mdf wardrobe doors

[gary watson]

Evening folks,

I'm building some fitted wardrobes in some alcoves in a bedroom in my house and having nearly finished the exterior carcasses and internal shelves etc I can no longer ignore the perplexing question of making the doors (perhaps I should have thought about this up front before I started .... but anyway....)

I am considering using MDF for the doors since (a) it's cheap and (b) it's easy to work with (allegedly).

Firstly, I have heard that there are available certain brands of MDF that are free from urea formaldehyde - does anyone know of any brand names and/or stockists of such MDF in the UK and how does its price compare with ordinary MDF. Alternatively, I have "heard" that a good few coats of oil based paint (on top of primer/base coats naturally) will seal ordinary MDF to render it "safe(r)". Quite how much it seals the wood is another question but I guess "common sense" would suggest that it may arrest the rate at which any nasty gases leach into the atmosphere - but by how much and how safe is probably anyone's guess. Does anyone else have any suggestions and or advice that I can add to my existing stock of conflicting opinions and general confusion ?

Secondly, concerning the actual construction of the doors themselves, the doors are to fit a gap approximately 60" wide and 70" high so I was contemplating making a pair of bi-folding doors comprising four "half" doors approx. 15" wide per half-door. I want to give them a framed and panelled appearance - just simple square edged frames - no fancy mouldings - so rather than buy square section wood mouldings I was considering using 6mm MDF sawn into long strips say 2"-3" wide and then gluing these to the main door panels which would themselves be

12mm MDF (Apologies for mixing metric and Imperial units). My questions concerning the door construction are :-

(1) Gluing the false frames to the panels :- does MDF-MDF glue well face side to face side ? Is ordinary wood glue suitable for this task ?

(2) Hinges:- I will be using ordinary hinges screwed into the edges of the doors and to the wardrobe door frame. I have heard that MDF does not take screws too well - does anyone have any advice for how to obtain a good secure fixing ? Even 12mm MDF seems to be very heavy stuff and I am concerned that the screw size permitted by the hole size of the hinges may not be up to the job. I am precluded from using "Blum" type hinges since the front of the wardrobe consists of a flat outer frame of 3"x1" (nominal size) inside which the doors will be hung - thus the door edges need to be hinged to the inside vertical edges of this frame - as opposed to kitchen cupboard type construction where the side of the carcass is at 90 degrees to the door face and allows the "blum" type hinges to be used (I hope you see what I mean - I guess a diagram would help - but an ASCII diagram would probably just look incomprehensible).

(2a) Is 12mm MDF thick enough to take screws of a reasonable enough size to support the weight of two 15" wide by 70" high doors.

I hope I have described my problem in a reasonably comprehensible fashion. I would be grateful for any advice any uk-diy readers can provide including alternative methods of constucting the doors (NB simple/quick methods - i.e. mortice/tenoned frame and panel type construction is out of the question).

Anyway, thanks in advance for any advice anyone can provide,

Gary

[Bob Minchin]

IMHO, MDF is not strong enough to support it's own weight and will not stay flat when used as doors in this way. I may be OK for a while but I fear it will end in tears.

Consider buying 'paint ply' doors from your timber merchant (not the sheds). These are cheap and light and available in width steps of 3" x 78" tall. With care, can be shortened if needed byy cutting and regluing the edge timber back in between the skins and also the width can be reduced by about

3/4" on each edge by sawing and planing. They can be painted as the name suggests or stained/varnished. Using standard mouldings, these can be made to resemble panel doors. HTH

Bob

[Rob Morley]

MDF is heavy and doesn't like taking screws in the edge.

I'd probably knock it together out of 4 x 1 (or thicker) softwood and

1/8" hardboard with lap joints.

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[stuart noble]

My 6ft+ doors have stayed perfectly flat for close on 20 years. They have

6mm mdf panels too.

