Using domino joints on outdoor elevated planter box

[andrew whicker]

Hi,

Looks like I might get some work to make some quality cedar elevated planter boxes for outdoors. I don't have a Domino yet, but I was thinking of using some of the revenue on this job to buy one. I would like to join the cedar end grain runners to upright cedar posts in the middle of the post. I was thinking of using a Domino to achieve this.

Other options:

- Use screws / pocket screws
- mortise and tenon (on a garden box?)
- come up with a different design. Probably one that looks cheaper though, in my opinion.

I have another job coming down the pipeline where I will need to buy the Domino, so I'm not in hurry to get one for this specific job unless it really is the best way. The screws might be better / just as good.

Was thinking of using cedar 2x4's for runners and cedar 4x4 posts for uprights.

I'm trying to impress this company. There is definite opportunity to get more meaningful projects. I'd like to do a bang up job.

cheers and thanks,

[Matt Day]

A sketch or picture would help us better understand the design better.

[Jim Becker]

Domino construction is perfectly valid for outdoor oriented projects just as it is for indoor projects. The only difference is to use Dominos that are appropriate for outdoor use; either the Sipo versions from Festool, or shop-made tenon stock from an outdoor friendly and stable species, such as mahogany or white oak.

[andrew whicker]

Thanks everyone.

I'm just talking about joining two pieces like this, except using a domino instead of a M&T. The male will be a 2x4 (runner) and the female will be a 4x4 post (upright)

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[Sam Murdoch]

What Jim says ^. To my eye pocket screws always look bush league if you can see them. They serve their purpose and are a valid system but they should not be seen. Having said that - I also think that exposed screws of any kind compromise woodworking projects. (Not too opinionated am I :rolleyes:.) If there is a no screw or hidden screw alternative use them OR play up the screw as a detail. That means nice bronze or stainless pan heads and if you are using straight slotted screws align the slots to one orientation.

For "quality cedar elevated planter boxes" and "I'm trying to impress this company. There is definite opportunity to get more meaningful projects. I'd like to do a bang up job." - I would go all out - within the budget - to make these as impressive as can be. No visible fasteners and rugged construction will set you apart from the regular "planter box" guys who are likely using stainless ring nails or stainless screws with buggered up heads (some of them anyway).

My 2¢ and all that it's worth. :) Good luck.

EDIT - seeing your example and reading that you are using 2x4 and 4x4 construction suggests that, if using dominos for the joint, they will need to be long and likely doubled up. I might also consider pinning them to help resist racking. AND - I would use epoxy.

[andrew whicker]

I was looking into getting the Domino 500 and using the 10mm cutter. I could do two 10mm dominoes per 2x4.

Thanks again for everyone's input.

[Brian Holcombe]

Draw bored mortise and tenon. Local to me there are tons of outdoor benches made in Indonesia, the ones that last more than a few years always have draw bored mortise and tenon.

Draw boring is not the same as pinning just FYI.

BORG cedar is usually pretty much sap wood, I would use some high quality cedar.

[Matt Day]

Simple mortise and tenon joinery like you’ve described is exactly what the domino is designed for. As said above, use exterior dominos, exterior glue/epoxy, and use an appropriately sized domino. If you plan to do large work like this often, the XL might be worth a consideration. I believe there is a way to use the XL and make df500 size dominos too if that’s if interest. I mainly do furniture so have the 500 and didn’t want to lug around the larger XL.

[andrew whicker]

I'm using cedar from a cedar fencing place. Their cedar planks are way nicer than anything at HD / Lowe's. The cedar planks were labeled Kiln Dried. I haven't seen these 2x4's yet. Just called to get the price.

The place is like an hour away.

Edit to Clarify: I built a privacy fence with treated posts and runners, but used 7\8" cedar planks. Hence why I know about their planks. I am not using planks on this project.

Cheers,

[Jim Becker]

I was looking into getting the Domino 500 and using the 10mm cutter. I could do two 10mm dominoes per 2x4.

Thanks again for everyone's input.

For material of that size you really need the Domino 700 XL and the 14mm cutter. The Domino 500 cannot cut mortises deep enough to provide strength in the joint for material of that stature.

As was noted, the 700 XL can be equipped to cut for the 4mm, 5mm and 6mm dominos with a third party adapter and has the ability to cut much deeper for 8mm, 10mm, 12mm and 14mm. I'm actually buying the DF 700 XL Kit this coming weekend when Bob Marino has them back in stock and plan on getting the Seneca adapters for the smaller cutters myself for "small work".

[andrew whicker]

Hmm.. The posts are 4x4. The planter is 3 ft by 6 ft. I was hoping to use dominoes on both the narrow side boards and the long side boards. In other words, from above the dominoes can only be ~2" deep before they touch each other on the X-Y plane. I could do some offsetting on the dominoes a bit, but they will have to overlap a little bit on the Z axis which means they will cross each other on the X-Y plane.

