General information about lacquer


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Old 09-09-06, 08:28 AM
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General information about lacquer

I have been looking through the many post here and have found that there is some confusion about lacquer. I have seen post stating that poly or varnishes are more durable or moisture resistant then lacquer, I have seen post stating that all lacquers are compatible, that lacquers will not work in certain areas and that in general lacquer is not a desirable finish for cabinets or furniture.

These comments are wrong in most situations, and in some the suggested advice can cause more problems latter. The following contains general information about lacquer, suitable for most brands.

Types of lacquer

There are about nine different categories we can separate lacquer into. Nitrocellous, CAB (butyrate), Pre-Catalyzed, Post Catalyzed, Conversion Varnish, Urethane, Polyester, and UV Coatings. (Note: Polyurethane does not refer to the brushable products that can be purchased at big box stores, hardware stores or anywhere else. It refers to a dual component product that releases isocyanates and must be applied in a shop.)

Nitrocellous lacquers are the type that everyone is afraid of. They yellow substantially over time, have little durability, and soften with heat. This means that they are not good for cabinets or furniture. However, little items such as picture frames will be fine if finished with a nitrocellous. Most manufactures know this and do not use these types of lacquer on cabinets.

CAB (butyrate) lacquers are slightly better then nitros but not a lot. They do not yellow at all. However, they do not offer much more durability then a nitro. Again, they are not used that often by cabinet manufactures.

Pre-Catalyzed lacquers are 90% of what is used by cabinet and furniture makers. Because of this you can imagine the amount of precats on the market. We can generalize a little about all the different brands. All have a pot life of anywhere from 1 month to 24 months. This is because of the chemical reactions that occur when the product is sprayed. We will discuss cross-linking later. The durability of the different brands and lines varies. Some precats will yellow a lot with time, some will yellow very little. In general the much better durability then a nitro, CAB or any brushable product. This is because of the chemical chains that are formed as the product cures. If the product is applied in accordance with the specifications it will perform great in most situations. There is no problem putting a precat on most of the woodwork in a house. On the kitchen cabinets and bathroom woodwork a precat is acceptable; however, it should rate a TR-4 from the AWI. The AWI will be discussed later on.

Post Catalyzed lacquers are similar to precats except that the catalyst is added by the end-user instead of the distributor or at the factory. This means that they can be more durable then a precat. However, there is some debate because many finish manufactures are creating precats that have similar characteristics to post-cats due to the marketability. These product dry and cure just like precats.

Conversion Varnishes are considered to be the best for kitchen cabinets by some people. However, there is no industry standard to define a conversion varnish from a post catalyzed lacquer. Most of the difference is marketing, playing off the fears that lacquers are bad. A true conversion varnish will contain no nitrocellous, has higher volume solids, and can be a little touchier then a catalyzed lacquer. The only description that matters to the home owner is the no nitrocellous. All finishes, regardless of type, will fail given enough time and abuse. When a finish that contains nitrocellous fails, it turns white. That is why people can see a lacquer failing. However, a brushable varnish, poly or shellac will fail faster then a lacquer, it just does not turn white. A conversion varnish contains no nitro; therefore if it fails it will not turn white.

Urethanes, for the finisher, are not brushable polyurethane that is sold just about everywhere. These are very durable; however, they must be applied in a shop by a professional. This is because the products have very short pot lives and release isocyanates.

Polyesters are used a lot in large operations. This is because the pot life is measured in minutes. Most finishers will never work with this product. Polyesters are very durable and will last quite a while.

UV coatings are also rare on cabinets. This is a coating that is applied to the substrate then sent through an UV light bank to cure the product. This is usually used on flat items, such as flooring or trim. About a million dollars in equipment is needed, so again a large operation will be using such as product. UV coatings are quite durable.

Catalization

I have mentioned catalization throughout this post. A catalyzed product has an acid catalyst added to a product to create a chemical bond between the molecules in the resin. Because there is a chemical reaction involved there is a limit to the amount of time the product can be used. This is the pot life of the area. Typically if a very hot catalyst is used, the stronger the chemical bond but the shorter the pot life. Any catalyzed material will out perform an uncatalyzed material. This is why any catalyzed lacquer or conversion varnish will perform better then a brushable product. Brushable products, such as varnishes, polyurethanes, or shellacs are not catalyzed. If they were there would be an expiration date on the can. After a product has past its pot life the chemical reaction no longer occurs and the product will not perform as expected.

