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A customer brought his guitar in to install a pick up.This is one of mine that was completed in early December.The e & b string bridge pins fall right out.Which was fine when it was built.But this is minor.The back is cracked in about 4 places.This is major.These are cracks that were in the grain that I fixed with Ca during the build,which I`ve done on several other guitars,and never had this problem.When the guitar was finished everything looked great.The customer says he`s been using the humidifier that I supplied with the guitar,a planet waves.I`ve never encountered this when a guitar has been humidified,so it makes me wonder if it has been humidified.I seriously doubt it,especially considering the loose pins which were once tight.Anyway any suggestions on fixing the back cracks without a complete re-finish on it? This is a real bummer,as the guitar turned out quite nice.
James

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James W Bolan
Nashville Tennessee

here are some pics OOCH!!!
The worst part is the owner never even mentioned this when he brought the guitar in .I didn`t see it myself until I held it in the light .He keeps it in his studio which is pretty dark hanging on the wall.He obviously doesn`t know.I lament.
James

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James W Bolan
Nashville Tennessee

Looks like some nice wood.

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"Preoccupation with an effect gives it power and enhances the error"
from "Your Owner's Manual" by Burt Hotchkiss.

Flatsawn, wild-grained wood that had already cracked while you were building, and you suspect the owner didn't humidify enough? This one is on you, James. Bad materials.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Howard I know for sure the guitar has been wall hung in a small hot room during a dang cold winter with extremely dry humidity.He says he had the humidifier in the guitar but like Todd says it does nothing.I told him specifically to keep it in the case with the humidifier in it when noy playing it.Also this guitar from the very beginning was kept in a properly humidified room for at least 3 months during building,and for a about a month after completion before he took possession of it.Never had any problems.I will take partial responsibility because I knew the issue,but I have been thru this same situation during building and never had this happen.Live and learn.Next time the wood goes back.Todd ,this is actually a piece of Mun Ebony,but your right it looks very similar to Ziricote and seems to have some of the same issues.What type of case humidifier would you recommend? Filippo, the finish is EM 6000.I can try to get it to close up and re-glue as you mentioned.With the cure time being minimal it`s worth a shot.I have a feeling since this has happened in a few places It will be a re-finish at least on the back. I`m not sure if flooding the whole thing with Ca will work .that`s pretty much what I did originally and also pore filled with 2 coats of medium Ca. Howard as for the supplier supplying bad wood as you seem to be saying.I`m not sure he would have known.The cracks only became visible ,to me anyway ,after it was thickness sanded.Probably beyond returnable at that point.But as you say I could have dicarded it for a back.So I admit I screwed up. Where to go from here? It may not be possible to fix permanetely without this re-occuring
Thanks for your input guys,
James (Skin)

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James W Bolan
Nashville Tennessee

Filippo you may have a good point.I` just always figured the general consensus was 42 - 45.Another thing that may have helped is sealing the inside of the guitar with shellac.Not sure on that one? I do this on the top,never have done this on a back.Also it may have something to do with the em 6000 not adhering as well as nitro in this situation, and maybe not offering as much protection as nitro.I just talked to the owner and he was totally oblivious.He said that he knows I told him to keep it in the case and humidified in dry conditions,but he figured it would be fine.It`s been hanging on a wall in a very small hot dry room for 2 months in the dead of winter.It definetely tried to kill this guitar.But ultimately Howard is correct.I should`nt have used the wood,even though I seem to have gotten away with it before.To assume people will do the right thing is foolish.I`m old enough to know better.Who knows it may have happened anyway.We`ll never know.Any suggestions at this point are very appreciated.Filippo ,I appreciate you trying to get me some help.
Thanks,
James (Skin)

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James W Bolan
Nashville Tennessee

Skin...I had a similar experience where the client returned his guitar during a cold and dry February with 2 cracks. This was in a QS EIR back... not flatsawn...so it can happen to anyone and with any cut of wood. At first blush it was a classic dehydration issue...especially when I re-humidified the guitar and the crack virtually disappeared. I glued and patched it but was unhappy with the look. Even though I knew the guitar was abused, I didn't want the visible signs of repair cleats to reflect on my work. So I unilaterally decided to replace the back at my own expense. During the process of closer inspection, I and another builder discovered tiny hairline cracks emanating from the PUP jack and aligning with the back cracks which clearly indicated that the guitar had been dropped. Had I been an experienced and a well-known builder, I might have refused the work unless the client paid for the repair. Instead, I ate the cost and chalked the whole experience up to the cost of entry.

