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#31
08-22-2017, 07:20 AM
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Most anesthesiologists aren't even the ones administering gas. That honor would go to CRNAS. Then you have hospitals solely run by CRNAS. Might I add they are just as competent as the mdas.
 just to muddy the waters a little bit.
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#32
08-22-2017, 12:38 PM
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I'm with Bruce: you should be able to get oil varnish to come in at around 0025"-.004" thickness. The other end of the line is held down by Ovation, so far as I know. I have a piece out of a top that has .040" of epoxy on it: a full millimeter. I'm told they sprayed it on in one coat. What does that do to the sound?
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#33
08-22-2017, 12:50 PM
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I've heard .002-.004" for french polish. What does a good nitro finish come in at?
Steve
__________________
www.denvirguitars.com
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#34
08-22-2017, 12:52 PM
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Quote:
{Sorry, I just realized I had to remove the sock...} I had a friend who sanded down an old Ovation (soundboard) and refinished it. According to him, it sounded wonderful (afterwards, that is). Last edited by Christopher Cozad; 08-22-2017 at 12:55 PM. Reason: Sock removal
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#35
08-22-2017, 01:18 PM
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Quote:
Nitro, well my body hasn't been able to handle that stuff for >15 years so I can't comment on it.
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#36
08-22-2017, 07:36 PM
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I do it all myself in a one-man shop, but if I had the option I wouldn't hesitate to farm out the finish. Easily the least pleasant part of the creative process, but needs to be done to the same standard as the rest of my craftsmanship. It's not easy and I'm picky.
I learned finishing the first time in New Zealand, but I feel like I had to relearn everything again when I changed brand and chemistry on my return to Canada. Finishing takes practice -- lots of it. So do setups, but I also work on repairs and service, so I do many setups for every guitar I produce.
__________________
Tim Mullin Shefford, QC CANADA
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#37
08-22-2017, 08:07 PM
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Ah, Poly! My understanding is that it CAN be done very thin as Tim describes, though not necessarily. The downside it that it is extraordinarily STIFF. Which is also an upside as it is much harder to dent than most finishes. All hearsay, I've never used it.
My understanding is that French Polish (which I also have not used) is always thin, and is surely the thinnest coating of all. Its downside is that it makes the varnish I favor look low maintenance.
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#38
08-23-2017, 06:50 AM
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Bruce, I am sure you are aware but many reading this thread may not be so when you mention "Poly" it can refer to straight Polyurethane (the solvent evaporative air dried version), catalyzed Polyurethane (the chemically cured version), catalyzed Polyester (chemically cured) and UV Polyester (Ultraviolet light cured).
Air dried polyurethane is typically the slowest drying and the softest version much akin to flexibility of oil based varnishes. It typically takes 14-30 days to reach its full cure before it can be buffed without shrinkage. Chemically cured polyurethane is much faster drying but still takes 2-14 days to reach full hardness. Its not any harder or less flexible than the air dried version but can be buffed much sooner with less risk of the finish shrinking. Chemically cured Polyester dries much faster than PU, usually to a full cure hardness in 12-24 hours. UV cured Polyester is fully cured in 30-60 seconds! It can be buffed almost immediately after cooling and sanding. Both versions of Polyesters are THEE hardest of the finishes typically used on guitars. These polyester finishes are the ones I believe you may be referring to when you mention "Poly". Polyester is most often used in large scale production shops and factories though its not uncommon for small one man shops to dabble in it as well. Both versions of PE have the steepest learning curve to properly apply because it has a much higher solids content of the professional finishes. Because of the high solids content it takes a while to learn how NOT to apply it too thick. PE can be found on most production Asian guitars and also on the Alvarez that Alan mentioned earlier. A final film thickness of .010" - .030" is certainly NOT uncommon. The downside to PE is film thickness control and when the film builds so does mass and especially added stiffness to all the vibrating surfaces. This added stiffness can add unwanted brightness, shrillness and a loss in bass response. The upside to PE is its like steel armor plating your musical instrument. The added hardness and stiffness of PE finish resists dents, scratches and ANY chemical known to