Spray Equipment for Waterborne Top Coats

Advice on cleaning guns and lines when switching between solvent-borne and water-borne finish formulas. February 15, 2009

I am currently testing Aqualux II, a waterbased sealer and topcoat and I am liking it. We are testing the material with a Asturo (Italian) gravity feed HVLP gun. We currently are spraying our topcoats using Chemcraft pre-cat with a Graco pump and a Kremlin MVX gun.

The question is if we start doing some volume with the waterborne materials, what is the best setup for spraying my top coat material? HVLP pressure feed with a stainless pot? Air-assist gun with a pump? I need a setup for volume so a gravity feed will not be satisfactory. I will be dedicating this setup for this material only. Can I leave it overnight? Any help would be appreciated.

Forum Responses
(Finishing Forum)
From contributor S:
Kremlin application equipment will work well with water based coatings. You can use your existing pump and gun for the water based coatings. When you switch to water, do a double solvent flush, and then a good water flush. Solvent and water based coating will jell when mixed. If you need to change back to solvent based coatings, do a double water flush, and then a good solvent flush.

Remember, three flushed when changing over from one type to the other. As for removing the coatings at night, I would leave the coating in the system. The only problem would come from the Graco pump, if it is not SS. All of the Kremlin pumps and guns are SS or Hard Chrome plated over SS. Therefore, there is no problem of leaving it overnight. We have hundreds of installations using water, and they never flush at night.