At right and below is the conduit-bender my husband created to bend the hoops for the low tunnels, which I said yesterday I'd photograph and post (click on either to see an enlarged version launch in a separate window). There are commercial pipe-benders that electricians use on this type of conduit, but they create angles. Anything but a rounded shape would cause wear (and eventually tear) on the plastic and floating row cover, so a smooth hoop is desired.
We found a seedsman offering a bending machine for low tunnels of a 4' width, but it cost around $100, including shipping. Another for a different width bed for another $100. We constructed this one from used 3/4" plywood and about $50 worth of off-the-shelf hardware store fittings ("tarp rope hooks" and screws from Concord Lumber). If we wanted to make hoops for a different width bed, the hooks could be re-set and re-used without further cash outlay.
To use: align the bottom of the 10' length of conduit to a line at the bottom left of the bender (not in photo). Insert the right edge of the pipe into the loop of the first hook on the left, bending just a little to the right. That will allow the next hook to be aligned with, followed by a small bend... next hook, another bend bend. This actually can be done in just 3-4 smooth movements, covering all 17 hooks in about 30-60 seconds.
Photos: ©2009 Deborah Bier