Is thick wood more stable than thin?

[Jamie Buxton]

In general, which is more stable with humidity changes -- thin wood or thick wood? Say you're making the panels for frame and panel cabinet doors. Should you make them thin, or thick? Or you're making a table top. Would a thick top be less likely to warp, or would a thin one be better?

To pose the question clearly, let's say that the wood is just run-of-the-mill flatsawn lumber. (Yeah, yeah, quartersawn is more stable, but that's not the question here. And the smile/frown orientation of the lumber reduces big warps, but again that's not the question.)

So which is more stable, and why?

[Jeff Sudmeier]

Well I can't really say, except to the extremes. I have seen 4 inch thick beams cuff. However, thin veneers, less than an 1/8th of an inch don't move much so they are glued to a stable plywood base.

I don't know if that helps or hurts, but that's what I know :)

[Steve Jenkins]

Intuitively I would say that thicker is more stable because it would take longer for any humidity changes to penetrate deep enough to cause the wood to warp. However since you are limited to a certain thickness depending on what you are making it is much more important to finish both faces the same and when storing unfinished parts either store them on edge or flat and covered. These practices will cause both faces to change moisture content at the same rate and prevent warping.

[lou sansone]

excellent question


I am not sure if there is a real good answer for it.

lou

[Tom Jones III]

Last week I was ripping some cedar. By accident of the cut size, I ended up ripping a paper thin sheet on the waste side. We had a weather change and humidity was low when I made the cut. The next morning humidity was back to normal and the paper thin sheet was rolled up into a U shape. I could not detect the slightest change in the 1.5"x3.5"x48" piece I ripped on the same cut.

I've never seen this happen to 8/4 wood, but then again this is an extreme example.