What is a preferred method for cutting thin sheet metal?

I need to cut many small pieces of sheet metal (maximum finished dimensions roughly 1 by 2 feet).





I'm using copper and aluminum roof flashing, so it's not particularly thick.





Up to present I've been scoring the metal with a sharp box cutter/utility knife, then folding it to break the metal. I'm not happy with how sharp and rough the resulting edges are though. It also dulls knife blades pretty fast.





There's got to be a better way, I just don't know what it is. Any suggestions?What is a preferred method for cutting thin sheet metal?
Tin snips? Sorry if I'm completely off-base here; I haven't been in a shop class since the eighties.What is a preferred method for cutting thin sheet metal?
If your just cutting straight lines, the angle grinder method above is good, but a better method is to fit a metal cutting blade (try and get a thin one) for an angle grinder and fit it into a circular saw. quick and easy straight lines.





Edit: OK Good advice from all below, some with years of so called experience. firstly I don't think some of them have read and understood your question. You are I take it cutting a lot of these pieces of sheet to the same size? If so use the angle grinder or my method if you can get a circular saw. clamp a load of sheets together with timber battons (you can use the battons as a guide for the saw.) and saw away. much quicker and easier than snips.
The best and fastest method although not the cheapest is a sheet metal shear. If you have a lot of pieces, you may want to go to a sheet metal shop and have them cut the pieces for you. Long straight cuts are a shears specialty.





The next method I would use if you have a compressor is to invest in a set of air shear. This will cut straight lines and curved lines in sheet metal quickly and easily. The manual method would be to use tin snipes. You can get straight, right and left tools.





Dave
Depends on what kind of tin snips you use. I have tin snips or sheet metal cutters made by Wiss. They are not the cheap ones %26amp; you can cut the metal a lot better. Get the ones with the red handle. more dpace between your hand %26amp; the metal surface as you cut it.





I would have included a photo but again Y/A is having a issue with that error 999 garbage again.
Use a heavy duty paper cutter with a metal handle that's on a wood board, like ones schools use. Not only is it fast, it cuts straight and clean. Also the top guide will make sure you're cuts are square. Copper and aluminum is a very soft metal and will not wear out your blade for a long time.
Tin snips as Monkey stated. You can get a good pair for 10 bucks or so.


if you have a whole bunch it might pay to take it to a sheet metal shop and pay them to run your stuff through a shear.
Tin snips or metal shears.


The edge will be smoother, but still sharp enough


to cut you.


'Pros' relieve their edges if the material must be further


handled. A swipe or two with a file does it.
De Walt makes an electric nibbler. It cuts wonderfully! Only draw back would be they cost about $325.00


There are also nibblers that can ba attached to an electric drill. They also work pretty good for a lot less money.
Electric Metal Shears


People who do roofing have them.. I think you can get them at home depot and lows
Cutting your self is bad.
I'd have to go with tin snips.
Tin snips or side cuts. See your local hardware store.
angle grinder ,,,,metal cutting blade .ok mate
First of all I hope you are not using copper and aluminum together. I would be concerned about corosion between two dissimilar metals in a wet and potentially acid (rain) environment.





You will notice that the aluminum is much thinner than the copper. For the copper you will need snips to get a good result. There are many types side cutters, straight cutters, curved right and left cutters there are even electric shears. The cutting will be slow (unless it is electric) but the result will be more polished. Where you have an exposed edge that you want to make look particulary good you will have to bend it back on itself and hammer it down.





Aluminum flashing is different. Unless you are trying to make a curved cut or a shape I typically use a utility knife. The removable blades are more sturdy than the blades of a box cutter which typically uses single edge razor blades (they are shape and good for paper but dull quickly on metal) You can get the blades 100 to a pack and you will not go through them all.





What you don't want to do is bend the metal to break it after you score it. This is what is giving you the sharp edge. Instead you want to rip it. For example suppose I had some 24'; aluminum flashing that was 50' long. I needed a lot of 12'; flashing. I would carefully score the entire 50' length at the 12';mark. (Once is usually enough) Then I would go to one end and work the edges at the end until it cracks and becomes a cut. (like opening one of those pill packages) Once you have started the cut you push one end down and pull the other end up and it should rip on the line you have scored. Once again it you need a particularly beautiful edge you will have to bend it back on itself. If you are doing a lot of bending you will need a ';brake'; ( a device for bending metal. )