Tools to work with 20 oz. copper sheet?

[MushCreek]

I have a project in mind that will use 20 oz. copper sheet. I need to cut it cleanly and bend it cleanly with some measure of control. This might lead to making a few bucks on the side if I can get my process dialed in.

HF has a 30" combination shear/brake/roll that would probably work OK, but it's a little more than I want to spend up front. I've thought about making a bending fixture for my HF 20 ton press, but I'd be limited to about 21" long. I could also fab up a typical brake out of angle iron to do the bending.

Any ideas on how I can cut nice straight lines up to 24" long? I'd like to make a prototype before plunging into added equipment.

 

[theoldwizard1]

A good shear and brake is what you need. Not sure it the HF qualifies as "good".

 

[MushCreek]

I'm wondering if electric shears and a straight edge would get me where I need to be. A jigsaw would be too ragged, and copper is funny stuff to cut. It's soft, but very gummy.

 

[nutjob]

I have the HF 36" brake that I was able to pickup used for $100. Performed some of the mods found for this item and it works well.

I am able to bend 16ga full width but as expected the center area is a bit bowed and not as crisp a edge. But for 20-22ga this has been working great. I was able to make some sheet metal projects that came out very nice that would have been a pain with angle iron and hammer....

Kevin

 

[4 FN 27]

and copper is funny stuff to cut. It's soft, but very gummy.

It can be soft but typically I have not found it to be towards the gummy side. A little light oil will fix that if it is hanging up.

Shearing can be an issue unless you have a Shear you can adjust the gap between the blades. 10% clearance is suggested but as you get thinner you may want to go tighter on the clearance.

20 lb copper is .027 thick thus I would try and get a clearance of .002-.003.

Bending wise to control the accuracy of the bends I would suggest a .236 (metic) or max 1/4 Bottom die with a standard 1/64 or 1/32 Punch. The bend deduction would be approx .037 for the 1/64 Punch and .047 for the 1/32 Punch. But you will need to play with it and see what works. I don't have a whole lot of data on Copper.

Another thing you can do is check into 1/8, 1/4 and 1/2 Hard Copper. There is a give and a take however. The harder the material the easier it will be to get a good clean sheared edge. That is the give. The take is it may start to fracture if you are bending parallel to the grain with the smaller radii. Increasing the inside bend radius will help with this issue.

If I was doing it I would have to do some playing.

If you are looking at volume there are some shops that will cut Copper on their Laser. We do not since Copper gets really shiny when you go to pierce the Material with the beam and it can bounce back doubling the heat in the optics and usually catching the Bellows on fire on a CO2 machine or it will burn up the connectors on a Fiber laser. Ask me how I know.

We either punch Copper or have it Water Jetted. In the case of really thin Copper we tend to have it acid etched.

I'd be interested in what you find for a solution.

 

[danski0224]

How straight does the cut need to be?

How many cuts?

It cuts just fine with snips. There are aviation style snips and pattern snips without the little serrations on the cutting edge.

Bending it "cleanly" (sharp bend) will be a problem without a tool to do so.

 

[theoldwizard1]

I'm wondering if electric shears and a straight edge would get me where I need to be. A jigsaw would be too ragged, and copper is funny stuff to cut. It's soft, but very gummy.

Any kind of hand shear will NOT give you good results.

A homemade brake for straight bends is easy to make and usually works well.

 

[danski0224]

Any kind of hand shear will NOT give you good results.

I'll call ******** on the first one. Of course, it depends on the person operating the tool.

For the 24" +/- distance the OP is talking about, something like Malco "Andy" snips will do the job and it will only take 8 or so squeezes to cover the distance.

 

[nutjob]

Any kind of hand shear will NOT give you good results.

You do need to know how to use them to get results. Here is a video recommended by Robert from MP&C

Kevin

 

[matt_i]

On a soft thin .027" material like that I would break it like trim coil.

Sacrifice a razor knife blade and clamp a straight guide.

Its possible you can score it a few times and just go right thru the thickness.

But I believe it could also be bent along the initlal score and then cracked like trim coil or drywall. If a slight burr is left then light file or sanding block.

You might be able to bend material that thin with a siding brake (for the aforementioned trim coil) which is a lot cheaper than a dedicated finger brake capable of 16ga+ steel. The roofing and siding material warehouse near me has a guy who "bends trim on the side for cash" and if you could find a person fitting that same description in your local area you could probably get a couple pieces bent for an appropriately sized green bill.

I'm sure you know but "box & pan" shapes are out with the siding brake as they have no provision for the already-bent perpendicular flanges to pass the bending edge.

 

[MushCreek]

The bends are only about 30 degrees, and aren't near each other. Any kind of brake will work, as long as I can control the depth for repeatability.