I’ve got some sheets of coated aluminum that I need to cut into custom shapes for some signs that I’m making. I need some advice as to which tool(s) I should use to accomplish this. The sheets are 12" x 24" x 0.02". The key is that I’ve got to cut them to shape without damaging the coating that is on the aluminum. Below is one of the shapes, for reference.
Any help and/or advice would be greatly appreciated.
The way I have done this is to rough cut (+1/8") the outline and then use the sanders in the metal shop to bring to final dimension. Run test and if the coating gets damaged use blue tape to help protect.
Since you can’t use the spaces, if you have access to a router and a pattern bit you could also finish the pieces by creating a thin plywood or acrylic pattern and using it as a routing template.
I would put a layer of masking tape over the coating for protection, and draw your cut line onto the tape with an ultra fine point sharpie.
For the rough cutting, .020" aluminum will cut easily with aviation (tin) snips or shears. As mentioned above, don’t cut quite all the way to the line.
Find the longest and smoothest flat file you can, and carefully sneak up on the line by hand filing. Hold the file at an angle, using the length to your advantage in making the edges nice and straight. I like to put the workpiece flat on a table, with the edge of the part just barely hanging off the edge of the table. Then file down and away from you (remember files only cut when pushing). You can carefully use the file to then deburr the edges when you have the shape done.
Take your time, “sneak up” on the line, and it will turn out great.
Thanks for the suggestions, guys. I’ve got 50 of them to do, so I might look in to the router option. I do have a plunge router,and can get a pattern bit for it. I can also easily cut a plywood template to use for it. I appreciate the information.
If you go with the pattern bit, spend the extra for a carbide version. With 50 of these to cut, a carbide bit should last for the whole set. Just be sure to rough out the pieces first, you really can’t plunge cut effectively into aluminum if you really want to protect the coating.
The material comes with a protective plastic coating, but I think roughing it out is a good idea. I’m checking in to what it would cost me to get the manufacturer to supply pre-cut blanks. It may be cheaper than what my time is worth.
For the rough cut, the handheld jig saw in the wood shop has been approved for metal cutting (at least it was by Tom, so I guess that could have changed). I used it to do a rough pass on some thin aluminum but did have to go get my own blades as woodshop doesn’t have any need for metal blades. Worked fine.