Painting house...help with Primer!?
And if I have to sand it, whats the point of primer?
Answers:
You do not have to sand the primer will bond than apply latex over that.
But since you did not paint the house before and it a kicthen it 50% chance this could be oil because this happens in kicthen and bathroom.
Kicthen for cleaning grease
Bathroom for cleaning mold
What you need to do is go back to Home Depot get a small container of, Goof-off or Oops put on a throw any rag rub the wall if paint comes off its latex if not its oil. If it comes off on rag its latex.
Than you know for sure if this shiny high gloss is latex.
1. Latex over Oil - no
2. Oil over latex - OK
3. Oil over Oil primer - OK
4. Latex over oil primer - OK
Other answers:
Sanding it , gently will get it where the wall becomes smooth- so when you paint over it, you will not be able to tell if you painted over another coat. I am not sure the reasoning for primer, but we did do the primer before painting with the main coat of paint. My boyfriend is the one that said we needed primer, so I just followed his lead lol
Sanding it , gently will get it where the wall becomes smooth- so when you paint over it, you will not be able to tell if you painted over another coat. I am not sure the reasoning for primer, but we did do the primer before painting with the main coat of paint. My boyfriend is the one that said we needed primer, so I just followed his lead lol
u will need s 2 sand it othewise the primer will jus peel and bubble
The bigger questions is whether the underlying paint is oil or latex. If it is oil, you will need to sand almost all of it off, unless you want to use an oil primer and paint (which although it looks good, is an AWFUL mess)
If it is latex, you can just use a latex primer and paint it and everything will be fine. The high gloss paint-although it looks hard to paint over-really isn't any different than a low gloss paint. Chemically speaking it will all work out the same.
And let me give you a tip I learned. Go to your local paint store (preferably Benjamin Moore if you have one) and get your paint from them. Its really isn't any more $$ than the paint you get at Lowe's or Home Depot, and its so much better. It covers so much more area. Even if its a little more (maybe $3 per gallon) you will only need half the amount of paint than you will if you buy the American Traditions or whatever from the home improvement store. Seriously. I was amazed at the difference. (Unfortunately I didn't learn this until AFTER I repainted my house. Work sprung for the good stuff when we remodeled and it was awesome. I could have saved myself several hundred $$ on paint had I know)
Good luck, I HATE painting. Edging is the worst.
i would sand it first...this gives the paint something to stick to...use a high quality primer compatible with the paint you are using...
To get one coat of paint to stick on top of another the two layers have to be able to bond together. If the original layer is shiny then it's difficult to form this bond so you need to 'key' the surface by sanding it. You don't need to go mad, just enough to make the surface feel a bit rough, just rub it over a few times with a medium grade sandpaper and then brush it over with a soft brush to remove the dust.
Primer is mainly used to seal bare wood or metal, if you applied normal paint to bare wood it would soak in like a sponge but the primer provides a base layer to prevent this happening.
On a wall or large area you can use either a watered down mix of PVA (about 10 parts water to 1 part PVA) or just use cheap emulsion paint. This will bond the surface and prevent it absorbing the finishing layers of paint.
If the existing paint is sound then you don't need to prime it or undercoat it, just apply as many coats as necessary to give a nice even coverage.
What I'd suggest is to give the paintwork a quick sand down all over and smooth down any rough bits. Fill any gaps or cracks with caulk or filler and leave to dry, sand the repaired areas to a nice smooth finish, brush off the dust, wash with warm soapy water, quick wipe with clean water to get rid of any soap. Primer on any exposed wood or PVA/emsulsion on bare walls, leave to dry, and then 2 or 3 coats of paint as needs be.
If your kitchen tends to get steamed up then check the paint you're buying, some are designed for use in kitchens and bathrooms whereas others such as matt paints aren't particularly suitable.
I just painted my house the living room & hall ways. I didn't sand anything nor did I pay unecessary money for a primer. I used BEHR paint with a Satin finish. I purchased it at Home Depot. This is only the second time in 10 years that I've painted. If the previous color was a dark high gloss, I would recommend using a primer. Sanding is mainly to smooth out the "bumps" in the walls. Have fun painting.
Gloss or semi gloss have more polymer in their mix for very specif reasons. The adhesion of falt or satin over is dependant on grabbing. Having places to hold to.
I'd sand it rough 80 maybe to add texture to the surface, and then apply Kilz.
The object is to make contact that will last certainly, The substance of gloss is to not allow that. with soil, etc.
Paint is the bargain, even in the effort to prep,,, improper prep will be the curse.
Rev. Steven
It's all about adhesion, and primer is not always necessary for adhesion. Primer is necessary to seal up raw surfaces. Sanding is necesary for adhesion.
Imagine what's happening on a microscopic level. When you paint, the paint needs to grab hold of something (this is known as a mechanical bond). Primer is made to have all sorts of little microscopic area where the paint can grab hold. Sanding serves this same purpose. Flat and eggshell Interior latex wall paints are so porous that there are lots of places for the paint to grab hold. However, glossier latex, exterior latex and all alkyd paint are smoother, and so sanding is necessary to guarantee adhesion. In those cases, sanding is even necessary for primer to have something to grab hold of (primer needs to bond also).
People at the paint stores only know what the paint suppliers tell them, and paint suppliers don't tend to emphasis the importance of sanding because people tend to not like to sand and if they actually told them the truth, they would sell less paint, or buy someone else's paint which doesn't tell people they need to sand.
If you paint without being mindful of adhesion, the paint will probably hold for a while, maybe even for multiple coats. But as each layer of paint dries, it shrinks, which puts tension on the previous coat. Eventually this tension builds up until the paint comes loose at the layer of weakest adhesion.
When sanding, it's not enough to just scratch the surface. Scratches are on a macro level compared to the bonding which happens with paint. You have to sand until the entire surface is dulled. Harsher grits do not guarantee better adhesion. In fact it's generally a good idea to not use so harsh a grit that the scratches show through the finish (it looks tacky).
This is all for the sake of creating a mechanical bond between coats of paint. There's also what's known as a chemical bond. The most common example of this is lacquer. When a coat of lacquer is applied over another coat of lacquer, the new coat softens the previous coat, causing the two coats to meld together and form a very strong bond. This is also what liquid sandpaper does (alkyd only, not to be used with latex). If you rub a surface with liquid sandpaper until you feel the surface bite, then paint, the new coating melds into the old coat, forming a chemical bond between the coats.
Your paint job will probably require two coats. The first coat will be un-even because parts will suck in to the sanded previous coat, but the second coat should then have the full depth and richness that you're looking for.