Official Luthiers Forum!

http://merv.metr.ou.edu/weather/run12z/zz_usa_rhum.html

I really 'want' to glue up today, but this chart says 'wait till late Sunday, it will be 'green' zone!

This looks pretty accurate for Colorado. I am hoping to glue up some stuff Sunday, and this says that I can!

I want a good 45%, no more to account for inaccuracy in the dial.

Anyone want to chip in on the accuracy/inaccuracy here of these charts, just post.

Humidity can fluctuate throughout the day and vary from one location to another around the house. In my basement shop I have to run a dehumidifier to keep things dry even when the air outside is at 45%. Then during the winter the reverse problem arises because the indoor temp is so much higher than that outside. I suggest getting a good hydrometer. Radio Shack has decent ones for not too much money. That will be the most important tool in your shop.

First, the outdoor humidity on the weather charts doesn't tell anything
about the humidity of the area where the wood is stored. If you have
closed windows, heat, air conditioning, etc., than those charts will mean
little to nothing in relation to building.

Second, humidity at the particular moment of gluing something up will
mean relatively little as well. What matters is the moisture content of the
wood, which will be dependent on the humidity it has been stored at over
the past days, weeks, or even months depending on it's thickness.

Weather charts of a particular hour on a particular day won't really tell
you anything about the condition of your woods. You just have to monitor
and provide proper storage conditions in the weeks leading up to gluing
up. Either that or work with a system of baking or drying out your woods
immediately prior to glue up, which is another system and set of
procedures all together.

_________________
Eschew obfuscation, espouse elucidation.

Wally world usually carried whirlpool dehumidifiers, and their prices are not too bad. I got a rather large one, all stainless steel, for around $100. It is one of the best investments I have made and keeps the shop good and steady as far as humidity.

*note*

You may not know it, but if you bring in large volumes of wood into your shop, you may run into the issue of acidity in the condensed water vapor in the air. The water that is drawn out of some woods is quite acidic and may harm some dehumidifiers. I do alot of woodworking besides guitars, so there are times when I may bring in a hundred board feet of lumber. This is why I went with a stainless dehumidifier.

Here in Florida I dont have the issue of low humidity as it is always high.

_________________
Reguards,

Ken H

I never knew about the "lead up time issue" for glue up. Now I will have to store everything in a humididty controlled box?

it never ends....

Basicly, Im in a garage in Colorado (dry) with a crappy door that is more or less humid to what the outside is, and I have no humidity control exept for a humidifier, which I havent used yet,and yea, it fluctuates daily etc... but if you look at that chart, in Colorado, it gives a relative good picture of what tomorrow will be, as well as a few days out. By Tuesday, it will be crap, 60% or more. My normal humidity is pretty constand around 45% in my area these past few months according to my hygrometer.

If people do not use indoor humidty control, this chart may provide a good window as to when it will be acceptable to glue up. I guess most people get the dehumidifer going. I really dont need one here, but if I move up the front range, I might.

 

 

 

 

It really is much more important what the humidity in your shop is than what the outside RH is.  Even in your garage with it's lousy door, the humidity will be different than it is outside.  Those national charts are useless for that info.  Get yourself a  hydrometer so you can see what your workspace humidity levels are.  It is probably the most important tool you will have in your shop, at least it is for me.  Yes, a lot of builders who have humidity issues do build a small storage area for their wood and parts that are being built so they can keep it in a humidity controlled space.  It is a lot easier to control the humidity in a box than it is in a big leaky garage.  My shop is in a big leaky 150 year old barn with no heat or cooling.  I built an insulated sealed and heated closet that I can store my stuff in during the winter months. I can control the temperature and humidity in there a lot easier than in my shop.  During the summer I can run a dehumidifier and keep the shop in the 40-45% range pretty easily so I can leave my stuff in there but in the winter, everything goes in the closet.   Being in CO where the typical humidity is very low, I wouldn't even think about bracing a guitar when the RH is 60% because you know as well as I do, the RH will be back down in the 30% range in a day or two.  That is a recipe for big problems.

Having lived in Colorado most of my life, I find it odd to hear about having a de-humidifier there.  When I lived there, dryness was the big problem and getting a humidifier was more the norm.  Heck, until I moved to upstate NY, I had never even seen a de-humidifier!    The biggest humidity issue I had to deal with in CO was learning how to walk across the carpet without shocking myself onto the floor when I touched a doorknob!

[QUOTE=John K]I suggest getting a good hydrometer. Radio Shack has decent ones for not too much money. That will be the most important tool in your shop.[/QUOTE]

Unfortunately, like most of the useful products it once sold, Radio Shack no longer sells hygrometers. They have two listed on their Web site but both are out of stock and I have not been able to find them at any of the stores in the area.

Jim

Why? Because it lets people falsely believe that they can be fair weather luthiers.

I think Im a bit spoiled, the hygrometer is generally around 45% all the time.

So basicly, the humidity was about spot on today with the map. Drove around and it was in the low 40's as predicted by the map. I'm in the "Gibson corridor" of the Rocky Mountains, so fair weather luthieri is the name of the game. The needle was pegged at 45% for the past 3 months.

There is about a 5% rise on the inside, but for general, for today, the map was accurate. Tuesday is like, dont even think about it. so I will be watching this map every day, and taking care to deal with the wood when its optimum. I guess I do need to rig up a nice storage cabinet for immediate use wood.

Always something new. At least I will know in general when and when I wont be able to glue up, or anyone who does not have a dehumidifier. I may get one down the road.