I've removed my old under-layout desk, and will be replacing it with a new one. The desk is inside a closet and spans the 5' closet door opening. The problem with the old desk is that it drooped in the center, because teh 3/4" plywood I used to span the 5' opening wasn't strong enough to support the weight of my desktop computer without drooping. I'll be building a new desk that can take the weight. My plan is to use steel or aluminum angle to support the entire length of the front and back of the desktop. This angle will be bolted to the studs. The new desktop will be 3/4" melamine. A keyboard tray will be bolted to the underside of the desktop. The layout will be above the layout. I need to keep the overall desk profile thickness to a minimum so I can fit my file cabinets below the desk and my computer monitor atop the desk. I have very little experience working with metal. I know aluminum is softer and I'm asuming easier to cut and drill than steel. I've found two options at Home Depot I'm considering. 1 1/2" Slotted Stell Angle. I'm positive this will be more than strong enough. It also will not need to be cut or drilled (good) but it has a larger profile. 3/4" Aluminum angle. The advantage to this is that it has a shorter profile, it will also look nicer. But will it be strong enough? Also, will I have trouble cutting it? I guess my main questions are will a 3/4" aluminum angle support maybe 100 pounds across a 5' span. If not, how big of an angle will I need to use?