Any brand of aluminum, any brand of small screwdriver. I went to Home Depot and got a roll of aluminum about 8 or 10 inches wide and many many feet long. Used for roof flashing under shingles at bottom edge of roof.
I grabbed a small screwdriver from my screwdriver collection, about 1/8 inch tip. I ground a bevel on edge, so one side was sharper, and sides were slanted and slightly rounded. Brand immaterial. I laid out the louvers on the sheet aluminum, and ran an X-acto blade over the side which is to be open. I took a piece of particle board and drew one louver on it, and made a little recess with an X-acto knife. Now, the aluminum has to be held over the louver recess in the particle board exactly. Hold the screwdriver over the laid out louver and tap gently with a small modeler's hammer.
One way to register the aluminum exactly over the recess is to use two pins. Drill tiny holes on each end of the slit in the aluminum. Actually, I drill these holes first, and it helps to slit the aluminum. I also drill matching holes in the particle board at the ends of the recess.I drive pins into the holes, and cut off the top part, leaving about an eighth of an inch sticking up.
I then lay the aluminum over the pin holes so it nestles down onto the particle board. I then hold the ground screwdriver, which is now a punch, with the sharp edge along the slit, and tap away.