Teak Door Core Material

Well-informed opinions about whether to use engineered core, a solid Teak core with Teak veneer, or simple laminations of solid Teak when building a Teak door. February 1, 2011

Question
I need to build a teak door with 12" wide engineered stiles with teak veneer faces. I was wondering what a good core material would be? It seems like it should be teak to match the stability of the teak faces?

Forum Responses
(Architectural Woodworking Forum)
From contributor D:
Tempting as it would be to use a less expensive core on such wide stiles, I don't think you could afford not to use teak for your core. I personally wouldn't risk it.



From contributor S:
What skin thickness were you thinking?


From the original questioner:
I usually make the face veneers about 3/16" and then sand, etc.


From contributor S:
I think you could make an engineered core work perfectly fine. I know teak can be a bit of a problem from an adhesion standpoint, but I canít see how gluing teak to teak would be a huge improvement. Sure the radial and tangential shrinkage factors between the core and skins will differ a bit, but the final skin thickness seems like it would be around 1/8", so I would not think that would be a problem.


From contributor D:
Before I started building doors, I worked on boats. Teak is the go to material, and I had the opportunity to work with it before becoming a full time woodworker. One thing you all might notice is that the tables in the book Wood As An Engineering Material for the expansion rates are old. The stuff we're working with today, in general, is not the same stuff we were getting twenty years ago, or even five years ago. Tension wood and improperly dried wood is more and more prevalent - something to consider when using teak in any application, but especially so on such a wide stile.

Sure, you are not seeing a huge improvement, maybe none at all if you're cores are a good match in movement. I'm a belt and suspenders type of guy, and don't like taking chances, especially on big ticket orders. I've seen quite a few cracked veneers, typically around the hardware mortises (done by contractors after they've left our shop) where differing expansion rates were the obvious cause. Relatively new doors being returned for repair are not good for your business, that's why I wouldn't take the chance on these. Would I use pine cores for forty poplar interior doors? Sure, and not think twice, these doors though it would be a good bet.



From the original questioner:
After giving it some thought I'm seriously considering face gluing two pieces of 5/4 X12" teak together and calling it good. The door is only 84" high and it seems that this may be the best way to go overall. Any red flags out there?


From contributor S:
Ok, so we are going from an engineered core to a simple glue up of flat sawn stock. I donít know, but maybe you have found some good stock.


From contributor O:
After watching this thread and seeing this go from engineered to solid, I'm just curious as to why the stiles are 12" - and the accommodation of that, and what this door is supposed to look like. Are we talking frame and panel or something else?

At 12", the stiles are going to move 2-3 times as much as a door with 4" to 6" wide stiles if they are solid or anything like solid. Just as a plank door has an internal frame (ladder frame) to control/limit movement, so should something with 24" of cross grain. How this thing is going to fit the frame - long term - is where my questions are.



From the original questioner:
The door in question is to be 96" w X 84" s/l French on a Rixson pivot. The stiles are wide only because it is the architects design requirement. Teak is very stable and if there were any situation where I could glue 2 - 5/4 X 12" pieces face to face this seems like it could be the one (and save many hours). But I welcome suggestions and concerns.


From contributor O:
Because teak is a very stable wood I would build it out of solid 8/4 stock. Carefully selected solid stock would most likely be more stable than two 5/4 boards face glued. Very often two boards face glued will result in a warped board.


From contributor D:
The first rip you make will tell you if you'll be safe going solid. If an offcut warps, wanders, binds slightly, etc, well I'd say that's that and definitely engineer it. If not you may be ok. Ultimately your name is on the thing - some here feel comfortable advising solid construction. I myself have no choice in the matter. We built only a few solid stiles years ago and had many problems. Now we have almost no problems and build three-ten doors per day. The owners have given me standing orders to engineer everything, and I've seen the benefits, so I may be a bit biased.


From contributor M:
I wouldn't hesitate to build these on a good quality fingerjointed pine core. Faces need to be more like veneer and not lumber, 1/8" or less.


From contributor P:
We build all of our doors from solid stock and have done a large amount of high end work - frame and panel, louvered, French, etc, all 1 3/4" finished and all from FEQ teak. We never had a problem or callback yet. We do use epoxy glue exclusively and again, have never had an adhesion problem or joint failure.