Completing the Varnish

Protecting the Color

The color varnish, as you might imagine, gets the instrument looking the way we want, but the clear coats keep it that way…we hope.

So, after the color coats were mostly complete, I waited a few days for the varnish to cure a bit and then added two clear coats as a protection for the color coats, so that they will not experience undue wear.

Final clear coats of varnish on five-string double bass. — Final clear coats of varnish on five-string double bass in sunlight.

Clear coat on double bass. — Final clear coat; Back view in sunlight.

Final clear coats in the shade on Double bass. — Final clear coats in the shade.

There is still a lot of work left to do at this point: There will be endless “re-touch” of spots in the varnish that I wasn’t quite satisfied with, but they can wait until after the set-up is under way.

Saddle

I usually wait until the varnish is complete, before installing the saddle. The saddle is the transverse piece of hardwood upon which the tail gut rests, as it crosses the edge of the front plate. (Ebony, frequently, but, as I had opted for an Ipé fingerboard, Ipé seemed the right choice for the saddle as well.)

I make my saddles with radiused ends, to avoid saddle-cracks. To some extent, saddle cracks are caused by the shrinking and swelling of the spruce plate against an essentially unmoveable ebony (or Ipé) saddle. However, the other factor (possibly more important) is that, for hundreds of years, luthiers have cut the saddle with sharp-cornered, square ends, requiring a sharp-cornered square-ended mortise in the spruce…which inevitably inclined itself toward eventual cracks. Sharp corners are extreme stress risers.

Round discontinuities (holes, for example) do not cause stress risers, and are far less likely to cause cracks. I try to leave the ends just a little loose, as do most luthiers, but the fact is, the sharp notch is the primary cause of the cracks. So I make round corners.

Tuning Machines

The next task was the tuning machines. There are many possibilities to choose from: I chose these tuning machines partly based on looks, partly on cost, but primarily because, with the curvy pegbox, I wasn’t completely sure that any other style could be made to work. (There are some multi-piece tuning machines, which, I would imagine, could be made to fit nearly any configuration, but I have no experience with those, so I opted for something I knew about.)

Anyway, I knew that this type of tuning machine has a tapered spindle, which is not designed to go all the way through the pegbox, so I designed and built a small reamer, all wood, except for the blade, which is spring steel (just because that is what I had available.) It works well, but I have to be gentle with it, and stop periodically to clean the chips from the reamer.

Handmade reamer for fitting double bass tuning machines.

I made a template, laying out the hole locations with the hope that I could avoid the strings from the G and D tuners rubbing on the tuners below them in the pegbox. I used the template to lay out the holes on the pegbox, then drilled to appropriate depths and used the reamer to taper the holes to match the spindles of the tuning machines.

Finally, I installed the machines and secured them with screws.

Tuning machines installed on five-string double bass.

It was amazing to see how much weight the tuning machines added. The bass no longer easily balances on the two bouts: it wants to rock down and put its head on the floor!

Ready for set-up!

I installed the nut at this point, as well, so the bass was really complete.

If you have sharp eyes, you will probably notice the hole above the tuning machines on the bass side. The pegbox was narrow enough there, that I actually went through the second side by accident, and was forced to create a plug for the hole, from some leftover rib material. I cut it to exactly fit the hole, and glued it in place, pressing it home, so that it was nearly exactly flush, then scraped the wood of the plug to exactly match the wood of the pegbox, and was ready to begin varnishing to complete the repair.

Repairs in progress for pegbox damage. When complete, the repair will be virtually invisible.

Anyway… that is as far as I wanted to go today. Some of you may have known from other forums’ content, that I had also had trouble getting the tailpiece fret to “stay glued” in its slot. So I eventually gave up, removed the fret, scraped all the layers of glue down to clean wood, and washed the Ipé with acetone. Then I reglued with epoxy, but this time I drilled and anchored the fret with six brass rivets! (It’s permanent, this time!)

Completed tailpiece for 5-string double bass. — Completed tailpiece.

Next time, I hope to complete the set-up of the bass and have it ready to play!

Thanks for looking.

Beginning the Neck and Scroll

Laminating the Neck-billet

All of the Big Leaf maple portions of this bass are made from a log I was given, years ago, by the late Terry Howell. The fellow I hired to mill it up said he did not know how to do quarter-sawing or flitch-sawing, so I settled for plane-sawing, which means that all I have is slabs. That is OK, because I like using slab-sawn wood, especially for backs; but it also meant I had no pieces thick enough for a neck on a bass. So…I chose to glue-laminate the neck billet, and produce a piece thick enough to use.

Contrary to my usual rule of “nothing but hot hide-glue,” I chose to use Titebond on this, reasoning that it is not supposed to ever come apart. One of the reasons we usually stick with hot hide glue is that it is always reversible. Titebond is not.) My son Brian lent me about a dozen clamps to make the job easier. He makes exquisite guitars, and learned early the value of having lots of clamps available.

Neck billet bookmatched, glued and clamped for the five-string double bass. — Neck billet bookmatched, glued and clamped.

The resulting billet was still about 3/4″ too narrow to accommodate the “ears” of the scroll, so I added a layer on each side, carefully chosen from nearby grain, so they would match (hopefully), and not be too obtrusive.

Carving the scroll

Finally, I drew in the planned shape of the entire scroll and pegbox, and proceeded to cut away as much waste-wood as possible, using a saw.

scroll and pegbox from a five-string cello. — I forgot to photograph the initial carving portion, so this is from a five-string cello I made earlier. The same process is followed.

Saw-work on a viola scroll. — Saw-work on a viola scroll…I forgot to photograph this step on this bass.

Removing waste wood using gouges. (Again, this is a viola scroll; but the same principle applies.)

All saw-work is done on the five-string bass scroll. — All saw-work is done on the scroll…time to remove wood using gouges and planes.

Removing waste wood from the 5-string double bass scroll, using a gouge. — Removing waste wood using a gouge.

Removing waste wood from the 5-string double bass scroll using a palm-plane. — Removing waste wood using a palm-plane.

Waste wood has mostly been removed from the 5-string double bass scroll. — Waste wood has mostly been removed. Time to begin the pegbox and volute.

Carving the Pegbox

Pegbox drawn and ready to carve, for the 5-string double bass. — Pegbox has been drawn and is ready to carve.

Beginning the interior of the pegbox for the 5-string double bass. — Beginning the interior of the pegbox.

Pegbox carving is complete for the 5-string double bass. — Pegbox carving is complete.

Carving the Volute

Beginning the volute for the 5-string double bass scroll.

Bass Scrolls are BIG!

Large viola scroll inside the five-string double bass scroll. — That large viola scroll fits easily…loosely…inside the bass pegbox. Reminds me of a mother monkey cuddling her baby. The bass scroll is simply huge, compared to any other instrument I build. (No, I will never build an octobass.)

As you can see, there is a lot that goes into carving a scroll…and this thing is really big! So, though I’m not done, I will go ahead and post this, and share the rest as it gets done. (The turns of the scroll will be more deeply undercut, and all surfaces more refined.)

Thanks for looking