DIYbanter - View Single Post - NOT a painter .. ping: Nailshooter, et al

Leon[_7_]

On 2/7/2013 1:46 PM, wrote:
On Feb 7, 10:06 am, Swingman wrote:
Well, opinions are like noses, everyone has one... so here's mine.
First, no rattle cans on a job that size with those features/
dimensions/trim profiles. It would probably take 7 - 8 cans to get
the perfect sheen you want, and even then you would have difficulty
doing it on such flat surface. Imagine trying to get a small car hood
surface perfect with a spray can...

Not a "painter", don't play one on TV, and can only be reasonably
certain about one color, "Black" ... sometimes.
..
1. Crank up the HVLP sprayer and spray a couple of coats pf BIN

2. Sand lightly in between where needed.

Since we know each other, I will be more blunt than normal and just
tell you what I would do without the candy coating.

No need to sand beyond 220 g. Not on any surface really, I think most
people do that to put off the inevitable finishing stage a little
longer...

And no sanding between coats. Not on primer, not on finish. Unless
you have a bug that lands in the prime coat or you drop a cup of
coffee on it while it is wet, no sanding. That is an artifact that
has carefully passed down by non professionals for decades. Unless
there is a problem in the finish itself, no need.

Put down two thin coats, and my big thing is to paint the primer like
it is your finish coat. Don't slough off the finish because it is
primer and you think you will sand out the imperfections. Your
stroke, your application method and prep should be every bit as good
as it is on the top coat.

So put down (spray) two thin coats (45 minutes between) of BIN and it
should look like it is cast from white plastic. No witness lines, no
sign anywhere that it was actually coated with anything. Just white.
If you see a dust nib, carefully sand it down with 320 gr.

3. Spray what? Now I'm at a loss.

OK... you are now about 2 hours in on the project. (Spray, 45 min
wait, then spray, then an hour plus wait for paint.) Although dry to
the touch, the primer isn't cured out. SO NO SANDING. Sanding raised
dust nibs, fouls the air in your finishing room and can leave witness
lines under your top coat. Since it isn't fully cured, your oil based
material will bond to it nicely, burning in just the right amount.

The client wants the plaque to be "black" like the last photo in the pdf
file. After discussion with him again this morning, we settled upon the
concept of "satin" (he doesn't want it to look "wet") ... no problem there.

Satin makes the finish much easier. Even in an area with high
reflectivity it will hide imperfections better than gloss.

Don't want to make a Federal case out of this, but I only want to do it
once, so recommendations/ideas as far a type of paint, number of coats,
flat black base coat(s) with use of a final clear coat, etc.?

OK... no more of that nonsense. There is every product under the sun
for every application these days. All that **** about home brews,
"something someone heard about" or a Google Guess doesn't count when
you have a paying customer. Get the right product, apply correctly,
collect the job and go on.

The downside to the rattle cans (along with the fact they don't put
out enough material when applying) is a fast dry will murder you on
any imperfections. (As a sidebar, if I was there I would apply a
prime coat with my CAS setup, have a cup of coffee, the apply
another. I would hold you hostage for a cup of day old gumbo, the
apply the first coat of finish with enough flourish to make you think
I was doing something special so I could get more gumbo at dinner...)

Since you don't have a lot of experience with spraying deep toned
enamels, I would use a long pot life, long layout material. They are
forgiving. If applied evenly and to the correct thickness, they will
tighten up enough to cover some of your spray errors. Fast dry
products need to be used on small projects that you can cover quickly
as anything that is applied just a minute or so after first pass will
show. In other words, if you get focused on spraying out the detailed
profiles, your overspray will go on to the flats of this project.
Then when you spray the flats, the overspray will show up under your
top coat and give it a sand or orange peel finish. (Then of course,
you must sand, which is a no-no.)