From above:

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[Tom Bain]

Just one word of caution on cedar. Even though it may be labeled as kiln dried, it may or may not be dried to the same standard as hardwood lumber. I made a large garden arbor from clear 2x and 4x cedar several years ago, and the wood moved on me during the project more than I was expecting. I used through mortise and tenons that were wedged in place. I got it all to work but the wood movement made the joinery more challenging that I would have liked.

[Mike Cutler]

You should be able to accomplish this with loose tenon joinery, which is what the Domino is/does. You will need the bigger model and the tenons will most likely have to be doubled. The same "rules" for M&T joinery apply to loose tenons, as well as integrated tenons. The Domino can't do magic. ;)
In your example above I would use "traditional", integrated, interlocking M&T joinery. The same could be done wth loose tenon joinery, the Domino, but you'd have to "fiddle around" a little bit with the tenons to get them to interlock inside the 4x4 post. Not hard, just some trial and error to get the dimensions correct.
For the long run, design aesthetic, I would definitely do a full shoulder on those rail pieces. In fact, doing a full shoulder would relieve some of the structural demands you need from the Domino.
If your weather is somewhat mild, and the boxes won't be exposed throughout all four seasons, I'd use epoxy, a structural adhesive type like T-88. If they will get wet, and stay wet, you may find that resorcinol is a better choice.

[Brian Holcombe]

Traditional joinery allows you to make a haunched tenon which can extend through the post. Cut them so that one goes above and one below. Draw bore so that glue is not used. Glue can succeed outside but I prefer to avoid as often as possible.

Waste the holes with a router, then chisel them square.

[Rick Alexander]

Just one word of caution on cedar. Even though it may be labeled as kiln dried, it may or may not be dried to the same standard as hardwood lumber. I made a large garden arbor from clear 2x and 4x cedar several years ago, and the wood moved on me during the project more than I was expecting. I used through mortise and tenons that were wedged in place. I got it all to work but the wood movement made the joinery more challenging that I would have liked.

If this is going to be an outdoor project you wouldn't want it to be kiln dried. Air dried is perfect for outdoor projects - even preferred. Less movement and the wood works easier if you ask me. Plus - if I'm using cedar throughout then I'm using cedar dominos I make myself and I'm using the DF700 to do the job. I want my dominos to move more similar with that soft a wood species. As for which Domino -buy once - especially on such an important tool. The DF700 will do anything the 500 will - can't say that for the other way around - that did it for my decision on which to buy.

[Josh Kocher]

Re: 500 vs. 700.

You can try experimenting with the 500 with wider shop made tenons with mortises cut on the wider setting, or even overlapping mortise cuts as an option too where more strength is required and you possibly don't want to stack your dominos. You don't get more than the 28mm depth, but you can make a beefier joint that way.

[Rick Alexander]

Re: 500 vs. 700.

You can try experimenting with the 500 with wider shop made tenons with mortises cut on the wider setting, or even overlapping mortise cuts as an option too where more strength is required and you possibly don't want to stack your dominos. You don't get more than the 28mm depth, but you can make a beefier joint that way.

You can also use your stops to make 2-3 passes in the same mortise to make a wider mortise if you're making your dominos. The stops used would be indexing on the opposite end of the mortise you would be cutting - if that makes sense.

[Edwin Santos]

Hi,
I don't agree that you "need" the bigger Domino machine (or either Domino machine for that matter). If you get the smaller 500 machine, you could simply do multiple dominos and achieve the same or more glue surface area of a single larger or deeper domino. In many instances double tenons are used in furniture for increased strength for this reason. Or wider mortises for shop made dominos as mentioned above. I'd say the loose tenon approach and a good water resistant glue is more than enough for a project like this.

If you're a purist craftsman, the idea of drawboring without glue or through tenons with wedging is very appealing also. Necessary? Maybe not.

[scott lipscomb]

My 2 cents-glue won't work on planter boxes. I am a landscape architect and contractor and during the summer, planter boxes get irrigated every day. The whole concept is get everything wet, then let it dry out, repeat. Over and over. Planter boxes need mechanical fastening.

Actually, wooden planter boxes represent a fairly difficult design challenge...

[Ted Calver]

Quality planter boxes will be lined (copper comes to mind, but galvanized would work) with provision for drainage. Minimize soil to wood contact to ensure longevity of the box. A 3' x 6' box will need some cross brace provision in the middle to keep the sides from bowing out. It can be hidden under the soil surface and I've had good luck with galvanized all thread. If you minimize soil contact the Sipo dominoes should work for you.

[andrew whicker]

What is the best method to put tenons on long boards? I have a local wood shop I can employ if the tooling is too expensive for me.

I'm willing to spend about $1400 ish on new tooling. I don't have a plunge router or a nice wood vice. So if using M&T's, I'm already down to $1100 ish.

Thanks and cheers,

Edit: I guess I could use my table saw, lay the piece horizontal and use my dado blades.