burl, pickups, bridge

[dwizum]

I figured I should start a build thread vs continuing to pepper the Workbench thread with photos of this bass.

It will be a 4 string following my now fairly standard design originally used in the Special Edition Build Off: The Thumfinizenvette bass.

Neck is curly maple and walnut laminates. Body is walnut. Top is the slab of buckeye burl I've been flaunting in the workbench thread.

For pickups, I'm making a set of my split bass soapbar design, which is more or less a mashup of a blade Jazz pickup with the coils offset like a P pickup.

Hardware is going to be a home-made brass and aluminum bridge and Hipshot ultralite tuners in satin.

Here's some shots of the progress so far.

Here's the neck, fresh out of router planing.

Neck blank is three pieces of curly maple and two stripes of walnut. I used a "tone block" style construction (I think that's a dumb term, but it seems to be what people call this) where the neckthrough laminates are 3/4" tall and a block of wood is glued to the back of the body section of the blank to get the thickness for the body.

After getting the blank squared up, I cut the headstock scarf and glued it back on. Normally, I orient the scarf such that the seam is up in the neck, by gluing the headstock on the face of the angled cut on the neck blank. This time, I decided to try the other option - gluing the headstock to the back of the blank.

The top came from a piece of buckeye burl I bought on eBay last year. When I get my hands on a piece of wood this nice, I try to let it sit for a good 6 months or a year out of respect for the wood, rather than jump in. This hunk of burl has been speaking to me lately so I figured it was time to dive in.

I didn't get a lot of photos of the prep process since I wasn't planning on a build thread. The burl slice is probably 36" long by a foot or so wide and about two inches thick. There's a wide section that is incredibly punky, to the point that it feels about as dense as packing peanuts or popcorn.

I pondered and postulated for about a week putting my templates on the burl in different positions and finally cut a hunk out that's bass-body sized.

The steel blue area near the center is dense and intact, while the darker tan section towards the outboard edge is the punky part.

After cutting to size I jointed the edge in a router jig

Then I sliced off a bookmatched top at a hair over 1/4" thick.

Because this wood has such punky sections I wanted to treat it well to keep it durable. I have used CPES in the past but wasn't a super fan of the intense odor and the fact that it only comes in kits larger than I really need. So I tried the TotalBoat version, which they simply call Penetrating Epoxy. It's a 2:1 mix that's very thin (maybe not QUITE as thin as CPES but close enough). Its smells like epoxy but isn't overpowering - although I wear a respirator 100% of the time I'm working with epoxy anyways, after having a friend develop a severe reaction due to over exposure after using epoxy in a hobby business for years.

The penetrating resin soaked in really well. The top drank up about twice what I expected. This stuff cures just like CPES - almost more like very hard rubber than a solid plastic. But it's very tough.

After treating with the resin, I cut out the pickup cavities (and saved the cutouts for the pickups) and I snapped a photo of the top and the fretboard placed on the body in a mockup. The resin is fairly uneven after going through the drum sander but you get the idea of what the top will look like:

After taking that photo I glued the top onto the body using TotalBoat's 5:1 slow epoxy, which is supposed to be a direct copy of West System 105/206, to the extent that they claim you can mix them (i.e. use their hardener with West resin or vice versa). I ordered it out of curiosity when I bought the TotalBoat penetrating epoxy, since it gets good reviews and it's cheaper than "real" West System products. So far so good. Once the top is cured I'll be using it to fill the voids in the top as well.

That's about two weeks of work and gets things nearly up to date. While the top cures I'm on to pickups and bridge construction!

 

[Jeff Siddall]

That top is awesome! Did you mention what wood the the fretboard is? Also, what are you going to do with the hollow section on the buckeye near the bridge?

 

[RichterScale]

Cool!
Just the other day I was thinking, I wish/hope one of these guys starts a new build soon.

 

[JRA]

you're killin' me with the beautiful stuff, @dwizum --- not to mention your 'eye' and your skills! really cool!

 

[dwizum]

That top is awesome! Did you mention what wood the the fretboard is? Also, what are you going to do with the hollow section on the buckeye near the bridge?

