Build project - resonator guitar from recycled bits

[ManFromGlass]

That didn’t quite sound like a laugh all the way over here . . . . .

[adrian_k]

@manfromglass No really it was all very jolly in the workshop that morning. Really.

So after a break for a bit of light-hearted swearing, I collected up as many of the little bits of rosewood that had splintered out when I pulled the frets as I could find, cleaned off the fingerboard, and using superglue, the splinters and sanding dust repaired the fingerboard surface as best I could. A final sand, check the fingerboard is level and still has the right camber (which it did), and start the refret, this time with new fret wire.

To do this I first cut the end off the fret wire using some flat backed cutters (normal cutters are no good as they leave a point on the cut end.) I then lay the wire along the fret slot and cut the wire to size, flat side of the cutters against the neck. Bang it in and on to the next. (Just realised in the pic below the order is clockwise rather than across)


I then superglued the fret ends and clamped them down as before, and chamfered off the fret ends. I was now back to where I had been at 6 that morning. I then stoned the frets level, this time no problem. I sat back and admired the day's progress:

[adrian_k]

Next I profiled (or crowned) the frets. I used a crowning file which has two grooved edges, one deeper than the other. I used the deeper edge to take off the sharp edges caused by the the stoning until there is just a narrow line along the top of the fret where the file hasn't touched, then the shallow edge just to finish off.

Then I took a small file to the fret ends to round them over, cleaned off any superglue with a file then scraped the fingerboard to leave it clean. Cleaning up revealed a couple of tiny holes I'd missed before so I dropped a couple of drops of superglue in them and will now leave it till next month. I estimate this guitar is now 15% superglue. The frets will be finally cleaned up and polished later.

[Guest]

So you'll soon be finished yeah?

[adrian_k]

I thought that a few months back!

But construction wise I am pretty much there. I’m sure there will be some drama or other before I get there but I can see the finish line.

Once I’m happy the guitar can be set up the next big job is finishing. Lots of sanding, more sanding, even more sanding not to mention sanding and polishing.

[BigRedX]

Looks fantastic!

Fretting IMO always looks like the hardest part. I did a solid electric balalaika in the late 70s when the only easily available resource for making an electric guitar was Stephen Delft's series in International Musician, and any specialised tools had to made be yourself by modifying standard woodworking ones. My fretwork was passable at best so when I made a six-string electric guitar the following year I bought a ready made neck (also because it didn't have the facilities to make a truss-rod from scratch).

[adrian_k]

I've done quite a few refrets but never fretted from scratch, so at least the fret slots are there (although often need deepening and/or widening depending on what's been done to the fingerboard). Tools wise having a crowning file helps enormously. When my brother started out he made or adapted all his own tools - no internet luthier supplies in those days.

This neck is on it's third set of frets and never been played!

[adrian_k]

Me again.

I was looking forward to getting a bridge on this month and maybe see how it set up. Col said nah don't bother, it'll be fine we'll sort it. I might be wrong but I sense he wants me to get this thing finished and out of his workshop, just something about the way he sighs and looks to the sky when I turn up...

So instead I cracked on with finishing. First job - sand all of the scratches etc out with 100 grit cabinet paper:



Next job - spray a coat of AC lacquer. I'm going with AC as nitrocellulose takes longer to dry, and to keep it simple I'm not bothering with anything fancy like sunburst, just clear lacquer all the way. I've never used a spray gun so this was going to be tough enough.



I thought I would hang the guitar and spray like I've seen others do on the internet, but Col's spray booth is small and set up for the way he works. You can't get round the guitar to spray both sides, and even if you could Col prefers to hold the guitar while he sprays as he has more control. That's fine for him but holding a guitar at arms length for any length of time requires muscles I don't have. Col doesn't care, says get on with it..



I did manage to get a coat on but it was a struggle. Doesn't look too bad (below) but I'm going to have to improve quickly to achieve any sort of finish. Few runs, couple of bits I've missed.

[adrian_k]

That first coat is really just to highlight any marks I missed when sanding and to start to get a bit of finish into the grain. Most of it gets sanded off. Here's what it looks like after sanding with 180 grit finishing paper.



There were plenty of scratches I'd missed, particularly on the maple neck where it's hard to tell scratches from grain in some places until you get some finish on, so I had to go at it pretty hard.

Spraying the second coat I decided to try it left handed (I'm often confused about which hand to use for things), slightly better but still getting some horrible runs:

[adrian_k]

Still had sanding marks showing through so went at it again and cut back with 180 grit, then sprayed a third coat.

This is how it is going to be for a while now - spray, cut back, spray, cut back etc, using finer grade abrasives each coat. Hopefully. If all goes well it'll take 8 or 9 coats.

I decided to bring the guitar home to cut back the third coat with 240 grit so it's ready to spray straight away next visit. AC dries in a few hours so in theory could do two coats and cutting back in a day with a final spray at night, but in reality there is other stuff going on and it's pretty tiring stuff.

At this stage I'm also using lacquer to drop fill any small gaps e.g. between binding and body:



I'll drop fill several times. sanding back each time with 240 grit.

[adrian_k]

Oh and here's the case I'm going to use - an old, well used thing that Colin couldn't bear to throw away but could never use for a new instrument:



That's it for this month!

[Wonks]

I'd have used nitro, basic drying times are similar and I'd have put more coats on before rubbing back. There's no single correct way to spray, so certainly carry on the way you're doing it.

