Shutters - How loose???

[Snap Marc]

I have milled up and shaped all the parts necessary for 20 raised panel shutters. These are built from PT Pine. I will prime, then paint.

Question: Many mentions of making sure the panels are loose in the rails and stiles to allow for movement. My question is how loose? And also should the panel itself be shorter and narrower to allow for up, down, left, right movement? Or should the actual thickness of the board be loose fitting within the grooves? Or maybe both?

The grooves routed in the rails and stiles are about .325". Should the panel be about .125" less? I realize the panel should not be glued, but if it's shorter and narrower, won't it slide around a bit?

Any help would be great.

[cabinetman]

If your panel is.125 less overall in both directions, you'll have 1/16" clearance. If the panel slips the groove, that is sufficient. You can tack the panel in the groove at the top center and bottom center, but not at the sides.
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[cgallery]

And I've heard some reports that painting the panels before assembly will prevent bare wood from showing if they shrink. Others have said painting after assembly, but while they're still "shop dry" is enough to prevent this.

[Stytooner]

If these are outside, I would seal the bottom of the panels with gorilla glue. This way you won't get water standing oin that bottom track. The rest of the panel can stay loose. Maybe a dab of glue at the center on the top panel. They won't shrink in the length. Most movement will be side to side.