Adventures in bending aluminum angle

[webbedouin]

Have been bending half inch wide, sixteenth inch thick, 90 degree angle aluminum over the last couple of days. You can tell I’m getting close to finishing because this has been put off forever.

Heard about annealing my very first day on this site. Figured that was the way to go. Tried it out. Pre punched the holes, found the very piece of plywood that the curve had been cut from, the perfect jig. Had determined that the screw holes would go in the inside leg of the angle, into the side wall. The inside leg being the part that has to curve for a half inch width. The outside leg being the part that has to curve around the outside of the jig. Along the one sixteenth edge.

OK so I didn’t smudge the aluminum with candle smoke, none the less, since the screw holes were on the inside leg they mal formed, puckered, crinkled and cracked. Had constant problems with the aluminum twisting since the angle kept wanting to be on the outside, could not hold the piece it to the jig even with welder gloves . The piece would continuously crimp and the screw holes as I worked beyond them. Very unsatisfactory. Way too hot for a 105 degree day. Would up tossing the piece into the scrap pile.

Decided that things could not be much worse trying to shape the curve cold. No freakin’ screw holes this time. (Though they might work well on the outside leg) My jig is in the shape of a symmetrical baseball field. With four inch flats along the outside of each foul line. Started the straight piece in dead center field and used a rubber mallet to start it off. Worked my way over to the right field line, constantly battling to keep it against the jig and of course it developed the twist. Worked my way over to the left field line, constantly battling to keep it against the jig and of course it developed an opposite twist. Managed to clamp it down along the foul lines and went to a steel hammer to de-twist the piece by hammering in the angle to the jig and then hammering the inside leg flat and adjusting the clamps as the metal spread. Repeat again and again and again. This worked really pretty well. Lottsa hammer marks on the side of the aluminum that no one will ever see and a few slight tweaks out of right angle. And of course, the finished piece springs out beyond the 22” radius of the jig and what I’m going for. Installation is going to be an exercise, but it will work!!!

This brings me to the first invention. Because the curve is wider than the fit, needed a tool to press the aluminum into place very tightly so I can screw it into place, once screwed, no problem. Took a couple of 1.5” square wood pieces. Cut one with two prongs on the outside of one end and the other with one prong on the inside of one end and put a bolt through all three prongs so I could push on the bolt, lengthen the wood and press the aluminum against the ceiling (so long as the other end was anchored) , put in the screw which press it in against the wall and all would be well.

Guess it’s too late to make a long story short, however. I was still looking for a smoother, cooler way of bending the aluminum.

Never had a ratchet strap before beginning this project. Never will be without on again. Bought four-one inch sixteen footers when starting the project to pre bend plywood pieces before installing them. Worked well. Found that they worked great at de-warping plywood parts also. Stick a 1.5 inch square piece of wood in the right spot to bend it the opposite direction by tighten the ratchet straps. Give it a few days to a week and viola! Warp forgotten.

Which brings us to the second invention… Took two of the ratchets and one strap. Looped the strap through the ratchet on the first base side by home, ran it down the right field foul line, around the straight piece of aluminum which was centered along the dead center field fence and back down to the second ratchet on the left field side of home plate. Hooked the two ratchets together a home. Tightened them up and proceeded to tweak the aluminum a few ratchet clicks at a time on each side, being careful to keep the inside leg above the jig, the outside leg on the edge of the jig and the ratchet strap centered on the aluminum angle.

The piece of aluminum pulled into the curve like magic. The only problem was the outside angle was close to 45 degrees to the jig. It was only at this point the hammer got involved. Banged along the angle to push it in and even with the jig outside edge, banged along the inside edge to keep it down, tightened ratchets and repeated until the strap had pulled it down and in as far as it could go.

Only really had one problem, as the ratchets got tighter, the strap coil gets thicker so it pulls more strap for each ratchet click, so about half way through the ratchet straps needed to be reset so the coils weren't so fat and then each click would be a shorter stretch.

It worked, by far, the best of three attempts, because the ratchet strap pulled clean and smooth while protecting the aluminum from the hammer, any tweaks from right angles could be seen and easily hammered out by going after the angle edge or the flat inside leg.. It still springs out from the jig when released, however it’sa true curve (no twists, no angles, real light on the hammer marks and very easy to clean) and with the first invention, it’ll go into place just fine.

Just thought I’d share the experience…

[toypusher]

I annealed my aluminum first using the candle method. Then clamped one end in place and just bent (by hand) it around the profile and used a rubber hammer to tap it down if it started to buckle any (top or side). Then I used a small block of wood that was partially rounded to support the piece while I drilled the necessary holes.

Just how I did it and it was very easy to bend the 1/16" x 1/2" angle.


Kerry

[ahjones3]

webbedouin,
Were you try bending the angle while you were heating it? I sooted up my aluminum and then heated it until most of the soot disappeared. I let it cool slowly to room temperature, and it bent like rubber. When i was going around the 6" radius on my door opening I had to help it a little with a rubber mallet. I drilled the holes before annealing, and screwed it down as I went. I was worried the first time I tried it, but my results amazed me.
Al.

[webbedouin]

Well i was heating & then bending, repeating. In retrospect think the real problem was the pre drilled holes on the inside leg. The metal keep kinking on the outside curve and crimping on the inside leg. Suspect it would have gone much better if the holes were non-existant or on the outside curve.

Probably should clarify the hammering on attempt number 3 with the ratchet straps, it was more like tapping with the hammer to push the angle up to the edge.

Anyway had no real problems installing that piece with the articulated elbow dealie bob. It was capable of providing the right amount of pressure in just the right spot to lay the piece into place for screwing. The pieces went in well. On the door side i was able to even anchor it in the door jam corner and use my favorite new tool, the ratchet strap wrapped around the frame rail and tightened to hold the elbow in place. Excellent! On the other side i needed a whole human being to work the elbow tool.

Sure wish i had done this before i put in the floor.

In any event, In terms of avoiding de-tempering the metal, must believe that a cold bend would be prefered. Gottada figure that there must be some sort of mandrel bending tool that would do the job to perfection. Anybody know of such an item???