I really can't comment as to whether your issue was primarily material or customer abuse. You're now in a situation where you want to make sure that your reputation is not harmed. I'd seriously consider replacing that back and eating the cost. The owner knows what he did and is more likely to keep humidification as a higher priority going forward. And at the same time, your instinct and decision making process will have been strengthened as well. It's a difficult experience like this that in the end will make us better builders as well as better decision makers. I feel for you bro, and compliment you on being honest in dealing with the issue on the forum. It speaks volumes about your character, refreshing in light of the recent character deficiency on the forum! Good luck going forward.

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JJ
Napa, CA
http://www.DonohueGuitars.com

Probably not if the guitar has been out of the case all winter. Shellac is very good at slowing down the transfer of water vapor but almost nothing will stop it.

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http://www.chassonguitars.com

JJ thanks for the input and your kind words.Replacing the top is probably the safest thing to do.Never done it ,but I think I can handle it.Any advice of course will be appreciated.Finding a suitable back may also be tricky,might have to use Mac Ebony.I don`t mind eating the cost.The important thing to me is that the guitar is fixed properly.Thanks again and I enjoyed meeting you a couple of years back in A2.Hope our paths cross again someday.
Skin

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James W Bolan
Nashville Tennessee

Wow.....that is really good advice. I might not be able to live up to it as I get overly irked by circumstances like this....but I will try.

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There is no difference between the man that thinks he can....and the man that thinks he cannot.

Chris I hear you about being Irked.I can`t help feeling everything would be fine under proper care.This I`ll never know.I made it perfectly clear that the guitar should be kept in it`s case and humidified during the dry months when it wasn`t played.But the reallity is we can`t expect people to do what WE wan`t them to do.This is probably true no matter what we are talking about.So I`m saying MY BAD as Howard said, and even more reason to be extremely careful about the choices and the way we build if we want our guitars out in public.
Skin

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James W Bolan
Nashville Tennessee

Personally, I would rehumidify the guitar until the cracks mostly close up, glue with CA or thin hide glue, stick a couple cleats inside, touch up the finish, and call 'er done.

But I ain't too picky about technical perfection... long as it sounds good and plays good and doesn't fall apart, everything else is icing on the cake (mind you, I do like a lot of icing if I can get it).

I might not have bought that back in the first place due to the obvious potential for problems, but for such a rare and beautiful species as mun ebony, even the low grade sets should go to good use (IMO). So if I could get a good deal on it I would use it, knowing and accepting that there would be cracks. In fact, I probably wouldn't even fix them if I was keeping the guitar for myself, unless they were rattling or causing some other bigger problem than their appearance. If the owner of this guitar hadn't noticed, he may be the same way. Talk to him.

Another thing I would do is a crack-stopping technique shown in Ervin Somogyi's "Making" book, where you glue little strips of veneer all the way across the back to stop most cracks from starting, and catch any that do before they get very big. Pictures show one strip between each back brace. Seems like it would make a tiny bit of tonal difference, but probably not enough to notice, and definitely would help with cracks in a plywood kind of way. He says he only does it on especially problematic woods like Brazilian rosewood. I doubt you could get these glued in without pulling the back though, which I say is more work than the problem deserves. And if you do think it deserves that much, then the new macassar back would probably be better than trying to save this one.

Question (hopefully not too far off topic since it's been mentioned at least twice in this thread).

If water vapor passes through shellac slower than wood then it's likely true that wood absorbs less moisture during brief exposure to abnormal moisture. But doesn't that also mean that it takes much longer to loose the moisture and stablize to a "normal" humidity afterwards? So if a guitar were left in low humidity for an extended period of time (like the winter), then it's likely the wood would be de-hydrated with or without a shellaced interior. However, when you attempt to re-hydrate the wood, seems it would take much longer for the wood with shellaced interior to return to normal conditions. Seems in terms of humidity, the only benefit of shellacing the interior might be for short term exposure to humidity changes (like one night outside in a jam session) but no real benefit for long term exposure (and even a hindrance when attempting to return the wood to "normal" humidity). Thoughts?

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Formerly known as Adaboy.......

