I'm just starting out woodworking, and don't have a lot of tools and jigs. I have a table saw I need to build a base for (so it's currently not usable), and a circular saw that I use quite a lot to make longer cuts, rips and crosscuts. I will probably build myself a simple rip cut guide for it, but have a question about what I could use as a dependable straight edge in the meantime. Honestly, I'd be happy with something very straight I could just clamp to some plywood, or some other medium, and run the circular saw up against it. In our old house I had used some hardboard, and a pine board to build it, but found that it stopped being straight after a while, so I'd prefer something that will last for a while.