Michael Minton
Forum Replies Created
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Ian is probably going to be your guy on this, maybe Doug too. Years ago Behlen made a product that would slowly dissolve into many finishes and even things out. Don’t know if that is still available and if it works on nitro though.
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Rather than replacing the missing/damaged peones, I would consider gluing in a basswood or spanish cedar fitted block covering the entire area of damage (plus a little more extending out past where the new top material will be joined to the existing), much like is done when making an arm rest. I worry about the sonic integrity of the critical top to side junction using small replacement peones. I would consider removing all that are suspect, shape the block, then fit it and glue it.
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Depends on what you are calling a “buzz.” The G3 at 196 Hz is going to be very near the T(1,1)2 main top resonance of the guitar. Notes fretted up higher on the G string could conceivably be near the cross dipole, long dipole, or a harmonic of the main top resonance. If the notes played (or their harmonics) were close enough to a resonance frequency, that would cause a wolf tone. But to me, a wolf tone doesn’t really sound like what I would call a “buzz.” You could check that by putting some poster putty on the underside of the top near the bridge, and again on the sides, to see if the effect goes away. If so, the fix is a much longer description.
It is also possible you might be getting a sympathetic resonance from a G string pinch on the saddle. This would sound more like a sitar effect than a “buzz” though. It that is what it is, then eliminate the secondary pinch point on the saddle. (you would want to damp all the other strings to make sure the effect is coming from the G string).
I would say both of these are sort of long shots.
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Another thing I forgot to add. The motor is mounted to a board connected to the chassis with a big ass hinge, so you can tension the belt with the spring
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For stuff like acetone, I use a 10 cc syringe
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It is so easy to use, and I’m getting great results.
One thing to add. Don’t buy a reversing switch for it. If you run it backwards, all it does is spin off the bolt. Don’t ask me how I know that.
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B string is usually the culprit.
Wasn’t raised right.
Looks to me like the top of the nut height needs to come down on both the B and E. Only half the string should sit inside the slot. Check the ramp on the back as well. Ideally, you want the string touching only at the break point, with a gap behind where it heads off towards the tuner.
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It is pretty much a guess on my part. That’s why I have emailed Trevor, to see what he thinks about it. The hypothesis would be that if you actually have 2 different break points on the saddle (the “true” break point, and the “pinch” point), you have changed the system, and potentially the mechanical impedance, the distribution of string energy, and possibly created a different set of standing waves (as the string vibrates, some of the energy is admitted to the soundboard through the saddle/bridge, and some is reflected back into the string. The energy that is reflected back can produce standing waves.).
Might be complete BS.
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Have you taken a peek inside? My guess would be that the heat and humidity that did the damage outside probably worked some magic inside.
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I agree with both Ian and Chris. 50% of the string in the slot is my target. If too deep, not only can you have binding/tuning issues, but getting a clean downslope to the headstock/tuner can be more difficult. If the string is pinched in the slot, that can affect intonation (the break point isn’t as precise), and increase absorption/admittance (rather than reflect that energy back into the string), thereby reducing string energy.
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Sunlight oxidation can darken wood. It could be that the way the guitar was stored, it had more light exposure on the dark side than the light side. You could test that by lightly sanding the top 4 or 5 mm around the top of the rim (which will be where the binding will be put in, so sanding there won’t impact you in the long run) on the dark side and see if it lightens up. If so, you could lightly sand the entire dark half of the rim to try to get a more even match.
Also, when you apply finish, it is going to slightly darken the wood, and differences will be slightly less noticeable.
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I’m now doing basswood or mahogany, 3 pieces, about 2.5 mm thick, which I prebend in my side bender (obviously, I’m shooting for stiffer sides). The first 2 are 15 mm tall, the last I do at 10 mm. I glue them in individually because I don’t want any gaps whatsoever (I mostly use “reinforced” clothespin type clamps and I don’t know if they have the mojo to do 3 at a time). I suppose by using a more powerful clamping method you could do 3 at a time (but I’d still worry about slippage). I glue them in the form, because I don’t want to take the chance of them changing the profile.
