Need some sheets bent past 90 degrees to about 100 degrees and since
I've done quite a bit of work on them I'm getting a little nervous
about breaking them. They are 10.5" wide where the bend will be
and I've oriented the grain with the bend. Am I OK? Do I need to
anneal them first? Would heat from a torch help?

You can't bend T6 very much, it will crack for sure. If you heat T6, you
lose the temper. If you don't need the temper, why did you use it in the
first place?
Steve

"Terry Keeley" wrote in message
. ..
Need some sheets bent past 90 degrees to about 100 degrees and since
I've done quite a bit of work on them I'm getting a little nervous
about breaking them. They are 10.5" wide where the bend will be
and I've oriented the grain with the bend. Am I OK? Do I need to
anneal them first? Would heat from a torch help?

Terry Keeley wrote:
Need some sheets bent past 90 degrees to about 100 degrees and since
I've done quite a bit of work on them I'm getting a little nervous
about breaking them. They are 10.5" wide where the bend will be
and I've oriented the grain with the bend. Am I OK? Do I need to
anneal them first? Would heat from a torch help?


I've done this a couple of times, mostly with 2024 that was .125" thick.
If you have some scraps of the material, try a bend on that first. A
1/4" wide strip will bend the same as a foot wide piece. Look for
cracking or pulling at the outer edge of the bend. If you see none,
then go ahead and bend the machined piece with confidence. If you see
more than the usual "stretch marks" then you need to anneal. I mark
the piece with soap, and then heat until the soap streak turns brown.
I immediately quench with running water. Note that the quench will
warp the piece slightly. Generally, putting the part in the brake will
straighten the bend almost completely. The part that was quenched will
be VERY soft for about 2 weeks, and will never reach T6 hardness without
post heat treating. I just heated the area right at the bend when I
did it, not the whole part.

Jon

Terry Keeley wrote:

Thanks for that info Jon, thought about doing a test first also.

If needed you annealed with a torch right at the bend point? Never
heard about the soap trick, do you just rub some hard soap on it or
brush dish soap etc?



I think I used Ivory bar soap, but something like that. It just left a
clear
smear on the metal, but turned a bubbly brown when heated. It just wipes
off after. Due to the thermal conductivity of aluminum, the entire sheet
will heat up, but the only place you need the annealing is at the bend
line(s), so that's where I concentrated the heat.

Jon

Steve Lusardiwrote:
If you don't need the temper, why did you use it in the
first place?
Steve


Machineability...

[/quote]
I've done this a couple of times, mostly with 2024 that was .125"
thick.
If you have some scraps of the material, try a bend on that first. A
1/4" wide strip will bend the same as a foot wide piece. Look
for
cracking or pulling at the outer edge of the bend. If you see none,
then go ahead and bend the machined piece with confidence. If you
see
more than the usual "stretch marks" then you need to anneal.
I mark
the piece with soap, and then heat until the soap streak turns brown.
I immediately quench with running water. Note that the quench will
warp the piece slightly. Generally, putting the part in the brake
will
straighten the bend almost completely. The part that was quenched
will
be VERY soft for about 2 weeks, and will never reach T6 hardness
without
post heat treating. I just heated the area right at the bend when I
did it, not the whole part.

Jon[/quote]

Thanks for that info Jon, thought about doing a test first also.

If needed you annealed with a torch right at the bend point? Never
heard about the soap trick, do you just rub some hard soap on it or
brush dish soap etc?

"Jon Elson" wrote in message
...


Terry Keeley wrote:

Thanks for that info Jon, thought about doing a test first also.
If needed you annealed with a torch right at the bend point? Never
heard about the soap trick, do you just rub some hard soap on it or
brush dish soap etc?


I think I used Ivory bar soap, but something like that. It just left a
clear
smear on the metal, but turned a bubbly brown when heated. It just wipes
off after. Due to the thermal conductivity of aluminum, the entire sheet
will heat up, but the only place you need the annealing is at the bend
line(s), so that's where I concentrated the heat.

Jon

Another method of annealing: I use an oxy-acytelene torch to anneal
aluminum. If you use a
pure acytelene flame and smoke the plate with a layer of soot, then go to a
nuetral flame to
heat it, the soot will "burn off" when the area reaches a hot enough
temperature to anneal.


