Understanding unfinished Paint-Grade Cabinet Doors

Although any cabinet door can be painted, not all materials used in cabinet doors paint equally well. Here are some tips on how to get cabinet doors that will paint well and remain beautiful for a generation.

The reason some wood types will give a perfect looking stain finish and a disappointing painted finish is the prominence of the woods grain and the way the different woods react to changes in relative humidity.

The finished look of a painted cabinet door made of Oak will have a noticeable grain pattern showing through the paint. A similar door made of Poplar, Alder, or Maple, when painted exactly the same, will show very little grain through the paint.

Most major manufacturers use Poplar for paint-grade cabinet doors, with Alder and Soft Maple sometimes used as well. Poplar is most often used because it sands very smooth and, after one or two coats of primer, paints exceptionally well.

Now lets look at the different styles of cabinet doors and how humidity changes affect the finished appearance of stained vs. painted doors.

There are two basic styles of cabinet doors: Inset (also called recessed or flat) panel doors and Raised panel doors.
Inset panel doors consist of a solid wood frame and a Plywood (or veneered) flat panel. Because plywood (especially plywood with an MDF core) doesn’t react dimensionally to humidity changes nearly as much as solid wood, the panels in recessed panel doors will not expand or contract significantly with changes in relative humidity.
Raised panel doors have a solid wood frame and a solid wood, glued-up panel. These glued-up, or solid wood panels significantly expand or contract to changes in humidity. This dimensional change in a solid wood panel is significant in the horizontal (against the grain) direction but insignificant in the vertical (with the grain).
In most woods the movement of a 16-inch panel in the horizontal direction will exceed 1/16-inch with a change in relative humidity of 30%.

In stained cabinet doors this panel movement goes unnoticed because the floating panel simply moves within the doors frame.
Painted doors aren’t so forgiving.
The problem with panel movement in a painted door is that the panel movement causes the paint to crack along the moving joint where the panel and frame meet.
Now you have a noticeable crack around the inside of the cabinet door.
This is not so much the fault of the door, which is behaving exactly as all wood has behaved for millions of year. The cracking is caused by the fact that the paint, once dried, is no longer as elastic as the wood.
Wood will always react to changes in humidity but dry paint can’t. Using primers, sealers and multiple coats of paint will slow the humidity-change caused dimensional changes buy won’t completely prevent them.

Now for the best partial-solution the industry has yet devised: MDF.
MDF, or Medium Density Fiberboard doesn’t react dimensionally to changes in relative humidity.
MDF also happens to take primer and paint better that most hardwoods.

That’s why we use MDF in all our Paint-Grade cabinet doors.
Better painted finish, greatly reduced panel movement, and much less likely to crack the paint around the panels.

An example of our Inset Panel Doors is the Shaker which can be seen, priced, and ordered online here.
An example of our Rained Panel Doors is the Heritage which can be seen, priced, and ordered online here.