Yes, however, if it is an oil-based clear you'll see an amber color to the tint. Water-based clears tend to be crystal clear and do not affect the underlying color.
Paint can be applied over varnish, but it needs to be a compatible type of paint for the type of varnish, and the surface needs to be prepared by removing loose material, dirt and sanding. If it is not a compatible paint the surface needs to be etch primed. Contact a local paint supplier for advice.
There are flat paints that are made to go over semigloss paint. Many inexpensive flat paints will peel almost immediately when laid over semigloss. The most common solution is to roughen the surface of the semigloss (sandpaper, sandblasting, steel wool, or trisodium phosphate). The actual requirement is to remove alkyds which migrate to the surface of some semigloss and gloss paints. The alkyds make it impossible for latex or acrylic to bond to the surface underneath. You also have to remove buildup of dirt, mildew, etc. Most primers are suitable for recoating semigloss. Read the label. A layer of primer followed by your flat paint is generally the best solution if the surface is relatively clean. Benjamin Moore Fresh Start interior / exterior acrylic primer is one example of a good primer for this application.
Yes, Spar varnish is a marine quality exterior varnish that can be used over many surfaces, however it does have an amber hue that will affect the color of whatever surface is being coated. If you're looking for a long-lasting crystal clear coating then a better choice would be a water-based polyurethane coating.
For oil paintings: best let it dry for a longer time (6 months or so), then put dammar varnish over it. The long drying time makes sure you can take off the varnish later, without harming the paint itself.
Yes, you can. Use workable fixative or retouch varnish.
That is not generally recommended.
You could use a clear varnish.
You can paint over the letters with a clear nail varnish, just make sure you don't get nail varnish all over your keyboard.
you scrape any bits of dead skin or dirt out and paint over clear nail varnish
Paint can be applied over varnish, but it needs to be a compatible type of paint for the type of varnish, and the surface needs to be prepared by removing loose material, dirt and sanding. If it is not a compatible paint the surface needs to be etch primed. Contact a local paint supplier for advice.
There are flat paints that are made to go over semigloss paint. Many inexpensive flat paints will peel almost immediately when laid over semigloss. The most common solution is to roughen the surface of the semigloss (sandpaper, sandblasting, steel wool, or trisodium phosphate). The actual requirement is to remove alkyds which migrate to the surface of some semigloss and gloss paints. The alkyds make it impossible for latex or acrylic to bond to the surface underneath. You also have to remove buildup of dirt, mildew, etc. Most primers are suitable for recoating semigloss. Read the label. A layer of primer followed by your flat paint is generally the best solution if the surface is relatively clean. Benjamin Moore Fresh Start interior / exterior acrylic primer is one example of a good primer for this application.
Yes, but I usually sand it lightly first.
Usually yes. You'd be advised to use a water based varnish, and rough up the paint a little before coating.
Yes you can
Yes, Spar varnish is a marine quality exterior varnish that can be used over many surfaces, however it does have an amber hue that will affect the color of whatever surface is being coated. If you're looking for a long-lasting crystal clear coating then a better choice would be a water-based polyurethane coating.
You can but you will want to give the vaneer a light sanding first.
Lacquer can cause the paint to bubble or crack due to the very hot solvent that is a part of lacquer. If you want a clear coat over paint, a better choice is spar varnish over oil base paint and arcylic urethane over latex.