Even if you are an experienced finisher, painting black can be
problematic. Painting black is fast dry is almost impossible. The
stuff in the rattle can is a lacquer/enamel, not paint as we know it.
Real fast dry enamels (like that really hot, high VOC stuff I like
that you thin with xylene) cannot hold enough pigment to get to
black. They are mostly solvent and don't have the body to hold
pigment. The only way you can get to black fast dry from here is a
two part catalysed finish, but I am remembering "no Federal case".

So use a long, oil based enamel. Plan your times of spray carefully
so you can stay on schedule and you can make Monday with good
weather. If it is really humid, the paint may not be 100% hard, but
after a couple of hours after the final coat you can bring this into
your house and let it finish out there. I have put sprayed in a large
closet on site with my halogen work lights and they have cured right
out.

My enamel of choice would be Sherwin Williams' "All Surface Enamel".
It is harder than their normal enamels, and wears very well. Called
my guy Brent at SW, and he confirmed this choice (again, limited on
colors in the fast dry department). The product number for satin is
A11B201 (you should verify) and it is available in the store in
black. They have to mix it, but you can buy a quart of it, not a
gallon.
And... this is big... they have it in satin. The number I gave you
reflects the satin base to be used.

IIRC, you have a two stage setup on your HVLP. This stuff is
surprising viscous, so don't be fooled about the black thick syrup
appearance. It is made to be sprayed. (As a thought... I might buy a
couple of quarts, one to mix and test, one to finish coat.) Try
hitting it with 10% (measure carefully...) and test out on a smooth
surface. That should do it. However, if you get any spray problems,
you can go to 20% thinned with no product desegregation. Try 10, 15,
then 20% if you need to go there. And remember, you use long oils to
improve adhesion and finished surface. If your finished surface is
smooth when you spray it, your final surface should be fine.

This SW product is particularly forgiving and I don't think you will
have any problems. It dries to the touch (depending on local weather)
in about three hours. You can recoat in 8, but can wait as long as
36! Full strength in 21 days.

So my batting order would be:

1) Get both coats BIN on today
2) Buy paint today and determine thinning amount for your equipment by
testing it out on some scrap, or my favorite, glossy cardboard. Both
first and second coats should be applied at about 4 mil thick, which
will give you a cured surface of about 1.5 mil per coat. Your goal is
3 mil finished when both coats are cured. Remember, a dollar bill is
about three mil, so just a bit thicker than that. (Seriously, with
this stuff you could probably go 5 - 6 mil of thinned product, but it
would take too long to dry)
3) Tomorrow, inspect surface in the morning for an settling dust or
bugs and spray first coat. NO sanding, NO scuff sand, NOTHING unless
you need to remove a bug, a nib or flatten a drip. Try brushing off
an contaminants, and only use 320 g and light strokes if you need to
sand
4) Last thing before going to bed, spray second coat. inspect surface
in the morning for an settling dust or bugs and spray first coat. NO
sanding, NO scuff sand, NOTHING unless you need to remove a bug, a nib
or flatten a drip. Try brushing off an contaminants, and only use 320
g and light strokes if you need to sand.

Remember, paint the detailed cornice work first, then the flats when
spraying anything.

Your project will be dry to the touch when you get up. If you can,
bring it in the house and let it sit out of the way Sat and Sun in a
controlled temp/humidity environment.

This will give it more than 60 hours of total dry time, probably
closer to 65 if you time it correctly. Last coat 6 pm on Friday, and
if you deliver around noon on Mon, that would be about 12 in the
garage, and another 50+ in a controlled environment, your house, to
dry until delivery.

No hill for a climber, eh? Problem solved using all locally available
products.

I have to deliver this puppy Monday morning.

As you can see... not a problem.

Any input is mucho appreciated (Wabbut ... hope you are not too es
spensive.)

I come there one time to paint one time but you say TOO HIY. You TOO
HIY!! Too spensive!! I no pay!!

Seriously, call me on my cell if you have any problemos.

Robert

You better come to Houston and do it for him. We'll have gumbo. ;~)