Like Tripolar said, you can get a permit to distill alcohol for fuel on your property. There are rules you have to follow, but I imagine you’d be allowed to redistill alcohol you produced until you reached the appropriate strength for fuel alcohol. I’m not sure if you’d be allowed to redistill alcohol you bought, or if you’d have to start with a wash you produced yourself. Keep in mind this is to produce a certain amount of fuel for personal use. If you want to sell or give it away, it’s a whole 'nother ballgame.
Distilling to produce alcohol for consumption (or producing fuel without a permit) however, is pretty much illegal, period. There are no “homebrew” provisions in the laws regarding distilling. If you put something alcoholic into a still (be it a wash you produced or a bunch of beer or spirits you bought) and collect what comes out the other end, you’re breaking the law. In order to do it legally you’d basically have to start your own micro-distillery, which would involve applying for and obtaining permits, paying for Fed and state licensing, applying for a bond for your distillery (which would have to be in a building separate from any domicile), keeping meticulous records, paying taxes, etc. A good friend of mine looked into it, and apparently it costs a few thousand dollars upfront in permitting/licensing fees, double that if you have an attorney do all the paperwork for you. It’s not impossible, but unless you’re starting a business it’s just not worth it.
Basically, unless you own a distillery, doing what you describe would be breaking the law.