man. There is NO paint stripper on the planet that will remove it! With the right skill set one can learn (speaking from personal experience) to apply PE pretty thin but its VERY difficult to do. As a disclaimer I no longer use PE for various reasons. As I grow wiser, through experience, I find myself gravitating to softer finishes. I think Bruce, Alan, Lynn, Kim and a host of other seasoned veteran builders would also concur. A softer finish adds warmth and sweetness to the tone that is so difficult to describe or put into words. I think we share a common desire that we want the completed instrument to sound its best, with the most natural, woody, unencumbered voice. When we tap on a guitar, in the white [prior to finish], that is the voice we want to hear after its finished. Using too much finish or even the wrong finish can significantly change that voice. Its such a fine line that we walk. Finishing a guitar or any musical instrument, is a complex subject and task. There are hundreds, if not thousands of finish products on the market and I have yet to find the one perfect finish, without its own unique set of quirks or challenges. But be informed that finish is yet one more important component, that contributes to the sum of the parts of the completed instrument that positively or negatively influences the final tonal envelope of the instrument.
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#39
08-23-2017, 09:51 AM
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For my current build, Joel outsources his finishing, and I'm happy he does this. On many levels (space, reduced overhead, hazardous waste, environment, to name a few) this makes sense for a luthier in my book, but the most important reason to do this is for the luthier and their families health. For this one reason alone, I would hope all luthiers seriously consider outsourcing this task if they have any viable alternatives. This is assuming that these finishers have better facilities to contain the hazardous aspects of finishing for their workers and the environment.
Whether these outsourced finishers can produce a finish that is 100% as good or better then the luthiers own hands is secondary to me. As a guitar purchaser, I would gladly give up a little perceived tone to protect the luthier's health. As luthiers seem to say that most of the tone comes from the skill of the builder, not the wood, l think that this can be applied to the finish as well. I would rather have 95% of Joel's tone, and to have him healthy, then harming his health for my benefit. Just my $0.02
__________________
Ian K. 2018 Michaud OO-R 2012 Webber Dreadnaught *SOLD* 2010 Eastman E20OM 1994 Guild D30 1979 Yamaha FG375S (retired) 1974 Norman B30 (retired)
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#40
08-23-2017, 10:33 AM
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An educational post for me, Tim, and thank you. After reading it 2 1/2 times and looking at your post earlier post re calalized (poly)urethane and followed by your statement that you no longer use PE, I can't tell what you do use (when not FP). Unless you mean that not all urethane is polyurethane, which I THINK it is. But I am not the expert that you do seem to have become on the subject. I am not being catty, probably just too lazy to read through again.
You are right IMO re the softer finish advantage to tone. Some argue that varnish increases damping, and I think that is correct. The nay-sayer's assumption is that increased damping is a bad thing, and at a certain level that is true, but at another level damping is just what the doctor ordered as it removes harsher edges from the tonal envelope making the tone relaxed and beautiful. I think it is a bit like really good sunglasses cutting the glare on a clear and beautiful sunny day. All opinion derived from direct experience and creative thought. IMO, in other words.
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#41
08-23-2017, 10:39 AM
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is it working good?
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#42
08-23-2017, 11:02 AM
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I hesitated to post in this thread with these professionals, but I do have enough direct experience to agree with them. I don't outsource anything, but I certainly understand why outsourcing inlay and finishing would make sense on a professional level. Those are both skills that have professionals that specialize in that skill, and are probably more proficient than the builder.
I finish my guitars with TruOil, which is a "wipe on oil varnish". I've used it enough to have confidence in the final result, and I've learned how to use it. I started using it because spraying nitro wasn't an option, I use it now because I prefer the results, and it's still available. I've always preferred an oil varnish finish, but it's gotten too difficult to find and the formulations are always changing, which requires learning how to use it all over again. Mr.McKnight's post is most excellent in highlighting the various products all known as "poly", and how different they can be. Putting on finish is a procedure, using the same sequence and materials each time. There's an infinite number that will work, and even more that won't.
