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Here is the latest Luthier Tips du Jour video. In this video I discuss the symptoms of the lack of or too much humidity.
This video as well as all my other videos are available via my website, https://lutherieacademy.com/videos , or on YouTube.
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Well that was surely a teaser Robbie!, I was hoping we would have gotten a much more in-depth video on the subject,
or at least something a bit longer,
Seeing as you oft mentioned your time in Brazil, with perhaps... what one might say, less than ideal circumstances
with such high RH levels.
I guess you've met, or indeed worked alongside luthiers exporting guitars to a much dryer climate, which would have made this a very interesting watch,
as presumably the luxury of a climate controlled room to work in, the likes of what's behind your bench,
might not have been within the realms of possibilities for some folk.

A revisit to this topic in detail I would be looking forward to, as I can imagine some fascinating workarounds regarding keeping an ideal MC in less than favourable conditions,
which I guess poses a serious challenge for the newer folks watching your videos, to say the least.

Things like how much time one could work on a guitar, with a given RH and temperature, before the need to be placed back into somewhat of a
more suitable environment...
or for how long various components need to be stored for, before commencing work, and might you have used/seen a weighing scales utilized for this purpose, or is the difference negligible regarding smaller/thinner/lighter stock to be of any sort of trustworthy rule of thumb?

That kinda thing interests me in my damp shed, as it's rare to come across any info of this, seeing as most of the pro's have much fancier sheds,
or the capital for sorting out such issues, rather than making do with things on a shoestring like myself.
Not complaining, I'm grateful to have such a place, and done the best I could in order to dry it out,
though even with drainage dug on three sides of the shed, it's still quite damp in here yet.



Cheers
Tom

A person might call that a moat, Tom!

I'm in Ireland. It's hard not to be obsessed with humidity and damp. Especially in a valley, in an old house in the west..

'Tis long filled in now thankfully Don, as it was a bit dodgy for the auld wolfies getting injured in the dark!.


Lol, it seems we're in a similar predicament, yet on opposite ends of the wesht!
Though admittedly, I haven't looked at a hygrometer in years, as the few offcuts of plywood I have, is telling enough.
Kinda given up on the idea of using the stuff, or at least for the time being, since it tends to get rather mouldy.
Thankfully that doesn't happen with the reclaimed tropical hardwoods I've hoarded from skips through the years...
so I'll likely have to laminate what scraps I have left of it, for forms and the likes, should I ever get that far.

I've got my work cut out for me for the next long while, just trying to make some space in there, and getting everything off of the floor,
with hope that perhaps... I can indeed become obsessed with such issues, and try and overcome such obstacles,
not per the usual sensible route though, as such luxuries would be a bit far fetched for me.

But hey, by the time I've got things sorted out somewhat, fingers crossed there will be some kind of solutions for those of us who's in the same boat.

All the best
Tom

I’d recommend focusing on humidity control inside your workspace.

A search of the OLF using "humidity" and " control" would be well worth the effort.

from elsewhere, here’s why:
https://www.mimf.com/library/Bad_back_c ... -2009.html

It’s been often said that the first tools you should buy for building guitars are a psychrometer and two or three hygrometers.
https://www.mimf.com/library/Humidity_q ... -2008.html

some ideas for work-arounds :
https://www.mimf.com/library/My_humidit ... -2008.html
https://www.mimf.com/library/Want_to_bu ... -2005.html
https://www.mimf.com/library/Dave_Lang_ ... -2012.html

I’ve found large zip-lock bags (sold for storing clothes, etc.) for storing braces, back and sides, etc. can be helpful, and can be aided by silica gel packets (re-usable by microwaving). When I was practicing as a veterinarian, a large percentage of our drugs and supplies came with small silica gel packets tossed in the box. If you have a pet or livestock, try asking the vet to save the packets for you, they are just pitching them into the trash otherwise.
ádh mór ort,
Randall

I’ve actually had more issues from overzealous humidification by owners of my guitars. It seems like once they swell up it takes quite a while to settle back down again as opposed to the other way around.