Hello, i am really sorry for you, it is always bad to see wood cracking, having problems with already finished work and so on, BUT, i would like to leave a few comments, opinions:

1. Mun Ebony is pretty new to the tone-wood market, isn´t it? I would say it is sold now for 3 or4 years, not much longer, via Allied or LMI or others. This means to me, you bought a set not so long ago, and built with it. This is nothing i would do or recommend. A flatsawn set like this, if i would buy it, I would at least have it stored and "aged" for not less then 10 years, to see how it behaves, moves, cracks. In the mean time i would use other, OLD wood. But buying from a tonewoodseller, even if he swears by god that it is old, and use it more or less immediatelly is nothing I would even think about.

2. Of course I explain my customers how to store and treat a guitar I built. But my goal is that my guitars don´t crack, never. So I use old wood and built in the range of 35-40 %, not higher. Here in Europe winters are strong long and cold, so we often have central heated rooms. Humihity often drops belwo 30%, and then the wood shrinks, arches drop in a bit, but the backs don´t crack.

3. "Making the guitar wet" again and then hoping that the crack closes and then glue it, is in my opinion a mistake. Because what will happen if the guitar comes into a dry environment agin? Just the same game starts again. The wood shrinks and it wil crack, just on a differnet place of the back. It is just the fact that the guitar-back has lots of tension still inside, and this will let its stress off somewhere, it has to.

4. I would go just the other way around. Put the guitar in a really dry environment, for a few weeks, and then close all the cracks, re-laquer the back, and then call her done. For closing the cracks i would perhaps use a really hard drying epoxy, like UHU endfest 300, mixed with sanding dust. Of course you will see these cracks, but they won´t open up again.

5. I know it is not..?...nice...?..... to buy a nice piece of wood, and then you have to say to yourself: Ok, in 10 years i will use it, but I think this is just a big and important part of guitar building. Patience.

6. I dont think ziricote or Mun ebony or other wood deserve to be called "Crackwood". I just think it went the other way round: Ziricote appeard on the market and everybody used it immediatelly without having it really well seasoned. Just to measure to moisture content, and then say: "Ok it is down to 8 %, lets built" just doesn´t work. It has to be:"ok, it has been down to 8% and went through 10 winters and summers, now we can start having a closer look at it."
So lots of people didnt wait long enough, so lots of problems occured, and then these woods got a bad reputation. But if you season the wood long enough, I think it will be as stable as any other high-density-dark-wood.

Wishing you the best, Alex

Alex the guitar has been in a really dry environment for over 2 months,hence the cracking.But you may be on to something with epoxy keeping it from happening again.Also maybe flooding a top that is questionable with epoxy instead of ca after thicknessing may be a possible solution.Anyone have any thoughts on that one,and what affect on sound if any this may have.It would be nice if some of the woods that are more prone to cracking could be used with more confidence.Some are very beautiful.As far as waiting 10 years to build with a piece of wood,at my age this just isn`t realistic.It`s possible I would be dead before the next build.This wood was acclimated for about 6 months in my shop before using.For me that`s long enough,although once I discovered any cracks it probably shouldn`t have been used.Also financially this makes guitar building a very expensive crap shoot.I doubt if a supplier would take anything back after 6 months,and certainly not after 10 years.Is staying away from woods of this nature the main option?Does this mean staying away from all Rosewoods? I know that sounds extreme,but all of them are prone to cracking quartered or not.And I would say even after acclimating.
Skin

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James W Bolan
Nashville Tennessee

A lot more.

I can't believe the sets people are buying these days.
There's going to be a lot of cracked sides and backs coming up here
real soon.

Unless most of this slab cut stuff is kept perfectly humidified (and it seldom is)
it's almost certainly going to go eventually. I've been working with wood for over
30 years and it's just a fact of nature.

Bring on the naysayers. But ask yourself: why have guitar builders, until
just recently, always used only quarter-sawn material?

Yes, it moves less but it still moves - no matter how old.

Years ago, I worked in New York City restoring antique keyboard instruments: square grands,
harpsichords and clavichords, etc.. I witnessed soundboards cracking on instruments 200 years old
when the radiator heat went on in the winter when someone in the shop forgot to have the humidifier
going under a particular instrument.

One other thing: gradual, and yet sustained, decreases in RH cause less damage than sharp drops.

