The seal is not made to take the outward pushing pressured of carbonation. They are meant to hold a vacuum which pulls the seal inward. In fact if you've ever canned and had something go bad and create pressure inside, you've seen that the seals are the first thing to go POP.
thanks for the fast response first time brewing and one of the guys at work suggested them i didnt think they would work but thought it would be cool if they did love the site think i could read for days and days