Customer service at DRfostersmith recommended epoxy putty. They said it would be visable, but the crack is on the bottom. Does this sound like it would work? They also have a product called ABS cement but after reading the directions I'm not sure if this is what I'm looking for: "Black ABS Cement
General Information - For all grades of ABS pipes and fittings for DWV and sewer up to 6" diameter. Directions for Use:
Square pipe ends and remove all burrs and dirt. Do not use flexible pipe that is not perfectly round where joined to coupling.
Check dry fit of pipe and fitting. Pipe should easily go 1/3 of the way into the fitting. If the pipe bottoms, it should be snug.
Clean pipe and fitting with a NSF listed primer.
Use a suitable applicator at least 1/2 the size of the pipe diameter. For larger size pipe systems, use a natural bristle brush or roller.
Apply a thin coat of cement to the inside of the fitting; avoid puddling of cement. Puddling can cause weakening and premature failure of pipe or fitting. Apply a second coat of cement to the pipe.
Apply liberal coat of cement to pipe to the depth of socket; leave no uncoated surface.
Assemble part quickly. Cement must be fluid. If cement surface has dried, recoat both parts.
Push pipe fully into fitting using 1/4 turning motion until pipe bottoms.
Hold pipe and fitting together for 30 seconds to prevent pipe push-out - longer at cold temperatures Wipe off excess.
Allow 15 minutes good handling strength and 2 hours cure time at temperatures above 60°F before pressure testing up to 180 psi. Longer curing time may be required at temperature below 60°F or with pipe diameters above 3".
Ingredients: Methyl Ethyl Ketone 78-93-3, and ABS Resin 9003-56-9."