Quick Question on build but late

[MARINE1142]

I had a question my cab is built already just need a little sanding and primar
i was reading somewhere in here that it was not a good idea to just screw the shelf for the 27" tv to just the side panel which is 3/4" MDF the shelf has 2x6 support under the shelf. Should i go back and put 2x6 support legs from the bottom of the cab to the under side of the shelf?

[Pasqualz]

Marine1142, It depends on many things:

1) What material is the shelf made out of (MDF, Plywood) and how thick?
2) How heavy is the TV? I used a 27" TV that weighed 42 pounds.
3) Did you screw through the cabinet sides into the shelf? How long were the screws?
4) If you didn't screw through the cabinet sides into the shelf, did you instead screw shelf supports into the cabinet sides, then rest the shelf on top of them?

I could ask many more questions, but a quick picture or diagram would make thsi process MUCH easier. Bottom line is you coudl definetly add 2x6 supports up the sides of the cabinet from floor to under the shelf and that would strengthen your cabinet alot, but you pay a price in weight. If you don't care about the weight, then go ahead. I don't even think you'd need 2x6, 2x4 would work too.

[MARINE1142]

The shelf is made of 3/4" MDF Shelf and supports screwed from the side panel 2" screws tv weight is about 60 to75 lbs two 2x6 two screw on each side and the shelf 4 screws each side. dont have a pic.

[amerish]

If you are concerned, reinforce it.

Or lets look at it from another perspective....

If the shelf failed and the monitor crashed down into your computer, would you be upset that you did not add the extra support?

[AtomSmasher]

I followed the book when building mine and it said to just attach it to the sides using 2''x2'' wood and 4 shelf brackets.  The sides are more then strong enough to hold the weight of the monitor shelf as long as the monitor shelf is properly secured.

[PCtech]

If you are concerned, reinforce it.

Or lets look at it from another perspective....

If the shelf failed and the monitor crashed down into your computer, would you be upset that you did not add the extra support?

 

[Crafty]

If in doubt go with the extra support...

To be sure... To be sure...

[MARINE1142]

Good point I m glad to have you guys here to straighten me when i m tring to cut corners thanks for looking out for me. I will add the supports.

[JohnNevets]

As has been said before, when in doubt go big, and if adding the legs makes you more comfortable, by all means do it.  It is by far a stronger way to go.

That being said.... The big problem was when people would screw directly through the sides into the edge of the shelf (think cheep build it yourself furniture) thus all the weight is being put on the thin bit of shelf left above the fasteners, and thus the shelf would fail, not the screws.  If you are instead screwing (or better yet lag bolting) through the sides into shelf supports (1x2 firring boards or metal angles are fine, 2x6's are definitely fine as long as the 6" side is flat against the side) and then resting the shelf on top of those supports distributes the weight across the whole shelf support not just the area above the fasteners.  The only other thing that someone might worry about it pulling the fasteners all the way through the side of the cabinet, but with the eight fasteners you got holding up under 100 lbs you should have nothing to worry about.

Hope that helps, 

Enjoy!!

John

P.S.  If you did have the 2x6's either with the 2" side against the side of the cab or the end grain against the sides with the 6" side facing up I would DEFINETLY run legs down to the floor.  Only one more way left and that would be you screwed into the end grain with the 2" side up, this should be fine since these are 2x6's and your talking about less then 100 lbs, but I wouldn't get in a habit of doing it.

[Pasqualz]

It just ocurred to me to make you all aware of what i learned when building my cabinet. My friend is a woodworker, so we built the majority of the cabinet in his workshop. When It came time to screw pieces together, my friend said that everything should be "Glued & Screwed." When you put a thin coating of wood glue between the pieces, then screw them, the glue bonds the wood so well that you could actuually remove the screws and teh cabinet would be completely solid (don't try this, keep teh screws there for extra support!)

Now, my cabinet was made with 5/8" plywood and 2x2 strips for extra support at all corners, but I'm sure that wood glue bonds MDF just as well. The only thing is that given MDF has a layered structure, you could still have a situation where the surface areas that are glued together, stay together, but the pieces fail farther inside the pieces and de-laminate. Still, if you want your cabinet to not have a single bit of swivel in it, USE WOOD GLUE!!!!!

[amerish]

I have built 2 UA IIs (why build one at full price when you can build two at twice the cost).

My previous answer was based upon the same concerns about the MDF shelf failing because the screws might not be centered.

I added a small strip of wood about 6 inches wide from the front of the cab to the back, glue and screws (screwed from the inside so no holes on the outside). Then I installed the shelf with more glue and then screwed down onto my supports. Very strong, no problems.

If you are concerned about deflection of the shelf from weight, add a center support under the shelf (think of supports for your flooring). There is plenty of room in the UA IIs for it.

I also installed a raised strip of wood (an inch or two proud of the shelf surface) across the back of the shelf as an added safety precaution to ensure that the TV I was using would not slide off the back.

Finally I added some mesh fabric grips stapled to the shelf (used for kitchen dishes to keep dishes from sliding). The result is that the TV does not slide back.