This is an excellent two part epoxy putty that does not shrink.
Imported from England, it sells for $8 US at hobby and some craft stores.
Michaels does not carry it, Hobby Lobby does. Same price there for white. The super white variety is $13 on Amazon. It also comes in yellow, black, orange, red?, and grey. It is kneaded in equal parts with bare fingers. Non toxic to skin, no odor. Workable for at least 30 minutes, and can be smoothed with water. It binds to plastic, metal, china, ceramic, pottery, etc. Can be shaped with sculpters tools. You can mix color pigment or paint into it sparingly.
It dries hard in roughly 3 hours. It can be sanded, sawn, painted, and sealed with glaze, or polyurethane.
A cracked, worn, or broken corner on a vacuum plastic part?
I discovered it when I needed a putty to repair a chip in a vintage plate. I didn't want the green color in the tube, but that is also very good.