Message Thread:
Outdoor Table Joinery
9/16/21
I'm planning on making a patio table soon. Most of the furniture I've made in the past was for use indoors in a humidity controlled environment. So there wasn't all that much wood movement that I had to be concerned with.
However, I now find myself getting ready to build an outdoor table, in Florida, where it will be left outside 24/7/365. The outdoor environment will be near the beach so there is a lot of salt in the air as well. A rather rough environment for wood.
The table plans that I found and like the design of are pretty simple. The gentleman who created them even has a video showing how to construct it.
Now I'm more a fan of traditional joinery and I was hoping to remove a lot of the screws from the project.
First I would like to use hidden mitered tenons for constructing the outer rim. There would be .5" tenons on 1.5" material. Then I would like to run a .25" dado .25" from the top of the inside of the outer rim. This dado is then where I would install the main table planks with .25" tenons. This will all be made out of plantation teak.
My area of concern is wood movement. Will the mitered corners fight and split? Does the fact that it is an octagon table help balance out the tug of war between the wood pieces? Am I better off skipping the traditional joinery and just going the glue and screw route with some nice SS screws?
Thanks in advance for any words of wisdom that you can spare.
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Table construction video
9/16/21 #3: Outdoor Table Joinery ...
All wood moves every season. Nothing prevents it, nothing limits it in flat sawn lumber. Shape will not "balance" out the tug of war. Every one of those top boards is going to move, no matter what the shape of the rim. The only thing that changes the amount of wood expansion and contraction is if you use quarter sawn wood. I am not a fan of youtube advice. If I find 1 out of 100 where the maker has more than 5 years of experience in his garage or basement, I'm surprised.
9/17/21 #4: Outdoor Table Joinery ...
RichC, that's why I came here to ask for further wisdom and guidance before I follow the plans as published. Wood expansion can be a pain, and once a video is shot you may not see the table a week or month later after it has shifted. Let alone that the moisture swings in the area of the maker may be completely different.
And you're right, wood will move. That's why it is my biggest concern with this project. I was playing with the shrinkage calculator on this website and knowing that the wood is to be used in Florida I figure the MC needs to start at around 12.3% and go up to about 14.5%. Calculating for flatsawn teak this shows that the wood movement will be about 1/32". These MC numbers come from the Forest Products Laboratory 1999 Wood handbook for Miami, FL.
I think the outer rim can handle this expansion and contraction amount without blowing out as long as I give the inner planks some room to move with a relief area at the tenon and making sure the boards have some space to swell in between them. If I use 1/8" space between each plank I think I should have plenty of room for wood movement.
Does this seem correct or am I going to be disappointed after a few months to a year?
9/17/21 #5: Outdoor Table Joinery ...
Jason, I don't know how it is in Florida, but where I am, all the Teak my suppliers carry would be KD. If I used 8% starting and 12% afterwards, there would be 5/16" across that top, so making it tight would be a mistake.
As for the band, making it narrower would be a really good idea. If you don't think your calculations for those miters would open, out at the toe when it expands, I hope you will report back here so we can all learn from you.
9/17/21 #6: Outdoor Table Joinery ...
That video is a homeowner project using materials and techniques destine to fail. If that is your guide you might want to consider another profession. As for a table left outside 24/7 there are materials that will work. Concrete would be one, stainless steel another. Wood will fail at some point.
9/17/21 #7: Outdoor Table Joinery ...
Jason,
Wood movement isn't a pain. I've been allowing for it for 49 years and others did it for a century before me. Why do you think woodworkers invented raised panel doors? Because they couldn't out the front door of their cabin in the spring! If you allow the center panel to move, you are fine there. Next issue is how wide you make that rim and how long the miter joints are. Each of the rim boards will expand and contract. That either opens the heel or the toe.
http://www.garymkatz.com/TrimTechniques/open_miters.html
9/17/21 #8: Outdoor Table Joinery ...
Keith Newton, Thanks for the reminder to always check the MC of the wood before working on it. I luckily have the advantage of time on my side for this project as I can wait up to 6 months before I need to make the table and have it ready. I'll make sure to store the wood outside where it can begin its acclimation process to be within the 12.3->14.5% MC range.
As for the miters, I kind of expect them to open a bit. I was hoping someone would suggest a different joinery method that may help hide/allow for the wood movement in the best way possible. I am not that skilled at this yet to know the ins and outs or methods for dealing with wood movement in all situations. But I'm willing and trying to learn. So fingers crossed.
I found other similar designs of the table when I was trying to find plans to start from. The design from bellacostaldecor.com seems to use separate pieces, almost like a floating tenon, to join the outer rim boards together. In your opinion, would this be better than the hidden mitered tenons I was planing on using? Assuming I let the wood properly acclimate of course.
Also, I'm not above getting the boards acclimated and then making the miters have a small gap between them that is then filled with marine caulk. If that is the best joint to make, then so be it.
