It is never a good idea to paint anything high gloss without sanding first. You don't need to sand clear though the old paint, but the new paint needs something to hold onto. If there is nothing but a smooth, shiny surface, the new paint will probably run if the surface is not horizontal, and then chip and flake very early on. Always run a piece of sandpaper or a sanding block, 150 grit is good, over the surface. Why do something twice?
It depends on the type of paint that you are using. You will most likely need more than Tempera paint to get the job done!
No, you can't you must sand it or use a good oil based primer.
I definitely would not.
Yes, you can do that.
Do you realize that you can get FLAT ACRYLIC PAINT. Flat paint refers to the gloss level. You may want Gloss, Satin, Lowsheen or Flat. Acrylic paint on the other hand refers to what the paint is based on or what binder is being used. Acrylic paint is also refered to as waterbased paint. You most likely are referring to putting flat acrylic over lowsheen or gloss acrylic. In answer to your question - as long as they are both acrylic than you will not have any problems. I am in this answer assuming that you are referring you house paints. If not than the same principle applies - acrylic over acrylic is fine. To keep acrylic from going glossy just don't polish it.
Yes, just ensure that the surface is clean, grease free and dulled.
You can just paint over the top as long as the existing surface is clean and lightly sanded to aid in the adhesion of the next coat.
The ingredient in glossy paint is acrylic. You cannot remove that ingredient.
Semi-gloss paint sometimes has problem sticking to walls that have a higher gloss paint type already on them. Usually, a light sanding and a coat of primer will help. Sometimes, semi-gloss paint peels if it was applied during high-humidity weather, as it doesn't dry all the way through.
Do you realize that you can get FLAT ACRYLIC PAINT. Flat paint refers to the gloss level. You may want Gloss, Satin, Lowsheen or Flat. Acrylic paint on the other hand refers to what the paint is based on or what binder is being used. Acrylic paint is also refered to as waterbased paint. You most likely are referring to putting flat acrylic over lowsheen or gloss acrylic. In answer to your question - as long as they are both acrylic than you will not have any problems. I am in this answer assuming that you are referring you house paints. If not than the same principle applies - acrylic over acrylic is fine. To keep acrylic from going glossy just don't polish it.
Yes, just ensure that the surface is clean, grease free and dulled.
You can just paint over the top as long as the existing surface is clean and lightly sanded to aid in the adhesion of the next coat.
The ingredient in glossy paint is acrylic. You cannot remove that ingredient.
Acrylic, like enamel paint, can be matt, gloss, or satin finish. Please see the related link below.
the high gloss acrylic would bead up and not give you an even application over the oil based
Latex and acrylic (both water-based paints) do come in a semi-gloss finish.
Semi-gloss paint sometimes has problem sticking to walls that have a higher gloss paint type already on them. Usually, a light sanding and a coat of primer will help. Sometimes, semi-gloss paint peels if it was applied during high-humidity weather, as it doesn't dry all the way through.
future floor polish or krylon spray gloss coat
Many other companies make a a comparable paint. Ask for there top or second line of high gloss acrylic and you should be satisfied.
Well I learned from experience NOT to use house paint, I would say Acrylic paint or spray paint. Make sure to use gloss!
Scuff sanding, that is sanding only far enough to break the gloss and produce a matt surface is not sufficient for blistered paint. If only the topcoat is blistered, it should be sanded off completely. If the primer is blistered, it must be removed too.