Cleaning Equipment when Switching Between Solvent-Based and Waterborne Coatings

How to clean and flush when going from water-based to solvent-based formulas (and vice versa). January 27, 2007

Do I need to clean the equipment with anything in particular before switching to waterbourne lacquer from solvent based post-cat? Methyl hydrate perhaps?

Forum Responses
(Finishing Forum)
From contributor G:
Water cleans out the waterbourne lacquer and the alcohol (almost any alcohol will do) dissolves the water. Then run some lacquer thinner through before using the solvent-based.

From contributor J:
I switch back and forth between wb and solvent based all the time and haven't had any problems. Like contributor G suggested, I normally clean the gun with water after wb and then run lacquer thinner through it.

From contributor A:
I prefer to use acetone. Lacquer thinner has some petroleum oils in it from the Naptha and other heavier solvents. Water and denatured alcohol are the best for WB cleaning.
I've never had an issue using the acetone. I worry about using products on my guns that are as aggressive as the methyl.

From contributor B:
First, flush your fluid hoses with the representing solvent that matches the solvent-based (SB) finish that last occupied the fluid lines and passages, such as lacquer thinner, MEK, acetone. Then follow up with an acetone rinse, then a warm water rinse. If this does not get the old solvent-based (SB) out of the fluid passages, then go and buy a new set of hoses. Clean your pressure pot the same way. Get a new pot liner. Once you do this, all should be okay to run water-based (WB) finishes.

From contributor G:
I need new glasses. I got my to and from mixed up. When going *from* solvent-based, I flush the lines good, then blow them out with air before rinsing with water and then run the waterbourne. This rinse may not be necessary, but it makes me feel that the inside of the line is more protected somehow.

From contributor M:
Why swap? Waterborne should have a dedicated gun.