Mandocello build thread

[sunburst]

I'm resting my eyes from scraping right now. I'll probably finish scraping, then touch up some places, then snap a pic or two before starting to spray the finish material.

[Mark Seale]

John -

Any particular technique or advice on staining the interior of the scroll area?

[sunburst]

No, Just get dye in there any way you can. I use a cheap (read: disposable) watercolor brush and an air brush mostly. Also, you can "shoe shine" a strip of cotton rag through there. I do that on the peghead scrolls more than the body scroll.

[tree]

I would imagine the owner's anticipation needle is pegged or maybe snapped off by now. Something about seeing the whole thing stained amber visually brings home how close it is to being finished.

I sure hope there's a sound clip sometime, but even if not this has been one of my all time favorite threads; I hate to see it end. Thanks for all of it!

[sunburst]

...I hate to see it end...

Don't despair, it ain't finished yet. The finish process can present all kinds of problems and take "forever".

[BradKlein]

What was I thinking when I extended the fingerboard this far over the oval hole binding?!

In all seriousness, on the 'next one' would you extend a bit less far than the 2 octave reach on the A string? Or was that just a moment of binding-scraping-induced declaration. The fret's look to be quite usable all the way up - but I can also imagine sacrificing the last couple of steps for more clearance around the pick...

[sunburst]

...was that just a moment of binding-scraping-induced declaration...

Yes.
I originally drew it with 22 frets, but since Mike Marshall's 'cello is the inspiration for this one, I think I changed the number of frets after discovering that his has 24. I could be remembering incorrectly, but I think that was the reason for the decision.
Regardless, it is tedious to clean sound hole binding tucked back under the fingerboard extender, and it is just a matter of degree. What's two more frets in the long run?

[Verne Andru]

I don't think those notes see much play time, do they? Looks killer tho...

[sunburst]

Bindings scraped, spots touched up, first lacquer spray. It will be looking about like this until the finish is fully applied then leveled and buffed. That will take a little while.

[sunburst]

...and sanding...

[sunburst]

Finished sanding the drywall, painted, and I just returned the floor nailer to the rental place. When I recover from three days of installing oak flooring, guess what? more sanding! Where would the world be without sandpaper?

[sunburst]

I think I have finished spraying the mandocello. I still have to level and buff the finish without going through anywhere, so I don't consider the finish completed until that is done. I'll let it cure for at least a week before starting the buffing process, if I sand or buff through the finish, it's back to the spray room then at least another week of waiting before starting to buff again. Needless to say, I hope that doesn't happen, and I'll try to be on my best behavior working on it.
It is nice to have a proper spray room with a good exhaust fan and filtered incoming air! I don't think there is even a single dust speck in the finish!

[BradKlein]

I'm not in the market myself, but I'm sure that many are wondering if this instrument will be for sale, if it's already on reserve, or is a commission. Forgive me if the answer has been posted somewhere previously in the long thread.

[CES]

Brad, it's been commissioned. John mentioned it early on. I only remember because I recently bought a Weber Yellowstone Cello, and I'm really liking it. If I bond with it and John is still willing to undertake it, I may be doing the same in a few years...gotta get the kids through college first

Phenomenal work, John!!

[MinkBrookRambler]

A question about grain orientation in the riser block. In post 294 the riser block is shown with grain running parallel to the grain of the top. This makes sense aesthetically, but is there any structural reason for it being like that?

This has become my favorite thread on the cafe. Thanks.

[sunburst]

I can't think of any structural reason.
Other than simply aesthetics, however, there is the glue joint to consider (actually a structural reason in a way) I want side grain at the glue joint between the riser and the head block so that it resists breaking loose or creeping. The grain could run either parallel to the top or perpendicular to the top and accomplish that, however.
There is finish to consider too. The ends of the riser block are carved to curve down from the fingerboard toward the surface of the top. Scalloped, sort of. If the grain ran perpendicular to the top that would present end grain for finish. Not a big deal, but I'd rather finish side grain.
The riser block is sort of a vestigial organ on a mandolin anyway, it's origin going back to Orville Gibson's early designs. It doesn't really need to be there if a mandolin is designed without it, and since it has no particular purpose other than aesthetics, might as well make it aesthetic!

[sunburst]

...And since I'm waiting for finish to cure, I might as well start making a bridge.
As far as I can tell, there is nowhere to just go out and buy a mandocello bridge, so I decided to make my own. I could have modified an archtop guitar bridge, but since this is a giant mandolin, I just started making a giant mandolin bridge instead.

I like to fit the bridge to the top before buffing the finish so that any finish scratches that happen are not a problem, so that will be the next step. I'll go ahead and fit the roughed out bridge base rather than doing any further work to the bridge.

[sunburst]

Those of us who have been working with mandolins for a few decades will remember when we could only get adjustable mandolin bridges with larger diameter thumb wheels. No one was making Loar replica bridges yet, no one was using the smaller thumb wheels we see everywhere today. Mandolins were very much an after-thought for manufacturers, and since electric guitars were the real bread and butter for them, they had bridge thumb wheels for electric guitar bridges, and hey, those are good enough for mandolin bridges.
As it turns out, having been around that long, I had some of the old large ones in the scrap pile and I finally found a use for a couple of them! A giant mandolin bridge needs giant thumb wheels! This pair, that I found attached to a broken mandolin bridge, is even decently presentable.

