Applying
paint or other finish such as varnish, takes some practice to achieve a
professional result. The best method of applying paint is the use of a spray
gun. The spray technique can easily be mastered, provided that the right procedures
are followed.
How to spray paint.
Proper
spraying techniques are very logical. Some of the basic principles for quality
spraying are the following:
Plan a systematic spraying routine that
will reduce waste and overspray. I start
on the underside of a piece of furniture. On a chair for instance, tip it over
and start with the legs and the bottom. Then turn it over and start from the
top by spraying the back, armrests etc. Lastly spray the seat. Always work from
top to bottom and the inside to the outside. Work from the less visible to the
more visible areas.
Make sure that you have adequate light.
Keep the spray gun pointed perpendicular to the surface of the wood. Avoid movements of the wrist. Move the whole
arm from left to right.Set your gun to a fan pattern that
covers the surface with the fewest
passes and
the least overspray. Use a small fan
pattern on edges, rails, turnings, and other narrow surfaces. Use a wide fan pattern on large, wide
surfaces.
Start spraying about 4 -6 inches from
the side of the wood, and move the spray onto the wood. Keep moving at a uniform speed.
Keep
the gun a uniform distance from the surface of the wood between 6 and 10
inches. If you move it too close, you
will make runs; move it too far away, and you will have dry spray. You usually have to hold an HVLP gun several
inches closer to the wood than you do a conventional gun.
Finish
your stroke several inches past the edge of the wood. Make it a habit to release the trigger of the
gun at the end of each stroke.
Make
sure that the strokes overlap to ensure even thickness. Also spray each stroke
at least two times - one stroke to the edge and back on the same stroke.
Overlap each previous stroke by half.
This will give an even thickness overall.
Avoid
spraying to much the first time around. Running of the paint may occur and then
you will have to redo the whole process. Rather spray several coats to make
sure you have adequate coverage.
Remember,
practice makes perfect. Don’t expect to be an expert spray painter after the
first couple of efforts.
First
spray a test stroke on a piece of scrap to make sure the spray pattern is
correct and the volume of air and material is adequate. After spraying a few
strokes, stop spraying and stand away and have a look against the light to see
if the painted surface is shiny and that it does not appear like a matt finish.
If the latter is the case, not enough paint is deposited and it must be
corrected by doing one of the following:
Make
sure the paint is not too thick and the volume of air and paint release is
sufficient.
Make
sure the paint nozzle on the gun is open and not blocked by impuities.
Close
the paint volume knob and spray to remove impurities. If this does not help, the
cup must be emptied and the gun taken apart and cleaned.
How to mix the paint
Another
important skill that is required for proper spraying is the ability to properly
mix the paint. In most cases the commercial paints are thick (especially water
based paint) and need to be thinned to achieve a good flow of paint through the
gun. Mixing takes a bit of practice. Water based paint can be thinned up to 10%
or even more. A paint measuring cup clearly indicates the 10% scale and should
preferably be used. A spray painter’s ruler can also be used. Always spray a
test stroke to make sure that the right amount of paint is deposited.
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Paint measuring cup |
Most
Acrylic paints must be thinned down to get the right consistency (thickness). Depending
on the brand of paint you might have to do some experimenting to achieve the
right consistency.
After
thinning, the paint must be filtered through a paint strainer to remove
impurities. There are different types of strainers but the most popular are
nylon mesh or paper funnel strainers.
Tip:
You
can make your own reusable paint strainer from the same strainer material that
can be bought from a paint dealer. Here is what you will need:
Fine mesh material
(obtainable from paint dealers for 20 liter containers)
Two empty 1 kg yogurt cups
Utility knife
Take
one yogurt cup and cut off the top part about 5 cm from the top.
Take
the mesh material and cut out a circle of 20 cm diameter.
Place
the mesh over the first cup and insert the cut-off top to hold the mesh firm.
The
mesh is totally washable with water mineral spirits or thinners and can be used
repeatedly.
As
an alternative you can simply take a piece of elastic and secure the mesh over
the empty cup.
DIY paint strainer cup with mesh
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DIY paint straining cup |
I have been spray paintnig furniture for many years and in my book
"How to spray paint furniture" I give details of issues such as the right spray tools to use, the best primers and paints to spray paint furniture, how to spray diferent types of wood and much more. You will also find many handy tips to
make spraying easier.