The voids in the top are going to get filled with epoxy. I may tint the epoxy, but I don't really know what color I would do. I'm not the biggest fan of all those wild tinted epoxy fills you see on basses these days, where you've got a lovely piece of wood and a giant patch of teal colored plastic in the middle of it. I might do black or something that blends in.

Although, that one big void will be mostly under the bridge, so it might not matter.

The fretboard is Ziricote. It has pretty nice colors in it, but it's kinda covered in gritty dust from the radius jig. I will get some nice photos once it's cleaned up.

Cool!
Just the other day I was thinking, I wish/hope one of these guys starts a new build soon.

"These guys" sounds pretty serious!

you're killin' me with the beautiful stuff, @dwizum --- not to mention your 'eye' and your skills! really cool!

Thank you! It means a lot to get feedback like this!

 

[Jeff Siddall]

Ooooh... ziricote. I gotta get me some of that, but sadly no wood stores near me seem to carry it. That should look amazing when finished.

I was mostly asking about the big void because with clear epoxy you would see the neck sandwich through the top which might look... odd. But black would probably look great.

 

[dwizum]

Ooooh... ziricote. I gotta get me some of that, but sadly no wood stores near me seem to carry it. That should look amazing when finished.

I got a pretty good sized board on eBay about 18 months ago. I've gotten fretboards for 4 ukulele, three basses, and a guitar out of it, and I probably have scraps for a few more left over. I really like it, it's like a more visually interesting version of ebony. It works and finishes about the same as ebony. I paid something like $60 or $80 for the board, so I've more than gotten my money out of it. Being able to resaw and thickness sand rough lumber is a pretty good way to save money in the long run, and get control over what you're using.

I was mostly asking about the big void because with clear epoxy you would see the neck sandwich through the top which might look... odd. But black would probably look great.

You know, I had not thought about that. I agree, that would look weird. I feel compelled to color it now.

Although the alternative I had thought about besides coloring it was to use a metallic filler in the epoxy. I was thinking about something like brass filings, since the bridge will have some brass in it. That might look cool peeking out from under the bridge. Or maybe it would look terrible. I might have to experiment.

 

[Bruce Johnson]

How about filing those voids with red-orange epoxy, to make it look like there are glowing embers or volcanic magma down inside. Like it's on fire. Put a bit of wrinkled aluminum foil down in the void before covering it with the transparent red tinted epoxy. Then black epoxy to fill the crevices on the surface.

 

[Williethump]

Looks like a psychedelic rorschach test. I like your void fill ideas. Do a test with metal filings, and if not then black epoxy fill would work. Look like black opal, or mahogany- snowflake obsidian. Never seen anything quite like it. Burl salvage too.

 

[Sushi Box FX]

I'm sure you already know this, but that is absurdly gorgeous.

 

[Billyzoom]

So beautiful...can't wait to see more of the process, let alone the finished product.

 

[dwizum]

I've got the pickup coils wound for this bass.

They will go into wood covers in standard-issue BC soapbar dimensions. I saved the cutout scraps from the top so the tops of the pickups can match the top of the bass. I have made several sets of these pickups, they're my favorite bass soapbar design right now. Very flat response, no major EQ lumps, so they're versatile. I made this set a little differently, the blades exend above the top of the Flatwork. I'm going to cut slots in the pickup covers so the blades can stick up flush with the top of the cover.

I also got started on the "anchor bar" that will go across the back of the bridge this morning. The bar has holes for the saddle intonation screws, holes for the string anchors, and holes for mounting. Lots of holes.

Hmmm... look at that.... a whole pile of brass shavings...

 

[dwizum]

oh, and I definitely have to do something in that void by the bridge. The neck laminations don't show through it, but my pencil centerline on the neck blank does.

 

[RichterScale]

What if you took small dark pieces off the other piece of the burl slab and placed them at the bottom of the holes before epoxy?

 

[Beej]

Hmmm... look at that.... a whole pile of brass shavings...

Wait a minute... are you going to use those brass shavings?

 

[dwizum]

@RichterScale I thought about that too. Or if you took some coarse wood dust using the bark from the burl you could make a paste to fill it.