Bill

I've done this a couple of times, mostly with 2024 that was .125"
thick.
If you have some scraps of the material, try a bend on that first. A
1/4" wide strip will bend the same as a foot wide piece. Look
for
cracking or pulling at the outer edge of the bend. If you see none,
then go ahead and bend the machined piece with confidence. If you
see
more than the usual "stretch marks" then you need to anneal.
I mark
the piece with soap, and then heat until the soap streak turns brown.
I immediately quench with running water. Note that the quench will
warp the piece slightly. Generally, putting the part in the brake
will
straighten the bend almost completely. The part that was quenched
will
be VERY soft for about 2 weeks, and will never reach T6 hardness
without
post heat treating. I just heated the area right at the bend when I
did it, not the whole part.


The person who did the aluminum body work on our race cars used this
technique when the material had work hardened. Using an oxy acetylene torch
adjusted to make black soot he would coat the area he wanted to anneal. Then
he would adjust the torch for a normal flame and heat the area just enough
to burn the soot off. I don't remember him quenching but this was 30 series
soft material not heat treatable.
Jim

Great info guys thanks!

According to Terry Keeley :
[/quote]
I've done this a couple of times, mostly with 2024 that was .125"
thick.
If you have some scraps of the material, try a bend on that first. A
1/4" wide strip will bend the same as a foot wide piece. Look
for
cracking or pulling at the outer edge of the bend. If you see none,
then go ahead and bend the machined piece with confidence. If you
see
more than the usual "stretch marks" then you need to anneal.

For whatever reason -- I'm not seeing the original question.

Assuming that the 0.080" aluminum was supplied that way as sheet
stock, rather than machined to those dimensions -- it will have a
"grain" from the rolling process which formed it to thickness. If y ou
bend across the grain, it does better than if you bend along the grain.
You can usually identify the grain by the fine ribs left by the roller.
If you can't tell for sure -- cut off a couple of samples and try
bending them each way to see which does better.

Of course -- the annealing mentioned here can help too - but you
might need both, depending on how sharp a bend you are attempting.

I mark
the piece with soap, and then heat until the soap streak turns brown.
I immediately quench with running water. Note that the quench will
warp the piece slightly. Generally, putting the part in the brake
will
straighten the bend almost completely. The part that was quenched
will
be VERY soft for about 2 weeks, and will never reach T6 hardness
without
post heat treating. I just heated the area right at the bend when I
did it, not the whole part.

Jon[/quote]

Thanks for that info Jon, thought about doing a test first also.

If needed you annealed with a torch right at the bend point? Never
heard about the soap trick, do you just rub some hard soap on it or
brush dish soap etc?


Good Luck,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Jon Elson wrote:

Terry Keeley wrote:
Need some sheets bent past 90 degrees to about 100 degrees and since
I've done quite a bit of work on them I'm getting a little nervous
about breaking them. They are 10.5" wide where the bend will be
and I've oriented the grain with the bend. Am I OK? Do I need to
anneal them first? Would heat from a torch help?


I've done this a couple of times, mostly with 2024 that was .125" thick.
If you have some scraps of the material, try a bend on that first. A
1/4" wide strip will bend the same as a foot wide piece. Look for
cracking or pulling at the outer edge of the bend. If you see none,
then go ahead and bend the machined piece with confidence. If you see
more than the usual "stretch marks" then you need to anneal. I mark
the piece with soap, and then heat until the soap streak turns brown.
I immediately quench with running water. Note that the quench will
warp the piece slightly. Generally, putting the part in the brake will
straighten the bend almost completely. The part that was quenched will
be VERY soft for about 2 weeks, and will never reach T6 hardness without
post heat treating. I just heated the area right at the bend when I
did it, not the whole part.

Jon

You can draw a line across the area of the bend with a Sharpie marker.
Enough heat from a torch to just burn off the marker line will give a
nice anneal. Sooting the line with an acet flame of an oxy acet torch
works well too, but cleaning up the extra soot can be a minor pain.

It naturally age hardens to about a t3 or t4, requires real heat treat
to get further.

