How would you like to route some teeth for a baffle of your sump? Here is one of the methods I've used.
You could create a "jig" that is re-useable, such as the thumbnail to the right. It provides me with a series of grooves for the router bit's shaft to trace, but over time it melts the material of the jig and has to be replaced. This is a good choice for a few uses, at most.