Wrinkling Conversion Varnish

      Why is CV wrinkling with dark colored stains? June 21, 2004

Question
Does anyone have experience with conversion varnish wrinkling on darker stains but not on lighter colors? I can spray ten cases (birch) with several different stains and only the dark stain will wrinkle after the topcoat is applied. It is a self-sealing conversion varnish.

Forum Responses
(Finishing Forum)
From contributor C:
Frankly, Iím stumped, but here are a few thoughts that may be relevant to your situation.

Three things come to mind when I hear wrinkling: dry time, incompatibility and contamination. The correlation between those issues and stain color is not obvious to me. However, since youíve noticed a trend, there may be an issue tied to those dark colors.

It would help if we knew what the light and dark stains were. If they are different colors from the same manufacturer and product line, it gets a little more difficult to diagnoseÖ for me anyway. If they are different stain products (not just different colors) from the same manufacturer, different products from different manufacturers or even microbrew stains, we might have more territory to explore for a cure.

On dry time, if the darker stain contained more solvent, contained a different solvent than the lighter stain or was applied heavier than the lighter one, a little more dry time might do the trick. If the darker stain is a film-forming finish, that might suggest a little less (or more specific) dry schedule. Recoating those stains without scuff sanding might lead to adhesion issues.

With respect to basic incompatibility, if there is anything in the stain that does not evaporate and is not compatible with the finish material, it could lift or wrinkle the finish coats.

Even if the stain and topcoat are completely compatible, maybe there is something different in the process used to apply a dark stain instead of a light stain. Every little bit of process information helps. I know itís a stretch, but itís the last thing that popped into my monkey brain.



From contributor S:
I will not answer your problem, but will offer my own experience on a tough problem. I had the same wrinkling problem when doing a dark brown stain over Doug fir. The stain was an oil based product. The wrinkling occurred in random spots ranging from the size of a dime to a finger. I re-sanded and shot another coat of CV (I seal everything and between coats with vinyl sealer) but the wrinkling reappeared in the same areas, except not as severe.

If dry time is the culprit, why is the stain not drying in only a few selected areas? If stain was not compatible with topcoat, then why, again, is the wrinkling occurring in only a few spots? My only rational explanation is contamination. Could be that my latex gloved hands had come in contact with some foreign substance while handling the doors. I don't know, but certainly will pay closer attention next time. Good luck. Another thing is that after the CV dried, the appearance improved somewhat but is still not up to par.



From contributor C:
Iíve seen things as weird as a new deodorant cause issues. Seriously. Anything new in the process is worth documenting.


From contributor R:
I think that darker stains contain more pigment, so they may take longer to dry. The CV just wrinkling in some areas may be that the wood soaked up more stain in those spots. I've had these problems before when trying to use the CV as a self sealing system. I'd always be crossing my fingers when applying the second coat. I now use a catalyzed vinyl sealer to seal in the stain. I haven't had a wrinkle in over a year.


From the original questioner:
I have dug up a little more info from the supplier. The CV is a catalyzed vinyl, so it meets the AWI TR5 spec. There are driers in the supplier's stains and as of last Friday, they are checking into the pigment to drier ratio. We have run all the lighter stains on the same schedule without any problems. To the best of my knowledge, the stain is a combination hard resin (Maleic) and a med oil resin mixed in hi-flash naptha. We spray the stain and wipe after about 60-90 min. Air dry 45 minutes and apply 4-5 wet mils of the seal coat and then scuff 280 after 60-90 minutes, air dry before topcoating.


From the original questioner:
I just wanted to clarify the stain wiping procedure. We spray and wipe after 60-90 seconds.


From contributor T:
I too had wrinkles with my SW CV. I had more wrinkling with vinyl sealer than without. I believe that a self sealing CV adheres better to itself than to a vinyl sealer with a different catalyst (if one is used at all?). I've used nothing but CV for over 3 years and since I refinish most of my work, I'm bound to face this problem again since my SW reps don't even know the answer.


From contributor M:
To the original questioner: Just curious, why do you wait after you apply the stain, instead of wiping dry right away?


From the original questioner:
By the time we get our biggest case stained, 60 seconds have past. We do wipe smaller units as soon as possible, but time does not seem to be a factor in the wrinkling issue.

As for the self seal adhesion mentioned above, we have tested self-seal vs. vinyl and I can tell you that self-sealing is by far better for adhesion. We have also experienced the wrinkling with the vinyl sealer. One thing I did not mention with this stain - when we sealer sand, I have noticed the powder turning red.



From contributor M:
Could that be bleed back from the red in the dark color stain, being reactivated from the coating?

Have you tried allowing a long drying time for the darker colored stain? Also, why not try another company's stain?



From contributor K:
I have seen this before with catalyzed systems. I would guess that the stain you are using is not acid stable. I would check with the manufacturer. Hopefully the area rep will know.


From the original questioner:
What do you mean by "not acid stable"? How would you make a stain acid stable or test it? I use other stains without the wrinkling problem.


From contributor K:
Acid stable means that the acid in the catalyst will not react with the stain. In one of your earlier posts, I believe you said the sealer coat sanded pink. I have seen this happen due to the instability between the stain and the acid in the catalyst. When I had this problem, I found that switching to the same manufacturer of stains and topcoats helped. I know Campbell and Chemcraft seem to have corrected this issue.

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