Cheers
Trevor Jones

I haven't seen anyone talk much about backing off the break and
putting in a sacrificial spacer. It increases the radius of the
bend and helps prevent that fracture line from forming. I am not
a tinner, but our tinner has done this on aluminum shapes when the
material wants to shred or crack.
______________________________
Keep the whole world singing . . . .
DanG (remove the sevens)




"Terry Keeley" wrote in message
. ..
Need some sheets bent past 90 degrees to about 100 degrees and
since
I've done quite a bit of work on them I'm getting a little
nervous
about breaking them. They are 10.5" wide where the bend will be
and I've oriented the grain with the bend. Am I OK? Do I need
to
anneal them first? Would heat from a torch help?

tomcas wrote:

Terry Keeley wrote:
Steve Lusardiwrote:

If you don't need the temper, why did you use it in the

first place?
Steve



Machineability...

And availability, and maybe he doesn't need high strength in the bend
area, and maybe he had it kicking around, and maybe.....
I would just go ahead and anneal it, hot form it , or use a larger bend
radius.

An easy way to put a bend radius in is to put another scrap piece on
top of the other piece when you put in in the brake. I would try a
couple of scrap bends before I went for the final one.


John

Terry Keeley wrote:
Steve Lusardiwrote:

If you don't need the temper, why did you use it in the

first place?
Steve



Machineability...

And availability, and maybe he doesn't need high strength in the bend
area, and maybe he had it kicking around, and maybe.....
I would just go ahead and anneal it, hot form it , or use a larger bend
radius.

DanG wrote:

I haven't seen anyone talk much about backing off the break and
putting in a sacrificial spacer. It increases the radius of the
bend and helps prevent that fracture line from forming. I am not
a tinner, but our tinner has done this on aluminum shapes when the
material wants to shred or crack.

I was taught this procedure under the name of "packing the brake". We
used strips of .063 1100 about 3 inches wide. If you are careful with
them you can build yourself up a set of nesting packing strips that work
well.

Better is to have radius nose blocks on the brake, but ya gotta do what
ya gotta do.

It's pretty much a given that you will not be sucsessful bending a
radius smaller than a certain number of thicknesses (3?,4?). Temper and
material cause variations, but IIRC thats about the normal minimum for
aluminum.

Cheers
Trevor Jones

Thanks for all the great suggestions guys, really good minds hang out
here, I'll report how it goes...

Terry Keeley wrote:
Need some sheets bent past 90 degrees to about 100 degrees and since
I've done quite a bit of work on them I'm getting a little nervous
about breaking them. They are 10.5" wide where the bend will be
and I've oriented the grain with the bend. Am I OK? Do I need to
anneal them first? Would heat from a torch help?


In the aviation world, we bend ACROSS the grain - not with it...

cavelambwrote:
Terry Keeley wrote:
Need some sheets bent past 90 degrees to about 100 degrees and
since
I've done quite a bit of work on them I'm getting a little nervous
about breaking them. They are 10.5" wide where the bend will
be
and I've oriented the grain with the bend. Am I OK? Do I need to
anneal them first? Would heat from a torch help?


In the aviation world, we bend ACROSS the grain - not with
it...[/quote:2d8118cbd6]

Ya, I'm seeing that now that I do a little research. Tends to crack
easier with the grain, I just figured it'd bend better.

Got some test pieces to try, gonna anneal some with a torch and do
some others in my kiln, should know soon if the min. radius figures
quoted can be attained!

I aways hate when someone asks a question on some forum and gets a
bunch of great advise and never reports on the outcome, sooooo...

Turns out the bend is about 103 degrees. I tryed to bend the piece as
is, it cracked. Tryed marking with a sharpie and heating with a
torch until the ink burned, that worked much better but there were
still noticable stress cracks in the bend.

I found some info saying to anneal 6061 you heat to 775F for 2-3 hrs.
then slowly cool, so I put a piece in my self cleaning oven and
letter rip. I know it doesn't get that hot but might get to 700 or
so. Guess what, a nice sharp bend with no stress cracks. I read
also it should harden again over time, not to T6 of course, but
harder than it is now.

Thanks again, great minds here!