Durability Comparison: Pre-Catalyzed Lacquers Versus Conversion Varnishes
Lacquers can be dissolved by some solvents after coalescing, while CV finishes cure by cross-linking and are solvent-resistant. Here, finishers discuss the comparison and its significance. November 13, 2005
Question
A customer of mine would like to see a quantitative comparison of CV versus lacquer - abrasion, water resistance, etc. Does anyone have such a chart?
Forum Responses
(Finishing Forum)
From contributor D:
Take two pieces of wood, spray one with CV and the other with NC lacquer. Then have the customer wipe both of them with a towel soaked in lacquer thinner. That should make up their minds in a few seconds. If you meant pre-cat lacquer, it gets a lot murkier depending on which pre-cat and which CV you are looking at.
From contributor R:
I could never understand the idea of soaking a rag in lacquer thinner and then rubbing it on a lacquer finish. Based on the number of times someone will polish their finish with lacquer thinner, this proves nothing except that the lacquer thinner will lift the lacquer finish.
Look at a product information sheet from a Sherwin Williams product and it will show you what happens to a finish when it exposed to real life scenarios. These product sheets can be downloaded from the Sherwin Williams website or you can get one faxed to you from a chemical coatings store.
If you do ask a customer to wipe the finish on your sample with lacquer thinner, are you going to ask them to wipe down the finish on their automobile as well? Many fine furniture companies use a pre-cat topcoating on their pieces, so that should tell you something. Many fine furniture companies use a conversion varnish on their pieces, so that will also tell you something.
From Paul Snyder, forum technical advisor:
Nail polish remover (acetone) is a realistic test. I've seen too many pieces with an ugly bare spot where the owner tried to wipe up the sticky mess when it was spilled. Contributor D makes a good point about the pre-cat lacquer. Ketones (acetone or methyl ethyl ketone, MEK) are a primary ingredient in lacquer thinner, so it would work as well.
From contributor D:
The point I was making is they are two different types of finishes. One is crosslinked and has good resistance to chemicals and the other coalesces and can be easily re-dissolved. You could do the same thing with a mild stripper, which would eat into the NC but wouldn't touch the CV.
I have always found my customers respond better to hands-on demos than to something in a brochure, but everyone is different. As far as wiping down their car with lacquer thinner, my guess is, if you wiped down one with thinner and it remained unchanged, and on the other one, the finish dissolved, they wouldn't buy the second one.
From contributor M:
I think it also depends on your shop conditions and how fussy you are about measuring and keeping track of mil film thickness. If your shop gets colder than 65 degrees, if you over catalyze the CV or if you apply more than 5 mils dry film thickness, your bulletproof CV will shatter like a cheap piece of glass. Applied properly under good controlled conditions, CV is a great finish. So is pre-cat lacquer. There are French polished tables that are over 100 years old that still look great and there are conference tables sprayed with CV or polyester that look like crap in 6 months. The main reason is how the owners of the furniture care for the piece after you install it.
From contributor S:
AWI has done such work. You can buy their Quality Standards book for $10. Great information, even if you are not a member. The quick answers are in this order - precat/cv (1-5, 5 being excellent, 1 poor): general durability 2/4, abrasion 4/4, moisture resist 3/4, solvent resist 2/5, household chemical resist 4/5, dry time 5/4, clarity 4/3, reparability 4/3.
AWI also lists pros and cons of each product.
From contributor G:
Most of the major lacquer manufacturers have test results available (for their own lacquers) and sometimes even head to head with their major competitor. Call them and ask.
