Spray Application For Pros – Sherwin-Williams


When you’ve got
a lot of surface area to paint nothing gets the job done faster
than an airless sprayer. To make sure you get
the best results without wasting paint or time
keep these recommendations in mind. Start by considering the type
of paint you’ll be spraying. Is it latex, alkyd, epoxy, urethane? Or maybe it’s a coating formulated
to deliver a textured finish. What surface is being painted? Drywall, masonry, exterior siding? Consult the coatings
product data sheet to ensure the spray tip you select is compatible with the material
and the surface you’re painting. Spray pressure is impacted by the length and diameter
of the hose you use. A longer hose will result
in a greater pressure drop, a smaller hose diameter
will also reduce pressure at the tip and if you’re connecting
two hoses together always attach the larger
diameter hose to the pump first to minimize pressure drop. While it’s not possible
to cover every combination, remember that your airless sprayer,
the tip and the hose, are part of a system and must be compatible
to operate effectively. So be sure to consult
the manufacturer’s instructions. Now let’s look at the spray tip, the most critical part
of your system. Typically paints
with higher levels of viscosity will require a larger orifice size. Assuming the size
of the orifice doesn’t change wider fan widths
will result in lower film thickness. Narrow the fan width
to achieve a higher film build. Likewise, if the width
of the fan doesn’t change a larger orifice will allow you
to apply more material. Diminish the size of the orifice and you reduce the amount
of paint that’s applied to the wall. Film thickness is also impacted
by the speed of application. Faster application speed will reduce the amount of paint
being applied to the surface and therefore diminish
the film thickness. Before painting,
be sure to purge the system of any residual
paint or solvent material that could contaminate the paint
and affect the finish appearance. When you’re ready to begin hold the spray gun
about 12 inches from the surface and aim it straight
at the area you’re painting. Don’t just pull the trigger
and keep moving up and down or in different directions, spraying
continuously the whole time. You could end up with double
the mill thickness every time you change directions. Aim your spray gun
so that the tip overlaps the previous stroke by a third. Start moving the gun first,
then trigger the spray. This simple technique will ensure that the entire surface
is coated evenly. If you notice the spray pattern
has fingers or tails, increase the pressure, until
you get even blemish free coverage. Even with a perfect
spraying technique it’s often recommended to
backroll to ensure a filled block, hide imperfections on the surface or to provide a
smooth attractive finish that also satisfies the coatings
recommended film thickness. Mill thickness is a measurement
of the thickness of the paint film when applied to the wall. It’s important
because paint is formulated to perform best
at a specified thickness. Apply too much paint
and the coating may sag. Too little coating
will result in poor hide or insufficient defence
against moisture or UV damage. The coating manufacturer
may express the required thickness as wet mill thickness
or dry film thickness, which simply refers to the thickness
before or after the paint is dried. Although there are several types of gauges used to
measure mill thickness, this common tool has notches
spaced at one mill increments. Hold the gauge at a 90-degree angle
to the surface and press firmly, ensuring that both sides
contact the substrate. The number
above the last visible notch indicates the mill thickness
of the coating. If you’re measuring
wet film thickness there will be
a trace of paint on the gauge. Make sure to clean the gauge
as soon as you’re finished so it’ll be accurate
the next time you take a reading. Proper maintenance will help achieve maximum performance
from your spray tip. Make sure your paint
is well mixed or boxed. Maintain clean filters and use
the correct filters for your gear. Remove the tip when you’re done and use a soft, bristle brush
to clean it. To get the most life
out of your tip, spray at the lowest
pressure possible that will
completely atomized the paint. To do that set the pressure control
at its lowest setting and slowly increase it until
the paint is completely atomized. This will also help to extend the
life of the sprayer’s piston pumps, pacing motor and
other wearable parts Over time, if you notice that your fan width is
lost 25% of its original size it’s time to replace the tip. For example if a tip
with a 12-inch fan width has gradually been reduced
to 9 inches over time That worn tip will spray
40% more paint but cover 25% less area. You’re wasting a lot of time,
money and getting a poor paint job. This illustration shows how
the painted surface area is reduced as a 12-inch tip wears down
to a 9 inch, 7 inch, and 3.5 inch fan width. To keep your airless sprayer
in top condition keep the pistons well lubricated. This wet cup is a reservoir that
holds throat seal liquid or TSL. Greco TSL is specifically
formulated to prevent paint from drying
on the displacement rod. It’s also clear and won’t impact the performance or
finish of the coating. Oil should not be used
in place of TSL. When you’re done for the day, flush the pump with
a recommended solvent or water followed by paint thinner
or a pump saver solution. This reserves the packing and helps
prevent rust inside the pump. Finally it’s important
to use electrical cords that are approved
by the sprayer’s manufacturer. Ports that are longer
or smaller gauge than recommended can cause the unit to overheat
and shorten the life of the sprayer. While airless sprayer
are generally safe it’s important to remember
a few safety guidelines. Make sure the work area
is well ventilated and that crew members as well as tools,
spray equipment and extension cords are properly grounded to eliminate any source of spark
or static electricity. Never run the sprayer
if the surrounding area is wet and if it has a gas engine,
never operated indoors. The high-pressure
generated by an airless sprayer can cause a potentially
dangerous skin injection unless proper precautions are taken. Stay clear
of highly pressurized fluids. Never remove protective devices
like the spray gun tip guard and engage the spray gun trigger
safety when you’re not spraying. Use proper pressure relief practices and never feel
for leaks with your hand or try to stop leaks
with your hand or foot. If an injection occurs, even something that
looks like a small cut go to the emergency room, tell the doctor that
it’s a fluid injection injury and report the type of material
that was being sprayed. Knowing how to operate
and maintain your airless sprayer will ensure that jobs are
completed safely and professionally and add years of life
to this critical piece of equipment.

6 comments

  • Noah Krietsch

    I'm going to have to disagree about having a reduced pressure from a smaller diameter hose. Given the same amount of fluid flow rate (paint) output from the actual airless paint sprayer unit, a smaller diameter hose will theoretically yield a higher output pressure than a hose with a larger diameter. Think about 1 gallon per minute of water coming out of a 2 inch diameter pipe versus 1 gallon per minute coming out of a 1/16 inch diameter pipe. Pressure on the 1/16 inch diameter pipe is immensely larger coming out of the smaller pipe. The actual volumetric flow rate is equal for both pipes, but in order for that same volume of water to come out of the 1/16 inch pipe as the 2 inch pipe, it has to have a huge pressure increase

    Reply
  • D.E.K. Outdoors

    From 6:40 to 6:55 spray is tailing when he sprays door !! lol

    Reply
  • John Bergeron

    why would they recommend you back roll a spray finish I'm a Furniture finisher and I never backroll anything that would ruin the Finish

    Reply
  • goodcat1982

    "often recomended to back roll" erm no it's not. That's the whole reason why people opt for spraying, so they don't have to roll! If you have to roll after then you have not sprayed it right. Is this the advice you give "pros"?? Terrible

    Reply
  • Angry Goyim

    WHAT A NOOB! You overlap 50% not a 1/3rd

    Reply
  • Raptor copter

    How TF did go to listening to music to this

    Reply

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