- Hey, YouTube viewers, this is Donnie Smith.
And welcome to this video series
that is designed to help you pass the ASE exam.
Now this video series
is specifically for the Paint Refinish,
and what we're gonna do is we'll go through the task
and give you the knowledge to pass the test.
What this is not,
this is not really your prep test type book,
you know, it's not just test questions.
If you want that, there is a link down there
in the description, you know,
you can get more information about that.
What this is, this basically goes through all the tasks
that you will need to know to pass the test.
In this video, we're gonna be talking about undercoating.
It's B10, in the Refinishing Painting,
and it's identifying a complementary color of undercoat
to improve coverage.
Now before we start talking about undercoatings,
first let's talk about paint real fast.
Paint consists of three things:
The first one is pigment, and that's basically the color.
And then you got solvents
that breaks the color down into a liquid form
that it can be sprayed or applied.
And then you have binders,
which acts like a glue, you know,
it holds it all together.
And you also have some additives,
like aluminum, for metal flake,
mica for pearls,
and there's some others as well.
Now with this in mind,
some colors have more pigment than others.
So that means the ones that have less pigment,
less color in it, is gonna be more transparent
than a color that has a lot of pigment.
So getting the correct color is gonna start
with the undercoat.
Because if it's a translucent color,
for example silver,
you know it has a lot of the aluminum metal flakes,
it has a lot of binders and solvents
and it doesn't have that much pigments.
So that is a more translucent color than,
for example, a white.
So this means that paints are translucent,
and that basically just means that you can see through,
you know it's hard to hide, hard to cover
with these translucent colors.
It's going to take more paint to cover that.
So the undercoating's gonna play a part
in the final finish.
So if the color's translucent,
the darker the undercoating,
the darker the color's gonna be.
The lighter the undercoat is,
the lighter it's gonna be.
So let's take us some different colors of undercoating.
Let's just go from light to dark.
And then we're gonna apply transparent blue on top of that.
And see, depending on the color underneath,
it's gonna change what color blue that is,
what shade of blue.
And if we had a transparent red, it's the same thing.
It depends on the undercoat,
it's gonna change the overall color.
Now traditionally undercoating was designed
to help achieve color hiding faster.
For example, one color of high-pigment undercoating
will reduce the number of coats of base coats
needed to achieve full hiding.
However, with the transparent colors,
the undercoating is gonna play a part,
like we talked about, the blue and red,
of the overall color.
So the undercoat becomes very crucial
in order to get the correct color match.
Depending on the products and the system that you're using
a primer sealer can be used, a primer surfacer
or even a base coat can be used as an undercoating.
Primer sealer is applied to the surface
after it's been all prepped, sanded,
ready in the booth mask, wiped down.
Once it's ready to paint, you apply primer sealer,
and then you allow that to flash.
You don't sand it or anything like that.
And once it's flashed off
then you can apply your base coat.
You're gonna have to read your technical data sheet
for the specific product that you're using
but you know, anywhere from ten, 15, 30 minutes,
depending on what the technical data sheet,
and it's usually one to two coats,
but it's always good, because every system's different,
to read the technical data sheet for that certain product.
But you apply your primer sealer, allow it to flash,
and then you put your base coat straight on top of that.
Some paint companies make primer surfacer
that's in the correct shades.
You know they may have the different shades of gray,
or you might can intermix them,
but to get the correct undercoat color,
and then that you do have to sand,
primer surfacer has to be sanded.
Once you get that block-sanded, final-sanded,
then you can pull it in the booth,
and where you had primed at,
Let's say you're doing a repair,
and now you've got that area primed,
you've already got the correct undercoat color.
So then you can apply your base coat
straight on top of that.
And like I said, every product's different.
There's some primer surfacers that can be tinted,
it just depends on the company that you're using.
So be sure, like I keep mentioning,
be sure to read that technical data sheet
and follow the system, follow the recommendations
to eliminate any type of problems that could arise.
Now another option is a base coat.
You know, base coat could be used as a undercoat.
Because basically
we're just trying to get that correct grayscale,
so if you're using a base coat,
it's gonna be high pigment, you know,
probably mixing like white and black together
to get the correct color.
One thing about this and the primer surfacer,
if you're doing that you can't have any burn-throughs
or anything like that.
You want, the surface needs to be ready to paint it,
so you don't want any metal spots or anything like that.
So if everything, you've block-sanded your primer,
you didn't burn through, sand through to any metal,
you can apply that base coat on top of that primer surfacer
and then you can apply your regular base coat
on top of that.
You may ask, why not just use additional coats of base coat?
You know, instead of using this grayscale base coat
if you're using this method.
Well,
the paint that you're gonna use
is gonna be a high pigment.
Let's say that you're shooting silver,
something translucent.
You could put a number of coats of that
and it's still not gonna hide what's underneath that.
It's not gonna hide your primer spot or anything like that.
So it's important that you use a high pigment,
which is, it's usually gonna be black and white
mixed together to get that correct grayscale.
Again, it's gonna depend on the company that you're using.
You know, you put one coat of that
and then you can come back and put you translucent color.
And in fact, there's a better explanation of this.
PPG has a video and I'll put it down here
in the description.
If you're at my web site,
the video's also embedded down here.
I'll put that down there.
And it does a good job of explaining
why you'd wanna do that.
This is more important with the base coat that we've found.
Because on the base coat a lot of times,
on the edges of your sealer,
you can kind of see that ring.
Where that, that rough edge of the sealer.
So this kind of eliminates that problem
and you get the correct grayscale at the same time.
Be sure and check that other video out, too.
It'll explain what I'm talking about.
But basically, as far as this task,
I just wanted to mention the things that can be used
as an undercoat.
And that's primer surfacer, primer sealer, or base coat.
And its main job is for hiding.
You know, to hide what's underneath that,
so that you can get the correct color match.
So to figure out what the correct grayscale is,
that's gonna depend on your paint company.
With the paint that I use, PPG, you look that coat up,
and once you do that, it will tell you,
once you look up the paint coat up,
it'll give you the exact grayscale that you need.
And then you can mix it with what system you're using
or if you wanted to use the base coat,
it'll tell you how to mix that.
And get that exact color for the undercoating.
It is my goal to keep these videos short.
S that's all we're gonna cover in this video.
Just give you little chunks at a time,
let you absorb that, and then you can watch the next video.
Down below is a link to the test prep books that I have.
But also there's a link that'll take you to all these videos
if you're wanting to go through
more than one video at a time
and take you through the entire playlist.
Be sure and check that out
to go through the ones that I've already uploaded,
and as they become available
they'll also be put on this site as well.
Thanks for watching this video, I hope this helps.
And good luck with your ASE exam.