Replies

1. 
   joinerswork | Apr 01, 2010 09:18am | #1

   In addition to what Richard said, the way to make a board and batten door keep from appreciably changing its width from summer to winter, is to break up the width into multiple narrow boards instead of gluing them into one wide panel.  The boards are individually attached to the battens, which hod them in place.  The individual boards can then come and go independently of one another, without their dimension changes adding to, or diminishing, the total width of the assembly.

   Ray 

   
1. 
   DonStephan | Apr 01, 2010 08:21pm | #3

   A different finish might also help.  My memory suggests tung oil is very impervious to moisture movement.  Almost no finish will completely block the movement of moisture, but one that is fairly impervious may slightly reduce seasonal expansion and contraction.    Before the wood has had time to fully adjust to the lowest winter relative humidity, and the highest summer rel hum, the season is changing.

   Just to confirm, the edges of the doors are finished with the same number of coats as the faces?  Edge grain responds to rel humidity faster than face grain.

1. 
   SgianDubh | Apr 02, 2010 06:46am | #4

   Don, I think you meant to say that tung oil is a relatively porous finish regarding the migration of water vapour through it rather than impervious. I imagine you suffered a mild brain burp when you were typing your response-- I get that too, ha, ha. Slainte.

1. 
   joinerswork | Apr 02, 2010 07:03pm | #5

   Richard,

   You are so genteel, with your brain burps.  My involuntary brain emissions are usually expressed from lower in the gstro intestinal system.

   Ray

1. 
   SgianDubh | Apr 04, 2010 08:55am | #8

   Flatulence Ray? Do you sound like one of those Harley's you hear farting gently along the freeway? Slainte.

2. 
   joinerswork | Apr 04, 2010 09:01am | #9

   Richard,

   "Do you sound like

   Richard,

   "Do you sound like one of those Harley's you hear farting gently along the freeway?"

   As I get older, my brain flatulence more resembles the space shuttle on liftoff.

   Ray

2. 
   DonStephan | Apr 02, 2010 08:27pm | #6

   Sgian:

   Thanks for your correcting my error, and so gently.  Yes, my fingers weren't typing what my declining grey matter was a thunkin.

   Hope all well cross the pond.

2. 
   SgianDubh | Apr 01, 2010 09:55am | #2

   It sounds from your description that you've made up panel doors out of solid wood, ie, solid wood slabs and therefore not frame and panel construction. The latter construction style would go a long way to alleviating the problems you seem to be experiencing because the expansion and contraction of the panel would be contained within the framework, which itself would not expand and contract significantly because of the narrowness of the stock.

   Hickory is one of the greater cross grain movers with a tangential shrinkage factor of 10.5% and a radial shrinkage factor of 7% (both in the MC range from 30% to 0%). This means that if your panel is 20" wide at a moisture content of 7% and experiences a moisture gain of 6% = 13%MC, a panel made of tangentially cut pieces will eventually reach a width of about 20-7/16". If the same 20" width of panel is made of radially sawn boards it will grow by roughly 1/4" to 20-1/4" if it experiences the same moisture gain, ie, from 7% to 13% MC.

   It seems your doors are gaining moisture from your description and they are therefore expanding and getting tighter in the door opening, hence your need to keep trimming them. My guess, based on experience, is that at some point the RH (Relative Humidity) prevalent withing the building will drop sometime in the future which will lead to the panels shrinking and the gaps between doors, and gaps between the carcase framing and the door panels will increase on the clapping side.

   If I am correct in surmising you have unsupported solid wood slab doors, one way you could help resist the tendency to cup across the width would be to rout a couple of dovetail housings (dados) on the back face of the panel, near the top and bottom, and make up cross bearers or battens of fairly stout wood, eg, about 1-1/2" wide by about 1" thick and work a matching dovetail profile on the narrow edge. Slide these into the dovetail housings dry and apply a bit of glue to the exposed dovetail when there's only an inch or so of the bearer left to tap in place. Finally just tap the last inch into place flush with the edge of the panel. Make sure you leave a decent gap at the other end of the dovetail housing, eg, about 3/8" or so so that the panel can expand and contract freely without the end of the dovetail housing butting up against the end of the dovetail on the edge of the cross bearer. This is not the only method for reducing the likelihood of cupping across the width of panels; you could, for example, do clamped ends, aska (also sometimes known as) breadboard ends where the clamps are, ideally, a good bit thicker than the panel itself. Slainte.

3. 
   bduffin104 | Apr 04, 2010 02:18am | #7

   slab doors equals frustration

   Thin solid wood slab doors is something I try to avoid and thankfully I've never tried them out of hickory.

   That being said, I have had success building slab entry doors with VG fir strapped with perpendicular cleats. Ive also done hardwood plank doors but always with a lamination with a VG fir core.

   Interestingly, I've had more trouble with shrinking than growing

   Bret