I'm gonna try some of these brass shavings in epoxy and see what I think, then plan some different options based on that.

 

[Fender_Bender]

Have you ever tried toughening up wood by letting thin CA glue wick into it ?. I've done it many times but with smaller objects.

 

[dwizum]

Have you ever tried toughening up wood by letting thin CA glue wick into it ?. I've done it many times but with smaller objects.

Yes, many times. It works great. I don't like to do it on such a large surface, especially with such soft punky wood. Based on how much epoxy it sucked up (more than I had guessed), this wood would have sucked up at least several ounces of CA. That much CA is really hard to control without disasters. I like CA on hard closed grain woods for surface hardening, i.e. for a fretless fingerboard. Or for hardening small parts like knobs, or hardening threads in wood parts, or filling small voids, or lots of other small uses. Uses where you're working a few drops at a time, or at max maybe a few ml at a time. Definitely not several ounces. I think the CPES style epoxies are really the best choice for toughening bigger soft parts. Especially if you're giving them a surface coat of a "normal" epoxy like west system or this totalboat stuff, which does better at gap filling than penetrating epoxies and adds a much harder surface to help counter the penetrating epoxy's softness.

Speaking of adding a harder surface, I have some more photos to share...

 

[GreyBeard]

You are the man

 

[dwizum]

So this morning I set up to do some epoxy work. I like to batch epoxy-based processes when possible and do a couple at once, it seems more efficient than doing lots of small batches and waiting for different parts to cure at different times. I had four things to do this morning:

- Glue in the carbon tow for the neck reinforcement
- Fill the voids in the burl with thickened epoxy
- Coat the top of the burl with epoxy
- Glue the tops on the pickup cases with epoxy

I tried to take some photos, but given that most of this process was done in gloves that potentially had epoxy on them, it was a challenge.

First I got everything laid out.

As prep, the truss rod has been coated with a thick layer of wax and it's channel has been made about 1/16" deeper than the rod.

I cut some strips of carbon tow to size. I taper them towards the headstock end. This skews the flex in the neck such that it's slightly more curved towards the headstock and slightly more flat towards the body. Then the gloves went on and I mixed a few ounces of epoxy.

I stack the tow strips up on top of each other on a piece of wax paper then dribble a tiny bit of epoxy over them. Then I use a piece of scrap wood (with the edge sanded smooth so it doesn't catch anything) to squeegee the epoxy into the carbon. I like to do this to ensure good wet out.

Then I use a disposable brush to carefully paint epoxy into the truss rod slot - just enough to wet the wood out. I pick the carbon fibers up and lay them in, then work them down with the same wood stick and brush.

Then I press the waxed truss rod into the slot to ensure the carbon is packed down and won't interfere with the space the truss rod needs.

On to the next step! I tried some brass shavings in a portion of the epoxy poured into another cup and really loved the look - it gets a sort of very dull bronze sparkly color once the brass is wet out. Really cool. So I used that to fill the handful of small voids as well as the larger void near the bridge. It's obviously not natural in appearance, but it fits the overall color palette of the burl really well.

I blobbed the thickened epoxy on above the surface of the wood since it'll sink down in as it oozes into the nooks and crannies in the void, and I can sand it flat afterwards. It was really hard to capture the look of the filled spots with gloved hands so I'll try again once it's cured and finished.

From the remaining un-thickened epoxy I dabbed some on the scraps of burl saved from the pickup cutouts and glued them on to a walnut box I'd put together following BC soapbar outer dimensions with inner dimensions to fit my pickups.

Once cured, I will saw the box in half lengthwise and end up with two pickup covers ready for final sanding.

Then I took the remainder of the un-thickened portion of the epoxy and squeegeed it on top of the burl to give it an even coat and seal up the remaining exposed wood.

Once it's cured I'll sand it back to flat and then the body will be ready for final trimming, routing, etc.

Doing four separate steps all at once like this looks like a lot of fussy work, but honestly it took me longer to type this out than it did to actually do the epoxy work. I think the real key is processing it all mentally ahead of time, getting tools ready, having everything laid out and at hand so you can dive in!