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Best way to attach hardwood edging to 3/4" ply?

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Forum topic by Walker posted 02-08-2020 03:35 AM 1145 views 0 times favorited 21 replies Add to Favorites Watch
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Walker

385 posts in 1275 days


02-08-2020 03:35 AM

I’m working on a mobile kitchen cart that has a plywood case with hardwood edging. I’ll be adding a wing on folding shelf brackets. This wing will be 3/4” ply with 3/4”x3/4” mitered hardwood edging. What’s the best way to attach this so that the miters don’t separate, and the edging doesn’t separate from the plywood?

Just glue? Splines in the miters? I just got a doweling jig. I don’t have a biscuit jointer, but do have a slot cutter bit and can make biscuits.

I’ve simply glued hardwood edging to plywood cases before with success, albeit just using butt joints. However, on a previous project with a similar layout on a bigger scale, (the edging was 2” wide) I did tongue and groove all the way around, with mitered corners. The edging shrunk and the miters pulled apart, also some spots the edging pulled away from the center piece. Although, this was hardwood attached to hardwood.

-- ~Walker


21 replies so far

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therealSteveN

5925 posts in 1377 days


#1 posted 02-08-2020 04:44 AM

Considering that for the most part the edge of plywood is edge grain. I like some form of interlock, so you are getting glue surface on face grain at least a little bit, that way you don’t hear all your glue getting slurped into the end grain where it isn’t going to do as much good for you.

The size is determined by the look you want, and also that the wider stuff stiffens the edge so you have less potential for sag.

But if all you are looking for is a way to hide the plies, glue on a solid piece, followed by some brads to hold it still have worked for a long time.

-- Think safe, be safe

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SMP

2248 posts in 708 days


#2 posted 02-08-2020 04:57 AM

I find that glue and brads/finish nails lasts longer than my wife likes the style or whatever and wants something else. Had a fish tank stand for 10 or 15 years that held up fine even getting splashed/leaked on with salt water.

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Walker

385 posts in 1275 days


#3 posted 02-08-2020 04:59 AM

I need the edging to be the same thickness as the ply. The “Better” picture is what I’ve done in the past, but the hardwood shrunk and it pulled apart the miters. Anyway to avoid that? I can’t store the wood in the environment it will eventually live in, because this will be a wedding present.

-- ~Walker

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bandit571

26126 posts in 3486 days


#4 posted 02-08-2020 06:00 AM

Picture #4….

-- A Planer? I'M the planer, this is what I use

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bilyo

1133 posts in 1905 days


#5 posted 02-08-2020 03:25 PM


I ve simply glued hardwood edging to plywood cases before with success, albeit just using butt joints. However, on a previous project with a similar layout on a bigger scale, (the edging was 2” wide) I did tongue and groove all the way around, with mitered corners. The edging shrunk and the miters pulled apart, also some spots the edging pulled away from the center piece. Although, this was hardwood attached to hardwood.

- Walker


This is not unusual when gluing hardwood edging onto the end grain of a hardwood panel. The hardwood panel will expand/contract across the grain and the long grain of the edging won’t. Something has to give. That is what breadboard ends prevent. The “good” or “better” methods will work just fine on a plywood panel.

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LesB

2572 posts in 4246 days


#6 posted 02-08-2020 07:42 PM

One solution would be to make the end pieces thinner and just use but joints. Instead of 3/4” just make them 1/4” thick (by 1” wide). It is enough to cover the plywood and stand up to minor abuse but not thick enough for significant movement of the wood. If the plywood is sanded smooth the glue surface will be stronger than the wood…Tightbond III. I usually make mine slightly wider than the 3/4 ply (1”) and sand or plane it down after the glue has set up. That way it is easier to glue and clamp and you know you have the plywood fully covered.

-- Les B, Oregon

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PPK

1767 posts in 1612 days


#7 posted 02-10-2020 06:14 PM



One solution would be to make the end pieces thinner and just use but joints. Instead of 3/4” just make them 1/4” thick (by 1” wide). It is enough to cover the plywood and stand up to minor abuse but not thick enough for significant movement of the wood. If the plywood is sanded smooth the glue surface will be stronger than the wood…Tightbond III. I usually make mine slightly wider than the 3/4 ply (1”) and sand or plane it down after the glue has set up. That way it is easier to glue and clamp and you know you have the plywood fully covered.

