anealing aluminum

[Southern Oregon Bob]

When anealing 1/16 chanel and Ls do I need to aneal all sides or just the 2 sides on the channel and the 1 on the L .

[madjack]

...SOB(hmmmmmmmmmmmmmmm) due to heat propagation properties of the Al. if you concentrate on the center all else will be annealed also...at least that was my experience
madjack

[Southern Oregon Bob]

Does annealing more than once do anything?

[madjack]

...yes if you are talking about annealing after you start your bends. Bending annealed Al re-hardens it and if necessary, you can re-anneal it
madjack

[toypusher]

When anealing 1/16 chanel and Ls do I need to aneal all sides or just the 2 sides on the channel and the 1 on the L .

I annealled some 1/2" channel and I blackened the outside of the channel on all 3 sides, then applied the heat to all three sides. Just rotate the channel or the flame back and forth slowly until the black disappears. Be careful not to over do it, as the aluminum will just melt instantly and without warning if you overdo it. I would suggest you do a short test piece first.

BTW I used the channel to put over the sides under where the hatch sits on them. It bent into shape without any persuasion at all. just used my hands and held it on one end while putting screw in, then pushed it into place and screwed it as I went along the rest of the bend.

[Southern Oregon Bob]

Thanks all. I actually from what I learned on this forum started with my U under my galley no problem, I then made a U that was 2 3/8" wide from a cube and bent it around a 6" radius at my door opening no problem. At this point I thought I had it down, so to save time on my side corner trim I used straight accetalene to soot it up but it must of gone on to thick because 1/2 way through an 11' L melted on me. On the secound try I went back to the candle but it buckeled in three places while bending. At this point my confidence was shot and I started asking questions. When people on this forum talk about massaging the metal to remove kinks, is that code for beat the hell out of it with a rubber hammer or is there more to it than that? Thanks again for the replys. Bob

[madjack]

When people on this forum talk about massaging the metal to remove kinks, is that code for beat the hell out of it with a rubber hammer or is there more to it than that? Thanks again for the replys. Bob

...essentially, YES

annealing can be tricky,,,too much heat and it just blisters and melts, not enough and it won't bend properly and the point wanted between them is VERY SMALL, I used a light sooting technique and move the flame back and forth continually without stopping on any one point, as the flame starts to "yellow" out it is time to move on down the piece. It is a time consuming process and alotta paitience is necessary
madjack

[TomS]

The method I used is best described as Heat and Beat

First I sooted up the inside of the aluminum angle with a candle. Next, I heat the aluminum with a propane torch. I work in small increments, about 6" at a time. As the aluminum approaches annealing temperature the soot will begin to burn off. If you try to to burn every bit of soot off, you'll melt it. Instead, watch the flame very carefully. When it begins turning orange, IMMEDIATELY move on to the next section



Note how the blue gas flame turns the orange after contacting the aluminum in this photo. That is what you are looking for. I found turning off some of my shop lights made that tell-tale orange flame easier to see.

In my experience a propane torch is more than adequate. With it, I can anneal 8-foot lenths of aluminum angle in about 10 minutes.

Allow the aluminum to cool slowly. It will be much softer and easier to bend.

After annealing, I can bend the aluminum angle to to rough shape by hand. The 6" radius at the bottom of the Cubby doors was tricky for me. Especially since, I needed a 1/2" leg on the inside piece to cover up a cutting error on my inside skins. The aluminum angle WILL kink on tight curves. However, these kinks can be flattened easily with a hammer. You may want to use a wooden block to keep from denting your aluminum.