Shelf design

G’day all,

Scenario:
Entertainment centre for a new wide screen TV.
The shelves have to be 1180 mm wide to accommodate TV
Construction material - oak veneered MDF (17mm)

Problem
I’m worried about the width of the shelves (1180) in that they may sag with the weight of the stereo equipment (eg the amp weighs 16.5 kg and TV, 22 kg - although these will be on separate shelves).

My suggested solutions:
1. Face the 17mm MDF with a hardwood strip 24 x 32 on edge. Would this be sufficient to stop the shelf bending?
2. Glue a strip of hardwood (say 13 x 100) on flat underneath the shelf across the width, then face the front edge with another strip of hardwood, say 24 x 32 on edge. The problem here is that I’m told gluing hardwood and MDF is LIKELY to cause the shelf to bend. Would an epoxy glue be less of a problem?
3. Glue a strip of veneered MDF (say 17 x 100) on flat underneath the shelf across the width, then face the front edge with a strip of hardwood, this time 24 x 34 on edge. Again the potential glue effects may cause the shelf to warp.

Any suggestions or comments on the best approach will be gratefully received.

Cheers
Bill

Only the shelf for TV needs to be that width.

Is the other equipment located underneath? If so, make that section divided x 2 or 3 with dividers used to support weight of TV.

I had an install job for a government dpt a while ago. The cabinet was similar to what you mention & yep the 17MM chip board shelf sagged the moment the big screen telly was placed on the shelf.

If you must span that sort of width there are a couple of solutions.

Lincon sentry sell an extrusion for strengthening the front of shelves. The shelf board slots into a recess in the extrusion, fix with a couple of screws.
However only availible powdercoated in white.

solution 2
face your board with some solid timber on edge & hide a piece of steel 25x25 rhs behind it.

remember these new big screen tvs can be real heavy 45-50kg some of them.

the shelf needs to be strong enough to sit a medium sized missus on.

don't forget to leave plenty of ventilation all this new gear produces plenty of heat.

cheers

Where I used to work we made these units and ALL were 34-8mm thick. 2 peices of 17 or 19 chipboard epoxy glued together then had a veneer strip added to front.
They were mass produced too :eek: Tonto

Does epoxy glue not have the same problems with MDF as the yellow glues? I have found that yellow glues make MDF bend! Particularly when gluing MDF to REAL wood.
Cheers
Bill