Building for a dry climate

[Nate Scott]

I'm beginning work a guitar that will live in a dry mountainous climate (Colorado) and part of the year in San Antonio, Texas. In such cases, do folks here alter their build approach to mitigate future low-humidity issues?

A quick survey of major builders' sites indicates that most are building in the 40%-49% RH range. The stand-out exception is Froggy Bottom; they report building in sub-20%-30% range (http://froggybottomguitars.com/The-Frog ... asics.html).

The wood I'm using is well dried. My shop environment is currently kept at about 45% RH/20-degrees C. I'm wondering if I should build it drier or consider sealing the inside. I'll certainly educate the owner about proper storage and humidification.

[Michael Lewis]

Make sure to use a significant arch in both plates, and dry your wood to about 8% moisture content. Wood kept in your 45% RH shop will generally gain up to 12% moisture content, even if previously dried to much less.

[Gordon Bellerose]

I live in a fairly dry climate. We do get rain fairly often in the spring, but the summer and fall are typically dry.
Our humidity can fluctuate from 20% to 85% in a day, and stay in either place for weeks.

I think storing a guitar properly, and letting it acclimate slowly is the trick. If you were to take a new guitar manufactured in a damp climate, out of the case and stand it in a corner, the top would almost certainly crack.
Alternately, trying to keep it in the 40% range perpetually is not feasible.
All I do is bring my instrument out to play, and then back into its case for storage, with a Planet Waves humidifier.
Sometimes the humidifier runs dry for a few days, or even weeks, but once the guitar is acclimated, it should be fairly safe.

[Glenn Johnson]

I live in a high humidity climate so I use an air tight box and store the back and sides with the braces in it with a reusable desiccant I bought from amazon for a couple of weeks. Then I glue the braces after I know they are dry then put them back in the box with the desiccant until I am ready to glue the top and back to the sides. This way I can be certain that the guitar can survive in a dry climate.

I have one of my builds with me In Vacaville CA at up to a 106 degrees now for five weeks out of the case it is starting to show a little grain ridge on the top but no cracking or any other problems although top arch has reduced slightly lowering my action a little. It was built in Washington in the fall where our humidity can reach 98% and most likely did while it was being built.

[Phil Walsh]

I've started bracing tops and backs in the winter, when the humidity in my basement shop is around 40%. I've not had a cracked top since.

Sealing the inside is not a guarantee; it's pretty much impossible to completely seal wood.

[Michael Jennings]

I do the same Phil up here in the pacific NW… Bracing is a winter project.

Mike

[Todd Stock]

I brace at 38%-40%, and finish at 40%-45%. If necessary in the summer, I run the central A/C and two dehumidifiers to dry the shop to the low number...in winter, just a case of shutting down the humidifier in that portion of shop. If I know the instrument will live in the usual range of 20%-80%, that works; consistently dryer and I'd have to consider bracing at 30%. What are the RH ranges in the customer's home(s)? Usually very different from outdoor RH.

On bracing at low RH...some folks brace at very low EMC and RH on what is essentially a flat or large radius (60') surface, then humidify...easy way to get a nicely radiused top that will go to no more than flat with a big swing down in RH. Sort of a prestressing process.

[Mike Ryan]

I am in southern Arizona and build at 35-40 percent, but have only finished 3 since coming down here up to 2 years ago. No cracking etc. yet but my whole house is at 35%. Getting up to 45 is impractical in my shop.

[Stephen Neal Saqui]

I've lived in Central Idaho for 10 years. Humidity in the shop averages 25% and I build at that. My wood sets are kept in the shop for a few months before I use them so they're acclimated when I build. My customers travel and have reported the guitars remained stable everywhere. I arch the top braces at 25" radius and the back braces at 16". My radius forms for glueing match the arch of the braces.

I've read the literature for years and believed it but I'm also a Martin Warranty repairman and constantly get Martins in with collapsed tops. Same with Taylor's. These educated folks are building their instruments too wet!

My suggestion is that if you can maintain 35% in your shop, then build the instrument at that once the wood has acclimated. Then for your own edification, build another guitar in the same manner and observe it's behavior.

There are others who build dry and having great success with it.

[Stephen Neal Saqui]

I've lived in Central Idaho for 10 years. Humidity in the shop averages 25% and I build at that. My wood sets are kept in the shop for a few months before I use them so they're acclimated when I build. My customers travel and have reported the guitars remained stable everywhere. I arch the top braces at 25" radius and the back braces at 16". My radius forms for glueing match the arch of the braces.

I've read the literature for years and believed it but I'm also a Martin Warranty repairman and constantly get Martins in with collapsed tops. Same with Taylor's. These educated folks are building their instruments too wet!

My suggestion is that if you can maintain 35% in your shop, then build the instrument at that once the wood has acclimated. Then for your own edification, build another guitar in the same manner and observe it's behavior.

There are others who build dry and having great success with it.

Correction: I meant to say, Build a guitar at 35% (with the wood acclimated at 35%. Then build another guitar in the humidity that you normally do and observe the behavior of both instruments in different humidities.