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Dado joints separating one year later

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Forum topic by JohnnyBoy1981 posted 04-23-2017 05:23 PM 1203 views 0 times favorited 30 replies Add to Favorites Watch
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JohnnyBoy1981

197 posts in 221 days


04-23-2017 05:23 PM

Topic tags/keywords: dado joint separating

I built this decorative bench a year ago. I had just started trying woodworking, and I didn’t really have any idea what I was doing. I tried using dado joinery for the first time, but I had to use an old router I rescued from a pawn shop and free hand it (at that time I thought a ‘jig’ was an Irish dance or something). I reinforced parts of the bench with wood screws since I didn’t really trust my work. I tossed three coats of a red indoor/outdoor paint on it (which is starting to fade already) and set it outside my house on the north side of the house absorbing the cold winds.

I noticed this year that the dado joints are beginning to separate. I can’t recall if I used wood glue in them or not, but I think so. Is this happening because of wood movement? Humidity levels? And can I do anything to fix it? The bench still holds my weight, and seems sturdy, it just looks tacky now.


30 replies so far

View Loren's profile

Loren

9433 posts in 3431 days


#1 posted 04-23-2017 05:49 PM

Take a look at the orientation of the growth
rings on the part that’s separating.

View Rick_M's profile

Rick_M

10290 posts in 2164 days


#2 posted 04-23-2017 06:23 PM

Hard to be sure through the paint but it looks like the grain is oriented the wrong way in the small dividers, they shrank.

-- http://thewoodknack.blogspot.com/

View papadan's profile

papadan

3584 posts in 3152 days


#3 posted 04-23-2017 06:30 PM

Squirt some glue into the openings and shoot a few big screws to pull it back together.

View bondogaposis's profile

bondogaposis

4397 posts in 2135 days


#4 posted 04-23-2017 06:36 PM

It looks like you used construction lumber and now the boards have dried and shrunk. Can you draw the joints tight w/ clamps? If so, glue and screw like papadan recommends.

-- Bondo Gaposis

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Rick_M

10290 posts in 2164 days


#5 posted 04-23-2017 06:54 PM

To clarify, the end pieces have grain oriented vertically, the dividers are oriented horizontally so they​ shrank in different directions. You could try forcing them together but I believe that would be a mistake. I would leave it alone and chalk it up as a learning experience.

-- http://thewoodknack.blogspot.com/

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JohnnyBoy1981

197 posts in 221 days


#6 posted 04-23-2017 07:17 PM

Here’s a close up of one of the two vertical dividers in the middle of the bench. The sides have the vertical grain pattern too. The horizontal top and bottom boards have horizontal grain direction. How should I have done this differently? In what direction does a piece of wood expand and contract?

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papadan

3584 posts in 3152 days


#7 posted 04-23-2017 07:23 PM

To me it just looks like you forgot the glue or your glue was not waterproof for outdoor use. Can you take a picture of the whole bench for us.

View Loren's profile

Loren

9433 posts in 3431 days


#8 posted 04-23-2017 07:24 PM

wood cups opposite the growth rings. Probably
the top board is oriented so it’s cupped upward
with repeated sun and moisture exposure. The
board edges would cup the other way if it were
flipped over and the joints probably wouldn’t
open up that way.

View jbay's profile (online now)

jbay

1740 posts in 683 days


#9 posted 04-23-2017 07:27 PM

I would just drown it in glue and clamp it closed and forego the screws so that you don’t have to deal with screw holes.

-- If anyone would like to see my Portfolio, PM me and I would be glad to send you the link.

View HorizontalMike's profile

HorizontalMike

7609 posts in 2697 days


#10 posted 04-23-2017 07:47 PM

At this point I am going to suggest clamping it and installing wood screws to hold it together. IMO, the mixed orientation calls for screws. I don’t think you have room to put plugs over the screws either.

Just my 2-cents…

-- HorizontalMike -- "Woodpeckers understand..."

View Rich's profile

Rich

1720 posts in 373 days


#11 posted 04-23-2017 07:55 PM

Another issue with the grain running vertical in those panels is that you screwed into end grain. Screws don’t hold well like that. Going into the long grain along the side of the board is better, since the screw threads bite into the grain and hold better.

-- No matter how much you push the envelope, it'll still be stationery.

View Aj2's profile

Aj2

1127 posts in 1581 days


#12 posted 04-23-2017 08:51 PM

Looks like the wood bowed up and away.
Just normal wood movement.

-- Aj

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Rick_M

10290 posts in 2164 days


#13 posted 04-23-2017 08:51 PM

Nevermind my post, like I said, was hard to see.


Here s a close up of one of the two vertical dividers in the middle of the bench.
- JohnnyBoy1981

-- http://thewoodknack.blogspot.com/

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JohnnyBoy1981

197 posts in 221 days


#14 posted 04-23-2017 09:18 PM



To me it just looks like you forgot the glue or your glue was not waterproof for outdoor use. Can you take a picture of the whole bench for us.

- papadan

Here’s a pic of the entire bench as it stands now:

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JohnnyBoy1981

197 posts in 221 days


#15 posted 04-23-2017 09:20 PM

I need to read some more of my beginner’s woodworking books, I guess. So would I look at the end grain of each board, and cut them (if possible) so that any expansion would go inwards or toward places where two boards connect thereby driving them together?

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