First a bit of background. I'm building a movie theater in my basement, but the walls are owens finishing system (insuation with fabric), so mounting anything to the walls is impossible. I want to hang 3 movie poster frames on the back wall. I had an idea yesterday, but before I start cutting I need to determine if it will work. Hopefully this is an easy engineering calc, just a bit beyond my expertise.

I am installing kitchen cabinets on the back wall, with full height cabinets on the left and right side leaving 8' in the middle for counter height cabinets.

I would like to attach an aluminum bar to the tall cabinets (spaning 8') to attach the 3 poster frames. Each one weighs 13 lbs, so 50lbs would be the max load. I would like the 6 holes in the bar to be slotted if possible to make adjustment horizontally possible. I would need to know the width and thickness of the bar needed so no sag is experienced, but it is as invisible as possible.

Thank you for your help


The optimum shape to avoid bending would probably be a L-profile.

For calculating the thickness required given the three loads, some calculation is required. These are basic (essential) static calculations, so there are lots of online sources available:

Click here for a beam calculator.

The calculation needs the sectional moment of inertia of the profile.

The L-profile has a moment of inertia as given in the following web page: click here to visit the page

You'll probably do these calculations either online or by using a spreadsheet calculator, or by hand (/calculator).

Of course, the calculations follow the forward analysis path. This means, you calculate the deflection given a load case and beam design. In order to find the optimum shape, that gives a small enough deflection, you will need to do several calculations.


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