AWI

The Architectural Wood Institute rates coating on a 1 to 8 scale. 1 is the worst and 8 is the best. In general brushable products are not rated, if there where they would all rate a 1 (less if possible). Most precats rate a 2 and most post cats rate 4, however, some precats rate a 4 as well. Conversion Varnishes usually rate between a 4 and 6. A 4 or better is great for kitchen and bath cabinets. A 2 is good for trim and doors.

Why is any of this important?

This information is important for a variety of reasons. First information is always good. Hopefully this will change the common perception that lacquer is bad. Second it gives people a base for questions if they are buying cabinets. Third, this should help people understand what they are dealing with if they refinish or are wondering if they should refinish.

If anyone has any questions please send me a message.
 
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Old 07-16-08, 05:43 PM
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I need help

I would love some help with my cabinets. We had custom cabinets made by a local cabinet maker. We have white inlay cabinets to the ceiling that abuts the crown molding. We showed the cabinet maker pictures of what we wanted before early on, and we discussed that we wanted the cabinets and trim to match in color. We chose Benjamin Moore white dove.

After the cabinets were installed, we noticed that the frame and doors were a different shade of white. They constructed the frames first and doors second. The frames are more yellow than the doors. They painted the cabinets Benjamin Moore white dove in a lacquer finish. Two issues from this: (1) we like the initial (non-yellowed) color better of the two and are not excited about all of our cabinets turning this color and (2) some of the frames are more "yellowed" than others. Regarding the different color of the frames compared to the doors, we have been told that this yellowing process occurs over a 90 day period and that the doors aren't finished "yellowing" yet. Regarding the different shades of the cabinet frames, we have been told that perhaps heat, perhaps varying UV light is to explain that.

Another issue is that we have a 3rd shade of white. . .the crown molding. Apparently, the cabinet maker, painter, and job supervisor never communicated to each other about our request to have trim and cabinets match in color. The trim has been painted in Benjamin Moore white dove enamel, and it is more white (no yellowing) compared to the cabinets. The difference in the shades of white are pronounced since the cabinets abut the trim.

Please help us. The cabinet maker is willing to re-spray the cabinets to get the doors and frames to match. We addressed with him that we liked the initial color of the cabinets best and would prefer to not have the yellowing process. We asked if there was another lacquer that didn't yellow, and he said yes but that it wasn't as durable as his product. Also, he stated that such a non-yellowing lacquer could not be applied over our current catalyzed lacquer finish. Is this true? What would you recommend for a lacquer product? Also, what advice do you have regarding trying to match the crown molding to the cabinets?

Thanks!
 
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Old 07-16-08, 06:35 PM
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I have a few thoughts on your predicament. First the yellowing. Lacquer does not yellow for a time and then stop, rather if it is going to, then it will do it forever. It is an interacting between UV and the ingredients of the lacquer. Specifically the Nitrocellulose (if it has any) and the Amino Alkyd resin. If the manufacture uses a soy alkyd, for example, it will amber quite a bit. Usually in a catalyzed lacquer, blends of various alkyds are used. If it has a lot of Nitrocellulose it will amber more. All lacquers have some Nitro as an additive; it is a matter of how much.

There are a few instances that can cause a catalyzed lacquer to yellow right away even if it usually does not. One thing I have run across happened when am item, a closet door, was finished with a pigmented lacquer and put back into the cardboard box it came in right away. This box did not allow it dry properly, and it yellowed quite bad right away. This product hardly yellows at all.

As for your shades, you may be seeing a few different things. One thing you may be seeing is shadowing. Depending on the angle of the light, the doors maybe casting a shadow onto the frame. Try taking a door off and placing next to a side panel. Have someone hold it for you if need be. If these doors are mission style and the shading is between the rails and styles and the panel, then if most probably is shadowing as they were all (most likely) finished at the same time as one unit.