It seems like when a lot of folks finally decide to pull the trigger on a luthier built instrument they immediately go a little nuts on picking the wildest wood they can. I think it's kind of a temporary insanity in a lot of cases and it's our job to be a little island of reason. I tell them it's like a tattoo. It seemed like a good idea at the time but you have to live with it. I failed once and there's a Koa OM out there with a flat-sawn back and laminated flat sawn sides but the owner knew the risk. So far so good but it's early.

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It's not what you don't know that hurts you, it's what you do know that's wrong.

James this post sure shows your integrity as a builder.
I'm not sure if that set was bought from us or not. If it was I can tell you that those sets were cut over 5 years ago.
They sat in our humidity controlled shop which we can at 45% i know that is not much consolation to you but thought you should know that it was seasoned for 5 years when you bought it. If it is not one of our sets then just disregard this old man. I would also take Todd's advice on repairing.

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Beautiful and unusual tone woods at a reasonable price.
http://www.rctonewoods.com/RCT_Store
The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

Very good post thank you Alex.

Must agree completely that despite wood reaching a certain moisture content low enough on a meter to be called 'dry', it also needs to be allowed to move with changes in relative humidity for a good number of years before it can really be called 'seasoned'.

I have no data to support this but I do know that wood settles over time. e.g. Move into a new house with a fresh cut roof of kiln dried timber...listen to the movement through the summer nights.....A tile roof will be full of creaks and pops where an iron roof is nothing short of dramatic symphony at times.

Come back to the same house in 7 to 10 years and listen...................zzzzzzzzzzz

This is why all of my back sets and tops are stored in a sticker press and kept 'out' of the RH controlled glue room until a few weeks before glue up. IMO tonewood, especially hardwoods, needs the exercise. The wood needs to be free to move as the 'seasons' change, but at the same time, I feel it needs a little directional coaching along the way



Cheers

Kim

If that's true, then it may be an argument for finishing the inside of an instrument.......moisture gains and losses would be more gradual.

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Formerly known as Adaboy.......

I just had a thought, ,
if one was to x brace the back, and use little finger braces on an angle,
instead of ladder braces, do you think it would make the back less prone to cracking from humidity changes?
Seems like the ladder bracing is fighting the cross grain of the back more.
Hmmmmm...

Maybe things are different in the USA but I have always been under the impression that the term 'seasoning' was derived from the process of exposing wood to changing seasons which is the same thing as 'aging'. Drying on the other hand is a process of controlled management when taking wood from a fresh cut wet/green state, down to equilibrium with ambiance from where it begins to season.

Also, just to be clear, I maintain that, to a point, wood does indeed move less with changes in RH as it ages. This is the whole point of seasoning and for evidence you need look no further than the stacks and stacks of carefully stickered hardwood that is used in rotation from the rear of any good joinery shop (if you can still find one). All that wood came into the yard milled and 'dry', however it is only after considerable 'seasoning' that it will be used for making door and window frames where stability is so crucial.

I think the seasoning/aging process has more to do with stabilizing the lignin which binds the wood cells of any given board together. To that point I do agree that the wood cells themselves, once 'dry', will always take up and expel moisture in the atmosphere at the same rate. But how much the whole 'board' moves from one year to the next in relation to changes in RH reduces marginally as the lignin, up to a point, stabilizes over time....I believe that the effects of 'baking' wood as has been discussed many times on various fori, simply accelerates the lignin taming process e.i. the wood becomes catastrophically seasoned.

Cheers

Kim

The point I was trying to make is that the sets were not freshly cut and then sold. I sticker our sets just like the picture Kim shows. I handle a lot of wood during the course of a year and also build guitars so I'm not just another know nothing wood vendor. I can tell you that I sold over 50 sets of this Mun Ebony again not knowing for sure if this is one of them and this is the first complaint of a crack. The proof is in the numbers not just here-say. Besides I don't have all the years to wait like some of you have.

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Beautiful and unusual tone woods at a reasonable price.
http://www.rctonewoods.com/RCT_Store
The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

Todd I have cut and dried a lot of ebonies. One in particular comes to mind. It was some gorgeous Black and White ebony that was curly to boot. During the drying process the sets shrank close to a 1/4" in width. Are you saying that over time and changes in RH this wood would expand that 1/4" . I see no evidence of that. The sets that survived were just fine with no cracking.

_________________
Beautiful and unusual tone woods at a reasonable price.
http://www.rctonewoods.com/RCT_Store
The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498