You had suggested a thinner band might be better. As far as I'm concerned the outer rim could be thinner. Right now it is calling for 7" wide. What do you think would be a good width to reduce that to?
View larger image
BellaCoastalDecor Table
9/17/21 #9: Outdoor Table Joinery ...
Bruce H, All materials will fail at some point. I'm hoping to build a table that will last somewhere in the 5-10 year range. I don't think that will be that difficult with wood as long as it is periodically cleaned with soap and water and the movement of the wood can be accounted for. Heck, I even want the grey patina of the teak so there is a little less maintenance right there.
But yes...metal or concrete should outlast wood. But that is not the material that was chosen for this project.
9/17/21 #10: Outdoor Table Joinery ...
RichC, 49 years?! Nice! That is a lot of experience. Thanks for offering it through your advice on this forum. I'm more at the beginning of the journey. But I'm sure you caught that.
I'm glad that you agree that the relief cuts and spacing of the planks should handle the inner wood areas movement.
I'm not against shrinking the 7" wide rim of the table down. I'm not sure how thin is too thin. I might need to make some models out of cardboard and compare. Any suggestions?
I'll read through that article tonight before bed. I'm sure I'll learn something interesting. Thanks!
9/19/21 #11: Outdoor Table Joinery ...
Jason, Rich knows just about everything there is to know about every single phase of wood working from planting the trees to cutting them down years later to make and finish wooden cabinets.
9/19/21 #12: Outdoor Table Joinery ...
Thank-you guys for the compliments. I haven't seen it all, but I've seen a lot. Unfortunately, I come across as too direct to many on the internet. A combination of strict German upbringing and a strong bent towards engineering.
9/19/21 #13: Outdoor Table Joinery ...
I built an outdoor table a couple of years ago with a 12 segment outer ring of about 4-1/2" width. I used what I thought were long enough loose tenons to join the segments, with epoxy glue. After the first Winter several of the joints opened up, some by at least 1/8". I'm in NY where the RH changes a lot; nevertheless, I thought my design would survive.
I posted some photos here and there was a substantial discussion about how to build that ring so it would survive. The general consensus was to use a two or three layer ring with the joints offset. I haven't built a new ring yet, but if/when I do it will be with that approach. In any case, I think a glued 7" ring would be doomed to failure where I live no matter how I built it. I would reduce the width of that ring by nearly half.
John
9/20/21 #14: Outdoor Table Joinery ...
Website: http://www.kdunphy.com
I looked at the video for sure the ring will let go only because water will work it way in the joint. Pocket screw are not joinery yet its number one on YouTube
Concrete ring would work
9/21/21 #15: Outdoor Table Joinery ...
This topic/project seems to come up often. For out door work, why not rip strips from a wide board, , keep them in the order you ripped them, and epoxy them around a form. The miter joint will stay tight as long as the ring doesn’t pinch the center panel.. All movement is across joint so no open heel or toe. Mortise and tenon, or use whatever joint you like best.
9/21/21 #16: Outdoor Table Joinery ...
John, it took some major google-fu but I was able to find the forum post you were talking about. It is linked below.
First, that table looks great. How is it holding up now? Did you use G/flex in the end? It's kind of like reading an authors unfinished work. Lol.
I want to read over the forum post again when I have a bit more time. The brick layered yurt portion was interesting. Thanks for sharing that information. I had not seen that topic last time I searched the forums.
https://www.woodweb.com/forum_fdse_files/aw/847482.html
9/21/21 #17: Outdoor Table Joinery ...
Matt, that's an interesting idea. I saw your post in Johns old topic as well. I'll keep it in my back pocket as an idea for now. I have a lot of wonderful information from all of you that I need to process. Once I do I'll come back with my second draft.
9/21/21 #18: Outdoor Table Joinery ...
What is the problem? That rim is only 3-4" wide at the butt joints (miters??). That is what you all are crying about?
Make your tenons like you have planned, running the full width of those butted rim parts. Assemble with Resorcinol glue. Flip the bottom up, and run several 1/2" wide x 1-1/8" deep routes in from the bottom, 3-4" long, bridging the butt joint. Make snug splines, and glue them in. Resorcinol.
OR
Make a butted joint that has two long (3-4" ) laps over each other, like the Grumbacher canvas stretchers. The clue is glue surface area.
You guys are all paralyzed over 'wood movement' when you don't even measure moisture or range. Worrying over the wrong factors. Solving problems that ain't. You need to expand your view and think outside the box you have put yourself in.
I almost forgot. Gather up all those Kreg screws and jigs and especially the wood plugs, and take it all out back and bury it where you will forget all about that crap.
View higher quality, full size image (1200 X 1200)
9/22/21 #19: Outdoor Table Joinery ...
Jason, I haven't taken any action yet on the table top ring. It's sort of reached a state of "stability" with the cracks that have opened up not getting any worse, nor better of course. I'll need to do something eventually to make it right but the customer is actually OK with it so there's no hurry.
Good luck with your table. Take your best shot and keep us updated with how well it survives.
John
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