Plywood Book Shelves advice please

@sal73 - are those new boards?

I totally agree..........

...........but am unsure about this. I speak as someone who rarely uses plywood as I dislike it, especially in terms of the quality of finish issue. However a good quality plywood is a composite and must surely be stronger as an equivalent thickness?

Sorry, but they look nasty to my eyes. You could make a rebated front edge out of real wood screwed down through the shelf and glued. It would add some strength too.
Personally finish-wise I prefer a stain, sealing and waxing to finish.

 

Although ply is a composite, remember that it is just layers of "real" wood glued together in alternating directions. Real wood is very strong along the grain but relatively weak across it. Imagine two shelves, one of wood and one of ply, but otherwise identical. The wood shelf is strong across the span (with the grain) but weak from front to back. The weakness is cancelled out by the shelf being supported across the width at both ends by the sides of the bookcase. Ply, on the other hand, has half of it's grain running in the "wrong" direction (ie front to back) due to the alternating layers. Those layers admittedly make the shelf stronger across the depth, but add nothing to the stiffness across the span.

Poor terminology on my part, I meant exactly what you just said! In fact that's exactly what I did on the shelves that Jungle Jane posted up earlier. Of course, if JWK doesn't want to go thicker than 25mm then the strip can be made flush top and bottom (although this doesn't offer any extra strength).

 

Allegedly the good (expensive!) stuff doesn't have voids, but I've yet to come across anything that good.

 

Are you simply getting the ply cut to size, or are you also getting the exposed edges finished? Hand finishing is difficult to get a satisfactory finish and will need to be rounded or have a bevelled top corner to avoid damaging the bottom edges of books.

A timber lipping glued and pinned to the exposed cut edges would work, but it has to be completely flush with the top of the shelf.

25mm solid beech is what's was used in a couple of village library projects I was involved in (in the days before they were all closed to save money).

 

We used both softwood pine 6x2 laminated together for some shelves and lengths of tulip 2" thick for the others. Be warned though tulip is very expensive but planes and beads up better than softwood does. Softwood is cheaper but required more work than plywood to prepare it after lamination. It worked out roughly £11 per shelf I think.

They were then primed and painted with two coats of eggshell.

You could always create a torsion box with plywood.......but then this would be even more leg work for you.

No worries about the questions btw. With a job like this you want to get it right first time.

 

...Just to elaborate on that a bit...

The pine shelves (mostly) had a strip of Tulip glued on the front. This was so I could bead the front edge easily, as like JJ said the pine likes to tear a bit. The tulip shelves are actually about 30mm thick, depending on how much I had to plane off the rough timber. They have a rebated strip glued to the front (as described by @sal73) to make them appear the same thickness as the others.

 

Will you get to choose which bits are missing?

 

Our bookcases have taken over 6 months so far. This project won't be done in two weeks. If you want to get a joinery company to cut the bits out they may as well make it (then you will pay through the nose). I've never bought a piece of wood cut square from a timber merchant.

Ours have cost just over £300 for both (Inc paint). Its a question of what's more important time or money. You can't really have both.

 

Dare I say it.
Veneered MDF with hardwood edgings, you can get it in various thicknesses.

800mm is not a massive span, if the shelf is fixed to a back on the unit, it would give it support.

Possibly more preparation time regarding gluing on the lippings and flushing down, but its a pretty standard way of knocking up a bookcase like unit these days.
You could get it all cut to size, but I wouldn't trust the likes of B&Q etc.

Biscuit and glue it together, screws where its not seen.
But I bet you dont have a biscuit machine.

A sand over with an orbital sander, and two or three coats of polyurethane as previously said.
Finish off with wirewool and wax for a nice feel.

 

Pete for us it`s all simple , orbital sanding and biscuit , I even use dominos at work , but for someone who`s not skilled , I think the best way it`s to go solid , easy and you can send as much as you want , I`ve just finished to hand polish my table and it`s smooth as silk ..... no book will get damaged ...what you need is just a skill saw (£30) and an orbital sander and job done .... to paint use clear floor paint and bee wax for the finishing ...