Anyone know about construction? How much support am I losing?

[ManBearPig]

So...i messed up my measurements. I'm building a TV riser to put my TV on top of and my huge center speaker underneath of. How much structural integrity/strength/support/whatever would i lose (if any) by going from TV riser A to TV riser B? The TV + stand weighs 76.5 lbs.

A:

B:

Sorry for the weird view, I havent built them yet and I was just trying to see what it would look like (I flipped the images).

THANKS!

 

[MagnusTheBrewer]

Measurements and materials needed.

P.S. That dust ruffle/duvet cover and the carpeting are making me hallucinate.

 

[Greenman]

How much load are you talking about? If it's just a flat screen it wont matter at all.

 

[dsfunk]

B will look better. How heavy is your TV?

 

[ManBearPig]

Its 3/4" MDF wood. The feet will be about 22" apart. I fucked up because i for some reason thought they'd be 12" inches apart...

TV + stand = 76.5 lbs.

 

[Jeff7]

Ignoring any strength effects with respect to abrupt collapse or anything like that, particleboard is going to bow over time.
A board a few feet long will bow under nothing more than its own weight after a year or two.

 

[MagnusTheBrewer]

Its 3/4" MDF wood. The feet will be about 22" apart. I fucked up because i for some reason thought they'd be 12" inches apart...

TV + stand = 76.5 lbs.

You're good to go for a year just like with ikea.

 

[ManBearPig]

Well im going to use adhesive to glue the feet to the top, nail the top into the feet with 2" nails, and use 4 L-brackets to secure the feet and top.

 

[MotF Bane]

Ignoring any strength effects with respect to abrupt collapse or anything like that, particleboard is going to bow over time.
A board a few feet long will bow under nothing more than its own weight after a year or two.

This.

 

[IronWing]

While L-brackets will help, I'd want a vertical crosspiece between the legs to keep it from swaying and collapsing.

 

[ThatsABigOne]

While L-brackets will help, I'd want a vertical crosspiece between the legs to keep it from swaying and collapsing.

This.

 

[ManBearPig]

While L-brackets will help, I'd want a vertical crosspiece between the legs to keep it from swaying and collapsing.

This.

I might do this with a piece of the scrap wood i have (he recommended it), but i think my speaker has a rear firing port, so this would probably not work. Any other suggestions guys?

Also, back to the main topic, are A and B equal or is one better than the other?

 

[IronWing]

The supports should be as close as possible to be directly beneath where the TV hits the top piece, maybe slightly to the outside of that. Plywood would serve better but if MDF is what you have, it should work.

 

[Jeff7]

I might do this with a piece of the scrap wood i have (he recommended it), but i think my speaker has a rear firing port, so this would probably not work. Any other suggestions guys?

Also, back to the main topic, are A and B equal or is one better than the other?

Making some assumptions...

A will be stronger with respect to stress in the horizontal wooden piece, and with respect to deflection in the center.

B will be more stable due to its wider base.

 

[ManBearPig]

Making some assumptions...

A will be stronger with respect to stress in the horizontal wooden piece, and with respect to deflection in the center.

B will be more stable due to its wider base.

Well, i think i will just go get another piece of wood then since i need it to be stronger w/ respect to stress since no one would ever actually touch it (im anal lol).

 

[AdMac]

if u add a strip of 3/4 by 1 1/2 in. pine to the front and back of the shelf, it will eliminate any "sag" you may get when setting heavy objects on it......put a face frame on it

 

[AdMac]

use glue on that mdf as well, brads and screws arent enuff

 

[AdMac]

http://www.google.com/imgres?q=shel...&ndsp=13&ved=1t:429,r:4,s:12&biw=1024&bih=643

 

[ManBearPig]

use glue on that mdf as well, brads and screws arent enuff

I was already thinking about doing that, but definitely will now. Any suggestions as to which kind of glue?

 

[Red Squirrel]

I would add a cross brace from both supports, it will help prevent it from bowing. Two may be better, add them a few inches in. A piece of vertical MDF may even do the trick, though I'd probably just use wood, a 2x2 should do the trick. Screw it through the MDF on both sides.

As for glue, I find Weldbond works great, though if you are going to go out and buy glue may as well get some that is specifically for wood. Weldbond is more of a general purpose glue, but works very good on wood. The nice thing with MDF is that it's very porous so glue will work wonders.

 

[ManBearPig]

I would add a cross brace from both supports, it will help prevent it from bowing. Two may be better, add them a few inches in. A piece of vertical MDF may even do the trick, though I'd probably just use wood, a 2x2 should do the trick. Screw it through the MDF on both sides.

As for glue, I find Weldbond works great, though if you are going to go out and buy glue may as well get some that is specifically for wood. Weldbond is more of a general purpose glue, but works very good on wood. The nice thing with MDF is that it's very porous so glue will work wonders.

Awesome. I really cant spare space on the inside...what if i used a lip (im kind of confused on this...is a cross brace a lip?) and just put it on the back, on either side with a break in the middle for the speaker port? Or a vertical lip on either side on the back.

 

[dave_the_nerd]

You can probably get away without a cross brace if you:

1) Use 3/4" plywood, not particle board.
2) Keep the legs =< 18" apart.
3) Connect each leg with at least two of these. (or something similar.) Use 1/2" #6 screws to attach.

I'd still feel better with a cross piece along the back though.

How the hell big is your TV? My 32" weighs like 25 pounds.

 

[dave_the_nerd]

Also, have you considered building it out of metal, and applying thinner wood as a cosmetic treatment?

 

[Red Squirrel]

You could have it right at the edge, though this way is the most optimum, if you can manage that. (guessing this is going over something?)

You could bring those braces at the ends, but having them near the middle is optimum. Think of joists that hold a floor, if they're too far apart it will sag.

 

[ManBearPig]

Also, have you considered building it out of metal, and applying thinner wood as a cosmetic treatment?

Im too stupid to work with metal, seems like it'd be harder, no?

My tv is this, with the stand (52"):

You could have it right at the edge, though this way is the most optimum, if you can manage that. (guessing this is going over something?)

You could bring those braces at the ends, but having them near the middle is optimum. Think of joists that hold a floor, if they're too far apart it will sag.

Damn, i definitely see what you mean about the brace but this would totally fuck up my measurements and i'd have to probably spend a bunch more to get more wood instead of just a small piece for $10. I could do the (back) outside vertical lip on either side, or a (back) horizontal lip on either side with a break in the middle for the port hole.

You're right, it will go over something...the reason this is such a PITA is because the gigantor center speaker will go underneath it while the TV will go on top of it. Thanks again for your suggestions everyone.