Humidity !!?

[dead_eye]

I was just on another forum,an acoustic forum and we were discussing humidity problems with acoustic guitars,are semi hollowbody guitars like our Rics just as sensivive as the acoustics?
Paul

[jingle_jangle]

Well, Paul, a statement like "just as sensitive" is hard to quantify, but look at it this way:

A Rick semi-solid is a beautifully-sculpted assemblage of many carefully-fitted-together pieces of hardwood. I'm not privy to what sort of glue is used; I would think that it's a water-soluble yellow wood glue rather than a casein glue or epoxy like Araldite. After all, the joint must be finished and it must "move" with the wood pieces it's joining.

The outside of a Rick receives what is essentially a non-porous finish that's incredibly glossy and durable. But look inside those cat's eye sound holes and you'll see a lot of raw hardwood, which absorbs moisture from the environment which the guitar is in. It's not live wood in the sense that it's growing and adding cells, but it IS an organic material (that's its beauty, after all). There is no question that once you get to know your Rick hollowbody, you will notice that it plays and sounds different in different levels of humidity. In most peoples' opinions, they play and sound better on "dry" days.

But, although moving from dry to wet surroundings will eventually take its toll, this adjustment to humidity will usually happen slower than the thermal expansion and contraction that goes on when temperature changes are forced upon a guitar.

Prolonged exposure to very wet and salty environments is the worst thing that a guitar can experience, unless it somehow is immersed in water or left out in the rain.

Because of the slower trauma to the unfinished wood, guitars are more tolerant of minor and gradual changes to humidity.

BTW, it's mostly the raw wood on the inside that gives a Rick hollow/semi hollow that wonderful smell when you open the case, along with some other undefinables (oil? wax? rubbing compound?). Solidbody Ricks are not nearly so memorable to the nose.

[loverickbass]

Why isn't the inside sealed with a clear coat or something like that? I'm thinkin' that you are probubly going to say that's a tone killer.

Cole

[billikenn]

Unless the finish hardens completely by chemical reaction and no solvents are used to thin it, it will be porus to water vapor.
Almost all finishes are porus on this level, exception would be a super high quality epoxy finish. but then if the viscosity is too high to spray your gunna add a solvent to thin it anyway, which will create pores big enough for water vapor when it evaporates out of the curing finish.

Finish will impede humidity diffusion, but not stop it.

to coat the innards would have little or no effect on theoverall concept. Your guitar will still increase and decrease in moisture content.

not to mention, finishing the inside could prove difficult.

.. if paint was that big of a tone killer on ele guitars, all would be naked.

JP

[jwr2]

yes ... rics are sensitive to humidity ... there are places for water vapor to enter and exit your Ric ... under the plastic, or chrome or other places ... most of my Ric basses shrink in the winter when it is dry and expand in the summer when it is humid ... I have to do setups twice a year on most of my basses ... sometimes it is as simple as raising and lowering the bridge ... but usually it involves truss rods ...

my old 1968 4001 went 30 years without a truss rod adjustment ... also my stripped 4003s5 that is now finished in tung oil seems to be more stable than my basses with factory finishes ... my new 4004C is shrinking the fret ends started to protrude from the side of the fret board and the neck bowed a little as it shrank ... I adjusted the trussrods and ground the metal ends down ... I think it is still adjusting ...

I was talking with Jaymi and we are thinking that basses that are stripped and allowed to dry out sound better with the "seasoned" wood ...

I like the woody sound of tung oil finished basses ... I have a 4004c and a 4003s5 that are finished in tung oil ... they both sound really nice ... the glossy finish adds a little weight to the instrument and changes the tone ... it will bring out the highs and lows ... the oil finish seems to bring out the mids ...

[jingle_jangle]

Josh, you are basically right (by my own experience) but your concusions don't go quite far enough, and are a bit absolute.

If there's one rule of wood finishing which guitar makers break as a matter of course, it is this:

"To prevent unequal stresses and resultant distortion on a piece of wood, whatever you do to one side, you should do to the other."

