go to home depot and ask for door/window screening supplies. get the aluminum strip that you can saw into pieces and get plastic corners to connect the aluminum pieces into a frame. then get fiberglass screen to put over it and the little ribber string that you press into a groove in the aluminum to lock the screen in place. took me under a half hour and under $12 to make and mine fits very tight and looks very professional
ill probably post pics later tonight
I have been running mesh tops for 2 years and have had no corrosion issues. If you are using a halide and it is close to the mesh, it will get brittle over time. I just had to replace the mesh on my tank with a 250 DE metal halide.
There has been some threads on other forums where I guy made curved tops for a 72 Bowfront. They worked out nice but it took a little patience to get it just right.
jake do you have any problems with corrosion? With the frame?