Viscosity and Matching Tip Sets
The #1 mistake is not having the correct viscosity for the tip set you are using.
If some sales person says you need a 1.4 tip set - that is not enough information.
KEY: Pressure is different from gravity which is different from siphon which is different from miniguns which is different from AAA and different from turbine.
i.e.
1.4 on a pressure HVLP is different from a gravity feed HVLP which is different from a siphon feed HVLP which is different from a AAA Setup.
You can do it the old fashioned way by Eyeballing your material.
Looks Like |
Consistency |
Suggested Tip Sets |
examples |
| Water, Alcohol |
Very Light |
.8 pressure / 1.2 Gravity Feed |
i.e. stains dyes, automotive base |
| Full bodied Sugar Water |
Light |
1.0 pressure / 1.3-1.4 Gravity |
automotive, very thin woodworking |
| Chicken soup stock |
Medium Light |
1.2 Pressure / 1.5-1.6 Gravity |
Standard Woodworking Lacquers Thin |
| Warm Thin Pancake Syrup |
Medium |
1.3-1.4 Pressure / 1.7-1.9 Gravity |
Wood Standard Lacquers and Enamels |
| Latex Paint Thinned to Olive Oil Consistency |
Heavy |
1.4-1.6 Pressure Feed or MiniGun / 2.0-2.5 Gravity Feed |
i.e. latex paint |
| Glue Industrial |
Very Heavy |
1.7-2.8 Pressure Feed / Gravity Feed 2.0-3.6 |
i.e. gel coat, industrial glue (thin laminates like 3M and wilson art 1.4 pressure) |
You can take some of our starting recommendations and find your best processes.
Here are some of our recommendations to start for very fine finish:
Stains and Dyes: .8 -1.0 pressure feed / 1.0-1.3 Gravity Feed.
For Cabinet makers Lacquer clears - the best tip sets are 1.3 Pressure and 1.5-1.7 Gravity Feed
For Cabinet makers Lacquer Pigmented White - Enamels not house paint grade -- the best tip sets are 1.4 Pressure and 1.7-2.0 Gravity Feed
Latex and Enamel house paint -- the best tip sets are 1.5 Pressure and 2.0-2.5 Gravity Feed
You can use exact measurements for consistency in your spraying
For the more scientific mind, you can use a viscosity cup and charts.
For a complete chart click here
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Viscosity
Ratings are available from the paint manufacturer. Remember, theses are
just a guideline as other factors such as curing time,
build, and environment, etc., affect your finish. Due to demand we now offer viscosity cups. We choose Ford #4 cups (see below) due to the extreme costs of Zahn Cups.
| Cup
Type |
Measure |
Light
Consistency |
Medium
Consistency |
Heavy
Consistency |
| Zahn
#2* |
Seconds |
14 |
14 |
15 |
15 |
16 |
17 |
18 |
19 |
20 |
22 |
24 |
26 |
28 |
30 |
34 |
37 |
41 |
49 |
58 |
| Ford
#4 |
Seconds |
5 |
8 |
10 |
12 |
14 |
18 |
22 |
25 |
28 |
31 |
32 |
34 |
41 |
45 |
50 |
54 |
58 |
62 |
65 |
|
| Suggested Tip Sets |
|
|
| Light Consistency - Ford #4 5-14 |
.8-1.0 pressure or minigun / 1.3-1.4 Gravity Feed |
i.e. stains dyes, automotive, thin woodworking |
| Medium Consistency - Ford #4 18-34 |
1.2-1.3 Pressure or Mini Gun / 1.5-1.8 Gravity Feed |
i.e. wood standard lacquers and enamels, single stage old enamels |
| Heavy Consistency - Ford #4 40-50 |
1.3-1.6 Pressure Feed or MiniGun / 1.6-2.0 Gravity Feed |
i.e. latex paint |
| Very Heavy Consistency - Ford #4 54-65 |
1.7-2.8 Pressure Feed / Gravity Feed 2.0-2.8 |
i.e. gel coat |
FORD 4 Viscosity Cup
When spraying, the material you are spraying must not be too viscous for the spray gun or spray system you are using. This quality of the coating is called viscosity. Matching your viscosity with the correct tip orifice size is the key to getting a well atomized finish. If it is too thick, the finish won't atomize well or may not even come out of the spray gun. Poorly atomized coatings create a rough surface and look poor. You will have to move too slowly or too close to get coverage. When the material is properly atomized, it looks like a fin mist and leaves micro tiny droplets on the surface. These tiny droplets flow together and like magic make a smooth, level film. When you spray material at the same viscosity you get more consistency in your results. Remember also that you material gets thinner as the weather gets warmer. Too thin and you will get runs and sags. You usually like to spray between 15c and 30c.
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How to use a Ford 4 Cup
Hang the Ford #4 viscometer cup. Allow the paint to stabilize at room temperature, or at whatever temperature you intend to measure the viscosity and spray at. Remember temperature will change the viscosity of your material. Measure the temperature for your records. Place a small container under the Ford 4 cup. Place your finger under the orifice to prevent the paint from running out of the cup. Fill the cup all the way to the top until a small amount overflows. Start a stop watch and immediately remove your finger. Allow the paint to run out into the container below. As soon as the paint stream stops flowing stop the stop watch. Record the time it took for the paint to leave the cup. The shorter the draining time, the thinner the paint.
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