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

I made a guitar for a friend recently, delivered in a rare dry period over summer with v low action and a low saddle. I visited him the other day in a stone house on top of a hill near the sea, action well up over 3mm. I'm starting to question the logic of building between 45 and 55 rh in a country that is regularly up at 80 percent plus...

I think that the idea of building an instrument at 40-50% RH is so that the instrument can handle both extremes if/when it is exposed to them. Yes, the instrument will swell or shrink, but it probably won’t suffer lasting damage. I live in a part of the US where the RH is high most of the year, but in the winter, when we fire up our furnaces, the RH inside our houses plummets. Early on in my building (late 1990s), I made the mistake of not paying enough attention to RH. Some instruments I built in high RH summers didn’t just shrink in the winter; their tops cracked. So, I wised up and put money/effort into controlling RH. I guess that, if you can be sure an instrument will always live in a high RH environment, you can build it in high RH. I just know that won’t work for me, given the RH swings I (and everyone around me) deal with.

Yeah I guess it can still occasionally get low here
How much movement do you think it unavoidable or unacceptable?

If anyone has any plans to ever sell their instruments and/or perhaps gift them as well it's really a duty to do what it takes so secure a stable RH environment.

Not only do countless instruments split and crack on a lesser level in terms of damage even more instruments become unplayable with the strings coming down on the frets, fret ends sprouting out and the dome on the top collapses. Sometimes the tops even invert.

Common caused of bridges lifting are an instrument that dries out and was not built with proper humidity control making the thing a weather vane.

We have gigging musicians who found they could not gig with their small builder guitar because a proper environment was not strictly observed during construction and that results in the instrument changing it's set-up in only an hour or so once at a dry or humid gig.

So the answer has been and will continue to be we all have to do what it takes to secure our building areas at an acceptable RH. I built at 42% to 48% and if I did it again and I do from time to time having to replace a top or two on instruments who's top had to be replaced because of the builder not observing proper RH requirement I would lean toward the low side 40 - 42%.

Some of the violin guys will build even lower.

I've given a lot of advice here on the OLF in nearly the last 20 years with the highest post count by far of any member ever here. This does not count the many PMs I receive when I help people off the forum and some here are also Facebook friends who ping me there for advice and help.

So these same words as to RH I've said here perhaps over 100 times and nothing ever changes nor will it. It is what it is.....

Job one for anyone who wants to build guitars is to do what it takes whatever that means wherever they are to secure a suitable range of RH. Temps matter too especially for glues to cure properly and if you use a dehumidifier they don't work unless it's warm enough.

Lutherie is not a cheap hobby and before anyone drools over a Laguna or other bandsaw seal up your shops, obtain a quality hygrometer that can be calibrated, actually get two so you can use them to check each other. When I built I was humidifying in the winter and dehumidifying in the summer. Dehumidifiers produce heat and that has to be deal with too.

The concept of building in boxes or bags for storage I would not recommend and I've known of many people that this did not get them where they wanted to go.

Digital hygrometers almost always suck and can either be way off or way off in certain ranges. They use an electro chemical reaction that the chemicals break down in our experience as soon as three years out rendering them useless. Most digitals can't be calibrated or like the Caliber series only have 6% of calibration starting with the caliber 4 which may not be enough.

On the up side all that we do to secure the RH and temps in our shop translates to a very comfortable space for humans. Your tools will no longer rust and will look like new for decades.

I collect guitars and I used to build having built 54 1/2 before I went into the repair business which I found and continue to find requires vastly more knowledge and that makes it more interesting to me. When a client brings a guitar to be repaired at our shop along with around 1,100 other guitar repair clients annually they find a shop where the RH is close to 45% at all times and the temp is 70F in the winter and 75F in the summer.

When my friends come over to jam at my house my entire home benefits from a humidifier on my furnace that is for a 4,000 foot space, my condo is much smaller than this so it never has to work very hard. My home is at 45% RH year round and 73F in the winter (I'm old....) and 79F in the summer (I'm getting even older and always cold...).

It's the price we pay and it is a price to pay and I would imagine that through the years I've spent thousands on humidifiers, wicks, chemicals and what not.

But my guitars are always ready too play, strings last forever with no rust or corrosion and it's very comfortable for we humans in our shop for the business and in my entire home that also has a guitar shop in that is RH controlled too.

