The show "How It's Made" runs on both The Discovery Channel and The Science Channel. A quick search of both channels came up with no upcoming airings of this particular episode.
EDIT: Also, if you are in a Comcast service area and have access to their Video-On-Demand, keep an eye on the "News & World/Science Channel/How It's Made" folder. Currently here in Sacramento the Weber episode is not available but could be at some later date.