ALL finishes are porous. Porosity is a matter of degrees. Your statement about epoxy being nonporous unless it it thinned by solvent, at which point it becomes porous, is nonsense. Ricks are finished with a catalyzing "conversion varnish", which for all practical purposes, is non-porous. Solvents used for spraying, evaporate as the first stage of a catalyzing finish's curing process, which is characterized by a chemical reaction and the result is that the molecules cross-link and convert into a tough, flexible film.

The insides are raw and very, very porous. I do believe that the guitars would lose a percentage of their warm, "woody" tone if somehow the insides were sealed. Sealing accomplishes little and raises a whole raft of problems of its own, mostly sonically speaking.

Jeff, your experiences jibe closely with my own over 40 years of owning guitars. I've lived in Pasadena where it's often dry, in Chicago where it's always "damp", and in Brazil where the atmosphere is salty hell and 90% humidity + all year round. My Ricks reside in N. California where things are usually around 40-60%. I too can see day-to-day differences in the surfaces underneath the varnish on both my new Ricks, just catching reflections across the flat areas. Note that it might be 60% humidity outdoors, but once you're inside a heated space, humidity drops precipitously and averages barely 10% without the addition of a humidifier.

Old-fashioned finishes like the labor-intensive French polishing which was done on stringed instruments as well as on furniture, were much more porous than current high-gloss polymers. Still, many older French-polished instruments aged badly due to climatic changes. It is a tiny minority which remain playable to this day.

[dale_fortune]

Rick uses Tite-Bond an Alphetic Resin Glue. Water soluble but once dried it's very stable to humidity. It is not practical to even try to spray the inside of any guitar to seal it. On acoustics it would bring out more high tones as the sealer creates a smooth surface and the natural wood resonates a warm tone. If properly stored in your case or in the house you shouldn't have any serious problems with humidity.

[jingle_jangle]

The man speaks!

Thanks, Dale. Titebond is the yellow wood glue to which I refer in my first post above. Thanks for verifying this, and for expressing better than I did, the result of sealing a guitar's inside (assuming it could even be done!): losing the warmth and gaining harshness, which Dale characterizes as an increase in high tones. Proper storage is the cue here.

[billikenn]

Paul, its true about the finishing both sides, but is this case the thickness is such that the moisture content gradient caused by one side being unfinished is minute. Unless it is exposed to a vast change in humidity. The problem arrises when one side of a board consistently has a significantly different moisture content then the opposing side.

I was unaware of conversion varnishes being a 2 part system. I just assumed a system of that nature would be avoided due to the complications it brings. That was my own undoing.

As to the pores caused by solvents, that was what an "expert" told me when I was searching for a vapor barrier in a finish a couple years back.
I guess if the chemical reaction reduces viscosity enough before the solvent can evaporate, it would be possible that holes would be left that the now firm fluid could not fill.

If that actually ever happens(seeing how most of the reactions are exothermic) is another question, one that is beyond me.

JP

[jingle_jangle]

Josh; you are correct about the two-sided moisture thing; that's why I didn't attempt to expand (no pun intended!) on that topic. The small difference you cite is still enough, given sufficient time, to mess things up, finish-wise, though. The curved surface of an archtop or carved/shaped guitar (like a Rick) is also by nature more stable structurally than a flat surface, so it's less likely to warp. Problems are more commonly neck shrinkage or fingerboard separation as Jeff describes, or binding deterioration or separation problems as are so common on vintage Gretsches.

In my experience, "conversion varnish" is a generic term for a type of woodworking finish that cures with the addition of a chemical catalyst, as opposed to one which air-converts, like older-type alkyd varnishes. I welcome enlightenment or expansion on this.

[sinjunkie]

is there a product or technique that you endorse to maintain a specific humidity level while your guitar is stored in the case?
or is it best to just let it find its own place?
also I was thinking are all theses neck problems and settling in troubles that I've been reading so much about possibly be due to the wood not being aged correctly or forced dried too quickly?

[admin]

David: I have a humdifier in the room I keep my guitars. I try to keep the humdity in the 40% range in the winter months as it gets very dry at -20C. A clay pot humidifer in the case also works very well. You just have to remember to resoak the clay pot every two weeks.