If indeed the problem is "hairline" crack, I think a product (flexi-seal)that was mentioned may be a good first step to remedy it.
http://www.homedepot.com/p/Rus...
But if the problem is more like a crack that may separate the portions of the pot, I would say that the technique of wiring both sides of the crack would be good.
I had a 25" diameter frost resistant pot damaged in a house move and I was afraid that the bottom was going to separate from the side. We first brushed on thickly a sealing solvent inside the pot to fill the crack and beyond, and then proceeded to drill the holes on each side of the crack. We then "laced" the sides with plastic covered copper wire, hopefully to prolong the life of this huge pot. It's been 2 years and still holding steady.
