I have an old porcelain sink. When the sink is dirty it takes a lot of scrubbing to get it clean. Can I put something on it so that it will be less absorbent?
I am considering this procedure: https://www.hunker.com/12259038/how-to-reglaze-a-bathroom-sink:
Step 1 Clean surface of the sink with a standard cleaning agent. This removes the initial dirt and prepares the sink for further cleaning.
Step 2 Eliminate silicone caulking with silicone digester. Get rid of as much caulking as possible because any residue will affect the end result
Step 3 Scrape the sink with an acid paste. This eliminates any leftover debris. Be careful and wear safety gloves when working with acid.
Step 4 Apply degreaser on the sink to give it one final cleaning before you start the glazing.
Step 5 Use plastic or newspaper to mask areas that you do not want to glaze, such as bathroom tiles beneath the sink or on the walls adjacent to it.
Step 6 Apply epoxy primer to the bathroom sink. If you are using a brush, make even strokes on the sink. For spray primer, hold the sprayer a few feet away. Glaze evenly and don't skip any part of the sink. Let the primer dry.
Step 7 Spray acrylic-urethane resin to get the glaze you're looking for. Wait 15 to 20 minutes to let the resin settle.
Step 8 Apply polyurethane coating to the sink for a shiny surface. Once everything is dry, reapply silicone caulking to your sink
I read the above instructions more carefully and realized they are for a BATHROOM sink, not a porcelain kitchen sink.
I started fresh and found three sources outlining a pretty similar process -- apply a strong acid or sand in small circles to ensure proper bonding; apply porcelain primer; apply special paint; finish with high-gloss polyurethane. Ventilate well and wait three days before closing up and using the sink.
Conclusion: I think Ed's guidance on finding the right size sink is going to be a better solution, especially as it's winter now.