Sean Couch

Being a newbie violin player, I have asked myself, and my violin teacher, this question many times. My violin teacher wasn’t much help. She admitted that she waits way too long between rehairs. lol. I did my first rehair three or four weeks ago. The rehair I had done before my current, lasted about 8 months. I don’t loose many hairs and my ribbon doesn’t get dirty except for where the side of my thumb touches the hair down by the frog. On average, I figure I play about a 45 minutes a day, and I don’t skip days. I don’t think I use much rosin. It doesn’t “smoke” when I play and I get very little build up of rosin on top of the violin. I wipe off my strings before putting the violin away, but I only have to wipe off the rosin dust every few months. I rosin the bow probably once a week with four, slow, full bow length, draws over the cake. So, with all that being said, I start looking for a rehair when I notice that I am having to rosin the bow more often to maintain enough grip on the strings to produce a good tone with my normal bow pressure. Or if I am constantly having trouble getting a string to respond with lighter bow pressure. Like when playing the variation of Long Long Ago from the 2nd Suzuki Book. If I can’t get the open D string to speak with a light touch, I know it is about time for some new hair. Most of the time it is me playing horribly, but if it happens three or four days in a row, I figure it’s the hair. lol.

I got the neck glued in this morning. Not too much cussing this time around and I am back to my 8 hour time frame. lol. I think I can easily cut out a few hours of time, but I was going pretty slow. It was a much more pleasant experience this time around and I actually got a nice consistent lock-up

Ahaha, you did better than me on my first sound post. The first post was too short right out of the gates. The second, I trimmed it too short. I finally got it kinda right on the third one. I ended up putting a fourth one in after a few months of playing. My f-holes were also tight. I kept those messed up sound posts and now use them as gauges for my f-holes. I also make sure my upper f-hole eyes are big enough to put a sound post through when the post is completely vertical. I use a 6.2mm sound post so making the upper eye 1/4 of an inch works well.

For getting the ribs down to thickness I made a small little tool. It is two pieces of one inch square aluminum tubing stuck together with some 3M tape I have. Then I cut a piece of Perma-grit and taped it to the aluminum. Then a couple of metal pieces taped on either side of the grit. It makes a nice little rib flattener. I scrape one side of the ribs to get a nice finish, hand plane the ribs down to 1.5 ish mm, and then use the rib flattener to take them down to their final 1.15mm thickness. I put the sanded side on the interior of the violin. For the arching, good templates help. You might have to make your own. I wasn’t happy with any of the readily available templates so I made my own. I have a set of partial templates and a set of full templates. The full templates include the purfling scoop and the partial templates do not. The partial templates have a flat area where the scoop would be. I use the partial templates when the ledge around the perimeter of the plate is still flat. I used 4.5mm as a ledge thickness so that is taken into account in the templates so that the template’s overall height is correct. In the upper and lower bouts I had to bring that 4.5 flat in further as there is a 30+ millimeter flat spot on some templates. Hopefully that makes sense. If not, let me know and I’ll grab some pics.

I have seen people do it that way. It is an interesting method and can probably be used with good results, but I am not up to trying it yet. Maybe one of these days when I get adventurous, I’ll give it a go. Hehe.

Right on. Thanks for that. I was trying to do something similar to that on my previous builds. When I am “in the moment” and working away, I think I get frustrated and then my plan gets tossed out the window and I go willy nilly to try and get it done. If, on this go round, I start to feel the urge to deviate from the plan, I am going to get up and walk away from the bench and take a break. I don’t like stopping in the middle of a task, but it isn’t worth trying to “force it” if things aren’t going well.

That’s what I did in October of last year. I bought a 5 pound bag of Bjorn’s 347 strength glue. I put one pound in a mason jar and then vacuum bagged the rest in one pound lots. I didn’t draw a really hard vacuum on the bags. I just removed most of the air before heat sealing them. I was scared that they would turn into solid bricks after a few years under total vacuum. Lol. Since I only build 2 or 3 violins a year, the five pounds should last me a lifetime. I feel like I waste a lot of glue by constantly making new batches of fresh, but even by doing that I only go through 25 grams of dried glue per violin. So I can build 90 violins with my glue hoard. It is amazing to me that violins are only held together by a few cents worth of glue. I mix the 347 strength glue at 4:1 by weight for everything except for the gluing of the plates to the ribs. For that I use a 6:1 ratio of water to glue. I am basically following Davide’s dilution ratios and temperature (70C) that he calls out in his videos. It seems to be working out quite nicely.

Aha. Thanks. Hopefully this one goes better than the last. I think it took me 12 hours to get the neck set on my third. The other ones were around 8 hours each. I still haven’t gotten a nice tight lock up, but haven’t had to fill a mortise… yet. I think I figured out my issue with the lock up. The heel shape on my previous violins weren’t correct. Instead of having a nice triangle shape that goes all the way to the main gluing surface of the neck, I had 4 or 5 millimeters that were at a 90 degree angle to the mating surface. Basically, I had no dovetail to help everything lock up nice and tight. I think I have that rectified for my current violin.

Sweet, thanks for the template. That will definitely save me some work when I finally try out a non-traditional scroll. You are the second one to mention the glycerin trick in the past few weeks. I am going to have to try it if I get brittle purfling again. I will also keep it in mind if my rib stock wants to crack in a few years. It will probably take me 3 or 4 years before I use up all of the wood from my last purchase.

