Yes, but why waste the varnish. - (it is meant for bare wood )
Yes, but if it's the same base you don't even need to sand it.
Yes, just clean with a TSP solution, sand to remove the gloss, prime with an oil based primer, then paint with two coats of either a water or oil based alkyd paint for washability and durability.
Of course can, we already proved it on offset printing..
You should never paint a deck, the paint will peel (unless you live in a very arid climate I guess. The deck may be stained, you can put either oil or latex stain over old oil stain.
If the same base, yes you can.
Yes, but if it's the same base you don't even need to sand it.
Yes, you can. You can always paint over with same paint.
Yes, just clean with a TSP solution, sand to remove the gloss, prime with an oil based primer, then paint with two coats of either a water or oil based alkyd paint for washability and durability.
Yes, you can gloss over most stains. Speak with someone at your local hardware store to discuss the type of surface you've stained to determine the best type of gloss to purchase.
Wood stain MUST penetrate the grain of the wood or it doesn't color. clear coats like Varnish or Urethaneare designed to seal over the stain "color" & keep the wood from being "stained" by all the dirt & spills it endures over time. If you don't sand the old finish off evenly it will keep the new stain from penetrating and it will also allow the stain to penetrate in areas where the old varnish was worn or damaged but not in others making the new stain blotchy & uneven. A good quality urethane is far better and easier to apply than Varnish. .
Of course can, we already proved it on offset printing..
You should never paint a deck, the paint will peel (unless you live in a very arid climate I guess. The deck may be stained, you can put either oil or latex stain over old oil stain.
If the same base, yes you can.
Stains are meant to penetrate the pores of the wood. The varnish seals the pores of the wood. Stain applied afterword just does not work well.
Assuming you are using a dye-based spray on stain, yes, if the gloss is already set up and scuffed! However,while spraying or applying, gloss is too wet/tacky to work with between coats! As I do at work using Acrylic Polyurethane paints onto cabinet parts, your best bet is to apply a first coat of satin, stain over that, then a final coat of satin to seal the stain! (NEVER apply gloss over an unsealed dye based stain, as the heavy material will have a tendency to pull your stain and make the color look uneven!) As soon as the satin is flashed off (10-30min, depending on paint and temp.) you can apply your gloss. This is the method we have used for decades on HIGH quality cabinets!
Clear coat is applied over a base color for the gloss
Yes.