To glue or not to glue...that is the question

[Al Bacon]

I am building four drawers in a pantry cabinet. The drawers are about 3" high and 20X21 square. Bottom will be 1/4" pre-finished plywood and the sides are 5/8" Maple. The expansion will be vertical so it seems that it would be correct to glue the bottom in place but I have learned over the years that many things that seem logical to me are not correct. Having learned that lesson the hard way, I turn to you... Which is the best way glued or floating?

Al

[Prashun Patel]

People float the drawer bottoms in slots to protect against expansion of a solid wood bottom panel, not the sides.

[Erik Christensen]

I have glued 100% of my plywood bottoms - oldest are > 5 years and no issues. IMHO the only reason not to glue a plywood drawer bottom is if your design is to have the back of the drawer above the drawer slot so the bottom can be slid in from the back & tacked and therefore replaced. a glued bottom keeps the drawer from racking and putting undue stress on the drawer side joints.

[Andrew Pitonyak]

I have never glued a drawer bottom in place. I assume that the bottom is captured in a slot and not say screwed or nailed to the bottom of the drawer. I have heard of some people wanting to prevent rattling, but then you need to be careful based on expected wood movement and such.

http://www.sawmillcreek.org/showthread.php?97816-Glue-drawer-bottoms

[John TenEyck]

A glued in plywood bottom makes an incredibly rigid drawer. The only plywood bottoms I don't glue in are the ones I slide in from the back. But when it's captured on all four sides there's no way to get it out later anyway, so I glue them in. There's essentially no expansion/contraction with plywood, and I've never had one fail - some over more than 20 years.

John

[Andrew Pitonyak]

A glued in plywood bottom makes an incredibly rigid drawer. The only plywood bottoms I don't glue in are the ones I slide in from the back. But when it's captured on all four sides there's no way to get it out later anyway, so I glue them in. There's essentially no expansion/contraction with plywood, and I've never had one fail - some over more than 20 years.

John

I recently created a large drawer that is made of regular wood (about 2.5' x 1.5'). Are you using regular wood for the sides? Won't the sides move and then if the ply does not move with it, won't there be a problem? I suppose that in our humidity controlled homes it is not as big a problem as it used to be. Just curious.

[Al Bacon]

I recently created a large drawer that is made of regular wood (about 2.5' x 1.5'). Are you using regular wood for the sides? Won't the sides move and then if the ply does not move with it, won't there be a problem? I suppose that in our humidity controlled homes it is not as big a problem as it used to be. Just curious.



Yes I am useing solid wood for the sides, front and back, however the movement should be vertical so it should not effect the plywood in any way. I am going to glue them in place. Thank you all for your comments.

Al

[Andrew Pitonyak]

Yes I am useing solid wood for the sides, front and back, however the movement should be vertical so it should not effect the plywood in any way. I am going to glue them in place. Thank you all for your comments.

Al
Good point!

[Peter Quinn]

I hot melt them in from below post glue up. A few thin beads at the intersection of bottom and sides does the trick. Hot melt remains flexible, so any moderate movement is accommodated, though with plywood it's hardly an issue. I have glued plywood bottoms in, if they are snugly fit it can be a challenge to get the drawer together, it's a fine line. I don't think it would hurt anything.

[Frederick Skelly]

+1 on table saw.

Unless the piece is small. Like today. I used the bandsaw to cut a scrap to 3" wide x 5" long. Then I used a sharp block plane to flatten/square the edge. Needed to sharpen the blade again afterwards, of course.

[Andrew Pitonyak]

As a side, almost unrelated note, in the back of my mind, I always figured that if I really needed to replace a drawer bottom that I had fully enclosed (but had not glued), I could set my blade and then run the back of the drawer over the table saw and cut a wee bit off the back of the drawer so that I could pull the drawer bottom out, replace it, and then use a single screw in back to secure it. Probably paranoia, however, since I have never had to replace a drawer bottom in anything....

[John TenEyck]

Yes I am useing solid wood for the sides, front and back, however the movement should be vertical so it should not effect the plywood in any way. I am going to glue them in place. Thank you all for your comments.

Al

Exactly, the drawer bottom lies parallel with the grain of the wood used for the drawer box so expansion/contraction is non-existent. Glue them in.

John

[Jacob Reverb]

I don't think it would hurt anything.

I don't think it would help anything. What do you gain by gluing? I don't get it. What are these drawers supposed to contain? Cannonballs?

[Mark Bolton]

You'd be surprised the abuse a drawer can take over its lifetime. Gluing the bottoms is commonplace in many shops. Already stated, the wood movement is in the wrong direction to cause a problem. It stops rattles. If your dado is a touch loose to ease assembly you can leave your drawers upside down and the bottoms will be at the top of the dado. And it makes a bulletproof drawer.

Every time we build a kitchen for a customer I think of actually how much could be put in a large drawer. Fill it with books or something else heavy and I want all the strength I can get.

[Kent A Bathurst]

Yes I am useing solid wood for the sides, front and back, however the movement should be vertical so it should not effect the plywood in any way. I am going to glue them in place. Thank you all for your comments.

Al

No problems with that approach - you have the wood movement issue all figgered out.

I don't do it simply because all the machining steps for floating bottoms are the same as if I wanted to glue them, so I just let 'em float. Couple screws up into the bottom of the back [shortened, of course] - I build them all the same, regardless of materials. Probably more out of habit than any rational thought involved.

The obvious exception - drawers in the shop, where I don't bother with dado/grooves, etc - glue and screw them right into the bottom edges of the sides/back.

[Kent A Bathurst]

Every time we build a kitchen for a customer I think of actually how much could be put in a large drawer. Fill it with books or something else heavy and I want all the strength I can get.

Oh, yeah - that is an exception to what I said before - deep drawers than can be filled with heavy stuff warrant the added strength/rigidity. Good point, Mark.

[Andrew Pitonyak]

Exactly, the drawer bottom lies parallel with the grain of the wood used for the drawer box so expansion/contraction is non-existent. Glue them in.

John

What is the average change in wood moisture content as the seasons change? A 3% change for the maple drawers I created looks like it will change about 0.15 inches front to back.

[Al Bacon]

[QUOTE=I am building four drawers in a pantry cabinet[/QUOTE]

The reason I asked was because a pantry drawer can hold quite a bit of weight. Reading the above comments it would seem that a glued bottom would, as I had hoped, make an almost bullet proof drawer.

[John TenEyck]

What is the average change in wood moisture content as the seasons change? A 3% change for the maple drawers I created looks like it will change about 0.15 inches front to back.

Actually, no. The length of a piece of wood doesn't change with seasonal changes in MC. All of the drawer parts have the long grain running parallel with the bottom.

John

[John TenEyck]

I don't think it would help anything. What do you gain by gluing? I don't get it. What are these drawers supposed to contain? Cannonballs?

It does help to glue in the bottom, especially when the bottom is made with really thin plywood. Gluing it in locks the bottom to the sides. That keeps the drawer square and a flimsy bottom feels substantially firmer afterwards.

John