I had a bit of mishap with my Jonah Thompson NAF while out hiking recently, resulting in a small chip on the mouthpiece. I figure this is an easy enough DIY repair with very light sanding then applying varnish. I think it’s too small to try to fill with putty or other filler. But I’m uncertain about what sort of varnish (or other application) to use, since obviously it should be safe (non-toxic) enough to putting one’s mouth on. Appreciate any tips/suggestions.
stiofan
Stiofan, sorry to hear about the chip, always a bit of a bummer when some damage occurs to a favored instrument.
Sealing the area of damage is simple enough: A coating of cyanoacrylate (super glue) will do the job and, once cured, should be quite safe, probably at least as safe as whatever the maker originally used on the mouthpiece. Of course you can always check with the maker (if still alive) and ask what they originally used to seal the mouthpiece, but that may not be strong enough to prevent further damage in an area that is now rough, hence my recommendation of cyanoacrylate.
If you choose to go the cyanoacrylate route, then I suggest buying the water thin type and some pipe cleaning twists to apply the glue in several layers, so you don’t end up with a big lump of awkward glue. I’d suggest proceeding as follows
(This step is optional, but recommended for best results, however BE CERTAIN THE TAPE WON’T STICK SO MUCH THAT IT REMOVES THE FINISH) Use painters tape or something similar that won’t damage the finish to mask off an area around the chip, so you are only getting glue where you want/need it. For something that small it might be easier to just cut a little hole in a piece of tape that is the size of the chip, then position the tape with the hole where the chip is.
Clip 6-7cm off the end of a pipe cleaner. Repeat so you have an half dozen or so of these.
(Note: Avoid breathing in cyanoacrylate fumes as much as possible. Work in a ventilated area, and use a vapor mask if you have one, or hold your breath while applying the glue. The vapors dissipate quickly and are not overly harmful, but if your face is very near the glue as it is being applied and curing this can irritate your lungs)
OK, overly scary health warning complete, here’s how to proceed. Apply a small amount of the thin superglue to the end of a pipe cleaner and then quickly dab the chip with the glue covered pipe cleaner. Just give the chip a quick, single coating, don’t try to build up a full thickness coating in one pass. If/when the glue on the pipe cleaner starts “smoking” you need to stop because the glue is curing and the pipe cleaner is about to stick to the mouthpiece. Dispose of that pipe cleaner.
Let the glue on the mouthpiece cure for a couple of minutes then repeat the process with a new piece of pipe cleaner. You should only need to repeat this process 2-4 times to build up a sufficient protective coating of glue sealant. If you are using a medium or thick superglue, which I don’t recommend for damage that small, one application will probably be the limit. Don’t over do it or you will have excess superglue that may be unsightly and/or uncomfortable in the mouth.
Give the layers of glue 10 or 15 minutes to fully cure, then carefully remove any tape, if you masked off the area, and you should be done. I don’t recommend sanding as you are likely to hit other areas on the mouthpiece in the process and damage the finish elsewhere. If you do feel the need to sand, do that before removing the masking tape, and be sure to also cover any surrounding areas you might inadvertently touch during the sanding process.
Finally, the purpose for using the pipe cleaner as an applicator is so you can fully control where the superglue is applied, and so that you don’t get excess glue running all over the mouthpiece, which can be a real problem to clean up. If you do somehow manage to get glue someplace other than right where you want it, under no circumstances should you use “normal” solvents in an effort to remove the excess glue, because those solvents will likely remove any finish on the instrument as well. I suggest purchasing a cyanoacrylate specific solvent like Golden West Super Solvent, which tends to be much safer on most surfaces and finishes, though I can’t guarantee it’s 100% safe on whatever finish your NAF has. Best to simply avoid getting excess glue coverage in the first place, really.
Hope that helps.
Loren:
Thanks for the detailed and in-depth repair instructions! It hadn’t occurred to me to think of it like a crack repair, which I know cyanoacrylate is typically used for (at least on wooden flutes & whistles). I ended up contacting the shop who now carries the maker’s instruments, and they’re kindly reaching out to him for repair recommendations. They initially suggested simply lightly sanding it and applying tung oil, which is what’s used in finishing theses flutes, but I wonder if a sealant like CA might be better. In any case, I’ll see what the maker has to say. Thanks so much.
