I'm building a big library for a client who keeps his home in the
winter at 20-25% relative humidity (RH). In the summer he says it's
around 50% -- which is fine -- but will I run into problems if I
deliver the cabinetry at the low RH? I know the finish will temper the
wood's gain or loss of moisture, but the extremely low RH concerns me.
BTW it'll be built of cherry.
Only if you offend the cross grain gluing god.
Just this morning checked some of my early furniture pieces at the
point in my woodworking life where I ignored the laws of cross grain
gluing and offended the gods. Cracks are at their widest point
currently, but will disappear by summer. :~)
There are other issues than just gluing...if you're using
stained/coloured solid wood panels then make sure you stain/colour the
panel before assembly so that if the panel shrinks the newly visible
bits are also stained.
If you build at the low RH (and the wood is fully acclimatized to the
lower RH) then this won't be a problem as the panel will be basically as
small as it ever gets. Otherwise, it should be considered.
I can see this issue with my kitchen cabinet doors right now...they must
have been made in the summer.
Yep, made all my bathroom cabinets in the summer, can currently see
that line, been meaning to touch that up........oh, well, Spring's
right around the corner......but I better take down that bathroom door
and plane the edge so I can close it this summer.....
Thanks for all your info. I have decided to invest in a dehumidifier
for the shop, just in case!
I looked at the RH/moisture content charts and decided it should not
be a problem. By the time the piece goes in, spring will be around the
corner and the RH of the house will be on the rise - the cherry won't
feel the effect much if at all.
Another insurance against problems: I bought quartersawn cherry for
the door panels, drawer fronts and countertop. Should look pretty
According to Hoadley, for relative humidity varying between 25% and 50%,
you're looking at an equilibrium moisture content for typical wood
species varying between 5% and 9%.
For black cherry in the tangential dimension you're looking at roughly
1% change in size. In the radial dimension it'll be about half that.
Plan appropriately for wood movement, and you should be fine.
Indoors relative humidity in Winter is normally 20-30% in North Carolina
where I am. It's not "keeping it at ...", it is that low because of the
lower outdoor temperatures. Colder air cannot hold much moisture and so
when you bring it indoors and heat it up, it is generally very dry. The
colder the outside air, the drier the indoors air will be.
I concur with the others: Build it with attention to crossgrain issues and
you should be fine.
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