The posts from the old broken mandolin bridge were too short, but a trip to the hardware store was all it took to find a couple of set screws to use for posts. Of course, I got that idea from Steve Smith over at Cumberland Acoustic, and like his, these can be adjusted up and down or removed and replaced using a small Allen wrench through the holes in the bottom of the bridge.
The bridge currently looks like this. It is sanded out to about 600 grit, it is fit to the top, but the top of the bridge has not been cut for intonation yet. I don't know what compensation it will need, so I'll save that step until the strings are on.

[Bernie Daniel]

...And since I'm waiting for finish to cure, I might as well start making a bridge.
As far as I can tell, there is nowhere to just go out and buy a mandocello bridge, so I decided to make my own. I could have modified an archtop guitar bridge, but since this is a giant mandolin, I just started making a giant mandolin bridge instead.

I like to fit the bridge to the top before buffing the finish so that any finish scratches that happen are not a problem, so that will be the next step. I'll go ahead and fit the roughed out bridge base rather than doing any further work to the bridge.

Great idea to fit the base up to the top before adding the saddle - much easier to manage and keep parallel with the top plate that way?

[sunburst]

Great idea to fit the base up to the top before adding the saddle - much easier to manage and keep parallel with the top plate that way?

I just did it that way this time because I didn't have my set screw/posts yet. As it turned out, there was a slight resistance putting the bridge top on the posts and that flexed the base just enough to change the fit to the top, so I had to relieve the holes in the bridge top a little with a round file so that there was no resistance and the base wasn't distorted in order to restore the fit.

[sunburst]

I started sanding to level for buffing, taking my time, not hurrying. Started with 600 grit because the final sprayed coat was so smooth. Progressed through 1000 grit and moved on to 1200, and that's when I finally sanded through. There are a couple of reasons why I sanded through where I did; when I built my spray room I thought: "what's the biggest thing I'll spray in here?" and I concluded that it would be the body of a large flat top guitar. I didn't anticipate spraying an archtop guitar nor a mandcello. I've now sprayed both in there, and the space is a little cramped but still adequate. Getting a good coat here, on the underside of the lower body point seemed to be a problem though, mostly because I had trouble seeing what I was doing with the over-head lighting in the spray room. So anyway, the finish film was a little thin and a little rough here and in an effort to get it ready for buffing this happened.

It's a small sand-through, it's in an inconspicuous place (you know, like where you test cleaners...), but it has to be fixed.
This is a crow quill (not a real one, an art store crow quill) and sepia drawing ink. I've been using sepia ink for many years to touch up brown colors and I know that this brand can be made to match nearly any part of a sunburst except for the center yellow/amber, as well as walnut, mahogany, rosewood and other things. I also know that it is very colorfast, meaning I can expect the touch-up to stay this color and continue to match as the instrument ages. This brand is very difficult to find, and I've experimented with other brands, some are too red, some are too green, some change color as they age, so I track down Pelican brand drawing ink A sepia when I need more, and use it with confidence.

Here is the touch-up done. Experience tells me that this will look fine under a finish, though it looks too dark now. I basically just inked over the light spot where the color was sanded away, and sort of drew the curl of the grain back in.

I masked off the surrounding finish and used an airbrush to spray more lacquer over the touch-up and the immediate area around it. The touch-up is undetectable. I can't see it myself, and that means that probably nobody else will either, especially where it is on the instrument.

I'll sand and spray this a couple more times over the next couple of days, then I'll have to wait another week or so for the finish to cure before continuing with leveling and buffing.

[HoGo]

John, is there a reason why you don't use the original stain you used for the burst for the touchup?
I've used q-tip with bit of stain for touchup like that (either sand-through or on worn spots of my instruments) with good success (undetectable) so far, but I have made just few instruments so I maybe got lucky :-).

[sunburst]

One of the people whom I learned a lot of stuff from in my early days of lutherie had a masters of fine arts degree. With all of that art training, he used art supplies for many things where most other luthiers use more common materials. He was the one who got me started using drawing inks for touch up work almost 30 years ago. I find it much more controllable that using dyes. In other words, I can put the color where I want it, use more or less to match, move it around, rub it with my finger, remove it and start over, scrape it off of finish or bindings, draw in grain, etc. etc. Almost the only time I use dyes for small touch-ups like this is when I don't have an appropriate color of ink, and even then I often use a quill rather than a q-tip or other such applicator.
As with many things in lutherie and other crafts, there is more than one way to do it. There are many ways to apply color, many materials to use, many tools to use, and good results can be had with all of them, but this is what I am used to and it works extremely well for me.

[Timbofood]

I'm curious, I spent some years in the art material business, what specific ink are you using? There were so many inks and dyes available some were not what were truly "permanent colors" one that was very much fugitive was "Dr. Martins". Great color but, they epwere designed for retouching and images which would be reproduced and original art would be filed for safety.
Pelikan drawing inks were significantly more permanent.
Thanks for the fascinating series too!

[sunburst]

[QUOTE=Timbofood;1602713
Pelikan drawing inks were significantly more permanent. [/QUOTE]

I misspelled it, but I did mention that the sepia ink that I use is Pelikan brand, and it is "drawing ink A". I also use their black drawing ink and "brilliant braun", which matches red colors of all sorts.
I more recently discovered that some black ink that I bought for refilling printer cartridges (an experiment that didn't work out) is some seriously black stuff! I started using it to black truss rod pockets rather than painting them.