MDF Desk - Bowing

[gaZ1976]

Hi all,

I'm planing on making some desk/bench tops out of MDF board but I'm concerned about the tops bowing.

The plan is to make two different sized tops out of 18mm MDF, one 610 x 1400 the other 610 x 1040. Then I'm screwing and glueing two pine battons 25 x 38 length wise down each board 205mm and 405mm in from one edge. The idea behind these battons is to reinforce the MDF and prevent it bowing. However, as I've never done this before will it actually work or do I need to do more.

The smaller top is going to have my computer on it so there is a reasonable amount of weight on it the other will be used for various tasks so could potentially have heavy objects on it.

Any advice would be appreciated.

Cheers,

gaZ

 

[Bespoke]

Hi

I am afraid you could just need to make some arrows to go with the bow you are setting out to make. Just think for a moment about kitchen work tops there minimum thickness is 28mm and they span a lot less than you want 18mm MDF with or with out reinforcement.

You top is way to thin you will need it to be at lest 25mm thick and reinforced with a minimum of 45 x 45 hardwood battens screwed to the underside of the top but not glued just screwed. I have done a drawing which you can get to via the link below and I have included another useful link that another member published not so long back this also may be of some help.

But why not consider using a 40mm thick kitchen work top it will still need to be reinforced with 45 x 45 hardwood but it will do you a lot better job and will also look the part.

The other thing you can consider is to use the back of the desk to support the top but I feel you will end up putting a centre leg under the work top. Have a look at using a stairs spindle or a chrome kitchen work top leg.

http://www.alanwakefield.co.uk/gaZ1976.pdf

http://www.woodbin.com/calcs/sagulator.htm

 

[big-all]

i have made several "computer desks"

in general the tops are made from 20mm solid timber or 12mm ply edged with 2x1" flat rebated and mitred at the corners

underneath there will be shelving at 90degrees at the end drawers cupboard either side with a knee well in the middle somewhere

in the knee well dependant on the tower there is a platform for the tower to stand on to bring up towards the top to make it easier reach
sometimes there is also a pull out shelve for keyboard ect

this gives a span of around 600mm unsuported without sag

now appart from the height being a bit high at around 950mm as opposed to a more normal 750mm
the fact its going to be worktop depth makes me think using kitcken worktop drawers and cupboards may be the easiest and quickest

failing that just make shure you keep your unsupported gaps to the minimum possible [600mm max]then you should be ok without additional depth on the front edge

 

[oilman]

Remember, MDF is only sawdust squeezed together with not-very-good glue.