Fretboard care question

**Jeff May** · Jun-16-2012, 2:16pm

I have a question about oiling the fretboard and humidification. Here's where I'm coming from:

Over the years I've had a few mandolins, a couple Webers, a couple KM1000s, and some less expensive Kentucky and Eastman models. The Webers and the KM1000s all had ebony fretboards. The entry level Kentucky models, which I still have, are rosewood, and I don't remember what the Eastman had, I think ebony. I also have a few guitars in the house that have rosewood fretboards.

I've been pretty diligent about keeping case humidifiers in all my more expensive instrument's cases, and I keep them cased unless I'm playing them. The fretboards on both the KM1000s I owned dried out in less than a year and developed that "scalloped" look, with the fret ends sticking out; the classic under humidified fretboard thing. I never had any humidity-like issues with any of the Webers. The less expensive Kentuckys have never been humidified and have never (yet) developed drying issues. I assume this is because of their heavier build and the rosewood boards being less prone to drying. The guitars I have likewise have never shown any signs of being under-humidified.

I've been told that I haven't had drying issues with the Webers because they're built near where I live and so they're acclimated to local conditions. I've also been told the KM1000 fretboards must have been "green" or something. I have no idea if that's likely or not.

I now have a couple of new (to me) mandolins, both of which were not built in my dry climate, and both of which have ebony fretboards. I'm a little paranoid about them drying out. So, my question (finally) is what else can I do to prevent the fretboards from becoming overly dry? I'm using Oasis case humidifiers. I add water every week or so and I change out the little crystals every year. Would treating the boards with something once or twice a year provide added protection against drying, or is that more of an aesthetic thing?

**Pete Summers** · Jun-16-2012, 2:43pm

I can't really answer your question, but I think most wood things like a relative humidity of around 40%, which is also comfortable for people. That's the level of humidity that humistat type humidifier systems installed in pianos maintain.

Perhaps a room humidifier would help if it's excessively dry where you live? I would think the case humidifiers would work also if you have one for each instrument as long as you remember to fill them.

I live in Missouri, so adding humidity around here is tantamount to pouring water into the ocean. It's routinely 80% humidity or higher, and rarely goes much below 40 percent.

**Justin E.** · Jun-16-2012, 3:27pm

Some use oils, like lemon, tung or boiled linseed. Same say not to use them, that they'll mess up nitro. Planet Waves makes a fretboard conditioner that might work for you.

**Ivan Kelsall** · Jun-17-2012, 3:03am

Jeff - I've used natural Teak oil on all my instrument fingerboards for close to 50 years.In my case,it's just to keep the f/board from loosing it's colour due to skin oils from my fingers & to retain a good colour. In the UK,we don't suffer the extreme humidity that you folks in the US get from time to time. My feeling is that the application of natural wood oil,such as Teak oil to a f/board,will help it retain the moisture within it.For the very small amount of time it takes to apply it,why not do it a couple of times a year. I remove all my strings,polish the frets to get rid of any crud & apply Teak oil 3 or 4 times a year - it's worked fine so far. Stay away from Linseed oil though,it gets a sticky as h**l,
Ivan

**sunburst** · Jun-17-2012, 10:46am

Wood reaches equilibrium moisture content (EMC) in the relative humidity (RH) in which it is kept. In other words, once a piece of wood is dry, and has been kept in say... 40% RH, the EMC will be about 8%. EMC will be higher in higher RH and lower in lower RH, but equilibrium will be reached in time. As you may gather, if the instrument is being moved from places of differing RH, or if the RH changes where the instrument is, the moisture content of the wood will change, and may never reach EMC because it may not stay in the same RH long enough. The wood can be constantly changing, in other words.
When the moisture content of wood changes, it shrinks or swells. Wooden fingerboards change in MC in response to RH, so they shrink and/or swell. If the RH and MC are constantly changing, the fingerboard wood is constantly moving. Oils and other treatments don't change that. Fingerboards do not dry out beyond EMC, though if the RH is extremely low, the fingerboard can become overly dry, leading to protruding fret ends and sometimes fingerboard cracks.
Woods are different in their stability, meaning different woods move different amounts in response to MC, and woods move differently in different directions. East indian rosewood is quite a bit more stable than ebony, and ebony is quite a bit less stable when "flatsawn" as opposed to "quartersawn". Horizontal grain and vertical grain, that is. Ebony trees are small, and finding large quantities of good quality, vertical grain ebony fingerboards is difficult, so manufacturers (and in fact small builders) often use horizontal grain ebony for fingerboards. If the fingerboards have a high moisture content at the time of manufacture, the fingerboard will shrink, the fret ends will protrude, and the 'board may crack. Applying oils and/or other treatments will not prevent or remedy that.
The best fingerboard treatment starts with the maker, using good quality, sufficiently dry wood, and continues with the owner, maintaining good levels of RH as much as possible (40% to 50% is ideal), and keeping the 'board clean. Wood does not need oils, wood is dead and does not need to be "fed", finishes only slow down and do not stop moisture movement in and out of wood.
If you like the look and feel of a light fingerboard treatment of some sort, it does no particular damage used sparingly, but no treatment beyond proper storage and cleaning is needed. I use Fast Fret, or more often Tibet Almond Stick occasionally to help with stickiness when playing in high humidity, but those are substances that evaporate, at least mostly, and don't build up in or on the wood of the fingerboard.

**Jeff May** · Jun-17-2012, 1:54pm

Thanks for the responses: I'll continue to use the case humidifiers and do the oiling/cleaning thing once or twice a year.

I guess what I was told about those KM-1000 fretboards being "green" was more or less correct.

**Greg Mirken** · Jun-22-2012, 12:25pm

Ivan, so-called teak oil is not a "natural wood oil". It is no more made from teak than baby oil is from babies. If you do a search for "teak oil msds" (for material safety data sheet) you'll see that these products are typically mixtures of kerosene and linseed oil. That being said, a light annual application does no harm and it does a pretty good job of liquifying finger-grunge buildup.

**Folkmusician.com** · Jun-22-2012, 6:14pm

Baby oil is not made from babies? I need to start paying more attention to ingredients!

In Montana, Weber would be pumping quite a few gallons of water a day into their shop. I would be surprised if they do not keep it up close to 50% RH (as any builder should). Our 1500sq ft in Reno, NV requires 3+ gallons per day to maintain 45-50% RH.

If you do not already have one, try sticking a hygrometer in the case and seeing what is going on. You can get a fairly accurate digital version for $25 or so.

**Ivan Kelsall** · Jun-24-2012, 3:18am

Greg - On the bottle of Teak oil that i have,the ingredients are listed as 'Natural oils derived from wood' & a 'blend of solvents including Naptha'. Admitted,the wood may not be actual Teak,but it's some type of 'wood oil'. However there may be several different 'flavours' of so called Teak oil & i take your point.These days 'Aromatherapy' uses many 'wood derived' essences (Oils) & i've often wondered re.their use on fingerboards - Aromatherapy while you play - mmmmmm !,

Ivan