Odors from Over-Catalyzed Varnish

Too much catalyst can cause offensive smells in a varnish job. Here, finishers discuss possible fixes. October 18, 2005

I sprayed some cabinets with CV last December and installed them in a residential kitchen. The owner is complaining of strong odors from inside the cabinets now, six months later. Interiors are clear maple plywood. Any thoughts?

Forum Responses
(Finishing Forum)
From contributor P:
Over catalyzation can cause a lingering odor that smells like baby puke :). Or is it a formaldehyde-type odor?

From the original questioner:
What can be done for either problem?

From contributor P:
The formaldehyde odor is a byproduct of the curing (chemical reaction) of most acid cured coatings. There's not really a fix for it other than letting it dissipate over time (doors open, air it out, etc.). Over catalyzation can only be fixed by isolating the over catalyzed coat with a properly mixed coat of finish or, preferably, a sand and refinish. Unfortunately, neither option is very appealing in this case. Over catalyzation is usually accompanied by an oily feel and/or discoloration of the finish.

From contributor D:
I agree that it is either the formaldehyde, which I suspect, or over catalyzed. If it's over catalyzed, you can tell by wiping the film that should appear in/on the finish and if it reappears, then you will know it's the acid spewing out of the finish. I do not think this is the problem. If you've ever been in a RV after it has been closed for the winter, you will still smell the formaldehyde even if the RV is a couple years old. I would suggest getting a small radiant heater and place it carefully in each cabinet for several hours. This should speed the curing. Place it on a heat-proof plate with the doors slightly opened. Also make sure you do not place it close to any sides. I think you get my point!

From the original questioner:
I checked to see how much cat my finish guy was using and found that he was using a little more than double the amount he was supposed to. So I think the excessive catalyst is the problem. I've got two solutions so far. Recoat, which would have to be done in place, in the home, or heat to cure the existing finish. You would think, since it has been sitting since Dec., that it would be cured. My client isn't very pleased and wants a solution fast. What would you do?

From contributor M:
If your finish guy used a little more then double the amount of catalyst, how come this is the only customer you have with this problem? How many cabinets have this problem, and did you check all the cabinets and inside the drawers?

From contributor D:
If the catalyst is the problem, then you need to get in there and wash all the cabinets down with TSP or maybe even acetone to remove the excess catalyst. It has been my experience that (in simple terms), the crosslinking resins used in CV's will only except as much of the acid in the catalyst as needed and the excess will keep spewing out of the finish almost in a chalking fashion. It is certainly worth a try before you end up refinishing.

From contributor B:
Is acetone the product to use to wash down over catalyzed CV? I thought it was mineral spirits. I would like to know for sure.

From contributor D:
Good question! Acetone should not touch a quality CV. Keep in mind he is using a wet rag and wiping the surface. Naptha would also work. I would tend to stay away from the mineral spirits because it would take a long time to dry. Also remember to take all the precautions of using solvents in a finished kitchen. I would try the TSP method first. You may very well find that you have a film that needs to be removed.

From contributor M:
TSP can be a strong cleaner that could affect the coating if not diluted. Mineral spirits take 50 minutes to evaporate, while Naptha takes only 4 minutes (no big deal). You can combine either of these solvents right into the acetone to buffer the KD value, which is a test used to tell the effects that solvents have on coatings.

From contributor S:
Excuse my amateurish input, but what if you buff the CV with a scented wax, like orange wax? Will that mask the offending odor while not affecting the CV that much?

From contributor M:
How many cabinets have this same problem, and did you check out all the cabinets and inside the drawers? There is a possibility that it's coming from the plywood. Take off a smelly door, and bring it to your shop, then wash it down, then try coating it with shellac to seal in the odor. This works on polyurethane with the same problem on the insides of furniture and cabinets.

From the original questioner:
Thanks. Unfortunately, this has been going on for quite some time. Why this has been the only complaint is beyond me. I intend to wipe everything down today.

From contributor O:
Wash the insides of the cabinet with ammonia and water mix. Wash a couple of times in one day and you should be fine. This in an old problem for the old Lilly and now Valspar users.

The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).

Comment from contributor L:
Such excess catalyzation actually begins to destroy the resins in the CV, and none of the aforementioned really "fixes" the problem. A proper recoat may help (after the ammonia wipe and water rinse), but problems of odor or checking may occur down the road. Remember - we are dealing with chemistry here.