Understanding how to read a viscosity table

[bpatters69]

Hello All,

I have an LVLP spray gun with a 2.0 tip and I plan to spray Latex paint. I also have a $4 Ford cup to measure the viscosity. I am trying to understand the Viscosity chart on Sprayworld's website. I need to know much water to add.  Here is a Link to Viscosity Chart. I am also posting a picture below.

So here is what I understand based on the chart. The tip size I need is from  1.6 to 2.5 for a gravity fed gun. I am using the #4 Ford cub so I am looking in the red numbers under the "Heavy Consistency" area. I see from left to right 50, 54, 58, 62 and 65. Does this mean that when I fill up a #4 cup that it should take between 50 and 65 seconds for the paint to clear the cup if the paint is properly thinned?



Thanks, Bill

[jteneyck]

Hello All,

I have an LVLP spray gun with a 2.0 tip and I plan to spray Latex paint. I also have a $4 Ford cup to measure the viscosity. I am trying to understand the Viscosity chart on Sprayworld's website. I need to know much water to add.  Here is a Link to Viscosity Chart. I am also posting a picture below.

So here is what I understand based on the chart. The tip size I need is from  1.6 to 2.5 for a gravity fed gun. I am using the #4 Ford cub so I am looking in the red numbers under the "Heavy Consistency" area. I see from left to right 50, 54, 58, 62 and 65. Does this mean that when I fill up a #4 cup that it should take between 50 and 65 seconds for the paint to clear the cup if the paint is properly thinned?



Thanks, Bill

The chart doesn't tell you how much water to add, it just tells you the recommended viscosity range for whatever gun and needle size you have.  So if you have a gravity feed LVLP gun with a 2.0 mm N/N set in it, the optimum viscosity range is around 50 seconds through a #4 Ford cup.  Measure the viscosity of the product you want to spray.  I'll bet it's a lot higher than 55 seconds.  Take a small amount and add 3 - 5% H20 to it and measure it again.  If it's around 55 seconds you're good to go.  If not, add some more until you get it down near 55 seconds.  Now mix thin enough to spray your job and have at it.  
FWIW, adding more than 20% water is not a good idea with waterborne products.  It can adversely effect how they coalesce and cure.  If you have to go that high you should get a larger N/N set for your gun.  Also, GF and BM both make an Extender product that greatly reduces the viscosity of waterborne products with only a few percent and they can help when you don't have a larger N/N.  Another option is to put a pressure cup on your gun.  You could easily spray BM Advance or SW's ProClassic (both around 500 seconds #4 Ford viscosity) with a 2.0 mm N/N  without thinning with 5 psi on a pressure cup such as 3M's PPS system.  
John

[bpatters69]

The chart doesn't tell you how much water to add, it just tells you the recommended viscosity range for whatever gun and needle size you have.  So if you have a gravity feed LVLP gun with a 2.0 mm N/N set in it, the optimum viscosity range is around 50 seconds through a #4 Ford cup.  Measure the viscosity of the product you want to spray.  I'll bet it's a lot higher than 55 seconds.  Take a small amount and add 3 - 5% H20 to it and measure it again.  If it's around 55 seconds you're good to go.  If not, add some more until you get it down near 55 seconds.  Now mix thin enough to spray your job and have at it.  
FWIW, adding more than 20% water is not a good idea with waterborne products.  It can adversely effect how they coalesce and cure.  If you have to go that high you should get a larger N/N set for your gun.  Also, GF and BM both make an Extender product that greatly reduces the viscosity of waterborne products with only a few percent and they can help when you don't have a larger N/N.  Another option is to put a pressure cup on your gun.  You could easily spray BM Advance or SW's ProClassic (both around 500 seconds #4 Ford viscosity) with a 2.0 mm N/N  without thinning with 5 psi on a pressure cup such as 3M's PPS system.  
John

Thank you John. You mentioned GF and BM offering an extender product. Can you tell me what GF and BM are? I am guessing they are abbreviations for companies but I am not familiar with either.

[jteneyck]

Oh, sorry. GF= General Finishes, BM = Benjamin Moore.

John

[bpatters69]

Oh, sorry.  GF= General Finishes, BM = Benjamin Moore.

John

No worries. Thanks