I used 2 tabs of campden to stop the fermentation of a cider ale I am making. I intended to keg this batch but later decided to bottle because I didn't want to tie up my kegerator with a specialty brew that only a few would enjoy.
Ouch. Depending on the size of your batch, 2 campden tablets might be way too much, especially if you already used campden tablets to kill off wild yeast when you pitched your yeast. You want to keep sulfite levels as low as possible. Most wine and cider has above 125 mg/l, while the maximum legal limit for commercial wine/cider in the U.S. is 350 mg/l. High levels of sulfites can give really unpleasant sulfury notes - like burnt matches. They can also give some people nasty headaches, dizziness, nausea or even asthma attacks.
It has been 2 weeks since the campden was used...... Is the campden still working?......... Can I add corn sugar as usual and expect to get natural carbonation or do I have to re-pitch the yeast???
Depending on how long the cider has been aging, how clear it was, and what you did to clarify it, it could be that there was very little yeast still alive and the campden tablets might have killed it off. In any case, the sulfur dioxide in the campden tablets is still in solution, so it will inhibit yeast growth no matter what you do. This means that if there is still yeast alive in your cider, it will take longer for it to carbonate it. In any case, it can take aged cider a couple of months to naturally carbonate.
When you rack your cider from the conditioning carboy to the bottling bucket, try to pick up some of the yeast slurry on the bottom. Then add some yeast nutrient as well as the priming sugar. Depending on the level of sulfate, it couldn't hurt to pitch a bit more yeast.
If you've got kegging equipment, it might be simpler and easier to just keg and force carbonate your cider, then bottle it using a counter-pressure bottle filler.