Inspired by the "Green Finish" thread a while back, I decided to try Sayerlack water base for exterior doors to replace Sikkens, our current door finish. Sprayed some samples using a gravity gun and like the product. Going to test in the weather for a while before we use it on a door. The last 2 steps of the material are pretty thick, and I had to thin quite a bit for the gravity gun. I would like to spray some samples with our Kremlin.
The Kremlin has never seen water base. Any cleanup tips for this? Do I need to use warm water? We also spray pre-cat, and I wonder if it is bad to use the same system for both type finishes. Just don’t want to turn the Kremlin green. Also, if anyone else has tried Sayerlack, I would like to hear their impression.
From contributor M:
Issue One: I have tried many times to run WB through my 10-14 and it does not work well. I get a lot of air entrapment, micro bubbling and striping at the ends of the spray pattern. I have warmed the material, thinned and retarded with no luck. I just go back to my gravity in order to get an acceptable finish. The line clearing is the other major problem. When you clean your line from solvent to waterbase, any interaction will cause a gorilla snot mess in your line filter, gun filter and in the ball gate valve. Try blowing air into the fluid pickup to purge all solvent from the system.
Issue Two: I have not used the Sayerlack product. But I have tried more than my share of WB exteriors and all seem to have decent film surface quality durability. Where they fail is in their UV filtration ability. Stains and wood will fade through the finish. How can the use of these materials be "green" when you end up prematurely stripping off the material (MC stripper is 100% VOC) in a year or two? Let's do the math… WB exterior at 275 gr/l, Isocyanate exterior at 550 gr/l, the life of the iso is between 4 to 10 years and the WB is between 1 to 3 years. As you can tell, I have stripped more that my share of WB finish (and it is not fun). Who knows - maybe Sayerlack has something different?
I got the WB material direct from Arch Coatings. They are trying to start with WB lacquer and do not have all the exterior coatings (or knowledge) at this time. Sayerlack has several different types for exterior depending on wood types. My cousin in Italy uses Sayerlack in his window shop. He shoots everything off an overhead chain conveyer and says the Sayerlack has good vertical hold. I do not know if he uses the WB or solvent type. The Sayerlack info says to get good UV protection the colored topcoats have to be used. So it is like Sikkens and not transparent.
I agree with you about “green.” If a solvent finish lasts twice as long, that is going to be better for the environment. Mahogany is the bad boy right now with environmentalists. But if a door or window lasts 50 years or more compared to an approved wood that only goes 20 years, what is the best for the environment? Especially when you figure all the transportation and energy used.
My concern is with a healthy environment in the shop. We have all the safety gear including a fresh air mask, but still the off gassing and material handling leaves everyone exposed. Sikkens makes my eyes water as soon as the can is opened, and that can’t be good long term. Same for pre-cat and conversion varnish. Europe has a lot more exterior finishes available than we do. Even Sikkens has WB finishes over there.
Contributor D, we finish about the same amount of exterior units a year and about the same refinishes. It is always nice to know what anyone else is using. Please do not tell me you are using spar or Home Depot poly.
As for AAA pumps shearing water-based finishes, you need to run a test. Not all WB's are as shear sensitive as they used to be, but there are still a few brands out there that can be shear sensitive. Talk to the manufacturer of the coating and get their guidance. Try it - you'll like it...
As for equipment, I have used an HVLP and now the more efficient LVLP version of HVLP. No problems other than operator error in settings. I have had problems with oils, solvents and such getting on the wood prior to finishing. I suggest that you purge your shop of all silicone based sprays for your machine tables and such. Silicone will wreak havoc with water based.