[Fergal]

Couldn't you just add another strip of wood (MDF or whatever) inside the vertical sections of the frame but set back from the face by the thickness of the door. This would enable you to use concealed (blum) hinges which have the advantages of not needing to screw into the edge of the doors and are also adjustable so you can get the door alignment just right. From the outside the door/frame combination would look the same or better IMO as there would be no visible hinges.

Fergal

[Adrian Berry]

A good way to put screws into the "end grain" of MDF is to use the old fashioned fibre rawlplugs/

Drill a tight fitting hole, fill with wood glue and tap in the plugs flush to the surface (trimming, if necessary, with a sharp chisel)

When dry, screw into the plugs - a good fixing is obtained and the chance of splitting the MDF is much reduced.

Even using this method, 12mm is very thin for an edge fixing - have you paid a visit to your local hardware shop to see if any of the cranked flush hinges will allow you to fix into the back of the door where you have a double thickness (door plus glued on paneling) to screw into?

HTH

Adrian

[Rob Morley]

Similarly you can drill holes through the panel in line with the screws, glue dowel into the holes and trim flush, then drill clearance through the MDF and pilot through the dowel and squirt some glue into the holes before screwing. This is fiddly but makes it very unlikely that the MDF will split.

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[gary watson]

I've never really used MDF but I picked up a 4'x4' sheet once and was surprised at it's weight compared to similar thickness ply.

I've never come across these but they sound interesting. I always try to buy large orders from a local timber merchant but have always dealt with them by phone/fax. Maybe I should ask their advice or go and have a wander around their premises - they are always helpful. I try to avoid the large sheds except for small last minute emergency purchases when I don't object to paying through the nose so much.

The only pre-made cupboard type doors I have seen are the louvre type doors that the large sheds seem to stock. If something like that is available but in a plain flat style then that might be what I'm looking for. I'll try and check it out.

Thanks,

Gary.

[gary watson]

...... snippety, snip .......... 8<

I'm not quite sure what you mean. Do you mean another strip that would be thick enough to form a substantial face at right angles to the face of the doors so that I could use the normal 90 degree blum type hinges ? If so that wouldn't really be practical for my particular case. Although I may have misunderstood. I'll attempt a quick ascii diagram to show my particular configuration (although you may have to cut'n'paste it into something like notepad that uses a fixed-width font for it to make sense).....

| | | | | | |_|_____ ___________ |_______||____________

I hope the above displays sensibly - it is a plan view - or horizontal cross-section I suppose would be more accurate - the vertical edge is the side panel of the wardrobe - the first (i.e. leftmost) horizontal piece is the 3" outer frame - the second horizontal piece is the leftmost edge of a door. As (I hope) you can see - I would need a blum type hinge that is engineered for fixing in a 180 degree closed position and opening to more than 270 degrees. I have done a quick google search and the best I can come up with are some blum type hinges that are made for corner type kitchen cupboards but these do not seem to have sufficient angle (i.e. door to side panel angle is

135 degrees).

I found the data sheets for the hinges difficult to interpret though since they seem to be more oriented to folks who will be setting up jigs for manufacturing large quantities of cupboard carcasses and such.

Anyway, thanks for you suggestion,

Gary.

[gary watson]

............................ snip, snip ................ 8<

I am aware that 12mm is very thin - my reason for using this thickness is that 12mm main panel thickness + 6mm thickness for the false frame = 18mm which is approximately the thickness of my edge frame (21mm or

1" nominal i.e. before planing). I guess I could go to 15mm thick MDF but the stuff seems so heavy......

On the other hand, would 12mm + 6mm for the false framed edges joined with plenty of glue not create a good 18mm thickness strong enough to drill and plug in the method you described ? Or am I hoping for too much from an MDF face-to-face glued joint ?

Thanks for your suggestion,

Gary

[stuart noble]

I think I might do it the other way round. 6mm panel and 12mm false frame. If you want the panels recessed, screw through the 6mm into the 12mm from the back. IME only kitchen type concealed hinges work long term on mdf