I'm also going to make a video using a box fan, based on the Alton Brown method from Good Eats. We were lucky to buy a dehydrator at a garage sale for $5, but many people have asked me how one could do this without buying a dehydrator.
I'm thinking if you oven has a real low temp setting - 200 or lower, you can try this in the oven, a convection is ideal. I have not tried this, but please let me know if you do.
We found this dog biscuit recipe works best when you spray the potato slices with a small amount of vegetable oil. Use a can of veg oil spray, it works best. Don't soak the dog biscuits in oil.
You could also use a brush to lightly apply oil to the sweet potato slices, but keep in mind a lot goes a long way.
We have some other dog treat recipes and videos on our site, GardenFork.TV