Perhaps an easier way is to use citric acid. A 5% mixture will get rid of rust in about a day, no need for electricity. Available cheap anywhere where they sell farm supplies.
Here's what I know about it:
1. Make a 5% solution into say, a bucket. I just use my eyes for measurement, still works.
2. Use a wire brush or something to get rid of loose rust.
3. Throw parts into solution. No need for gloves, you could even drink it. Bubbles will start to form on rust.
4. The warmer the solution, the faster it works. Room temperature is fine, next to radiator even better. Mixing it up every once in a while also helps.
5. Once it's done, you can see black pitting where rust used to live. Just rinse parts with water, dry and apply primer. The parts will go brown fast if you don't paint or dip in oil or something.
Put a lid on your container if you want to reuse the solution, otherwise it will develop mold. Or just flush it down the drain.