Troubleshooting a Conversion Varnish Failure

      What caused the bad crazing? Bad formula, bad moisture control, and early re-coating are all suspects. March 17, 2005

Question
I have a job that is all vg fir with a Gemini conversion varnish (clear) sprayed at the millwork shop. In both the veneer and the solid wood finishes the varnish is crazing. Some cracks are in all directions and about 1/4" in length, others are more vertical and slightly longer in length.

Portions of this job have been sent to a lab, with no definitive answer on the cause, but more importantly I am trying to find a solution. Does anyone have any suggestions? Do you know of anyone who might specialize in such situations, and if it can be fixed in place? The house is finished.

Forum Responses
(Finishing Forum)
From contributor D:
You need to fill in a lot of blanks. How old is the finish? What is the temperature and temperature range in the house (a constant 68 or a range from 65 to 71, for example)? What is the relative humidity in the house? Did these problems appear at once or did they start gradually, appearing little by little? On what pieces and in what rooms are the problems?

Did the finisher follow the spec sheets to the letter, observing dry mil thicknesses, catalyzation ratios, checking the moisture content in the wood, using the approved sealers, compatible stains, etc? Did the finisher go off in a maverick direction (we all do sometimes) and operate outside what the spec sheets suggest?

Short of any details the way to fix the problem is to strip the finish and put on a new one.

Operator error or problems caused by end users are the most likely causes for most finish failures. The odds are that these problems are caused by human error and not a product defect. You need to get real specific if you are to contend otherwise. Right now, void of your details the fingers are pointing at you. Demonstrate otherwise because that is what the Gemini labs ought to be asking you to do for them.



From the original questioner:
To fill in some blanks: First, from what I've been told, this is probably an application error, more than a product error. I do not know if the finisher went off in a maverick direction and doubt that I'll ever be told.

The problems first surfaced prior to the house being finished and have been worsening ever since. It's been about 1.5 years now. The entire house suffers from the problem; it is not limited to one room.

The house always had heat on during installation and stays between 10% and 25% humidity. We're in an extremely dry environment, my skin and lungs can attest to that. Our average indoor temps are between 65 and 75 degrees F (since I've had my weather station for the past six months). We're located in the Sierra Nevada’s on the West coast of the US.

Obviously the original product was sprayed in a booth. For the parts that cannot be removed easily is it reasonable to spray in a house? It sounds like everything would have to be removed. The whole idea behind this job was to have the millwork installed pre-finished to avoid spraying in the house.

I'm not sure which end user you're talking about, the finisher or the owner of the product. When the finish starts universally failing throughout a building prior to occupying, I think it would be difficult to point a finger at the user.

I should note that there is one area that did not fail and that is the base and window trim. This was the first package sent to the job and it's been fine.

Any other words of wisdom would be appreciated. I'm really looking more for reasonable fixes than causes, but any thoughts on causes would be appreciated too.



From contributor J:
Anytime that a catalyzed product is used certain time frames and/or measurements have to be followed to ensure success. For pre-catalyzed coatings the main cause of this "shattered" appearance is not adhering to the recoat window. This is a time when the coating is in the stages of being not fully cured enough to spray another coat on. What happens is that the cross linking or bonding process is dry to the touch but not yet fully cross linked with a little more solvent yet to flash off.

The addition of another coat (new hotter solvents) reacts with previous coat and shocks this chemical cross linking process breaking it apart and/or throwing everything out of whack. Somewhat the same thing happens with post-catalyzed products with the catalyst usually the blame for strong reactions like your describing. The catalyst not being added in proper measurements (too much or too little) is usually the cause for a shattered coating.

It'll look like a car windshield that was smashed - 9 times out of 10 this is due to hot solvents or catalyst having a quick interaction with a molecular bond. In another but similar reaction this is how crackle lacquers work but they are reacting with a drying shrink pulling apart a layer of silica (crackle lacquer) to form cracks. Do any of these time or coatings reactions sound familiar?



From the original questioner:
You should understand that I am not in the wood finishing industry, but am attempting to become more educated. I have to deal with this problem and so far there have been a lot of vague answers. Your crosslink and catalyst explanation sheds light on some of the things the first lab guessed at which were "cure time and catalyst."

I'm still looking for the fix. It has to be stripped? A large millwork firm in Chicago suggested to a friend that they were able to coat something over a problem like this once but I don't think it was as severe. I worry about damaging the veneers when the wood is stripped. And I worry about base cabinets that are under installed granite counter tops and etc that will probably have to be fixed in place. I thought spraying conversion varnish in a residential setting is a no-no.

Sorry for my ignorance, but I'm trying to find reasonable solutions to a large problem.



