Sunday, 21 May 2017
Friday, 12 May 2017
What is the best material for bookshelves?
Red deal (higher quality smaller boards) or white deal (bigger pieces) - this kind of "softwood" is strong and long but because of inconsistencies and knots the surface often needs quite a bit of preparation, so to end up with a presentable finish it usually needs to be planed and/or scraped and sanded, and then filled and sanded again before being painted.
It is rare for softwood boards to be perfectly straight in their raw state, or completely uniform in thickness. Over time they can dry and shrink a little. They can be coaxed into shape, however, and allowances can be made for shrinking.
"Hardwoods" such as oak and mahogany are usually denser & smoother. They cost much more, but they often look decorative and they are usually oiled or varnished/lacquered - but because the whole surface is visible, extra time & care is needed for the most accurate joinery.
18mm thick shelves - require vertical supports maximum 700mm apart
25mm thick shelves - require vertical supports maximum 900mm apart
As far as the depth of wooden shelves is concerned, we are limited to the width of the available boards, unless boards are joined (typically with "biscuits").
Alternatively edge-laminated softwood boards (with limited length) are available - these are made of numerous chunks, glued together.
Other Wood-based Materials:
Furniture Board - made of small pieces of wood glued together like a patchwork quilt. Strong and smooth, not given to warping but expensive if knots are kept to a minimum.
Plywood (not as smooth as MDF) - is made of layers of wood. There are many different types, some with hardwood veneer.
Block board (which has thicker pieces in the middle of a ply sandwich).
Chipboard (rough surface, bendy).
Laminated chipboard (e.g. contiboard): the surface is smooth and already white. Thinner varieties are not strong - shelves tend to sag under even a modest load, although kitchen furniture is often made of thicker laminated chipboard.
with laminated chipboard:
12mm thick shelves - require vertical supports maximum 300mm apart
all the above wood-based materials require veneer/trim on the edges and they have severe limitations when it comes to inserting screws.
Medium Density Fibreboard:
MDF is made of dust and glue. It has a smooth finish and deceptively sharp edges (I have found to my cost), but the inside is furry, in the types that are widely available. It has a certain superficial toughness, but as a shelf it is not as strong as wood. Strength can be built up by gluing boards on top of each other, and MDF can actually be very useful in conjunction with real wood in vertical components.
MDF doesn't warp or twist (unless it becomes damp), and the thickness and consistency are very uniform, which means that it can be machined with a greater degree of accuracy than most softwood.
It can be unpleasant to work with (because of the toxic dust) and it always needs veneer/trim on the edges. MDF is usually painted, as the bland colour isn't to everyone's taste, but it's amazing what a strip of oak lipping and a whipe of Danish oil can do.
18mm thick shelves - require verticals supports maximum 500mm apart
25mm thick shelves- require vertical supports maximum 700mm apart
Reclaimed materials, such as crates, old books, old pianos, old cars
Thursday, 20 April 2017
What are the components that you get on top of some shelving systems?
some architectural terms include:
entablature - upper section
architrave - moulding along the bottom of the entablature
frieze or facia - the part between the architrave and the cornice
cornice or crown - moulding along the top (which could include coving)
pediment - triangular top
raking cornice - cornice on the upper slopes of a triangular top
tympanum - the bit in the middle of the pediment
corbel - ornate bracket
impediment - something in the way
How big should bookshelves be?
I'm thinking of the individual spaces within a bookcase here - the height between shelves, the depth from front to back and the width between uprights.
Small books: some paperbacks measure only about 180mm high (A Format books: 178mm, Penguin 181mm), so a shelf height of just 200mm (about 8") might be considered adequate in extreme cases.
Minimum depth 152mm (6") but more usually about190mm (7½").
Medium sized books: (B Format 198mm, Demy 216mm, A5 210mm, Royal 234mm) In practice there's a variety of book sizes on most shelves and I suggest that a shelf height of less than 255mm (10") can look a bit cramped.
For most books I recommend a shelf height of between 260mm (10¼") and 305mm (12").
Depth between 240mm (9½") and 305mm (12").
Large books: I have several ("coffee table") books which are around 380mm (15") from top to bottom. In most cases you wouldn't need shelf space high enough for these, as they can just as well lie horizontally.
Records: I would allow at least 330mm (13") to allow for the generous size of some box sets. Depth also 330mm (13").
CDs: I suggest a minimum height of 135mm (5¼") and it's useful to install a backstop 147mm (5¾") from the front edge to stop the CDs sliding away from your grasp.
Sheet music: most of my sheet music lies flat, and so do quite a few of my music books. The height of the shelf can be quite small - that can help with keeping the music sorted into identifiable sections - from around 155mm (6").
I recommend a depth of 255mm (10") and width of 375mm (14¾").
Ring binders: they need about the same height as records.
Document wallets: height 305mm (12") depth 380mm (15") width no more than 500mm (19¾").
Every instance is also dependant on the space available and how the bookcase would look in the room. You might want to leave spaces for windows, ornaments, displays, musical instruments or box files...
Width: this depends on the size of the available space, the appearance of the bookcase and the strength of the material. Wooden shelves can in theory span 750mm to 1000mm (about 30" to 40") but this seldom looks right, as the broad width tends to conflict with the vertical emphasis of the books themselves. With 18mm mdf (which is smoother than wood and not given to warping) I would suggest that the maximum span for a book shelf would be 510mm (20") to avoid sag. The span can be increased with thicker material (e.g. 25mm mdf) or gluing pieces together in an mdf sandwich.