clear coat over latex paint to protect buffet table

Another clear coat on latex thread? :-(

Random misc comments:

- Most waxes add some color. Even in a perfectly clear conservators wax (carnauba), will change surface color when the solvents pick up embedded dirt and oils from surface.

- Never used water based Spar Varnish. Sounds like an oxymoron. May have to buy some for chits and grins.

+1 use a glass top if want to protect the latex top surface.
- Acrylic clear top coats are soft, tend to be easily damaged, and are not good for table top. The drawbacks of acrylics are the primary reason that automotive and furniture industries primarily use 2 part WB polyurethane clear coats in production.

- Acrylic Latex is a good top coat for walls, but a lousy top coat for furniture. It is designed to be stain resistant. This means it is harder for anything to stick on the surface. NO clear coat will stick well to surface long term, without very careful surface prep. This means sanding/scuffing until the surface is rough, cleaning oils/fingerprints, and making sure surface has zero shine or imperfections.
This process is no different when adding any top coat, but with latex there are no prep shortcuts. Scuffing a soft latex is PITA compared to pigmented lacquer, pigmented varnish; or something else designed for furniture use.

- As stated above, Oil based Spar Varnish is supposed to have heavy dose of UV blocking additives for out door use. These additives make it more amber, than a varnish without UV additives; and 'warm' the color tone. As these UV blockers, or the oxidation absorbing agents are consumed; they chemically change to a darker amber shade. The darker color is by design a replacement for used up UV chemicals.
Why add this history?
Water clear WB finishes use different UV protection chemistry. This new chemistry still turns amber over time, so mfg add very small amounts of dye to counteract the change. Most common dye is blue. If you see a pink tone, the WB has been designed to mimic oil based amber change over time. The intention of blue dye is to push yellow one into a 'cool' green tone, which turns into a 'cool' tan when UV additives are used up; avoiding the normal warm color change with oil based finishes.
When freshly applied, these WB clear coats look clear on most woods; but have strong color tones in off axis lighting. These tones can be really annoying when clear is applied to bright WHITE surface. Over time the uneven color shifts with UV exposure are even more annoying.

- When using a new finish, or new finish schedule; direct testing in your environment is best way to learn if the results will be satisfactory. Finishes behave differently based on local environment; both when applied, and during use. Only you can decide what kind of surface protection is acceptable, which might be different than commercial furniture made in Mexico, and shipped around world; or what I need in a house full of Klutz kids.
Don't forget use testing.
If you are looking to prevent white turning into yellow, this testing should include weeks/months sitting outside in sunshine. If you want tough surface, test clean the cured finish with Fantastic cleaner, and a magic eraser. Fair warning, IME no single part WB finish survives a magic eraser cleaning without scratches and/or a change in sheen. :-(0)

Thanks for reading to end.

Best Luck on your finishing experiment, and YMMV

Paint for furniture?

There are many companies that sell; pigmented lacquer, pigmented conversion varnish, and pigmented polyurethanes; when you want solid color furniture coating. These are not available at local big box store, and require a trip to your local industrial/commercial wood finishing supplier.

Not all brands have distributors in every city; which means it is difficult recommend ONE brand. There is a lot of similarity between brands, making any almost brand manageable to use.

For solvent based pigmented/tinted top coat, look for: Sherwin Williams, ML Campbell, Benjamin Moore Lemar wood coatings, Lorchem, Mohawk, Sikkens, or Chemcraft (in random order).
Acrylic modified lacquers are most popular due clarity, flexibility, and ease of application. If you need a durable coating for bath cabinets or table top, then likely want a 2 part conversion varnish. If you need the most durable 'bar top' finish, 2 part polyurethanes are common recommendation.

Water based finishes can be more challenging to locate as they are relatively new (compared to SW conv varnish used as an industry standard for over 2 decades). Beyond the companies mentioned above, can also get WB top coats from; General Finishes, Target Coatings, Renner, Milesi, and IC&S-ILVA.
Water based top coats have been inferior to solvent based coatings in past; as they all use 'softer' acrylic polymer instead of harder resins found in solvent coatings. The newest WB 2K polyurethanes from several Italian mfg (last 3 in WB list) are some the most durable finishes in market, even when compared to gold standard solvent based 2K conversion varnish. Just like a solvent based top coat, the most durable WB coating will be a 2 part system.

IMHO - Instead of asking random forum for wood finish recommendations, suggest you ask your local professional finish supplier. They will work with you to ensure success, just like they do with any other furniture maker in the area.

There are a lot of existing finish top coat threads on LJ.
Can search for the mfg names listed above to find them more quickly, and to help you learn more.

As always with finish recommendations, YMMV.

PS - None the the above are automotive paints. The automotive finish distributors and products are completely different, even if a company above sells into both markets.