But given your limited available spraying time, I'd have just added more layers without sanding. Then when you came back next month, you could have both sanded and polished on a cured finish.

[Folderol]

Nice to see this project is alive again, and props for sticking with all that sanding. I can't think of anything I hate more

[Drew Stephenson]

The whole coating and sanding thing does get tedious pretty quickly, but it's the only way to get a good finish and there's really no shortcut.
Good to see a bit more progress.

[adrian_k]

I don't mind the sanding, I do a lot of grunt work for Col when I visit so I'm used to it. Also can be very satisfying (yes I am weird).

Re the one coat vs many before cutting back question, as Wonks says there's no right way and in fact I think the manufacturer's guide for the AC lacquer says put three coats on at a time.

The reasons I am not doing that are: 1) I want to get as many surface imperfections out as possible before I get too much finish on, single coats early on really highlight where more work is needed; 2) my spraying technique ain't that good and I don't want to risk runs on runs that I then have to sand hard back anyway; 3) this is how Col does it after decades of trying different approaches and subjectively I like the finish on Col's guitars better than many that come in, more silky smooth to the touch, depth of finish looks better and less build up in the nooks and crannies like at the neck/body join. I accept I may be biased.

Talking of imperfections I forgot this: When I cut slots into the guitar sides for the bracing I carelessly went too low on one of them. I put a small pad in to support the brace but it looks a mess from the outside. This was before the binding channel was cut, and its ended up visible below the binding. And of course it's on the upper bout where I'll be staring straight at it. So I filled it in with coloured wax, and I may just touch it up with a dark stain it to make it look more like dark grain:

[Wonks]

I looked up one datasheet for AC lacquer and a) you should definitely be wearing gloves and have your arms covered when spraying and b) they say no coarser than 320 grit for between coat de-nibbing.

[adrian_k]

Fair point about the gloves but hey I'm old and I'm not going to be doing any more of this.

Re the grades - I'm not de-nibbing yet. The first two or three coats I can end up sanding a lot of it off as it uncovers problems. Once I'm happy with the surface I'll go to 320 (and from this point onwards try very hard not to cut through to the wood), then go 400, 600, 800 wet then finish on 1000 wet, then polish. But depending how it goes I might do more than one coat at any grade or (hopefully not) have to go back a grade. I'm happy to take it slow and steady anyway

[Wonks]

I'm more concerned that for heavier sanding you aren't letting the finish dry properly, which means that you are probably making things harder for yourself. With the finish still quite soft, the sandpaper is liable to tear out bigger 'chunks' (relatively) than if the finish was harder. So, you end up creating small pits than then need to be filled again etc. The two hours dry time for sanding is really for 320 grit and light sanding. For coarser grit I'd wait 24 hours, or the best part of. Also, any runs will be thicker and will take a bit longer to dry. I'd personally wait 1 or 2 days before sanding those down.

[Wonks]

You'll obviously get there in the end, but if Col wants you out fairly quickly, then more spraying and less sanding will get you there that bit quicker. It may sound like I'm having a go at you, but I don't mean to.

[adrian_k]

Your concern is noted and appreciated! and all input is welcome.

I also haven’t been very clear. The first two coats are left overnight. In fact I’d never go to two hours drying because despite what manufacturers say and working in a humidity and temperature controlled environment, it doesn’t always work out like that. But I might go to two sprays a day later i.e. 4 hours if things are going well.

But I’ve been doing the sanding bit for Col a few years now and this process does work. And though he might want me to finish, we both want a good result and this approach is proven. (Caveat - with this finish. Nitro, french etc all different).

[adrian_k]

I brought the guitar home last month and sanded back one coat in the garage still at 240 grit. I also did a fair bit of drop filling with lacquer, basically dropping lacquer into all of the gaps that appear when you start sanding back. For example:



That particular gap between the binding and guitar side was where I hadn't done a good enough job of cleaning up the binding channel. The sides are laminate and tend to split at the edges. I ended up drop filling that gap five times, sanding back each time.

[adrian_k]

Back in the workshop, I gave myself a break from sanding Frankenbro and test fitted the machine heads before I started getting any more lacquer on. I couldn't get any used ones that fitted in the timescale so ended up buying new Schallers. Probably for the best, worn machine heads can be a pain to live with.

The existing holes in the headstock were fine for the tuning posts but needed widening at the bottom to accommodate the base of the posts. Also needed to drill pilot holes for the fixing screws which were in a different position to the existing:



And test fitted:

[adrian_k]

Then sprayed a fourth coat - starting to see the finish build up now:



This is the stuff I am using:



Cut that coat back with 320 grit then sprayed again, then cut back again with 320 as there were still areas that needed flattening - each coat reveals more imperfections.

At this stage there was enough lacquer on to apply the waterslide logo, bought from Rothko and Frost:



You can also see where the tuning post holes have been widened to accommodate ferrules, not strictly needed as the posts fitted well but they'll look better and Col had some in his box of leftovers.

[adrian_k]

That's it for this year. Sprayed another coat and have brought it home for cutting back with 400 grit (going very gingerly over the logo) and yet more (minor) drop filling.

That's the end of my spraying - my technique isn't good enough yet and the final three or four coats need to be put on nice and even, no runs, so I'm asking Col to do it for me next visit in return for beer and curry.

[Wonks]

Keep going Adrian, you're almost there!