We're thinking of pressing veneer over an Extira [waterproof MDF] core for two fixed panels in a 2" white oak entry door. The panels would be glued in as opposed to floating. Alternatively, I'd consider a foam core, but have never made one. We're concerned about the weight of this very large door. Does anyone have any opinions?
(Architectural Woodworking Forum)
From contributor J:
Sounds like that should work fine. I've used 3/4" pink eps foam sandwiched in between two panels with good results. How wide is the door? Did you do stave core or are the parts solid white oak? If you use good ball bearing hinges and your joinery is sized appropriately the weight shouldn't be a problem.
Traditionally, panels are solid and left to move. Nowadays, some of the best builders of doors are using a stable core with a mitered perimeter of solid wood (see AWI specs). Of course, the stable panels can be glued in place if one likes, with no ill effects. Each method has it advantages and disadvantages, limitations and freedoms. How much solid wood panels will move is the tough question. Do you figure interior RH, exterior RH or both?
Solid wood door makes a better impression on a customer who is asking for that "custom" door for their home. Otherwise they would have settled for a Home Depot or Lowe’s door. What is the questioner’s customer going to think when they find out he uses particle board in his door? MDF engineered in that customers mind is just particle board unless clearly defined and even then you have suddenly put a hurdle between that customer and ordering the door.
I always had a cross section (a 45 degree cutoff corner) of my door construction for them to take apart, feel, see the parts before and after construction and when they saw deep mortise, tenon, and all solid wood. Banding a raised panel made of MDF is ok for kitchen cab's but not an exterior door.
Bookmatched veneers, very wide panels, inlaid panels, and two sided doors lend themselves to using stable panels. More often than not, these are still solid wood, 5-7 layers of solid and veneers to make them dimensionally stable. We don't typically glue them in place in the frame as a directive, but it does happen, and is fine.
Some of my customers are 2,000 miles away, so explaining the cross sections is typically not necessary or advantageous. 25 or 30 cross sections, plus drawings like crazy, are available if needed, but it is more important that they trust us with their work, and give us the freedom to make the best product we can. I don't tell Honda how to make their disc brakes, and I don't need to know anything about it to appreciate the fact that they work.