On another note, I’ve decided to start learning the recorder, and got my first alto (an ABS Zen-On Bressan) from Von Huene a few weeks ago. I recognized the shop’s name from all the posts here on C&F where you’ve mentioned your past experience there.
Happy to help Stephen, and yes, cyano glue has several useful applications for woodwinds: cyano is good for some (but not all) cracks, it makes for creating excellent “lip plates” to prevent skin contact on allergenic woods. Superglue can also be used to seal the bore and/or even the entire exterior of a flute or whistle.
Glad to hear you have a line on getting some advice from the maker.
You could certainly sand the affected area prior to using superglue, or any other repair. That would generally be best practice with everything other than something like a chip repair, where you have the chipped out piece and you intend to glue it back in place. One wouldn’t sand either surface in that case, obviously.
The only reason I didn’t recommend sanding is that the affected area looks tiny in the photo,so attempting to sand the spot may take off a significant amount of finish around the area, creating both a larger and deeper divot that may be significantly more noticeable, both visually as well as what you may feel in your mouth. Just something to consider when making a choice regarding how you wish to proceed.
Enjoy the new Recorder. Those Zen-Ons are excellent, and quite popular, amazing bang for the buck.
Update: The flute maker (Jonah Thompson) has offered to do the repair himself, so I’m sending it off to Arizona this week. Interestingly, his solution (since the chip is fairly small) is to shorten the mouthpiece just beyond the point of the damage, then make necessary alterations so that it plays in tune with itself. Lesson learned. From now on I’ll carry a flute that fits completely inside my backpack.
CA glue has proven to be one of the most useful items I’ve encountered in woodwind making! I use it constantly: thin, medium and thick. As you say, it is good for most repairs, and it’s a very effective sealer. Mixing it with linseed oil makes a nice finish as well. Plus it has the virtue of curing very quickly 
. I use it on a daily basis, despite the fact that my go-to brand has gotten quite pricey. I can imagine that if 18th and 19th century flute makers had CA glue, they’d be pretty excited! Though to be fair, shellac works miracles as well.
Agree will all Geoffrey.
I don’t recall mixing ca with linseed oil for use at the shop, but I have done so occasionally for other woodworking projects. We actually used a linseed oil and spar varnish concoction at the shop as one of our sealing/finishing processes, but the way we used it was messy and time consuming, so not for the home repair crowd.
What brand of CA do you use? Last time I bought Starbond CA’s I did think to myself “I don’t remember this being so expensive a few years ago…” but I don’t use CA much these days as I’m not often working on instruments.
For quite a while now I’ve been using the Titebond brand, which I really like. I’ve used some others, and to be perfectly frank I have not noticed a big difference. I assume that if the formulation is where it should be then they all perform pretty well. I started using the Titebond because one of my local woodworking supply stores started carrying it (they had previously carried a Japanese brand that I liked, but it went away). I just took a peek at the Starbond, and it looks like it prices out the same as the Titebond.
I think that all sorts of companies hiked their prices during the pandemic due to “supply chain issues”, which I’m sure were legitimate at the time. But I suspect that all sorts of vendors decided to keep the prices hiked up after the supply issues resolved 
. This is just a suspicion, because I’ve seen a lot of this among suppliers that I use. I have used Deft lacquer for many years, and they recently were bought out by another company, and when I went to buy a quart of lacquer recently it was more than $30. That seemed a bit over-the-top. Luckily a quart lasts a very long time for me, so it’s not a deal breaker, but it just made me raise my eyebrows.
But pre-pandemic, I think I was paying about $9 for a container of CA glue that now costs $13.50.
Update: Just got the flute back from the maker, Jonah Thompson (via Kachina House, the shop in Sedona, AZ that sells his instruments). He shortened the beak just enough to ‘repair’ the chip. As expected, it plays just slightly sharp since the overall blowing length is marginally reduced (though only ~2¢), which is fine since I only play it solo.
Shortening the beak shouldn’t change the pitch at all as the window to far end distance is unchanged, but a shortened windway may have more turbulent output, though you have an air chamber between that and the next constriction leading to the window, so it likely has less impact on the sound quality than shortening the windway on a whistle.