JBA-4 (code-named "Jenny") - first build

[quiet1_au]

After trying a trial alignment using Dingo Bass' high & low string alignment method (as Brendan suggested), I found I couldn't get enough tension in the strings to overcome the natural stiffness and pre-rolled curves in them, not to mention the pickup magnets, to accurately position the bridge... It did show me that the strings were evenly positioned from the edges of the fingerboard along it's length though so it was not a wasted effort.

So tonight I had another go, but this time substituted some regular string (cotton cooking twine in this case) for the steel strings and had much better luck. The string is thin and springy so allowed for enough stretch to prevent sagging but still make the repositioning pretty painless without having to readjust clamps on the strings. After some checks with a short and a long steel rule I was happy that my bridge was parallel with the bridge pickup and in the right position - within a millimetre or two of Dingo Bass' measurement as it happened - so I marked the seven holes in pencil then pressing the points of the screws centrally as a more permanent mark ready for drilling on a drill press at work.

Then it's back to sanding...

[quiet1_au]

I think I've had enough of the sanding now... I started with P80 for shaping some flat spots in the curves and shifting some rough grain, through P120, P180, P240 and finally P320 tonight. I'm removing wood (lots of wood dust) but no longer seeing a noticeable change in the surface/grain after the sanding, although the amount of grain lift when the wood is given a damp wipe over is definitely much reduced. The wood has a natural satin sheen to it now, and to finish up the job I've dusted it with a synthetic brush (which I've used the last couple of sands too) then given it a final wipe-down with metho (instead of water) to remove the bulk of the dust without raising any more "fuzzies".

Next stage - dissolving (and possibly filtering) my shellac and experimenting with this new finish material before tackling the bass body and the headstock to match (I need to work out exactly how much to cover, so I'll check out my factory instruments to see what they've done)

[Brendan]

With the headstock, make sure you leave enough wood for the tuner heads - they're bigger than I expected and I managed to just leave enough wood on one of my necks to cover it. Near think though.

[quiet1_au]

Brendan - I deliberately left the wood along the top of the tuners untouched for this reason, and indeed did all my shaping to avoid sawing as much as possible (knowing that keeping it neat and straight is tricky with a coping saw). The only part I was thinking of making more F-like is the corner near the nut which I could cut a radius - but I'm thinking I've had enough of sanding so will probably just leave it now. ;-)

[Brendan]

Understood! It does get that way at times - hence DB's other mantra - sand, sand, sand, etc and then get someone else to sand for you!

[quiet1_au]

LOL Sadly I don't have the luxury of a sanding assistant so it was just right arm, left arm, repeat until the paper disintegrated and/or I'd had enough. I used a half sheet per grade and perhaps an hour of on-float and hand-held (for the edges and cut aways), a damp paper-towel wipe-down followed by a last quick sand to knock down the whiskers/fuzz - it seemed about right, I mainly worked by feel and sight. I used a cheap 3" synthetic brush to get rid of the bulk of the wood dust each time, and the last clean-up I've also used a metho wipe-down and a new microfibre cloth as static-duster.

Tonight I fitted the body hardware before I switch into finishing mode (in case of drill slips, etc that may have needed sanding out). I had to work around the pickguard not fitting around the neck issue so found that by careful measuring and cotton-string mock setup the neck pickup was nicely centred in it's rebate so I ran with that. It was almost right, but I should have had it half a millimetre or so further forward to get the pickguard perfectly aligned with the neck socket. But with no experience, only a hand-held cordless drill and pencil marks drawn in the hole I was pretty chuffed to have it so close to spot on! I just hope not to make a mess of it trimming the pickguard overlap off now (it's mainly the top edge of the recess, the bottom can stay as is or be fixed with a quite sand) - but that can be replaced at least, and I intend on taking it slowly and gently.

I'll probably mount the tuners tomorrow night or over the weekend, but the string-tree can wait until the very end (it might need a little deburring of the grooves before that, it's a little bit rough and I wouldn't want it to damage the strings)

[quiet1_au]

Three coats of shellac on lightly steel-wooled between layers to knock off any fuzz, and a bit harder were there were witness lines/ridges or too much overcoating. I discovered too late I made a rookie mistake of forgetting to sand the pickguard holes flat... No biggie, I think I'll do a gentle sand with 400 grit to knock these down and prepare for another few coats. I'm not sure how many I'll do in total yet, and I need to experiment with my test piece to see if applying a water-slide decal is likely to cloud the shellac before deciding whether to do the headstock too. Looking good though, I'm really happy with the finish and colour. :-)

[gavinturner]

Wow! Looks awesome John. The shellac has really popped the ash grain nicely. That honey(?) colour the shellac brings really suits this wood and this model. Really, really nice. This is going to be one fantastic bass!

cheers,
Gav.

[Brendan]

Looking great John - starting to want a JBA-4 for myself... Maybe if they come out on a Sunday Special ..

[crundes]

Looks fantastic john! You may have mentioned it in an earlier post but what sort of shellac did you use? is it mixed with a stain to get that colour?