Controlling and Estimating Finish Thickness
A cabinetmaker facing a lawsuit learns a few basic concepts about wet and dry finish thickness. January 24, 2014
Sprayed Kemvar for the first time yesterday in a shop heater to 70 degrees with a 2 QT spray gun. Mixed it with 2 oz. of cat and 10 oz. of toluene to thin per instruction as a sealer coat. Waited 24 hours to sand and it still felt tacky, and when sanding (with 220 per instructions) it powders slightly but wants to almost gum up. Called rep and said he has never had heard of this before. (Supposed to be able to sand in 30 - 60 minutes.) Any suggestions?
From contributor C:
Check to make sure you used the right cat. There are two, one for sealer and one for the topcoat.
From contributor A:
Possible issues I can think of are: 1. Did you use the correct catalyst? SWP CV requires V66V21. V66V26 would not be a strong enough catalyst. I have gotten them mixed up before and had that result. 2. Was it Kemvar Plus? Kemvar Plus requires more catalyst than regular CV. I think 6 oz per gal instead of 4.3. Did you mix the catalyst in completely before reduction? if you added catalyst and reducer at the same time, that would cause a problem. 4. I have never used toluene as a reducer. Xylene works best for me. Also butyl acetate and MAK in equal parts.
From contributor G:
I too have experienced SW CV not powdering when spraying as a sealer. However, I did not have a rep to contact on a Saturday afternoon. When the CV was sandable, I did so and sprayed the second coat. To my dismay, it wrinkled! In 18 years, I have never had a finish wrinkle. When I called the rep the following Monday, he stated that I was out of the recoat time. The PDS does not give a specific recoat time. He said they don't give a critical recoat time because it would be different in Vermont vs. Arizona. Seems funny that other CV manufacturers can give a recoat time.
From the original questioner:
Thanks. I met with the rep this morning and he gave me a gallon jug of new catalyst and it worked great. Dry to the touch in 30 minutes and sanded nicely shortly after. The first catalyst was drawn from a large container into a quart can. So I think your assumption was correct when you suggested the wrong catalyst was given to me. Thanks again, and as always WOODWEB and its members rock.