I used this to fill in holes on a porcelain tub as well as to partially re-attach the lower valance on my 2002 F150 which tore a little bit when I backed through a pile of ice.  The can arrived slightly dented, but it came with the hardener and there were no leaks, so I was happy enough.  I followed the directions for the bathtub repair and noticed that I had about 2-3 minutes to set it in place before it hardened and the remaining became unusable.  So, when I went to repair the valance on my truck, I used less (about 2/3 of what the directions recommend) hardener and was able to use it for about 5-6 minutes before it hardened, which was more than enough time for my needs.  There is still a ton of this left and I still have a fair amount of hardener to boot.