The public is invited to attend a demonstration of a 19th century construction technique being used in the restoration of the Bunker Mill Bridge. Friends of Bunker Mill Bridge and the North Skunk River Greenbelt Association are presenting the hot riveting demonstration at Max Cast in Kalona on Tuesday at 10am. Nels Raynor of Bach Steel, the company currently restoring the Bunker Mill Bridge, will demonstrate, and those who attend will be able to give it a try. The vertical posts riveted that day will eventually become part of the Bunker Mill Bridge.