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
resultStep 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
Edit
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.
Best Answer
If you've got the time, don't want to get rid of the piece, and have some degreaser and muriatic acid lying around, you might save a few bucks.
For any application of coating, preparation and the right materials are essential. After getting rid of caulk and taping off, filling in chips and cracks with epoxy, some light sanding, an acid wash and degreaser, you'll have a surface that's as ready as you can get. Try something along the lines of 2000 grit with a light touch to keep the surface nice and smooth. You're not looking to strip the current coating, but put a little tooth into it. Blow with your compressor (I always tape an airfilter to a cheap box fan to gather up the dust) and you're ready to go.
When the surface is clean and ready to go, don your PPE, ventilate, and give a few light applications in succession. Usually, you have to let the current coat get tacky before the next. Don't try to spray heavy, because you get runs that have to be cleaned. The technique for spraying is finding the appropriate distance, and doing smooth passes in a line in succession. Of course, follow whatever instructions the product gives you.
On such a small unit, I wouldn't buy any fancy kits. For less than $15 you can spring for an aerosol solution. Don't bother messing with rolling and brushing this stuff on. Be careful because there are spray products meant for appliances like washers and driers and it's cheaper in cost, but not the same.
In my way of thinking, if it's a nice piece, you work quickly but carefully, then worst comes to worst, you're out of an afternoon of time and maybe $20 worth of materials if you're not satisfied. Then you can go pick out a new one, and you have the experience to tackle the same project again down the road.