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I have a guitar on the bench that is showing some pretty serious finish issues. It is em6000 over a pore fill of Zpoxy. Also, the areas affected are points of contact: the neck, the upper bout side (where one’s arm goes) and to al lesser extent the lower waist where it sits on the leg. Top/ back are fine with no issues…. Has anyone experienced this? Is this a situation of needing to remove the affected areas and respray?




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One of my customers does that to his guitar. It’s something in his sweat. On the advice of Jeff Weiss from Target, I stripped the affected area and resprayed, but using the Target crosslinker to make the finish more durable. The new EM6000 burned into the old just fine. I couldn’t remove the sweat caused differences in top color, but overall the refinish went fine. It took that customer about three months to eat through the new finish. We haven’t done anything about it, yet. I suspect that we’d have gotten the same results with nitro—I have seen many nitro finished guitars with degraded finish in the contact areas. Jeff told me last year that he had something tougher coming out later that year. I haven’t investigated yet. Even though the crosslinker did not seem to make the finish anymore resistant to this guy, I still use it more often than not, now, because it seems to help the wet finish flow out better with fewer pits at misfilled pores and less edge avoidance.

I’ve been using EM6000 and its precursors since about 2000. It’s on well over 100 guitars that I have built. Except for this guy, a professional who plays several hours each day, I’ve not had any finish issues that I know of. One of my personal instruments that I built in 2006 and used professionally until I stopped performing to avoid Covid shows no finish degradation other than finger and pick wear near the soundhole.

I had a similar failure of EM6000 over Z-poxy on the neck of one guitar. It occurred only on the neck and it only happened on that one guitar. The finish on the treble side of the neck lifted and blistered along the length. It appeared that there was an adhesion problem between the EM6000 and the Z-poxy because only the finish lifted. This was in the fall of 2019 about 9 months after the finish was originally applied. I repaired it in March of 2020 and it is doing fine today almost 4 years later and this guitar has been my main player over that time. I don't know why it happened on this guitar but not on any of the others that have EM6000 over Z-poxy. All the other guitars that have EM6000 and Z-poxy are older and some of them have a good deal more playing time with no problems at all. Weird.

The first two photos were taken after I removed the finish where it had lifted and the last two photos are after the repair.

To repair, I feathered the edges of the finish around the areas where I removed the lifted finish by sanding with 400 grit sandpaper to get a smooth transition. I didn't apply more Z-poxy since the original Z-poxy was still there. I then applied EM6000 to the bare areas using the same finish schedule as when the finish was applied originally (I brush the finish on). I overlapped the applied finish onto the existing finish about 1/4" on all sides, feathered. After letting it cure for several weeks, I sanded and polished it and the results are in the bottom two photos. That's how it looks today.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

I had debonding problems with one where there was EM6000 over a repair that didn't get shellac. On a guitar I made in 2009 and played daily for about 5 years. Areas where there was shellac were fine. I didn't have to worry about a customer so I just sanded the whole neck down and put on TruOil.

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Steve Smith
"Music is what feelings sound like"

That happened to me a lot when using waterborne acrylic. I was using KTM9.

Problem disappeared using waterborne urethane, KTM-SV. I’ve a personal guitar with it that still looks great umpteen years later.

EDIT: Hey, what happened to Hesh's post about how bad waterborne finishes are and how great nitro is that this post was in response too?

Actually, the nitro on the Martin I bought brand new in 1992 at Elderly in Lansing failed on the face of the headstock. It blistered and pealed right off. Note that headstocks don't receive physical contact from the player like the neck and body so that failure was particularly egregious. The folks at Elderly told me that I wasn't alone in seeing that failure.

Based on my reading of posts on this subject over the past 12 years or so on multiple forums, the vast majority of water-borne finish failures occurred in the early days mainly in the 2000s and particularly with KTM9. The number of posts I've seen about finish failures tapered off dramatically in recent years as people moved to more recently developed finishes.

As far as I'm aware, nobody knows what the actual failure rates of any of the multiple water-borne finishes are. Anyone who says otherwise is just guessing.

Speaking for myself, track records like Bob's allow me to sleep just fine at night.

EDIT: I don't know how I forgot this fine example of nitro failure which is sitting right in the other room. It's a Gibson Custom Shop L-150. The finish cracked and fell out all along the front edge of the bridge about twenty years ago. After this happened, I did a web search and quickly found photos of 8 other Gibsons built within a couple years of this one with the exact same finish failure.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

to me that simply looks like a misrouted bridge footprint…

Not sure what you mean.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

To me the cleaness of the line in front of the bridge makes it look like the finish was routed off in the wrong place. Like the jig for routing off the finish was 1/8” too short but some one just stuck the bridge on anyway…

That bare strip was originally covered with finish. The finish then cracked, crumbled, and fell off. In the photo of the other end of the bridge below you can see lifted finish that still hasn't fallen off. It doesn't show in the photos, but the finish also lifted in places along the back edge of the bridge. It hasn't cracked and fallen out (yet) though. One of the best repair people in my area diagnosed it as a finish adhesion problem.

