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Flush Entry Door9/12
I have an exterior door coming up that will be a flush v-groove door. I have not built a flush door for an exterior application before, so I decided to see what others have done on this forum. It seems to me after looking on and off for the last couple weeks that a ladder core with ¾” solid planks glued to the core with space left between the planks for expansion is the most reliable method for this application. I am not opposed to doing it that way but would rather not see a gap in the v-groove.
My idea would be to build a ladder core made out of LSL to provide a stable core that would be less affected by any moister that my fluctuate throughout the year. Then apply a ¼” marine grade skin on both sides to make everything rigid and create a stable foundation for ¼” solid skins. Before applying the solid skin I would band the core with solid. I realize that at 1/4" wood starts to act like solid wood and not veneer, but my hope would be that any tension that might occur will be released in the v-groove. The only thing I don't like about this is laminating the solids to plywood.
Bad idea? Let me know.
Also, the door will be east facing, under an 8’ overhang, so no harsh sun or rain. The door will be made of genuine mahogany. I also plan to use epoxy.
Attached is a PDF to clarify any confusion.
Thank you much!
Click the link below to download the file included with this post.
You are fighting the nature of this type of door. The plank door has certain qualities that make it what it is. Trying to eliminate or control some of those qualities will likely result in a door that is less than it should be.
The purpose of the solid wood framed ladder core is to isolate and limit the expansion/contraction of the door in width. As is, with the two stiles at 4" or so, you will have effectively an 8" panel that will respond to changes in environmental humidity. Well within reason. Look at the Shrinkulator to see what this means for your species and anticipated MC changes. I bet it ain't much.
I do not know how much the LSL will move under the same conditions - do you? I doubt that a 3/4" pc of LSL has more rigidity along its flat length than any hardwood.
With your extraneous layers of 1/4" you are building a complexity stable panel AKA a flush door. Why not use particle board or MDF for the core? Or buy a solid core, exterior rated door and apply veneer both sides, and then V-joint at will.
As for the planks, if the gap is .020, is that going to be seen? You can have tooling set to make the V's go to a point instead of a blunt, minimizing the detection of a gap. At any rate, since each plank moves within its own space, the V becomes a crush zone if needed.
After giving it a lot of thought, I think it is overthought.
we all have our training,ideas and experience. and will probablycontinue to disagree, but here goes.
Dave, thanks for the response. I value your input. After thinking about it, your probably right that the visual gap will be negligible. The door will be stained as well, probably with a darker color. So you won't see the dark shadow lines.
I thought about using the LSL only because I figured there would be less of a chance the door will twist or warp from seasonal humidity. I'm thinking the less solids the better with a door like this.
If I can't find enough support here to construct this way, i'll revert to the tried and true method of solid planks and solid ladder core.
Doug, Thanks for sharing your method. Your right, we all are learning new ways of doing things. That's why I love the trade, there's always a new challenge to take on.
James - I'll be a bit confrontational here for a moment. Don't take it personally: What makes you think the wood will twist or warp from seasonal changes in humidity?
This seems to be an emerging prevailing, predominant fear on the forum, if not the profession - that wood will warp and twist, and it should never be trusted. Everybody seems to be fleeing from using our favorite (?) material in favor of gawd-knows-what cellulose and glue, ground up trees and glue or what have you.
Where is the love? Where is the trust? Wood is one of the most scientifically analyzed natural materials. There are no mysteries for the most part. Woodworking is probably the oldest profession as well as the oldest hobby. It is a known quantity, and only the novice or unsure or fearful will re-invent the wheel in order to avoid using solid wood.
I have worked wood for 46 years and I can count the number of board warps/twists/etc on one fully fingered hand. I have had to replace 4 doors that I can recall in that 46 years. I have come across any more that do not go into the project, or get cut up for blocking, crating or knockwurst.
I tend to assume that the wood will NOT warp or twist. I have had much bigger problems with glues that do not do what they are marketed to do, man made products that do not measure up to the marketing hype, tooling that is marginal, and rap music in the shop.
Wood is my friend. Hell, my best friend! I depend upon it. I make my life work with it. It will humble me, and I will learn to respect it all over again. I don't ask it to do more than it has ever been expected to do, but I do expect it to do what it has done for centuries - shelter us, and improve the quality of life around us.
Doug's methods are sound and should produce good doors. Everyone needs to find ways to work that are comfortable and successful. Icon't know what the hell LSL is, and I don't care. It simply is not needed, so why worry about it?
I like things simple, and the board doors I have seen do well are made with a ladder core and planks glued to it. Nothing fancy at all.
David, no offence taken. That was actually refreshing to hear, and makes me want to go to the shop and cut some wood!
As far as twisting and bowing, I was probably overthinking things like you suggested. But lets be honest, a poorly constructed door will warp and bow. That's why we leave a gap between the planks, otherwise the summer humidity will probably bow the door. I think I read of someone on this forum that had a bowed door because i'm assuming didn't leave room for expansion.
It's true, we often think of worst case scenario and become feared by what could happen. I learned through the years that things usually turn out better than we think, and in the end there was no need for all the stress wondering how things would turn out.
We often used LSL (Laminated Strand Lumber A.K.A TimberStrand) for the center ply of our panels, stile and rails. We always had good success with it and epoxied everything. It just came natural to me to use it for a door like this.
I like your keep it simple approach. Usually, simple works best! Thanks
David is correct on his statements on wood. Unless I missed it, the use of rift and quarter sawn wood should be the primary consideration. The use of juvenile trees, poor kiln drying, and most importantly the attitude that the basic laws of wood movement may not apply to every woodworker, has put the fear in quite a few people. But if you follow the rules, use the proper cuts, and buy from reputable dealers, twisting and bowing is very limited.