Humidity

[Adam Sandler]

So I have gone a little humidity obsessive lately? I bought a dehumidifer for my basement (where I would like to store...ranges from 40%-55% right now) casue it was to humid. I bought a humidifier for my bedroom (where I currently store...ranges from 35%-50%) becasue it was to dry. Can anyone help me out with the ranges of humidty and what they will do to guitars? And would be a good % to keep these rooms at?

[fryovanni]

The main goal of control will be to smooth out seasonal changes a bit during construction(and depending on your normal humidity levels help with curing glues and so forth). To give an extream example; if your ambient humidity in your area in the summer was say 80%+ and your wood was aclimated to that level of moisture(it will be stable). You will have issues with glue curing properly though. If in the winter the normal humidity levels drop to say 40%. The wood will have to reject a fair bit of moisture to stabalize(and this will leave you working with wood that is constantly making large changes-not real good). If your "normal" humidity is in the 40-60% range you should curing should not be an issue, and that is not going to be too radical from season to season(mind you temp. can play into how agressive the changes are in terms of acceptance and rejection). If you want to control your shop to keep it pretty even(that is the key) it will be good. Unless you have a compelling(curing issues etc...) reason to drop the moisture significantly, don't do it. After your guitar is done it will leave your shop and be subjected to aclimating to whatever humidity it lives in. No finish will stop the seasonal transfer of moisture(film finishes retard the process that is all). A good humidity range for your shop can vary with depending on where the guitar goes after it leaves your shop. If you are manufacturing guitars in the middle of the desert and shipping them to everglades for use(you best be thinking about what that will do to them while they aclimate). If you are in a moderate climate your normal ambient levels may be the best level to maintain(less radical the change the better). Try to not get too caught up in following what a manufacturer may choose to do, as it may not be the best choice for your situation.

Give some more details on your normal amb. humidity in your area from season to season. Tell us what you do with the guitars after you are finished with them(do they stay in your area, or do you ship them all over the world). Have you checked your meters to be sure they are even reading correctly if you are trying to maintian such tight control(+/- 5%). Try placing the meters side by side in the same area to compair there reading if you have not yet.

Peace,Rich

[Adam Sandler]

My area ranges from roughly 33%-69% (51% avg) in the winter and im sure its a little higher in the summer. All my meters are reading with in 5% of each other so i am taking the average of those and coming up with a rough idea of what it is in the rooms. It gets kind of dry in the upper (30%-40%) level of my house during the winter casue of the heat though. Im not shipping my guitars anywhere. They just go back in the causes, although I am going to California with my Les Paul in February. Gibon told me they keep there factory at 45% and 70 degrees which I am trying to replicate.

[fryovanni]

To tell you the truth. Shooting to hold 45% at 70 in your climate is probably not that big of a deal compaired to what your house is going to be at naturally. If I were you and basically my normal humidity is very similar to yours. I would not be extreamly worried about the changes given you have the wood in a temp controlled(and humidity controlled to an extent) in your house. The actual movement you will see in the wood after it has stabalized to your workshop vs a 70deg. 45% workshop will be very slight. I would even suspect your greatest changes may occur in transit to the other shop. Anyhow... here is a link to a great source for info-click .

P.S. Generally the moisture content of wood I keep in my workshop stays between 6-8% moisture content(generally closer to 8%). I do not really take extra ordinary measures to control humidity. The one time of the year I am generally the most concerned about is the summer when the air conditioning runs for a couple weeks. The house gets notably dryer during that time and warmer and dryer air can really dry things quickly. It is not a problem for the wood that has been in my shop and is staying put. However shipping wood to other places or bringing in new wood that is not aclimatized yet is more touchy.

Peace,Rich

[Mattia]

Important thing some other kind folks just reminded me of: Humidity means diddly without temp. My workshop/shed is currently around 85-90% humidity...when the temperature is not all that far above freezing. Kick the temp to something comfortable, and the humidity drops.

ie, it's actually quite dry in there. Which is what it feels like.

[Adam Sandler]

To tell you the truth. Shooting to hold 45% at 70 in your climate is probably not that big of a deal compaired to what your house is going to be at naturally. If I were you and basically my normal humidity is very similar to yours. I would not be extreamly worried about the changes given you have the wood in a temp controlled(and humidity controlled to an extent) in your house. The actual movement you will see in the wood after it has stabalized to your workshop vs a 70deg. 45% workshop will be very slight. I would even suspect your greatest changes may occur in transit to the other shop. Anyhow... here is a link to a great source for info-click .

P.S. Generally the moisture content of wood I keep in my workshop stays between 6-8% moisture content(generally closer to 8%). I do not really take extra ordinary measures to control humidity. The one time of the year I am generally the most concerned about is the summer when the air conditioning runs for a couple weeks. The house gets notably dryer during that time and warmer and dryer air can really dry things quickly. It is not a problem for the wood that has been in my shop and is staying put. However shipping wood to other places or bringing in new wood that is not aclimatized yet is more touchy.

Peace,Rich

Isn't that pretty much desert dry (6-8%)???

[fryovanni]

To tell you the truth. Shooting to hold 45% at 70 in your climate is probably not that big of a deal compaired to what your house is going to be at naturally. If I were you and basically my normal humidity is very similar to yours. I would not be extreamly worried about the changes given you have the wood in a temp controlled(and humidity controlled to an extent) in your house. The actual movement you will see in the wood after it has stabalized to your workshop vs a 70deg. 45% workshop will be very slight. I would even suspect your greatest changes may occur in transit to the other shop. Anyhow... here is a link to a great source for info-click .

P.S. Generally the moisture content of wood I keep in my workshop stays between 6-8% moisture content(generally closer to 8%). I do not really take extra ordinary measures to control humidity. The one time of the year I am generally the most concerned about is the summer when the air conditioning runs for a couple weeks. The house gets notably dryer during that time and warmer and dryer air can really dry things quickly. It is not a problem for the wood that has been in my shop and is staying put. However shipping wood to other places or bringing in new wood that is not aclimatized yet is more touchy.

Peace,Rich

Isn't that pretty much desert dry (6-8%)???

Moisture content of the wood(6-8%). No that is not dessert dry. You can force wood to near 0 moisture content, but it is not a real good thing. You must have taken that as ambient humidity of 6-8%.