Stewart Paint, viscosity cup

RScott · #1 05-26-2009, 08:37 PM

Stewart specifies a Dupont M50 viscosity cup for measuring paint viscosity. I called all over the Portland area and none of the automotive paint suppliers carries the thing. One did want to sell me a Sata cup for $48.

Turns out Stewart carries the M50 for $11.

Order your viscosity cup when you order your paint.

mbell · #2 05-26-2009, 08:57 PM

Richard, did they give you the latest DVD on painting metal aircraft? It's a work-in-progress but very helpful. Anyway, in there they recommend weighing the paint instead of making volume measurements. Then you can skip the viscosity testing.

RScott · #3 05-26-2009, 09:33 PM

Thanks, Mike. I do have the new DVD & did watch it. Yes, they did weigh the components, but I am pretty sure they used the viscosity cup also. I'll check--I was planning to watch it again, anyway.

DakotaHawk · #4 05-28-2009, 06:55 PM

Richard, I'm just finishing up the paint on my RV-7. I did the same thing as you - searched all over the local area for the correct viscosity cup. Finally called Stewart Systems and talked to Dan. He told me to skip the cup - just use a postal digital scale that reads in grams.

Off the top of my head, the ratios are as follows...
Part A
Part B = Part A / 2.75
Distilled Water = Part A / 3.33
(disclaimer - don't use these numbers until you check them. I'm quoting from memory!!!)

Mix part A and part B well, then add water. No need to check viscosity, since you're dealing with weights, you'll get good results every time!