Tweaking Conversion Varnish for Hot-Weather Performance
Finishers suggest additives to eliminate CV orange-peel problems in hot weather. November 8, 2007
Question
I am spraying SW CV and am having problems spraying it in this hot weather. I get along pretty good until it gets over 80 degrees. Any ideas would be appreciated.
Forum Responses
(Finishing Forum)
From contributor L:
We need to know what the problem is.
From the original questioner:
The finish goes on orange-peeled and stays that way.
From contributor M:
What type of application are you using? Siphon gun, HVLP, airless? I take it SW CV is a type of conversion varnish? Normally orange peel is caused by spraying too dry and the material doesn't flow out well. Is it everywhere on your product, or is it on the vertical pieces? Can you try a slower thinner?
From contributor L:
Use a retarder in place of your thinner. Usually the maker (SW) will have several to choose from. If you have been using normal thinner, and it works up until 80º, I would jump to the 2nd slower thinner. If this doesn't solve your problem, then go all the way to their slowest thinner. I use MLC products and our thinners are as follows.
Fast
Standard
Reducer
Retarder
Flow Enhancer #1
Flow Enhancer #2
From contributor A:
I've had the exact same problems using same product. Chem guy at SW recommended butyl at 4oz to the gallon. I still add about the same amount of thinner along with the butyl and don't have the orange peel problems anymore.
From contributor B:
Butyl what?
From contributor A:
Sorry, I didn't know there were different types of butyl available on the shelf at SW - I just took what was given to me!
From contributor R:
Try a small shot of MAK (metyl AMYL ketone) or else try high flash naphtha as your reducer.
From contributor P:
For Kemvar, MAK works well as a retarder. If you're thinning 10%, use 2%-4% MAK and 6%-8% the regular thinner you use. You can get the tech data sheets for all the Sherwin Williams products at their website. The data sheets list thinners/retarders.
From contributor P:
You typed your answer too fast, contributor R. It wasn't there when I started pecking. ;)
From the original questioner:
Thanks for all the responses. Recently I purchased a Kremlin pump and my salesman said I shouldn't have to thin my product at all. Who knows how much of this product he has used.
From contributor W:
Butyl cellusolve.
From contributor S:
Toluol, a petroleum distillate and a common solvent sold in many paint stores, may also help the flow out in CV coatings in a pinch.
From contributor I:
Butyl-Acetate as thinner.
R7K27 as a slow thinner.
From contributor R:
I spray SW CV all day long in hot weather with Kremlin guns, with no problems with orange peel and no thinner. Maybe there is a problem with your gun setup? What size tip are you using and what are your pressure settings?
From contributor N:
Contributor R nailed it with the MAK. A good amount is 4oz of MAK to a gallon of CV. This works in Phoenix, AZ and if it works here, it will work anywhere in the world and likely also on the planet Mercury.
From contributor S:
The coating manufacturers are slowly running out of solvents. They are scraping the barrels now for anything that will work and not be on the banned list. Solvents that were once used to make up remover are being used in the coatings. At one time acetone was a solvent used with the distillates; today it is a solvent for coatings. You rarely found acetone in a finishing shop. Better days are coming.
