Brian Gray
Posts: 339
Joined: 2004-01-21
Location: Sandusky, OH
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Recently, I moved my shop to a new location, and one thing that's underway is controlling shop humidity....new doors and windows along with proper insulation are the remedy...the doors and insulation is done, and even though the windows aren't finished, I've reached a point where I've got enough weather-resistance that I can control the humidity pretty accurately.
I've been reading a lot about humidity lately, and I noticed an article in Fine Woodworking #39 that raised my brow.
Hoadley mentions that urea-formaldehyde glues will not bond well if the wood is DRIER than about 7% moisture content...therefore, a shop with less than 40% relative humidity may not be ideal for storing wood that will be adhered using urea formaldehyde.
Now keep in mind that this article was written in 1983, so I'm thinking that technology involved with urea formaldehydes has remedied this problem....so two questions...
1. I assume that his statement no longer applies to urea formaldehyde glues and it's just outdated...True? False?
2. Is humidity any concern at all with Unibond? Is there a wood moisture content level too high or low for Unibond?
Also, as a side note, I thought I'd share something that I've learned (or at least was reminded of it's importance...) through my recent readings...
As people who do a lot of veneer work, relative humidity of the area that we store veneers and substrates is a lot more crucial than what we may think. The problem comes from the fact that veneers will reach their EMC (equilibrium moisture content) much much faster than hardwood, or whatever man-made substrate we use.
So let's say that we store our veneer and substrates in a more humid storage area. When we move our veneers and subtrates into the shop to start the project, the veneer may literally reach EMC within an hour, whereas the substrate will take weeks or months. This could lead to some major movement problems if we aren't aware of it, and don't allow proper drying time for both materials to reach EMC. I guess that my point is that relative humidity is of much more important to the person who does veneer work, than someone that uses only solid stock with no veneer.
Just thought I'd share...monitoring my current humidity situation has led me to rethink and re-learn some things....for instance, I think that I'm going to do my best to make room in the shop for veneer and lumbar storage. Originally, I thought that I'd put it up in the loft, but there's no humidity control up there....
bg
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