My goal is to bend 1/4-inch thick aluminum strip to make a mounting bracket for a rectangular box.
i would think you would need some steel that wouldn't deform when you went to bend it around it. also it would be easier if you had something that was at a fixed position so you could push the plate against it and it wouldn't move. I don't know if you want to hammer the plate because if will leave dents in it. if you want a sharp bend, maybe you could place the sheet on concrete, place a block of wood on the bend line, put something heavy on top of the block of wood, maybe drive a car tire on top of it, that way it won't move. start bending the plate up by hand to aroud 45 to 60 degrees then take another block of wood and place against the part your bending up and strike the wood with a hammer to get a straight uniform bend. if you want a rounded bend you could use a piece of pipe in the same manner. If your bending more that one piece or can see where you would have use for a bender in the future, harbor freight tools sells a kinda crude brake for about 30 bucks, i bought one a while back, best i can remember you can bend up to 18 wide materials at a straight bend.
You nee a tool called an aluminum brake. It is used in forming aluminum siding and other metal bending uses.
there is a special break press to bend the metal. you can also fold it over a board and hammer it, but that will not be a nice, smooth bend. You can go to the hardware store and just buy a mounting bracket or even a bent piece of aluminum.
How To Bend Aluminum Sheet
a brake press but be careful. Some types of aluminum have a grain and it will split. Also if the radius is to tight, it can fracture from stress. 1/4 aluminum is pretty strong, but you can use 1/8 and just make the bracket longer. Then you should be able to bend it quite easily on a roofers brake or manual box and pan brake. If all else fails, and it is just for home handy man use. You can use a vice and clamp it tight, on the other side clamp a piece of ply wood to distribute the force and then tap it down with a mallet. (not a hammer) You dont want to leave tool marks so the ply wood will help Do not make the bend to sharp, do not bend to quickly with a mallet or it also may get stress fractures (about 8 to 10 strikes should do it) I am curious, why aluminum. Steel has a higher tensile strength and its easier to work with .
