Skim Coat

Thank you Kramarat,

But it is still not clear by my stupid head. Skim coat is somewhat similar to mastic?

The term "skim coat" doesn't really matter. Tell me what it is that you are trying to accomplish and I'll do my best to help you. I do this stuff for a living.

This guy is applying a skim coat to cover imperfections. A light sanding and it will be ready for paint. A picture is worth a thousand words. You probably don't want to do this on an exterior surface.

English is my second language so I don't know how to understand "skim coat". As your explanation above and the guy, I could see that "skim coat" same as "mastic" which is kind of powder.

But mastic is more familiar to me than skim coat. But for mastic, we can apply it on interior or exterior wall.

You from USA and you do this stuff for a living, do you see my photo familiar to you? This is mastic made by USA suppliers and other.

Yes. Same thing. Mix with water and you have the mastic, which can be used for skim coat. Unless you're just filling very small nail holes or something, I would not recommend using these products outside..................even if the package says you can. It won't last.

Oh, thank you.

If it would not last, so what I should use then?

Once again, what is it that you want to do?

The products in your picture will most likely, A) separate from the substrate. B) Completely break down if exposed to moisture, if used outside.

There is exterior spackling, (mastic), available, but it is not intended to be applied as a skim coat, only to fill small holes.

Frustrating Ay - when you know the stuff and every man and his dog "muddies the water" - some blindly "uninformed"

In my world it's called 'spackle', or spack filler, or in automotive 'spot filler' - but you'd think they'd get the concept.

Never mind, I'll cruise through this and GA all your posts.

'Cause they are (bar one)

Not really necessary since all of my answers pretty much just repeat the same thing.............bar one.

Reading the OP's other threads, it looks like he may be trying to write a bid/estimate for a job.............................or something.

Well, you are correct in this point that I am trying to comprehend the bid even construction is not my field. If so, you will not mind replying my threads?

Wait a minute, you used to mention that "skim coat" is applied only inside and same as mastic. But why?

Kramarat has been giving complete and accurate answers.

You keep saying 'mastic', an implication of an adhesive. That is not correct.

The skim coat can be compared to both the brown coat and finish coat in a stucco wall or ceiling system. The function is to level out a finish, usually in a wall or ceiling. It is not always a finish, or final coat, but an intermediate, to ready a surface for final finish and decorating.

"Skim coat" is a process, not a product............see the picture I posted.

What you call "mastic" is a product that can be used for a skim coat.

Nobody here minds answering a question, but this is getting tiring. Please state exactly what it is that you want to accomplish.

I think trying to translate a bid, one phrase at a time, is going to take far longer than either of us, (or anyone), is willing to spend.

Sometimes I got a good answer that I say to myself "ok, it can be used". I am sure I sometimes cannot judge it right or wrong but because it simply makes sense. You know, naturally, his name will be noted in my mind because I appreciate the answer and, of course your answer is voted for one or several GAs. And then someone else jumps in putting a new idea and ask me in the other aspect. So, I struggle again after answering that question so as you mention that sticking around is popular here and you (the respected gurus) should not let it happen.

Moreover, why you mention that the "mastic", Ok, I repeat it, that should not be applied for external wall... any reason...and how about the skim coat? Because if you are correct when I state here that skim coat can be applied inside and outside... it would be a disaster. You know...

Mix up some of your mastic, apply it to an exterior wall that you don't care about, allow it to go through several wet/dry cycles and you will have your answer. The same thing will happen if it's painted, it will just take longer.

And that would be yours!

It would seen that someone just likes to see their name in print. Offering nothing but trash talk. If you don't have anything positive to say it would help us all if you just went back to sleep.

A skim coat is not a product. In the process of laying 2 or more coats of plaster, stucco, drywall compound etc. the skim coat is usually the final coat.

If one were going to wallpaper a wall, one would skim coat and sand a number of times to achieve total flatness.

Textured walls don't require as much smoothing work prior to painting. the texture hides a lot of flaws.

I think what you are referring to is a watered down 1st coat of paint to seal the surface before building up the coats of paint at full strength,this is normally done on new plaster or render work.

What I mean, is that I want to know what is skim coat? Is there any thing different from Mastic which we are using here.

And, why we jsut can apply skim coat for the internal surface only?

See answer 4 above for skim coat plaster or you can use a skim coat which is then scratched to give a key so additional coats can be applied to build up a finish.

I can only reference your question in terms that relate to concrete preparation or stucco on a house. In concrete applications, when applying a skim coat you are smoothing out imperfections in the concrete surface to give a very smooth texture. First you apply a mastic or concrete link that helps the very thin coating of concrete( fine sand and cement only ) adhere to the surface being smoothed out. It must have a very fine texture as it is a skim or 'surface only' application. On stucco, you do the same process. Coat the underlying material with a link or mastic to help the skim coat to adhere to the surface. In these cases, the mastic or link helps the skim coat adhere to the surface.

Not sure this helps but is the best I can offer.

"What we've got here is failure to communicate". Strother Martin, "Cool Hand Luke". 1976.