Thursday, May 2, 2013

Getting Your Spray On Part Two: Using the System

 
 
 
 
FAUX FORCE FOUR...
Fighting for Truth, Justice, and Better Finishes
 
 
(Talented Kansas City Finishers Brenda Macaluso, Kerry Phillips, and Mona Kurtz.)
 
 
 
Ah... the first signs of Spring.  Bruce is dry cleaning his Hawaiian Shirts, the dogs are leaving grass stains on the carpet, and I have monkey palms because I still don't know the right way to apply self tanner.  But most importantly (and to the point of this post) it begins the optimal time for many finishers to use their garage for cabinet/furniture jobs!
 

In Part One, I talked about the basics of a HVLP spray gun and reviewed the parts.  Of course, what you do with those parts is another story....
 
 
 
For example, these are parts to a car
 


 
and depending on how you use them, you end up with a DeLorean
 
 
or this.  Where do you think he put the Flux Capacitor?
 
 
So let's assume that you read the last blog post or your owner's manual and your spray gun is correctly assembled. But you are still having problems getting that fine factory finish you (and the client) are hoping for and the reason you purchased a spray gun in the first place.
 
The first thing to check does involve the parts. Make sure you have the correct sized needle, air nozzle, and air cap for the viscosity of your product. Thicker products such as base coats and crackle medium need a larger numbered set-up. Thinner materials such as topcoats and crackle size require a smaller set-up.  If you match the thinner topcoat needle to a base coat sized air nozzle your product will just stream out the tip.
 
Next, make sure your product is thinned properly.  The beauty of a water-based system is that you can thin your product with tap water.
 
 

The product line I use, Faux Effects, is on the thicker side.  That can be a good thin because thinning with water and spraying gives me more product square footage.  I use Setcoat as my base paint for cabinets and thin it about 1/4 cup of water per quart of Setcoat.  You want it to resemble half & half.
For topcoats, I again start with 1/4 cup water per quart of product.  Topcoat should be the consistency of whole milk.
 
Make sure your topcoats are well mixed by dumping in a separate container to get the solids and liquid well blended.  Just spraying the liquid without the full benefit of the solids will create a shiny surface with spotty coverage.
 
 


After thinning, you need to strain your product. It should flow easily through a medium to small screen.  I usually thin and strain my product beforehand rather then on site when I am spraying on site.  In a pinch, you can make a strainer from folded cheesecloth (or pantyhose if you happen to be wearing them or robbing a convenience store later in the day).

The only products I do not strain are crackle size and crackle medium.  For the size, I thin 10% with water and use the topcoat setup.  For the crackle medium I thin to paint thickness and use the basecoat (larger) setup. If you strain these products you will end up spraying tinted water and nothing will crack.


Put some petroleum jelly around the gasket in the spray gun lid-this will improve the seal.  Getting the lid tight and straight are two different things. You should feel a click if your lid is on properly.  If product is bubbling around the lid then the top is not on straight even if it is tight.


Attach the gun to the air hose and make sure the hose is open. In the picture above the air hose lever is in the open position.   In the picture below, the air hose lever is closed. You should hear the turbine strain.




This lever is a great way to control air speed-especially working off a ladder or scaffold.  By adjusting the lever I can slow my speed which reduces over-spray and increase precision.


In the picture above, the needle is even with the air nozzle and air cap opening. This is the "normal" setting for covering a cabinet door with some overspray and is a good setting for a spray booth situation.  The air cap in the above picture is set on the diagonal which means my spray pattern will be an elliptical:


I use this setting for corners, dental molding, and when I spray heavy material like crackle medium.
The air cap is usually turned for horizontal or vertical spray directions. This is one of  two adjustments you may make with this set-up to control over spray and spray direction.  The other adjustment is made with the black ring on the front of the gun.

By turning the black ring (seen below), the needle either moves out further or retreats back.  The further out the needle is, the larger the spray. You cover more area fast but you also get more over-spray.





For less over-spray and precise spraying, rotate the black ring counter-clockwise and the needle retracts (picture above).  This also means that covering an area will go slower. My air cap is turned to a horizontal pattern.

The biggest concern most people have is spraying in the home. But, with a little practice and the right settings, you can control the overspray!




 In the picture above I've used 9"masking paper around my door. The door covers 2"inches of the paper.  I retract my needle to even or less then the air cap.  And I barely turn my air hose lever to reduce the airspeed. 
 


Hold the gun about 6 inches from the surface, compress the trigger, and slowly follow the rails and stiles of the door.  Going slow will give you better coverage and minimize drips.  Don't bring the gun in closer as you move across the surface. The movement is fluid-not a windshield wiper.  Release the trigger when you get to the end of an area.


When I want to spray the vertical sides, I only need to turn the air cap to the vertical position:

And here is my door:


And here is my over-spray on the top:



And on the side:


To show you how easy this is, I sprayed the door with my right hand and took the pictures with my left hand while I was spraying.


This is sprayed topcoat on black so you may see it.  My needle is slightly out compared to the nozzle (rather then even or recessed) and the air cap is set in the vertical.


Common Problems and Solutions:

The product is spitting out of the gun. First check that the air hose lever is open. Next, with turbine off, remove the lid and make sure the air spout at the top is not clogged using a paper clip or spray gun cleaning kit.  If both things are fine then your product is not thin enough.  Add more water and stir into your cup.


The product is running down the surface.  Product may be too thin.  Also you may be spraying too heavy-tighten the back ring setting on the needle. This will make the trigger harder to pull all the way back.



There are bubbles or rings on the surface.  This is a fish eye.  Usually it means there is a containment on the surface or in the product.  I only spray water-based products in my gun and make sure any cleaners such as Latex Lift-off or Lacquer Thinner are thoroughly removed.  If on the door, rinse or wipe the finish off.  Clean and re-sand the door.

The finish is dimpled.  You are standing too close.  Setcoat actually lays out really well even with a few dimples.

The finish is spraying unevenly.  Make sure that the all the air cap holes are clean.

There are 3 holes in this set-up including tiny ones on either side of the air nozzles.  See that gold bracket on the side? It attaches to the gun air tube and needs to be cleaned as well.


The topcoat is drying white in the corners.  This is from spraying too heavy and the product settling in the corners of the door.  It is always better to spray multiple thin coats (following 2nd coat instructions based on product) rather then one thick coat. The other reason for this has nothing to do with spraying.  You need to put a gloss topcoat on a dark finish. When the gloss dries, you may apply a satin, matte, or dull finish.

The best thing you can do is practice. I have sprayed bed frames with the mattress on, closet doors with clothes in them, and crown molding on a curved staircase next to a freshly painted ceiling.

All it takes is confidence, good plastic/paper masking skills, and a client out of town.

In the final installment, we will cover how to set up for a real spray job both in your studio and on the job site.





 
 

2 comments:

  1. I like your blog a lot. Its informative and full of information. Thank you for sharing.
    Airless Paint Sprayer

    ReplyDelete
  2. Thank you for sharing this interesting and informative article, painting with airless spray gun will be faster and more interesting!

    airless spray

    ReplyDelete