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Need some advice on outdoor table

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Forum topic by Dustin posted 03-29-2017 07:15 PM 398 views 0 times favorited 7 replies Add to Favorites Watch
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Dustin

405 posts in 577 days


03-29-2017 07:15 PM

Topic tags/keywords: question cedar joining

Hey, fellow jocks, seems I’ll be doing another little project. I’m planning on building an outdoor table for some budget conscious friends (plenty of reno on a new house down the line for them), and found this build by Bryan Pryor replicating a Chatham outdoor table:

http://www.bryanpryor.com/2013/05/22/diy-cedar-patio-table/

Now, I’m not crazy about his use of pocket hole screws, so my thoughts were this:

-Instead of wrapping the apron around the legs, mortise and tenon them in with Titebond 3 (and maybe hardwood dowels).
-Tenon table top “stiles” (for lack of a better descrition) into the longer rails (glue here or dowels?).
-Same with the slats making up the top.
-Use hardwood dowels to secure the tenoned top slats rather than glue.
-Use “L-blocks” to mount in a groove in the apron to screw to the underside of table top.

My local mill only carries 4/4 and 8/4 cedar, but the rough saw it on the thick side and I can usually get 7/8-1” surfaced after running through my planer, which I figured would be adequate for the top. For the 4×4 legs, I’ll probably have to resort to the BORG.

Any problems with how I’m planning this, structurally or otherwise, or any helpful suggestions (i.e., tenon size recommendations)? I’ll probably head to the mill next week as I have a couple days off.

Thanks!

-- "Ladies, if your husband says he'll get to it, he'll get to it. No need to remind him about it every 6 months."


7 replies so far

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JBrow

1274 posts in 757 days


#1 posted 03-30-2017 02:31 AM

Dustin,

Your plan sounds good to me.

Assuming you leave a gap of 1/8” or so between the slats making up the field in the table top, I would think the mortise and tenon joints could be glued. However, I would limit the glue to about 1” to 2” across the width of the tenon at the center of the tenon so the slats can expand outward from the glued center.

The mitred joints in the table top frame could fail over time unless the mitre joint is reinforced, perhaps with a spline. A lapped mitre joint could also be used. I think the lapped mitre would be stronger but some end grain shows on the end of one half the mitre.

Clin and others on prior LJ posts, as I recall, have argued that as wood expands, the mitre joint can open up a bit at the outside corner. This phenomenon seems dependent of the width of the wood coming into the mitre. The narrower the mitred parts, the less this occurs, if I under the math correctly.

I like the idea of adding dowels to further secure the mortise and tenon joints. However, my concern with using hardwood dowels is that if the cedar shrinks more than the hardwood or the hardwood dowel swells more than the surrounding cedar, the hole in the cedar through which the hardwood dowel passes could become enlarged and the joint lose some of its strength, since cedar is fairly soft wood. I am not sure that this would be a problem. But if possible, I would be inclined to use cedar dowels as a substitute for the hardwood dowels just in case I am correct. Here is one site I found that claims to carry cedar dowels. By the way, I have not purchased from them.

http://www.dowelsondemand.com/prices.html

I am sure you have thought about it, but if not, the legs could be a lamination of 4/4 or 8/4 cedar to get the size you need. If you do not like to see the glue lines from this lamination, I am aware of a trick whereby a piece of cedar veneer about 1/8” thick is glued over the glue lines of the laminated legs. A slight easing of the edges would mostly conceal the glue line from the cedar veneer. However, if you can find solid cedar to yield the 4” x 4” legs, that would be the better way to go.

My last thought is relevant if the legs may spend time setting in puddles of water for more than a brief period of time. If the end grain of the legs sets in water, water could wick into the legs. Since the end grain of the legs is setting on the ground or some solid surface, moisture that enters the legs could take a long time to leave the legs. If a finish is applied to the table, this high moisture in the lower section of the legs could cause the finish to fail. A foot consisting of a piece of ¾” thick cedar, cut smaller than the footprint of the legs for a shadow line (for example for 4” x 4” legs, a foot measuring 3-1/2” x 3-1/2” would create a ¼” shadow line), could be face-screwed into the lower legs and act as feet and offer some additional protect to the legs. Since the feet are screwed in place, a problem foot can be replaced.

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Dustin

405 posts in 577 days


#2 posted 03-30-2017 02:20 PM

JBrow,
Thank you for the thorough response. I should have mentioned in my post that I don’t intend to miter the corners of the table top, but will either half-lap them or use mortise and tenons, due to concerns for the very same reason you mentioned.
For the legs, I’m not opposed to laminating them together, but was concerned about doing this on an outdoor table that will take quite a beating from the elements, even when properly stained/sealed.
That dowel link is great, I’ll be looking into that some more!
Lastly, I like the idea of a small “foot” on the bottom of the legs to help prevent moisture wicking. The table will be on a deck, so direct ground contact, but as a simple and effective preventative measure that also crates an aesthetically appealing shadow line, I really like that idea.

-- "Ladies, if your husband says he'll get to it, he'll get to it. No need to remind him about it every 6 months."

View JBrow's profile

JBrow

1274 posts in 757 days


#3 posted 03-30-2017 03:16 PM

Dustin,

I appreciate your concern about the lamination of the legs potentially becoming a point of failure. However, I am very impressed with the strength and outdoor durability of Titebond III. Probably 5 or 6 years ago I built a picket style fence with what seemed like a million or two half lap joints to join the pickets to the upper and lower rails. I was a little concerned that the elements and moisture entering the red oak from which the fence was made would eventually lead to failure. That failure has never come. The joints remain as solid as when the fence was built.

Nonetheless, if possible, the solid cedar legs would look better, with no glue lines, and there would be no glue to fail.

View MrRon's profile

MrRon

4492 posts in 3080 days


#4 posted 03-30-2017 05:07 PM

IMHO, I don’t like the use of any wood joints (M&T, miter, T&G, etc) in outdoor furniture. When left out in the elements, joints tend to absorb moisture and eventually fail. You can spend a lot of time building a “furniture quality” piece for outdoors and it will be junk in a year. Sealing and refinishing periodically can extend the life of such a piece, but once done, I don’t want to have to think about it again. I too am planning on building an outdoor table, but I plan to use recycled wood/plastic decking boards for the top. The stuff has a 20 year life with no protective seals required.

View SawduztJunky's profile

SawduztJunky

71 posts in 995 days


#5 posted 03-30-2017 05:28 PM

Like this?

-- I don't think I'm ever more "aware" than I am right after I hit my thumb with a hammer. Questions about solid surface? Just ask. http://www.swiiitch.portfoliobox.net

View Dustin's profile

Dustin

405 posts in 577 days


#6 posted 03-30-2017 06:37 PM

Aww, Sawduzt, now you’re just showing off!
The table I’ll be doing is quite a bit simpler, but I really do like that trestle table approach to an oudoor table. With the doweled through-tenons, does the table breakdown for seasonal storage?

-- "Ladies, if your husband says he'll get to it, he'll get to it. No need to remind him about it every 6 months."

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SawduztJunky

71 posts in 995 days


#7 posted 03-31-2017 01:33 PM

No way man. It’s solid as a rock! Lol

-- I don't think I'm ever more "aware" than I am right after I hit my thumb with a hammer. Questions about solid surface? Just ask. http://www.swiiitch.portfoliobox.net

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