From contributor F:
To the original questioner: You have been here before, on another matter, haven't you? To sum up the education you just got concerning conversion varnish, there is no easy solution, short of re-doing the mess you have now. You didn't describe the finish, as to whether it was a multi step finish, or simply a stain and finish. Knowing this may change the complexion or possibility of going over the top of the c.v. with another finish altogether. The only possibility I see of this happening is that who ever does the job, has the flexibility of sanding the c.v. beyond the crazing, and not removing color as well.


From contributor M:
There are a ton of possibilities and my guess is you will hear them all. None of which will get the job repaired. To the best of my knowledge, Gemini has several post-catalyzed finishes. Some have extreme "pot-life" windows and some that are more common, such as 8-12 hours once the catalyst is mixed with the coating. I believe Gemini offers a post-catalyzed product that is good for something like three weeks after catalyzing.

Try to find out exactly what product was used and it may shed a little more light on the steps to repair this problem. If the finisher used the "3 week" product my guess is that it is a little more than a glorified lacquer and you may be able to soften the finish with a combination of acetone and butyl cellosove to "reflow" the cracks. If the finish was the more common post-catalyzed material I do not think you would be able to reflow it. It certainly would not hurt to try as what’s your alternative?



From the original questioner:
This is my first time here, but I'm learning a lot. This product is a clear high performance semi-gloss finish 55. There is no tint or stains. The wood has darkened dramatically over the past year, making any replacing of wood difficult to match. That's another question - if we replaced with non-tinted wood, will it catch up with the rest of the in place wood in a few years?

Contributor M - the pot life is 12 hours - bad news for the flow solution huh?

Sorry for repeating this part of my question, but given that everyone is pointing to stripping the finish, does anyone have any thoughts with respect to finishing on site and possible veneer damage mentioned in my previous post?



From contributor J:
To answer some of your questions: I would be hard pressed to say yes that the new wood would blend into existing, My reasoning is that possibly the old Conversion Varnish might have had additives or lack of them that helps in protecting the wood such as U.V. inhibitors etc.. Added to this factor no one could guess accurately on what color the new wood will which could be way different than the original wood color. The interesting point you made about the base and window finishes being the only parts in good shape has me thinking.

Can there be any type of cleaner or type of treatment that was done to everything else but those areas? It would seem probable that if someone were to have wiped the cabinets down with something to not bother bending down to get the base and not bothering with the windows because they're not close enough to the cabinets for anyone to notice that something had gone wrong. When the woodwork was just installed did it look like someone had wiped it all down with a lemon-like oil? Does the finish look hazy or slightly milky when you look into the grain?

I know you’re looking for a quick answer but if you recoat over a finish that is failing out and out, then you'll be back at square-2 in two more yrs. Yes there is a coating/s that will go over this finish without stripping but either way the crack will have to be almost eliminated before that takes place. The reason for this is because C.V. will not soften like lacquer does so therefore a coating sprayed on top of this failed one will not hide the fractures. All doors drawers and trim can be removed and finished offsite which only leaves the cabinet faceframes and finished ends to deal with. Ending on a positive note – you’re lucky that the finish is a clear and doesn't have a stain and or a toner underneath!



From the original questioner:
Ok, you have me convinced that I'm stripping this finish. If you could only see how much wood there is. They have a few off areas that are milky, oddly enough in the trim work which is not affected by the crazing problem. I don't think that it was treated in any different manner once on site. No lemon smell etc. (are you referring to something as heinous as Pledge)? I have their special stuff to apply to the wood periodically, but the wood is only dry dusted and I believe only wiped down with a damp cloth at the construction clean which was done by a professional team aware of high end finishes.

I do think that the trim and baseboard was delivered first, and thus in a position when the job was still on schedule. Things fell behind and I know the millwork sub was pressured to deliver on schedule. I read some great posts about finishers being at the bottom of the heap and thus under huge time pressure to make up for everyone before them. I wonder if this happened. I seem to remember (I toured the shop) that they had to shut down everything else while spraying the conversion varnish. Since I gather the majority of the work is not CV this was a hassle. It just makes me wonder if things were rushed and thus the problem that you explained in your first reply. It's really a mystery that I'll probably never solve. I know the touch-up crew was not given enough time to do all fixes properly, one finally told me as much in the field.

There are other exciting things in the finish - it will go from matte gloss to a high sheen. Where joints were glued, or touched up, excess smears have discolored the wood. There are also veneer buckles and I have no idea what happened there. One piece that was replaced has a white haze and has never changed color like the rest of the wood.

The idea is to have a very uniform looking residence; the only wood used was the vg fir. So you can imagine how intimidating the fix is. Do you have any thought about sanding on the veneers or how you spray the items that are in place? I still haven't found an answer about spraying cv in a finished house! Yikes.



From contributor B:
If this is really a CV finish, I'd think it would be next to impossible to strip, unless someone knows something I don't (which wouldn't be the first time). Secondly, crazing is most likely caused by too much build during application, exceeding 4 mils. I would measure the film thickness and test it with a few solvents before coming to any conclusions.


