Can I use potato starch as a thickener for pie filling? From what I see it's not supposed to boil, but I cannot avoid this with pies. (I've tried it with a fruit pie and it doesn't seem to thick it much.)

If potato starch is not good for this, what approach should I take instead, provided I have no cornstarch or tapioca or any other usual substitute? (Potato starch is about the only variety of starch in local stores.)