- LesB

+1. Edging doesn’t need fancy joinery. Butt joint is just fine for plywood. I use a flush trim router bit, and then sand. Never had edging come loose. Use TB III.

-- Pete

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PPK

1767 posts in 1612 days


#8 posted 02-10-2020 06:17 PM

One further thought. There’s several things to consider when deciding what joint to use… Time, looks, strength. Lets face it. Plywood is going to de-laminate far before a butt glue joint fails. If it’s not an aesthetic adder, then why use it? And try to beat the time of a butt joint… Those are all things that go through my mind anyway.

I guess on the other hand if you really enjoy the process, then go for that “fancy” joinery! :-)

-- Pete

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Walker

385 posts in 1275 days


#9 posted 02-10-2020 07:27 PM

The plan is to use the 3/4×3/4” edging to match the rest of the project. Ok, so butt joint is fine for the edging to plywood joint. Or T&G if I’m feeling fancy. My concern really is the mitered corners pulling apart. Do I use glue in the miters? Splines in the miters? Nothing in the miters?

-- ~Walker

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PPK

1767 posts in 1612 days


#10 posted 02-10-2020 09:45 PM

For a long time, I’ve used only glue on 3/4” edging with miters. Never had a problem with them opening up. You’re using plywood, which doesn’t have any significant movement, so you’re fine with nothing. Again, a spline or other joint looks fancy, but not necessary in this case.

-- Pete

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Bill_Steele

714 posts in 2534 days


#11 posted 02-10-2020 09:53 PM

If the edging is 3/4×3/4 there does not seem to be much room for reinforcement (e.g. a biscuit). I suppose a spline may add some reinforcement but probably not necessary. I would say just make sure you get plenty of glue on the end-grain of the miter joint and it should be fine.

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ChefHDAN

1700 posts in 3652 days


#12 posted 02-11-2020 04:27 PM

There are some nice bits to do this with your router table, take a look at these bits I have a larger 1/2” shank version that I will use when a straight glue up won’t work. Do the two short sides and glue them in place, then use a backer block and cut the profile on the other sides all the way through he applied hardwood. It will lock it all together and give much more glue surface for your miters.

-- I've decided 1 mistake is really 2 opportunities to learn.. learn how to fix it... and learn how to not repeat it

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JackDuren

1255 posts in 1762 days


#13 posted 02-11-2020 04:31 PM



For a long time, I ve used only glue on 3/4” edging with miters. Never had a problem with them opening up. You re using plywood, which doesn t have any significant movement, so you re fine with nothing. Again, a spline or other joint looks fancy, but not necessary in this case.

- PPK


Agree. ......

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Jimothy

56 posts in 1743 days


#14 posted 07-09-2020 06:47 AM

Yeah, I’m not surprised the miters came apart when it was hardwood to hardwood. The edging on the ends of the hardwood are cross grain and couldn’t handle the movement of the middle/main section. With plywood though, considering the movement is very minimal, just using glue is fine. I’ve done it many times without problems! But yes, if you were to use hardwood on hardwood again I would definitely use miters, dowels or some other reinforcement on the miters.

View Underdog's profile

Underdog

1514 posts in 2838 days


#15 posted 07-09-2020 12:12 PM


Yeah, I m not surprised the miters came apart when it was hardwood to hardwood. The edging on the ends of the hardwood are cross grain and couldn t handle the movement of the middle/main section. With plywood though, considering the movement is very minimal, just using glue is fine. I ve done it many times without problems! But yes, if you were to use hardwood on hardwood again I would definitely use miters, dowels or some other reinforcement on the miters.

- Jimothy

Actually on hardwood to hardwood you should accommodate the wood movement, and not use miters. You should make a sliding joint on the end grain. Otherwise you’ll be disappointed every time, because the wood IS going to move… Especially on a piece of any size. For small boxes you might get away with it. But on a table size object? You’re just asking for joint failure.

-- Jim, Georgia, USA

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