How to finish a homemade painted desktop?

I bought a used corner computer desk, but the desktop is too small to comfortably use for dual monitors. I bought a piece of plywood and cut it to the shape I want, with the intent of simply screwing it to the old top to increase the work area. I put two coats of paint on it, but I’m wondering if I should do something else for a final coat?

Once you have painted it you are pretty much locked into staying with the paint system you started with. Most modern paints are pretty good, and the wear and finish should be good no matter what you used. The most important thing is preparation, and for the final coat, obsessive attention to sanding to get a perfect base to apply it over.

Did you use glossy or matte finish paint?

This. If you want to do something completely different, you have to sand off the existing layer of paint.

If you are talking about some kind of sealant or varnish, you will have to talk to a specialist. There are finishes designed to be applied over a coat of paint so as to protect it. However, you need to make sure your finish it matched to the formula of the paint and your expected use. You can’t just go to the art store and buy a random can of art finish and expect it to work on a desktop.

It’s not so mysterious. Get a brand of clearcoat that is the same brand as the paint you used. If you used a latex or acrylic paint get an acrylic clearcoat. Or same with oil based paint.
Do a light sand, use a tack cloth and clear coat. Remember it’s just paint, it’s relatively cheap and it will strip or sand off if you screw it up.
ETA also it just a piece of plywood, not Grannies antique chest.

A coat of polyurethane is pretty standard as a glossy, durable finish. You can get a spray version, if there’s lots of crevices and fiddly angles to paint.

I’ll second this. I have found most paints don’t stand up well to abrasive forces as you’ll find with a project like a desk surface, but I have had great luck with Minwax water based poly in a rattlecan over painted surfaces. As a bonus, if it starts to wear you can easily recoat.
I’m sure there are other good brands as well

I had an old built in desk that I repainted. Then I got a piece of glass cut to the size of the top, and used that.
Glass makes a wonderful desktop surface for many reasons.

If you painted with an acrylic (plastic) paint, be prepared for items placed on the desk to “glue” themselves. with the help of gravity, to the surface. This is just the way acrylics are, and even if you topcoat with a clear “protective” finish, the problem will persist, because a compatible topcoat will probably have the same mechanical characteristics as the color coat.

The suggestion for glass is an excellent one, and if the shape you are trying to match is irregular, jigsaw a top out of thin plex.

Dan

Another idea; get a sheet of Formica or the generic equivalent and use contact cement to glue that to the tabletop.

Gloss black. The existing desk is a glossy black.

I used Behr interior paint in a gloss black to try and match the existing desk.

I woudn’t clearcoat it all. If it matches well. Being a desk top it will wear. But it’s easy to repaint down the line. Behr is good paint. You’ll be good for a couple of years.

Thanks everyone.

I’m late to the party, but another very low cost solution I’ve done for a laminate (Ikea) desk top is used a sheet of clear vinyl wrapped over the top and sides and attached to the underside of the desk top with double sided tape.

However, I’d add that based on my experience I disagree with the comments knocking clear coats.

A few years ago, I made bookcases out of new plywood then primed and painted them with Behr interior semi-gloss white. They were in my kid’s room and held various crap like piggy banks, action figures, books etc. I found that lots of stuff would stick to the paint and pull it up when moved, especially during high humidity periods in the summer. I kept hoping the paint would completely dry and it would stop, but this went on for a couple years.

On a woodworking forum I follow, I asked about solutions and was resoundingly told to give the the shelf tops a light sanding and then a couple of top coats of semi-gloss water-based polyurethane (I used Minwax). I only coated the top of the shelf (the part where the items sat). There was no colour variation at all between the shelf tops and the rest of the book case.

That was several years ago, there’s been zero yellowing and you still can’t tell it was top coated at all. I’ve never had a problem since, I do a lot of woodwork and whenever I make something with a painted surface that will have anything resting on, I always top coat it with a clear water poly. It’s is a great solution.