My theory as to why it follows the shape of the bridge is that since the area of the top in front of the bridge is dead flat rather than domed due to significant bridge rotation, there was a band of bending stress on the finish in front of the bridge that, combined with poor finish adhesion, caused the finish to lift and crack.

Btw, there is no lifting of the bridge from the top.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

You mean, J what happened to the post I thoughtfully wrote about intellectual honesty and breathing one's own air and then came back and deleted because I don't need the additional.... grief right now?

I lost my 92 year old Mom very recently and another friend on this forum just lost his 96 year old Dad so a few of us are struggling. I'm really struggling and decided I'll let this one go and not die on the waterborne vs. nitro debate hill. Someone once asked me here if I have to die on every hill and one of the many amazing things about me... is that I actually not only listen at times I actually hear others and take what they offer to heart. What a concept.

But to quote one of my heroes: Just when I thought I was out.... you drag me back in.... Kidding of course.

I mentioned this, my grief in my post that you read J but since you insist on bringing me back I'll get to the point.

I'm in the repair business and I see what results from the poor decisions of others especially some small builders who can't tuck their egos away at times and consider that we as Luthiers, no matter what the experience level are always, always learning and must keep an open mind.

Dave my business partner is one of the most experienced Luthiers around. He's lived this for 47 years and been professionally trained, formal apprenticeship, hundreds of guitars built and he taught Lutherie professionally to folks paying thousands to learn. He also created me No easy task I would add.

He belongs to a Looth Group where a number of highly experienced Luthiers are on line with each other in our shops at times daily. Amazing concept and pretty cool when you consider the loneliness of the Luthier life in a single person shop. These guys have more experience than this entire forum but they still come back to learn from each other and share. They are intellectually honest and when one of them screws up they often discuss it. It's how people learn, improve and grow.

A post above I thought to be not intellectually honest. A poster blames the client for his body chemistry. News flash lots of folks have body chemistry that eats guitar finish I see it often. With nitro I rarely see it but have seen it even with nitro just less often and the results are typically not a complete failure of the finish and it falling off. Instead nitro will lose it's luster much like when someone has bug spray on and touches the instrument.

As builders this is the world we must build for including the folks who's body chemistry eats finish. It is the business we are in....

Servicing over 600 guitars annually personally and 1,100 our shop sees a lot of failures of the best of intentions. When someone calls and says they have a small builder instrument from so and so will we repair it we may not even agree to look at it depending on who built it. If our experience with that builder or person is that they do lousy work we do not want to get any on us and are far to busy to have to do that in terms of our opportunity costs.

On the contrary a small builder who has their stuff together we are happy to help and do when they come our way if we have openings. It's case by case with us and what we seek to avoid is called scope creep. We don't want to take in a crack repair and find the frets falling off that will push back someone else's repair.

So we see waterborne finish failures far more than we ever see nitro failures and nitro does fail at times but not nearly at the rate of waterborne.

What's the remedy for someone who purchased an instrument with a failing waterborne finish? Refinish and we don't and won't do that it's not the business we are in. This leaves those who are in this situation.... SOL unless they can find and contract with a professional refinisher.

This forum is filled with examples of waterborne finish failures and what you said J that in your opinion this was a product of the industry early on and not the case now I would push back on as well. Just as I do not know if waterborne has really, really improved over the years you don't have the data either. But we do have the reports here and most are from who I would consider credible people/members.

I also wrote if I recall correctly before I deleted my post that I had high hopes for waterborne when I was building guitars in my back bedroom with white carpet in my condo. The toxicity was on my mind and I didn't want it in my life and I am speaking of nitro.

But every time I purchased hard shellac (not waterborne I know but a raved about alternative finish that was not ready for prime time either...) or KTM9 and tooled up to shoot it someone posted on the OLF about it falling off or having a blue tint or, or, or. Body chemistry and waterborne seemed to be a common complaint.

So it got a bad name here and I was unwilling to shoot it.

As for nitro failing J it does and I'll one up your swing at nitro and invoke Rick Turner RIP who was very personally interested in nitro reaching 80 - 100 years old. He believed that it's going to flake off and completely fail at that age and some of his predictions are coming true we can see now with time. Shellac seems to be holding up a century out better than nitro as Rick predicted.

But for most players, most body chemistry nitro is far more durable to the ravages of Smoke On the Water and beer bottles flying across the stage than waterborne and always has been. This is pretty indisputable and evidenced by not a single example of a major manufacturer concerned with warranty claims using waterborne finish.

Let me repeat this: Not a single major guitar manufacture uses waterborne finishes

So J I tried to stay out of this you brought me back. We disagree and I would add the word strongly here. Waterborne finish has not demonstrated to me that it's ready for prime time and I am far from alone. I'll add that when a finish does fail it's not like a loose fret that can be repaired - it's a disaster and a crying shame for a client and to be avoided at ALL costs.

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Ann Arbor Guitars