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nails vs screws for plywood desks

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Forum topic by mamalbh posted 09-23-2012 07:42 PM 3704 views 0 times favorited 18 replies Add to Favorites Watch
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mamalbh

7 posts in 723 days


09-23-2012 07:42 PM

Topic tags/keywords: question

Hi, this is my first post & I’m still pretty new to wordworking.

I’m making three of these desks out of plywood. The plan calls for just nails and glue, which would be a lot quicker than screws, but I’m worried about how strong they’ll be.

We homeschool so these desks will be used a LOT, and hopefully last a long time. Will nails & glue be strong
enough?

(FYI – everything is already cut & primed)

Thanks


18 replies so far

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Cosmicsniper

2199 posts in 1810 days


#1 posted 09-23-2012 07:55 PM

There’s an old saying, “carpenters use nails [and screws], furniture makers use glue.”

Glue two boards together along the grain and it’ll be the wood that breaks, not the glue line.

Not true when gluing end grain, but that’s the job of a talented woodworker…to figure a way to join the pieces in a way that you can use glue to make a solid joint. So, it depends on the design as to whether it’s good enough. If the plan uses a lot of mortise and tenon joinery, dovetails/half-laps/box joints, dados/grooves, and even dowels to increase the glue surface at the joints, then it’ll be more than sufficient. Otherwise, you better have more screws than nails.

My two cents.

-- jay, www.allaboutastro.com

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Cosmicsniper

2199 posts in 1810 days


#2 posted 09-23-2012 07:59 PM

BTW, nothing wrong with fasteners. I use my pocket screw jig all the time. Just stating the importance of a good glue joint.

-- jay, www.allaboutastro.com

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Cosmicsniper

2199 posts in 1810 days


#3 posted 09-23-2012 08:29 PM

Looking at the plan for that desk where everything is butt jointed, I would use screws, especially if you use MDF. Be careful with the MDF. Predrill your holes or else it’ll split the second board. I’d use plywood.

To me, screws are faster than nails anyway and less risk of denting the wood.

Edit: I just noticed you said everything is primed? That will definitely affect the glue’s adhesion. Generally you do that after its assembled…or you don’t prime on the glue areas. Not too big a deal here, since everything is a butt joint, but it jut shows that you should use screws.

-- jay, www.allaboutastro.com

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mamalbh

7 posts in 723 days


#4 posted 09-23-2012 09:00 PM

Thanks – I’m doing the interior of the desks in bright colors – those sides are actually already painted because I couldn’t see how I’d be able to paint inside such small spaces.

So, screws it is. I’ll probably use my kreg on the outer pieces, and just counter sink on the shelves/dividers

One more question – after all the cutting was done the smaller ‘divider’ pieces all bowed slightly. I don’t have the time or money to not use them. Any suggestions to make them work?

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Cosmicsniper

2199 posts in 1810 days


#5 posted 09-23-2012 09:12 PM

What materials are you using?

If the warped wood is to be shown, I would replace those boards. You can use cross braces with screws to straight them up, but it wouldn’t be pretty.

-- jay, www.allaboutastro.com

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mamalbh

7 posts in 723 days


#6 posted 09-23-2012 09:23 PM

Arauco plywood.

None of the pieces are visible from the front, unless the doors are open, one piece will be visible from each side.

I did let the wood sit (inside) for quite awhile before & after cutting – unfortunately the weather wasn’t very good and perhaps the humidity changes are to blame. But I need to get it done ASAP

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Cosmicsniper

2199 posts in 1810 days


#7 posted 09-23-2012 09:32 PM

Definitely the humidity. As stable as plywood is, it will also bow on you if the conditions are right.

You could use clamps to hold the wood square as you screw them on. Once screwed, they should hold their shape somewhat. Tough call though. If you are a perfectionist, then it might bother you.

-- jay, www.allaboutastro.com

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mamalbh

7 posts in 723 days


#8 posted 09-23-2012 09:53 PM

Here’s a crappy drawing of what’s going on – the desk is essentially three deep narrow boxes, 2 vertical, 1 horizontal. There will actually be three cross pieces (top, middle and bottom) only top piece is shown, and only one side piece is shown. Hope that made sense.

I very visual and can’t picture how to use clamps to keep it straight while being screwed. Could you describe how? Sorry & thanks

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mamalbh

7 posts in 723 days


#9 posted 09-23-2012 10:47 PM

Maybe just clamp the bowed plywood to the straightest 2×4 I have while screwing? Would that work?

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Loren

7543 posts in 2299 days


#10 posted 09-23-2012 11:55 PM

If the desks are attached to a wall you may not have problems,
but such designs (a lot of the “modern” stuff takes structural
risks) may not hold up as well as freestanding pieces.

-- http://lawoodworking.com

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Rick M.

3947 posts in 1032 days


#11 posted 09-24-2012 04:15 AM

The nails in that project are meant to act as clamps while the glue dries. You won’t get good holding power with nails or screws into MDF.

-- |Statistics show that 100% of people bitten by a snake were close to it.|

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oldnovice

3759 posts in 2019 days


#12 posted 09-24-2012 05:05 AM

I would use biscuits and glue!

If you want you can add cleats to the hidden inside corners for additional glue surface and to straighten out any pieces that may need straightening.

At the other extreme you could use steel dowel and screws. These come it a variety of sizes and colors which can be left exposed or counter bored and plugged. If you leave them exposed you can knock down the desks for transport and or storage.

-- "I never met a board I didn't like!"

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Loren

7543 posts in 2299 days


#13 posted 09-24-2012 05:24 AM

Look into “Miller dowels”. It’s a form of dowel that uses
a stepped drill and goes in more or less like a screw from
the outside of the cabinet. You can clamp and nail your
cabinet, then drill and insert the Miller dowel from the
outside. The strength of the joint is great, assembly
easy, and the appearance is very good.

-- http://lawoodworking.com

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exelectrician

1558 posts in 1079 days


#14 posted 09-24-2012 06:52 AM

Nix the nails! Pocket screws and bisquits with Titebond III glue – You won’t be sorry.

-- Love thy neighbour as thyself

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MrRon

2830 posts in 1895 days


#15 posted 09-24-2012 05:09 PM

It would depend on the plywood used. If you used Baltic Birch, glue and nails or screws would be fine. Cheap big box plywood or MDF; no way. You may be better off using pine shelving or glued panels.

I just realized you had the pieces already cut and primed. That changes things. For strength, you need to use joints of some sort. Butt joints won’t make it. Check with the catalogs on-line; Rockler, Woodcraft, etc for knockdown hardware. these are used with butt joints for sturdy connections, no glue needed.

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