From contributor T:
To contributor J: It's catalyzed lacquer. You’re correct in thinking the CV would not shatter. I thought about it too and I’ve been there as well.


From contributor R:
The three best ways I have found to make CV shatter (If indeed it is CV) are:
1. exceed the max dry film thickness, usually 5 mils. This works almost every time.

2. Add extra catalyst. (One guy told me he did this intentionally because it made the finish flash off faster like lacquer.)

3. Spray or let cure for 48 hours or both in an area where the temp dips below 68 degrees.

I also have to agree, if it is CV then you are looking at a major strip job. I think sanding it down would end up being more work than stripping it even if you can get through the crazing you would probably have many burn-throughs to repair and there is no guarantee that it wouldn't craze again in the future.



From contributor N:
Contributor J has hit it right. I think you've got a moisture content issue at the heart of this problem. If it’s not that then too much film build could be occurring. The testing lab should be able to measure this with a sonar based meter. Douglass Fir is notorious for having very high moisture content. The last time I re-sawed this stuff water was literally running down my bandsaw.

Also, as Contributor J mentioned, the finish might not be CV and if that's the case you've gotten a lucky break. I've fixed (well sort of fixed) this kind of a problem in pre-cat lacquer by first sanding off the ridges from the cracking so that you cannot feel any bumps and then shooting a light mist coat of pre-cat (let it completely dry (two hours) as you're using it as a barrier coat) and then coming back with a full coat. This doesn't look perfect but certainly improves the situation. Don't go heavy on the first coat or the solvents will penetrate the cracks and lift the finish. One quick pass and that's it. It might also work on a CV base if it's truly CV and it's worth a shot to try.



From the original questioner:
I'm a part owner of the house, which I live in full time in the Lake Tahoe Area. The millwork shop was not Imperial. A lot of time and effort was put into the design of this house, including full shop drawings just to put the millwork out to bid. It was very extensively planned and not the usual "let's figure out the trim as we go" house that is found in the same price range in this area. The doors were made by a different company but all the wood was sourced from the same company and then all finished at the millwork company. We even had WIC premium specs in the contract.

The infamous millwork company is not a fly by not company. However, given the scope of this project they have been very defiant. They put the burden of developing a punch list back onto me which took a really long time as the finish continues to craze and have issues. I submitted it to the contractor today and thus my research.

The house has been a long haul, and I needed to just enjoy it for a year prior to trying to tackle this problem. I moved around enough while building it that I just can't handle the thought of moving out again, but this appears to be where I'm headed. It's really no fun. You spend a lot of money on doing a nice project, and you want it to be done and done correctly.

But it gets better. They took a few solid drawer fronts away to refinish about 1.5 years ago. Then they took another door to a lab, where it was deemed that the layers were ok. But I bet Contributor R’s number 2 and 3 apply along with the moisture content problem. Anyway, the refinished drawer fronts are showing some signs of crazing again, the door that went to the lab was supposedly destroyed in shipping and now it has the same problem too! So the fixed items have the same problems. I wonder if the door was really rebuilt though.

By the time they did get underway it was early September and work continued until March I believe. The finishing occurred in Nevada just the other side of us - still a very dry climate. The contractor also sent a door off to another lab with no solid results, but no one has mentioned that this isn't conversion varnish, which I would expect to be odd, given that the millwork company supplied the Gemini specs. But that thought about it not being CV crossed my mind.

I'm actually in the construction business in the structural framing side of things. If there is one thing that I've learned, it's that you never really know the whole story unless you witness the entire process. So I'm stuck guessing while we get ready to figure out how to resolve this and who will resolve this issue. I'm trying to do research so that this company doesn't try to pass a fast one on me again.



From Paul Snyder, forum technical advisor:
This is an interesting problem. To get a good idea of the cause of a finish failure, all the facts about the product and how it was applied are needed. Contributor D was right when he said there are a lot of blanks. The info that's available comes in pieces as the thread progresses but there are some gaps that aren't answered. To get the "big picture" of what's known, I've summarized your responses;

* I have a job that is all vg fir with a Gemini conversion varnish (clear) sprayed at the millwork shop. In both the veneer and the solid wood finishes the varnish is crazing. Some cracks are in all directions and about 1/4" in length, others are more vertical and slightly longer in length.

* Portions of this job have been sent to a lab, with no definitive answer on the cause.

* First, from what I've been told, this is probably an application error, more than a product error.

* The problems first surfaced prior to the house being finished and have been worsening ever since. It's been about 1.5 years now. The entire house suffers from the problem; it is not limited to one room.

* The house always had heat on during installation and stays between 10% and 25% humidity. We're in an extremely dry environment, my skin and lungs can attest to that. Our average indoor temps are between 65 and 75 degrees F.