__________________
Rodger Knox, PE 1917 Martin 0-28 1956 Gibson J-50 et al
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#43
08-23-2017, 11:58 AM
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The best study on finish properties I've seen was done by Schleske, published in the Catgut 'Journal' in November of '98. He focused on violin varnishes, but did include linseed oil, and possibly walnut (it's been a while since I read it) and nitro. He applied the same amount of different finishes to wood samples and measured the changes in properties, both immediately, and after a lapse of time. Basically he found that drying oils add mass and damping and don't provide much protection from moisture. Whether Tru-oil shares those properties I can't say, as I have little experience with it. In oil-resin varnishes the damping goes up as the oil content increases. 'Rubbing' type varnishes use less oil than 'Spar' varnish. Most resins had low damping, with nitro and shellac being the lowest.
It's generally assumed that high damping is undesirable on guitars, but what level constitutes a problem is open for debate. Given that nylon and gut strings already have much higher damping than steel, and hence much less available energy in the high frequencies, it's probably beneficial to avoid high damping finishes on Classical guitars. I've re-topped a few Ovations, and refinished a couple of tops on them as well, and they always sound better afterward. At one point some years ago my then-partner and I tried a water born finish. It went on thick, and never did seem to harden well. He decided to scrape it off of one of his Classicals, leaving the strings on as long as he could, and stopped periodically to see how the sound changed. After that we threw the stuff out. Most of the newer water born finishes are better. One of the big advantages of outsourcing is the time saved. I could make more guitars if I didn't do my own rosettes, inlays, and finishing. It's said that if there are a lot of ways of doing something, it's a sign that either everything works, or nothing does. I'm of the opinion that there is no really good guitar finish. All you can do is find the ones that have features you need and drawbacks you can live with.
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#44
08-23-2017, 01:11 PM
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For me it makes sense to outsource things that I can get cheaper pre-made rather then making them myself. That includes things like kerfed linings or slotted fretboards (typically for normal scale lengths), standard bindings and so on. I can't do shell inlay too so DePaule is a God send for stuff like that.
But I am surprised to hear that some luthiers outsource their setups. I can't imagine how much extra that would cost and it just seems to me that if ya build the darn thing you ought to be able to make it playable  As much as I hate finishing, with the exception of FP I actually like doing that, I would never outsource it just as a matter of pride frankly. I learn something new on every finish so I guess in 50 years after I'm long gone I'll finally start getting 'good' at it. 
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#45
08-23-2017, 08:38 PM
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Quote:
It is as flexible as many of the oil varnishes I've tested with similar mechanical properties to your beloved Ace brand. However, it's nearly water white with only a hint of Amber. It has crystal clarity that allows the beauty and chatoyance of the wood to be seen without any distractions. It sands without loading paper, buffs easily, it's chemical resistant after its cured and is abrasion resistant. It's tricky to spot repair but not impossible. Th downside to most urethanes is that they can be susceptible to delamination from the substrate if subjected to an impact. This shows up as a white ring around the impact area and is a dead giveaway to the repairman that they are dealing with a urethane product of sorts. The McFadden product was susceptible to delamination early on but they engineered around it by formulating chemistry changes. The latter formulations of the McFadden product bonds really well to their sealer and it's a nearly foolproof system once you learn its nuances. Then they went belly up which left many of us scrambling for a suitable replacement, which eluded us. Fortunately I had about 4 gallons left which got me through quite a while until Seagraves bought the company and resurrected many of McFadden's products. Phew... I still have a fondness for varnish and continue to experiment looking for that perfect yet elusive finish. I know it's out there, somewhere in the cosmos... Last edited by Tim McKnight; 08-24-2017 at 07:48 AM.
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