Buck Turgidson wrote:
I have a step to a door where a chunk chipped off the end. If I built a
wood form and filled it in with concrete or straight portland cement, would
it bond to the existing concrete?

Cement repairs bond fairly well, but you need to choose your material
carefully. First, old chipped concrete is inherently dirty. Start your
repair by chipping down to fresh unexposed concrete. Chisel a few
grooves if you can to key the repair in place. Build a form. You should
have a HIGH STRENGTH concrete patch or mortar mix on hand, which you
bought at Menards, Home Depot or wherever. Mix what you need and follow
directions on the bag precisely, not too dry, nor too wet. Dampen the
chiseled area and pat it dry or use a bit of compressed air if you
have it available. Trowel on your mortar and smooth off and work out
the bubbles. Let it alone for a couple of days and take off the forms.
A little work with a mason's mortar stone will smoooth off the little
imperfections and you're good to go. HTH

Joe