One last comment. One night nearly 20 years ago I had finished bracing a top for an OM and needed to do the final sanding and clean-up. I like the insides of my guitars to look like someone gave a **** about them so I am rather wrapped too tight about details. I thought what the heck I'll pour a scotch on the rocks and go out on my back porch over the pond and sand it while I had a drink.

In only 20 minutes the top with a 25' dome on it went completely flat. Within a few more minutes it went concave.....

It also ruined my drink.... So I brought it back into my shop and let it sit for several hours and it started to recover. Then I weighted it down in the radius dish I used, 25' and left it over night. It recovered fully the next day.

And really lastly a guitar that has not been built in proper humidity OR with properly seasoned wood will not only crack but attempts to close cracks will only transfer future stresses to other areas of the top and it will crack again and again. As mentioned the set-up will be a weather vane and there is very little that anyone can do to remedy this once it's been fully built.

So please everyone Lutherie requires some major considerations when it comes to the environment of your shop. It's not cheap or easy and depending on where one lives can be very involved. We just put a new humidifier in our business shop that cost us $2K, is made in California, uses reverse osmosis and then sends steam into the air. Works great but cost big bucks.

I hope something here helps but the real point if one only hears one thing from me is doing what it takes to secure a proper RH and temp environment in a Lutherie shop is unavoidable and should come before anyone ever builds anything but perhaps jigs.

Thanks

Heed the warnings of the Don and the Hesh! Wait… did I just invent a luthier based tv show where each week they kick in the door of your shop and chastise you for RH management and not using hide glue?

I have a tiny room in the basement where wood is stored and all bracing glue up and box closing takes place. It’s 42% & 72deg - 24x7 365.

It was designated this way because three of the walls are exterior (insulated), the concrete floor was coated with drilok, then subfloor with a vapor barrier installed, and finally LVP on top. The ceiling is acoustic panels though I’m not 100% sure if that does anything or not.



Hey, don’t forget the monthly zoom meeting is today.

Brad


Sent from my iPhone using Tapatalk Pro

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I heat and dehumidifier and have several versions of humidity meter, I've read many of your posts reiterating the importance of humidity control but realistically in Ireland most instruments are not kept in such conditions. They spend 80 percent of their life at 70+ rh and then then occasionally lower. Is the solution two saddles as standard?

I also don't understand why building at 45rh makes an instrument more stable through environmental changes. I understand it is a suitable mid point to avoid cracks in dry conditions. Why is your anecdotal small shop builder guitar so quick to dry or swell?

Ideally the guitar should be built at the humidity level it will live at. If the instrument lives at 75% +/- 10% or so year round I would build it at 75%. Yes, if it moves to a dry environment you will have problems.


Don is correct here. Manufacturers like 45% because they don't know where the instrument will end up and it's the most logical choice, shoot for the mid range and hope for the best.

Hesh's comment about digital hygrometers is so spot on. They are a hazard in your shop IMO. The amount they're off fluctuates depending on the temperature, the one I have fluctuates a lot. I have Abbeon hair hygrometer and digital. The digital can be spot on, or 20% low in colder weather.

I have seen a number of guitars that suffer from being exposed to high humidity for too long, they can be really distorted and peel off bridges due to the extreme convex shape of the top. In one case the body was like a blown up a balloon!

_________________
Jim Watts
http://jameswattsguitars.com

Most of the instruments are not kept in 40 - 50% in the US either but it was adopted as a suitable compromise for the variance in both directions of most conditions not only in the US but world wide. Martin uses the same numbers that I cited as do most guitar producers. They invest millions in their RH solutions in very large production facilities.

An instrument living in too much humidity to a point... is less problematic than an instrument drying out severely down in the 20% area. Structural failure will occur with the dry instrument where the over humidified instrument usually survives and can also often recover.

You might want to give George Lowden who is a very nice guy a call and see what he recommends for a suitable RH range where you are Mike? Since George builds for export it would not surprise me if he has a range not far off from Martin.

Some builders ship with a summer and winter saddle, I did that too but a better solution is to either keep it in a humidified case or humidified room and then you never have the set-up changing.