I use a 28 foot radius on the top, 15 on the back. Interestingly, I’ve found that that I don’t have to “pre-trim” them (a la Michael Bashkin’s technique) to get them to accommodate the radius, except maybe a tiny bit on the upper bout of the back that I trim off and it isn’t really noticeable.
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I’ve never made a scooped cutaway, but I’ve devoted a significant amount of time to studying the physics of the soundboard and features that play a significant role in the production of sound (including reading he Gore books and attending a 3 day class with Trevor). I think the impact of the scoop would be essentially zero. The upper bout isn’t much of a contributor to begin with, and the position of the scoop is so close to the very stiff area of the neck block there isn’t really much potential to affect the transmission of standing waves in the plate. I don’t think Al Carruth is a member of the Looth Group (maybe Ian should grant him a complimentary membership based on lifetime achievement) but he is a frequent and generous contributor on the AGF. You might run it by him there.
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This tool will probably do the trick. I made mine, not that difficult.
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I suggest moving the slider on the Windows settings input level to 100%, not exactly sure about the UMIK but most USB mics use unity gain.
Then go into the REW software under the “Preferences” drop down, and make sure your input device is selected as your UMIK-1. Then go back the main REW menu and select SPL meter. Say something into the mic and see what sort of levels you get.
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If you have a joint where the glue might be visible, the high clarity is more transparent.
Some say it might be a bit more tacky or viscous than regular in the same gram strength (thus less open time), but I haven’t observed that.
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Michael Bashkin did a podcast with the late, great Frank Ford. In it, he talked about the initial meeting/interview with the customer, and going over the customer’s expectations, the luthier’s expectations, and the potential problems, pratfalls, and making expectations realistic. As I recall, he said it might be the most important element in the whole process. It would probably be worthwhile to listen to that podcast to see if you want to include a section in your intake document that covers topics like those.
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I have used Australian Mother Of Pearl.
www.mopsupplies.com
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I glue on the bridge after finish. My finish is UV poly, about 5 mils thick. I use an acrylic template that precisely matches my bridges, and rout out the finish (plus another couple thou) using a small flush trim bit. I use double-sided tape to precisely position the template. The corners I have to correct with a violin knife and chisel. The bridge basically “snaps” in. I’ve gone to hide glue on the glue up. You need to have all the clamps set and at the ready for this, and you pre-warm the bridge to ensure things don’t gel as you do the glue up.
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The answer to your first question is yes.
Eccentricity at only the top and bottom of the arcs makes me wonder if your post processor is perhaps interpreting the arcs incorrectly (assuming your circles are properly drawn arcs showing only the nodes necessary to create a perfect circle). Are you sure you are using the latest/greatest post processor that exactly matches your machine? And have you double checked the vectors you are using to see if the nodes look exactly right?
Another possible suspect is your hold down mechanism: a) to make sure the piece isn’t moving on the table; and b) using tabs to ensure your piece doesn’t move when the cut through completes.
Assuming you are only cutting a millimeter or two of wood, it is highly unlikely that tool flex is the issue, even if you are using a very small end mill for the profile cut. Hopefully it is not a mechanical issue like lead screws.
As you may know, Vectric has a forum that is very good. If you post the file there (along with the g-code that is being generated by the post processor) and a statement of the problem, you are very likely to get more helpful input. And there are a lot of the folks on the forum who use the Nextwave Shark.
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I like that idea!
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I have a Cure UV lamp system and use Simtec’s finishes. If you want to discuss, message me with your phone number. There is a LOT to consider, and plenty of bumps in the road to (hopefully) avoid. I’ve had lots of help, I’m not sure I would have figured it out on my own. Michael Greenfield very kindly helped me out with the overall process, a very talented local spray guy taught me how to control an HVLP gun, and a local supplier helped me get my air system in shape.