I am getting ready to set the neck on violin #4. I can already feel my anxiety increasing by just thinking about it. lol.

I started using a toothed blade for the spruce on the build prior to my current. I did it because I was not so great at sharpening the little arched plane blades. I now have the sharpening issue resolved, but I still like using the toothed blades on the spruce for the reasons you mentioned. The toothed blades can be very aggressive, so I set them for a very fine cut, it is pretty amazing on how well they work on soft woods.

Beautiful work. That first picture makes me realize how much I need to improve my rib bending skills. Those ribs look very nice and perpendicular to the form across their entire height. I always get a bit of a concave shape to my ribs where they flare out by a half millimeter on the edges furthest from the form. I keep thinking about “stealing” your scroll design you use on these Sultanas and put them on a violin. I would probably change the square shape to a shield shape and then do a pegbox that has no floor to it. I know it goes against all tradition, but man, I really despise carving a traditional closed pegbox. For me, it is about the worst part of the build. I don’t mind carving the scroll, but the shape of your Sultana “scrolls” are just as pleasing to my eye as the traditional scroll.

80W of UV from fluorescent bulbs is a bit misleading in my opinion. It’s no fault of anyone here, it is just how the bulbs are rated from the manufacturer. I’m sure all bulbs are different, and I am going to give one specific example for the bulbs I use in my enclosed UV box. It is a small box, but big enough to allow the violin to spin. I think my walls are about 18 inches wide and the height of the box is about 30 inches tall. I have Philips Actinic UV bulbs in it. The bulbs are 24 inches long and are rated at 18W and I use four of them. That would mean I have 72W of UV right? Nope. The bulbs I have each use 18W when running, but the specifications from Philips says that each build emits 4.5W of UV. That is 25% of what the build is rated at. I am not getting 72W of UV, I am getting 18W. The enclosed box works well for curing my oil varnish. It is dry to the touch after about 6 hours and passes the finger print test in 24 hours. But it is very slow to tan the violin if you don’t put on any nitrite/nitrate/protein treatment. I gave one of my violins 400 hours of UV and it barely had a straw color to it. I have never had any issues with burning the wood or scorching it and my chamber is smaller than Davide’s with almost as much total wattage. But you can see from the video below, my temperatures are pretty low. Here is my enclosed UV box with violin #3 in it: 20260314_131007.mp4 I have built a new UV rig that looks like a cage. I haven’t used it yet, but hopefully I will give her a test run in a few weeks with my fourth violin. It has 365nm wavelength UV led strips mounted on aluminum extrusion. I have the UV strips running on a dimmer (just in case it is too much) and at 100% power, they are pulling 100W from the wall. About 5x more than the fluorescent bulbs so I am hoping to get some decent tanning from them without using the nitrite/nitrate/protein washes. Here is a picture of the UV cage:

Awesome, thanks for the info. It is very much appreciated. I could have had the top at a much higher frequency but I was trying to match the back. I cut the f-holes pretty early in the process. I think I cut them when the top plate was 4.5mm all over. I was under the impression that the top should be the same or lower than the back. But when I got to the point where I was removing mass, and not seeing the M5 drop accordingly, I stopped thinning the plate. On one of those iterations, I saw the mass drop and the M5 frequency increase. I bought enough wood to make eight violins and this violin is the first in my experiment. All the spruce tops came from the same log and so did all the maple backs. I know there will be differences between the wedges I have, even though they came from the same log, but they should be more similar than if they came from different logs, hopefully. My goal for the back was 360 to 370Hz for the M5 and a weight from 120 to 130 grams. Definitely heavier than the “normal” 110 grams or less. My maple is at a specific gravity of 0.54/0.55. For the next violin I am going to try an arching height of 15mm for the top and the back and see what happens with my thicknesses and weights. My weight target for the top is between 62 and 69 grams without a bass bar. Once I get the arching heights figured out, then I am going to vary the distance of the scoop’s minimum thickness from the edge and see what happens. The first violins in this experiment are going to be on the thicker side, and the second set of violins will have the thinner, more common grads and weights. It might take me a few years to build them all, but it should be an interesting endeavor.

Aha, yes that would be quite the brick. lol. I don’t think I explained it very well. I probably should have called the “minimum thickness” something else. I was trying to describe how far in from the edge that I located the bottom of the scoop. For the c-bout, my 3.5mm thickness of the fluting channel is 6mm in from the edge and the 3.1mm thickness of the fluting channel in the upper and lower bouts is about 9mm in from the edge. The other plate thicknesses are close to the numbers you show in your videos. I am working on trying to find a good arch height to use for violins with thicker plates. I think I made the back arching too low (14.5mm) and the top too high (15.5mm). My back plate is thick (124.7g) and the M5 frequency came in low at 340Hz so I was trying to get the top down to match the back. Without the bass bar, I couldn’t get the top down below 305Hz. I was removing mass, but the M5 wasn’t going down so I stopped making it thinner. With the casein application and a bass bar, the plate now has an M5 of 350Hz and a plate weight of 65.3 grams. That is with edges rounded and a 4g bass bar. It should be interesting to hear how she sounds when all strung up.