Glue a 1-1/2-inch PVC x 3/4-inch FIP adapter (A) onto a female PVC trap adapter (B). Note: This allows you to attach your shop vacuum to 3/4-inch pipe. The barbed fitting (C) connects to 1/2-inch ...

Use 1-1/2 to 3-inch diameter pipe, cut into 1-1/2-inch wide sections; slit the sections across the width. They'll give 8 to ...