Need to make a 90* bend with a ~3" radius from some 1/4" thick by 2" wide by 5' long copper bar stock. Two of these will run horizontally in front of the battery bank, turn the corner, then connect to the inverters. Anyone here have experience bending this bus bar this heavy? Will it break into at the bend? Will heating it with a torch help?
Bending 1/4" Thick Bus Bar
- Thread starter Kornbread
- Start date
42OhmsPA
Who likes Electrical Gremlins?
I don't have any experience with stuff that thick.
I would get a piece of pipe the diameter of your bend and wrap the bar around it.
I would get a piece of pipe the diameter of your bend and wrap the bar around it.
Wessss77
Solar Enthusiast
That's exactly what I have as a busbar... Didn't have to bend it though... Drilled and tapped so I could put in 8mm bolts, I think they were 8mm, could have been 6mm. That's gonna be a beat to bend with that radius but it shouldn't crack I wouldn't think.
There's so much spring back with cold bending copper that for a 3"R I think you'd need to start with a 2" - 2 1/2" radius. It will depend on the hardness of the copper
The first thing I try is annealing (heating then cooling) and bending.
Heat bending can be done but copper has a huge amount of thermal transfer so:
-the whole lenght of the bar will get cooking hot which will required clamps to hold it
-You'll need a tiger torch to heat it....or 1000 heat guns
-it takes some skill to heat the bar evenly. Copper is like aluminum in that there is no visual warning between it being hot enough to bend and too (melting) hot.
Pg 13 has info on forming/bending
The first thing I try is annealing (heating then cooling) and bending.
Heat bending can be done but copper has a huge amount of thermal transfer so:
-the whole lenght of the bar will get cooking hot which will required clamps to hold it
-You'll need a tiger torch to heat it....or 1000 heat guns
-it takes some skill to heat the bar evenly. Copper is like aluminum in that there is no visual warning between it being hot enough to bend and too (melting) hot.
Pg 13 has info on forming/bending
OzSolar
Whatever you did, that's what you planned.
I've had pretty good luck with a rubber mallet and my bench vise with thinner stock. Not sure how successful that would be with .250 though.
1/4" needs a 1/4" inside bend radius. Less than that the copper will crack.
Rednecktek
Expert Newbie
You'll need at least MAP gas, preferably acetylene, to get it hot enough fast enough to do a bend around a pipe form. If you can clamp the bar to your form you can start heating in the center and just keep tension on it. As the beginning starts to bend you walk your heat up the length and just walk the hot spot as you bend it. It's time consuming and if you start to see a color change or the bar gets real EASY to bend, back off your heat a bit.
Heating copper is only needed if the material is hardened.
What is needed is a form.
Rednecktek
Expert Newbie
Needed? No. At 1/4" thick though it REALLY helps.
Done this with steel many times but never copper. Have you used this process several times and was it always successful?
This is out of a bus bar installed in the ceiling of a factory for powering equipment. It feels a little harder than normal copper bar.
P.13 says easier after annealing. Easy enough to try.There's so much spring back with cold bending copper that for a 3"R I think you'd need to start with a 2" - 2 1/2" radius. It will depend on the hardness of the copper
The first thing I try is annealing (heating then cooling) and bending.
Heat bending can be done but copper has a huge amount of thermal transfer so:
-the whole lenght of the bar will get cooking hot which will required clamps to hold it
-You'll need a tiger torch to heat it....or 1000 heat guns
-it takes some skill to heat the bar evenly. Copper is like aluminum in that there is no visual warning between it being hot enough to bend and too (melting) hot.
Pg 13 has info on forming/bending
DPC
Canada, Great already
This is EXACTLY how I used to do it in the break press.
And I used an iron worker to punch it rather than drill.
As you work copper it hardens.
Its still softer than steel but it gets that springy quality too it.
I've heated copper wire to soften it sometimes to pound or shape it but i have never heat treated buss.
I had to make a 90° bend in my copper bar. I heated it up then bent it. Worked fine. Was the heating necessary? I don't know, but it seemed to bend readily without having to pound on it.
Did you bend the flat side, or the narrow side?
To make a long bend, no amount of heating seems to be able to help, the bar will need a form and pressure to turn without twisting.
Flat side. I can't imagine bending the narrow side.
Copper is much much harder to do. Your using a torch that has more BTU on a martial that doesn't change color when it is close to melting.
Copper indeed does change color.
DO NOT TRY IT IN DAYLIGHT.
but copper will turn three shades of red before going orange, then INSTANTLY TURNING LIQUID.
I torch copper all the time.
There is plenty of warning.
Aluminum is the scary stuff to heat.
Zero color change with aluminum.
Unless you work in total darkness.
I tried bending 1/8" aluminum without heating it. Not a good result. I think I would rather TIG weld it than try to bend it.
Bending is the way but it needs the correct IS bend radius.
Last edited:
Your bending 1/4" copper?
The secret to bending aluminum to run some Sharpie Marker lines on it. When the lines disappear/burn off it's ready to bend.
DPC
Canada, Great already
It will change colour, but its very subtle
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