The issue of your crown and cabinets not matching is, alas, not uncommon. In all probability a painter applied Satin Impervo or something from Benjamin Moore tinted to White Dove. The cabinet maker had the lacquer matched to the same. This can lead to a slight variance in color. This comes about from a few things. 1) it is not a machine doing the match. It was somebody tinting and doing samples in all likelihood. To this personís eye, the colors may have matched. 2) It may have matched in the store and the shop but in your house it doesnít because of the light source. If a color looks right in one light source but different in another, the cause is what is called Metamerism. This is where colors match in one light source but not another. It is due, primarily, to the fact that different colorants were used to achieve the same color. In this case, we also have different coatings. 3) you could also be seeing a lack of Quality Control on the part of finisher. I donít want to speak ill of your finisher, as I do not know him (he maybe a customer?). But sometimes a finisher will buy single gallons for a job and not box them together. One could get the same product tinted at two different times with two different batches and end up with slightly different colors.

Finally the product. He may be right in that he cannot put some other product over the one he currently uses. If you could tell me the brand, I would have a better idea, but it maybe too hot. However, it strikes me odd that he says he cannot put the non-yellowing over the catalyzed and that the non-yellowing is not as durable. I would have to know brand to get a better understanding. However, one thing to watch out for is dry film build. This is the total dry mills (1/1000 of an inch) on a substrate. Typically, manufactures want no more then around 5 dry mils. Again depends on brand. So, if he has to re-spray, he may have to strip or sand first.

I would pick the piece you like best and have him do another door to match that. You should get this sample door and look at it compared to the piece you like. If it looks good, then have all of it done, if not, try again. I am going through this right now with another customer of mine. So far we are on our 3rd sample. As for product, I sell M.L. Campbell, so I would recommend that because I know it the best.

I hope this helps.
 
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Old 07-16-08, 07:29 PM
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thanks for the help

More information:

I really feel that our cabinet maker is unsure why our cabinets are so yellow. His assistants came by last week and when we mentioned it, said that they couldn't figure out why they looked so different. I was wondering if heat--his warehouse is not Air conditioned--and either was the house. I felt like his "90 day" ambering process seemed a little suspect. I am worried that my yellow cabinets will be canary yellow soon--with banana colored doors....


I know that he used a catalyzed product. Can he use a different product (one that doesn't yellow) with his same equipment?

About the shadowing--we had hoped that it was lighting that was the issue--but it isn't. One of the issues with our cabinets is that they were sprayed at different times, so doors that were sprayed two weeks ago, were put on frames that were sprayed 4 months ago.

His plan is to paint a few samples and leave them outside for a week. Then I can pick the best color and he will respray everything. However, I don't think that is a very scientific way to go about finding a color for inside my house. How do I know that sample "B" that was outside for 5 days will equal the amount of UV light my cabinet would receive?

We also found out that the painters used a different paint and had it color matched to BM, even though our contract states BM and our sample was BM white dove. When confronted, the painter and builder lied to us. We found old containers with specific labels of Devoe paint and took it to our paint store. Then, it was admitted that Benjamin Moore products were not used for our trim. I would like to get the color of lacquer right, then have the trim repainted. (These cabinets are in all of our upstairs bathrooms and in our Grand Room Built-ins)
Should I go with a darker color than white dove?

Sorry for all the questions--I am just overwhelmed to have spent so much money on cabinets and not to have an answer on how to fix them (correctly)!
Thanks!
 
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Old 07-16-08, 07:43 PM
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The heat may have had an influence on the color, but I doubt it. I live in state where we get 100+ days and -40 days. So far, no major discolorations strictly from the environment. If I had to guess, I would say someone messed up somewhere. With the boxes done 4 months ago and the doors being done recenlty, I would be looking for a tinting error or batch variance. If he bought all the lacquer at once, it could be that some of solvents flashed off and the product changed color. I have seen that in clears if a five sits half enpty and unused for month or two.

It could be that the match in the lacquer was done to to trim paint not the BM sample. if that match was wrong and the lacquer match was poor, it could lead to this variation.

His idea of putting stuff outside sounds, well, dumb. your are right to wonder if the UV exposure is the same in the house, furthermore, if the discoloration is not from UV exposure, then what the hell does it prove?

He can use the same equipment to spray the new lacquer as the old.

as for a different color, White Dove is not very dark. It should be just fine.

One thing that just occurred to me: I wonder if the store had a difficult time matching it. sometimes those off-whites can be very difficult. If he is using a brand that has it's own color deck, pick a color out of there. then there is no matching. If he uses M.L. Campbell, their colors are the same as Pratt & Lambert paints. so, bone white in Magnamax is the same as bone white in gold semi-gloss.
 
 

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