sweet potato fries

A single sweet potato chosen for its shape was vented and baked in a countertop convection oven. The sweet potato was cut into planks and left on the countertop to dry. It never fully dried. The planks were coated with a light dusting of corn starch and deep fried. They were removed from the cooking oil with a crispy exterior that rapidly remoistened by interior moisture. So ultimately the fries are delicious but soggy. 

This is the second attempt at crispy sweet potato fries, and the second failure. What is it going to take to dry out these potatoes sufficiently? ... Hmmm ... A dehydrator?

Is it worth investing in a dehydrator just to have crispy sweet potato fries? What else could the dehydrator be used for? Would it be worth the trouble of having it around?  Should one have a dehydrator before one has a waffle iron or a sous vide? Could a waffle iron double as a panini maker or a tabletop grill? Can a sous vide be contrived from a FoodSaver and aquarium equipment? I seem to be digressing here. What else could a dehydrator be used for? Could it concentrate ordinary ingredients without necessarily drying them entirely so that more of the item's flavor can be exploited without introducing more liquid like banana cupcakes and ice cream and so forth? Would all that flavor concentrating be worth storing another machine? Is it worth the electricity? These puzzling questions require further consideration. In the meantime how else can I dry out sweet potatoes. Maybe I can bake them on low heat for an exceedingly long period and see what that does. Maybe I can freeze them uncovered causing water to migrate to the surface and crystalize then violently knock off the surface ice crystals and rime. I did that once with a regular potato and that made it even more soggy. 

Conclusion: Fail. Good taste but unpleasant texture.