DIY MDF making fitted shelving unit

Is this unit going to fit in between two walls, or a recess? Ie - little chance of it falling sideways?!

In which case, it'll virtually be self-supporting, so no special joints, rebates or grooves required.

Screws? Pah! Dowels? Pffft! Just butt them beauties and schtick in a panel pin or two.

Ok, I'm assuming - hoping - you'll be painting these afterwards? So any slight irregularities/gaps can be filled and painted over...

The upright partitions need to be cut fairly accurately, and if you don't have leccy tools that'll do this accurately, then I reckon the best thing to use is a good, fine-toothed hand saw. By the time you finish this job, you'll be a sawing expert.

Mark out each panel accurately - use a good quality try-square and steel rule. Once marked out, score along the cut line with a craft knife, and continue this line around to the other side. Saw with loooong, slow strokes using the full length of the saw blade - don't peck at it like a, um, pecker.

Obviously the scored line is on the edge of this cut - you don't saw on this line. You are sawing on the waste side of the score, but ideally touching it.

If it needs tidying, place all the similar panels together in a 'workmate'-type bench, and plane the edges level, and finish with a belt sander or hand-sanding.

It doesn't have to be perfect, but doe need to be 'pretty good'.

All you then need to do is ensure these vertical dividing panels stay in place. Simplest way is probably dowels where they fit into the bottom panel (yeah, yeah - I know what I said about dowels...) and then when the upper horizontal panel is fitted on top, chust slam in two or 3 panel pins which'll go around a half-inch into the partition.

All with a goodly dollop of PVA which is wiped clean with a damp cloth after nailing.

Use 'dowel pins' to mark the dowel holes. If you go wrong with this by a mm or so 'cos the drill bit moves (very annoying...), then just drill an oversized hole to cater for this, and add a goodlier dollop of glue.

MDF is great stuff, but has it's limitations. One being that it does tend to sag over time if it isn't adequately supported.

How wide will the vertical partitions be spaced? Will you have a support rail along the back for the shelves? What thickness of MDF are you planning to use?

 

You could plod away with a saw and effect a fairly good job. But I usually do some calculating and get it cut by the suppliers, then really all you need to do is line it up and glue and either pin or screw. I screw usually, having marked out all the positions beforehand. Don't screw or pin less than 2 inches from the edge or the mdf will split.

so i would make it up out of 4 sections. each section having two long sides and five equally spaced shelves. giving the 4 compartments. to keep the thickness at 18mm, for the central joining sides i would use 9mm. so you would have two sections with 9mm sides and two sections with one 9mm and the other 18mm sides. So all abreast gives you the 16 compartments. To achieve the effect of a t on its side, i would carefully cut out the unwanted shelf or side section, once its all glued and set.

You will still need some clamps to bring it all tight together, as you make up the sections.

Getting it all cut beforehand just makes it easier to get started on actually producing what you want.

 

If all the sections are symmetrical, I'd put the 2 sides and 5 across sections together first, then vertical dividers after. Assuming you are making it up in the room but not in it's final position ?
Assuming also 18mm mdf, I would rebate (mortise) the 3 shelves positions in the sides 3mm deep, glue and screw the shelves in. Top and bottom outside glued and screwed to top and bottom of sides.
Cut all the vertical dividers, fit them all, square them up and see the finished item. Mark them well, then one by one remove them and glue them back in. Inline, they will support the shelves and the top all the way up. Fill any showing screwheads(they will only be on outside of sides).
Then the rest is fitting to space and painting(or vice versa, whatever).

Mr. HandyAndy - Really

 

Good idea DW - if he has a reliable timber merchants, he should be able to give them a list of panels to cut. This could work particularly well if there are a number of panels the exact same size, so ideal for the vertical 'partition' panels - if they are all a couple of mm out it hopefully shouldn't matter - as long as they are all the same!

Screws are fine, but do need pilot holes drilled to receive the threaded portion of the screw - 2mm for a 3mm screw, etc. If you coat the thread with PVA, it'll making fitting smoother, and also bind the MDF fibres inside the screw hole making it more solid (and the screws can still be undone if needed).

I don't fully understand Frenchie's design; is it full-width shelves with spaced partitions? Will it be fitted between walls, or against even one wall? Will it have a back-panel?

If any of these, then assembly is a lot more easy, and it'll all be perfectly strong without screws, rebates, etc. All that's needed is a way to keep the vertical partitions from being knocked sideways, and concealed panel pins from above, and probably dowels below will do that, along with PVA.

For the end part - the "'T' on its side", as he describes - then probably more strengthening will be needed. Here you will need something better - possibly glued dowels, possibly glued screws will do depending on weight, or a rebate into the side (but hard for an amateur), or a simple addition of a quadrant beading underneath if it ain't too much of an eyesore.

 

Another consideration you may want to look into is adapting existing bookcases/shelving. Ikea do a budget range called the "Billy series". You would struggle to buy the wood cheaper at some of these prices. The bookcases can they be reduced or extended accordingly, just need a bit more thought and planning but at least you can take yourself to the nearest store to visualise what you will get. Also minimal cutting, lots of accessories (doors etc) and all the fixings come too. In fill pieces can be used where necessary and you can always paint it afterwards. Good luck.

 

Some of those spans are too big, google the sagulator for shelf dimensions.

 

Frenchie, Ashtree's suggestion is a good one. There's a world of difference between a professionally-finished shelf and one that you cut, sand and paint yourself. There's a danger that such home-made shelves can look 'cheap', unless steps are taken to finish it well - perhaps slightly bevelled edges on the panels, etc.

Anyways, as Chippie says, some of these spans will sag like a saggy thing. The smallest spans - ~400mm - should be ok, but even they could sag over time if loaded with books and heavy stuff.

If you have a back panel fitted, that can be used to support the backs of these shelves, so will help a lot. (But you might not want to go to the trouble of fitting panel?)

The right side of the unit makes contact with a wall? That's good - it means the whole caboodle will not be keeling over, so a much simpler construction can be used. I think I'd just build the thing up from the bottom - fit the vertical panels using dowels or similar, and then plonk the horizontal shelf on top. Panel pin down into the verticals. PVA the edges first.

The unit sides are best as full height, tho', and this will require something strong enough to take the weight of the shelf ends. Drill pilot holes and screw would probably be best here.

I notice that the left-hand side is double-thickness? That's good - it'll really help the appearance of the unit, make it look more 'contained'.

The 600mm space between the rad wall and the unit - a chair is meant to fit in there?!

The attached photos are essentially MDF shelves but with a 'return' on the side to make it look a bit better - more like a proper bookcase 'unit'. The back panel is chust 3mm hardboard but with V-grooves routed into it so's it looks like panelling.

These shelves are wide-ish at around 1m, but are supported along their full length at the back using small quadrant (as in earlier photo) and they are only around 200mm deep. And the shelves are actually flooring chipboard cut into strips and coated with hardboard top, bottom and front edge, so stiffer than MDF. But they have still sagged a small bit.

 

The left hand end will also look better for not being just 18mm thick .

The vertical V groove on my left hand end strip is not routed, it's two pieces of MDF (one is the front edge of the unit's side panel, and the other is a 75mm-wide return strip added to give it more a 'built-in furniture' look) butted and glued together after having all their corners bevelled around 2-3mm with a plane. So when the two bevels meet you get a V. All the panels have this wee bevel and it gives the whole unit a softer, more finished look I think, rather than the stark crispness of the just-cut panels.