reelinron wrote:
OK, I guess I'm the odd ball here.
I have always put finish on the inside of my case goods and all parts of drawers. I see no reason not to.
I can't see going through all the work of building a piece of furniture and skimping in the finish. Are there any real advantages to not putting finsh on those parts? Dirty fingers on unfinished drawer dividers will leave dirt marks over time that might not happen on finished wood.
As far as the humidity equalization thing, I have seen boards with paint or finish on one side warp. I even did some one year to see what happens as a lesson with my students. Now on a properly made piece, the joinery may hold everything from warping, but there must be some stress on the pieces.
My two cents.
You're not the only oddball here, Ron.
There's so many variables that can cause problems later on, that I'm thinking that some of what is said below is probably true - that problems blamed on not finishing both sides equally may very well be the result of wood quality, construction technique, and so on. Some of the pieces I'm using on this project have shown internal stresses when cutting, so I'm taking account of that as best I can, by letting it rest for a few days then straightening with a handplane, before assembling. I expected some of that due to the fact that some of the walnut has fairly decent figuring and/or knots, which always indicates internal stresses.
Anyway, here's what someone said on another forum (I edited some out ):
I ran furniture factories for over 20 years, putting out literallly thousands of truckloads of mostly solid wood furniture. Since then, for the last ten years or so, I have done custom woodwork, refinishing and antique restoration, and custom finishing. I also still try to keep up with current production methods.
This first-hand experience has shown me that wood which is stable in storage and in the shop will usually be stable in the final product. Proper construction will generally easily resist any tendency to warp or cup. The only thing you can't constrain successfully is cross-gain movement, and plenty is written about that.
Finishing one side allows the wood to absorb or give up moisture faster on the unfinished side, but the wood stabilizes and balances out the moisture remarkably quickly, in my experience, and in an indoor environment changes in humidity tend to be pretty gentle. Proper construction and constraint also seems to cause the wood that wants to warp to take a "compression set," that tends to make the wood even more stable over the years. Bob flexner did some experiments to demonstrate and published an article on it about a year ago.
What I am trying to say is that in most cases I don't worry about finishing the inside of a chest of drawers, or even under a solid wood table top, of which I have made quite a few.
With UNCONSTRAINED panels such as drop leaves or unsupported chest lids, I would be very careful about selection and layup, and finish both sides equally. But since they show, this is generally done anyway.
Think about it: When was the last time you saw a panel in a frame do anything other than split from improperly constrained cross-grain movement? Would finishing both sides have prevented that?
When was the last time you saw a properly constructed and mounted table top warp badly unless it had been stored in harsh conditions or made from poorly dried lumber?
When was the last time you saw a breadboard construction warp at all without the ends having first let go due to excessive heat or moisture (and no pins)? And yet I have seen my own tables (the relative few with that construction) move easily a quarter inch across the grain from season to season.
When was the last time you saw the side of a chest with any kind of locking construction (not a rabbet and nails) come apart due to warping?
How many times have you seen lacquered drawer sides damaged by plasicizers migrating into the finish from objects stored in the drawer? Would that have happened if the drawer sides weren't finished?
I have seen a lot of really messed-up furniture, but I really can't remember the last time I saw damage that would have been prevented by finishing both sides.