What is it that you're thinking about adding?
Older pieces should be soaked in a water bath until they absorb some water. Depending on where the join is, you might see a difference in the color of the two pieces. You can attached a fresh piece by forming directly on the older piece or form the new piece in it's mold--let it setup (few hours???) then attach with the cement mix that you used or a mortar mix. Some people like to use Arcylic fortifier (available where you buy your cement) in the water of the new piece--makes it stickier. Handles can be tricky. Unless made as a one piece unit, handles added after the fact will be decorative. You can mortar or use hypertufa or whatever cement mix that you originally used to attach two pieces. I've added mortar cast leaves to lamps, pots and troughs using mortar, hypertufa and liquid nails. Depending on the size, weight and what storage you have also effects what you cement together. Combining two pieces might make the piece just way too heavy. Hope this helps. Billie

Thanks I will try it. I want to duplicate wood trim using hypertufa and add it to planters, columns and whatever. If I can figure out how to post pictures I would like to share what I have been doing. I took a basic hypertufa class from a lady in Indiana 5 years ago. Everything else I have done is trial and error.

tooty, Are you talking about faux bois? If so google thegardenartforum or Donald Tucker or Carlos Cortez or studiocortez dot com