Cleaning and Storing Sprayguns and Lines after Spraying Waterborne Finishes

Advice on cleaning and storing spray equipment. September 26, 2013

(WOODWEB Member) :
I've recently had my Kremlin pump rebuilt, since after a long time of inactivity the seals had gone bad. Back when I was using Duravar, I'd leave thinner in the lines and in the pump, but we've switched to waterborne finishes. What should I leave in the lines now? Clean with warm water, then alcohol, then acetone and leave empty?

Forum Responses
(Finishing Forum)
From contributor D:
I have left waterborne in it for a month with no ill effects. I have also left water in it for just as long. If it were me I would leave water in it unless you will store it for more than 2 months.

From contributor S:
Flush it clean with water, then flush it with a 1:1 Polychem and water, store.

(WOODWEB Member) :
Thanks. What's Polychem?

From contributor S:
It's expensive but it is the best waterborne paint remover to flush your pumps. It's very concentrated and you can use it to keep your pumps clean. We even flush our solvent based pumps with it if they are going to be down for several days. I believe the automotive industry uses it as a nonflammable chemical stripper. We have over fifty AAA pumps here at the shop and I use Polychem with all of them.

From contributor V:
You can store with just water, though any remnants of wet paint may start to go off through bacterial attack and the water in the pump becomes putrid. A little household bleach in the water will stop this (this is only necessary if you are going to shelve the pump for a few months). Many of the paint and lacquer manufacturers offer flushing fluids for pump systems, and a dilute solution of this can be used.