The dome built into the top is not just another pretty face. It's there for RH reasons so when the guitar dries the dome can shrink and the top to a point won't crack. So the point is how we build, many of the operations that we do such as inletting braces are also done with RH damage in mind as well as if the thing takes a hit.

Yes 45% is a suitable mid point now combine that with the knowledge that higher RH is not as problematic as low RH and that should serve you well.

There are places that building is not easy. You may live in one of them. Indonesia is another place where the RH can be nearly 100% yet they still build great guitars there but with strict RH control.

You asked why is the small builder guitar in some circumstances, not all by any means more prone to RH swings and damage? Because many small builders do not take RH control as seriously as they should and then they sell their early guitars. These instruments are time bombs and often so terrible in how they were constructed that professional repair luthiers won't touch them.

I have a client who paid $7K for a guitar made by someone who has produced over 100 instruments and his guitar cannot hold a set-up the wood moves so much. What often happens is they have it fixed and then it happens again and again because there was not proper RH control when it was built. Then they sell it to someone else dumping the thing. They also are not keen to ever buy from a small builder even the good ones again.....

There are plenty of quality small builders who can be trusted but there are also plenty of people who did not know what they were doing and decided to take money from others and sell them a problem.

I have not built since 2011 but I built 15 prototypes, gave three instruments to players and asked them to beat the hell out of it and give me data and then I learned from the data I received. I never sold my prototypes and most of them are in my living room right now. So I waited some years before selling, only sold my 16th and beyond and never, never, never sold commissions and refused to do so. I wanted a customer to sit in my home and play the exact same instrument they were asking to buy. I have always seen commissions as selling futures and stuff happens. People die, jobs lost, etc life's events if you will.

While all of this very careful approach to selling a guitar was happening with me taking me years to get through I also professionally apprenticed with one of the most skilled luthiers out there these days. He was professionally trained, now has 30 years experience, he professionally taught at a guitar building school and then he worked in a quality, large repair shop with some of the most respected Luthiers alive today. He's my business partner or was I'm semi retired now and a contractor only working morning 4 days a week but still repairing around 600 instruments a year myself.

Mike I took it as serious as a heart attack because I think that people who enter this trade have a duty to know what they are doing, be responsible and honest with people and proved real value.

My goal was never to build a guitar. My goal was always to build a very high quality heirloom instrument that with care should last 100 years.

RH and temp management are not something that would be nice to do - it's required if you want what you produce to be a quality wooden stringed instrument. This needs to be said and people need to have the expectation that building a first guitar is not a kit from StewMac.

There are thousands of dollars of tools that eventually are required. It takes years to learn and there is no escaping what humidity does to thin wooden plates.

On this forum we often witness someone new asking about what bandsaw they should get or how to build a spray booth but RH is neglected. But in my view the most important thing is to secure your building space so that when you measure a top across the lower bout on Monday and come back on Tuesday it has not moved 1/4" because it may..... Secure that same top to a rim and you may hear a loud crack at 3:00 coming from your shop.

One last comment for Jim. Jim my friend I disagree. Overly humidified instruments are not nearly as problematic as a dry guitar. I can slowly recover a wet guitar and the bridge usually stays put in my experience. But a dry guitar gets loose braces, fret end sprout, becomes unplayable with the neck in back bow and strings on the frets and the bridge patch shrinks at a different rate than the bridge lifting the bridge. As the bridge lifts the center seam or near it cracks on the top. It ain't pretty....

Not recommending building wet but I think that a guitar built in 42 - 48 or 40 - 50 should be OK at 70%. I would keep it in a case though and use D'Addario's system to knock the RH down when it's in the case.

The small builder’s guitar built in a humidity controlled environment is likely to have thinner plates and thinner finish than a factory instrument. As such, it will absorb and release moisture from its components faster than that instrument with thick finish and parts. A responsive instrument is more likely to be responsive to environmental conditions as well as to the player’s touch.

Hesh, I wasn’t trying to say over humidifying was worse than under humidifying. They’re both problems. And they manifest themselves differently.

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Jim Watts
http://jameswattsguitars.com

Jim I understand and I am trying to say that a dry guitar is less problematic than a wet one, generally.

That makes sense to me thanks.