Question on strength of TV unit

[Denno]

Hi guys, first post here

I was just after people's thought on my design of a TV unit in terms of strength. I have attached a photo - I designed it in a 3D CAD program so you can get a good visual impression of what it will be like.

The wood is MDF.
I have 7 lengths of 2440mm x 500mm x 16mm
I plan to cut them up. The long piece along the middle of the stand is a full length piece, so that is the full 2440mm long and 500mm wide. The further shelving above is goin to be different lengths but at a width of 250mm (basically cutting some of the 7 lengths I have in half).
I added the green 'wall' behind so that it's clear which parts of the unit don't have backing.

Also, the door's part may be canned, and replaced with just a shelf.

If you need better clarification to give good advice then please let me
know! I plan on making this a summer project once uni finishes.

Thanks
Denno

 

[freddiemercurystwin]

16mm MDF shelves only supported at the ends will sag a bit and whilst they won't fail it will look shi*te. Try and get some more supports by getting a few vertical supports in there. Unless you're fixing it back to the wall you'll need to introduce some bracing too. This needn't be diagonal bracing just introduce some rectangle sheets at the back of some of the recesses.

 

[Denno]

Thanks for the feedback.
I'm not sure if you looked at the pic or not, but I don't have the MDF supported just at the ends, otherwise yes it would sag. I have 4 vertical supports, 2 on the ends, approx 100mm inside the very ends, and then two toward the middle, approx 795mm from each end. So the lengths of MDF that aren't supported are 100mm on the very outsides, 680mm on either side of the middle, and 820mm in the very middle.

Will this combat the sagging?

And I'm pretty sure I understand what you're saying about the bracing , that shouldn't be too difficult.

 

[freddiemercurystwin]

Thanks for the feedback.
I'm not sure if you looked at the pic or not,

Err yes, strangely enough I have, although it is the size of a postage stamp.

It will depend what you sit on the shelves, even with nothing on them, over time

680mm on either side of the middle

will probably sag a bit,

820mm in the very middle.

will likely sag a bit

If you expect to support anything weighty on them they'll sag plenty.

 

[Norcon]

How about getting some thicker sheet material like 25mm for example or using sheet suppliers flat bonding facility for thicker materials.

 

[Denno]

My apologies about the picture, I thought that was a click-able thumbnail. I've updated it now so it's a good size to look at.

Well I've got these 7 lengths of MDF for free, so I'd much rather use them if possible. I'll add more vertical supports in. I plan to put my 32" LCD, which is pretty weighty I guess, so I'll definitely want more support for it.

So MDF doesn't really make good shelving?

 

[stef86]

Your Drawing is pretty good I think If u have any sagging issues I would get myself some small 20mm L shape brackets like the ones you mayb use whe fitting a kitchen base cabinet to a wall they are small and pretty strong as they are metal I would build your unit put it up against you wall and level it and plumb it up then i would work out wher it needs fixing and were it should b okay depending on the colour your gony pick u can get some chape hardboard and paint it and do as the guy above said and pin it onto the mdf which is a lil thin and should be HDF but free is free and i can see why u wanna use what u have.