Table saw for long cuts, a miter saw for short cuts. Light sanding on the edge and then flame polish.
You can probably get away with just the miter saw for the short cuts you are making. I just cut my weir with a table saw a few days ago.
A miter saw with a very fine toothed blade and low speed, correct? You say light sanding and flame polish. I have to do some significant prepping on these edges after I cut with the dremel, and they still aren't completely flat. Will those tools really give that smooth of a cut?
Also, my tank is already assembled, and is 30"X20". The weir will be divided into 2 lines, both 12" long. You still think a miter saw or table saw would work if I have to cut those lines 1 inch below the top rim of the tank?
If you can send me the stock I can cut those smaller pieces on a laser cutter for you. Don't know if it is worth the hassle for you.
I would, however, I still need to cut the weir into the tank itself. Since I still have to do that, I figure I may as well just find a solution that takes care of both.
I dont think you want the high speed that a dremel offers to cut acrylic. It probably gets too hot and burns/melts more than cuts. You might be better off buying a handheld plastic/plexi cutter and using a good straight edge or using a circular saw with a real fine toothed blade for finish work.
Are you talking about the handheld manual scraping tool? I used that to cut 1/8" acrylic. It took a very long time, and the cuts were even worse than using a dremel. The acrylic I need cut is 3/8", I don't even want to imagine how long that would take. I know what you mean about the melting, however, the type of blade I'm using greatly minimizes it. It still melts a little, but significantly less than if I were to use a different blade.