I would like to print customized water bowls for my pets, but my first attempt in PLA leaked through the 4 top layers and infill very rapidly. I used linear infill for the top and bottom layers and line for the infill. Is there a slicer setting that will print a water proof layer?
The leaks may be occurring on the perimiters rather than the surfaces. For water tight vessels, increase your perimeter count in Slic3r at: Print Settings > Layers and perimeters > Minimum Perimeters: and update the value to 2 or 3, depending on the degree of angles. If you have a lot of angled surfaces, the more perimeters will give you a larger stepped perimeters.
I might suggest printing a customized water bowl holder rather than a bowl itself. Even when you get the slic3r settings dialed in and create a surface that will hold water, that same surface will still have very small voids in it, which could over long periods of use (years, etc) start to pick up bacteria. You could seal the inside of the bowl with a food safe epoxy surfacer, or design something that would take a stainless steel bowl liner. If it’s just water, the risk is low, but it is there and something to be aware of.
Or you can print ABS and do a vapor bath!