* I should note that there is one area that did not fail....and that is the base and window trim. This was the first package sent to the job and it's been fine.

* ...some of the things the first lab guessed at which were "cure time and catalyst."

* Dennis, the pot life is 12 hours.

* They have a few off areas that are milky...oddly enough in the trim work which is not affected by the crazing problem.

* There are other exciting things in the finish.....it will go from matte gloss to a high sheen. Where joints were glued, or touched up, excess smears has discolored the wood. There are also veneer buckles and I have no idea what happened there. One piece that was replaced has a white haze and has never changed color like the rest of the wood.

* ...the finish continues to craze and have issues.

* They took a few solid drawer fronts away to refinish about 1.5 years ago. Then they took another door to a lab, where it was deemed that the layers were ok. ...Anyway, the refinished drawer fronts are showing some signs of crazing again,...

* By the time they did get underway it was early September and work continued until March I believe. The finishing occurred in Nevada just the other side of us - still a very dry climate.

Those are the facts that stick out. The finish has been tested more than once and the lab(s) couldn't determine the cause. If the finish wasn't CV, the lab should have identified that and let you know what it was. Rick listed the most likely causes of CV crazing in a small shop. And like Contributor N pointed out, one of the first tests they would do is check the dry mil thickness using one of the various gauges to see if it exceeded the allowable limit. But the lab indicated "the layers were ok." So if film thickness isn't the cause, you're left with over-catalyzation and cold curing. Adding too much catalyst can also explain the "milky or haze" appearance. I'm a little surprised the lab wasn't able to determine if the catalyst was the cause since they can do a chemical analysis. You didn't mention it, but didn't the lab want a sample of the finish that didn't fail for comparison?

The fact that portions of the job are okay and others have been re-done at different times still leaves it open as to whether the catalyst or cold curing is the culprit. Was it warmer when the first delivery of material was finished and delivered? Was the weather cold when the refinishing was performed? If the catalyst is the problem that means the finisher has consistently added too much ever since the first delivery, including the refinishing/re-work that was done (unless it wasn't really refinished). Anyone ask the finisher what percentage of catalyst was added?

The moisture content of the wood will contribute to finish failure, but I'd expect to see some peeling, especially at corners and joints. Does the crazing go all the way through the finish to the wood? Or is it in the top layer(s)?

With the finish continuing to get worse, re-coating probably isn't a good idea. The only exception would be if the crazing was just in the top layer and it could be sanded back to remove that layer.

Stripping and refinishing on-site is a huge undertaking; it could be more expensive than ripping out all the bad work and starting over. The buckled veneer may be repairable or it may need to be replaced.



From contributor O:
Has anybody checked the moisture content of the wood? Are the miter joints still tight? 10% to 25% relative humidity is considered severe by the AWI and would probably void your warranty. Wood shrinkage would explain the crazing and veneer bubbling. The milky appearance could indicate the loss of adhesion again due to shrinkage. Change in sheen is again a moisture problem.

I find it strange that the refinished pieces cracked again. Was the original wood a furniture grade fir, kiln dried to 6-9% moisture content, or was it a structural grade fir at 12-16% MC? I have the feeling that there are still blanks that need to be filled in. It is very strange that a lab hasn't been able to figure out what was wrong. Have you actually seen their report?



From Paul Snyder, forum technical advisor:
I didn't write all the stuff I was thinking in my first post so I'll try to explain some of the points better.

1) Film thickness measurements were acceptable.

I agree. The only thing we've heard that the lab had to say is that "the layers were okay." That means the lab found no fault with the substrate, substrate preparation, individual coat thickness, inter-coat adhesion, or over-all film thickness (if the lab did a thorough job). So if the lab did a decent job, all these things can be eliminated. It's easy to tell if lacquer (NC, pre-cat, post-cat) was used and the lab should have tested to see if the finish was actually CV. I'm no chemist, but it seems like the lab should also be able to tell if the finish was over-catalyzed or the CV had a problem with it's formulation from the manufacturer. That's the whole point of sending it to the lab.

2) Information on finish (Pre/post catalyzed) supplied to lab fell within acceptable range/s for said finish."

I still wonder why part of the job was okay, and the rest, including re-work, was not okay. I wonder if the lab tested the good portion of the finish and compared it to the bad? If not, why not?

B. Customer will never find out temp. range at and during finish and shipping date/s.

This job has been on-going for 1 1/5 years at least. I was wondering if Elizabeth could possibly eliminate temperature as a likely cause based on the times of the year that portions of the work/re-work were done. If I understood correctly, all but the very first install are crazing, including re-work. Maybe it was a warmer part of the year when the re-work took place.

C. Finisher will respond to question about ratio of catalyst to C.V. exactly as it is written on manufacturer’s sheet.

That's very possible. Especially if the finisher knows the correct answer and intentionally deviated from it or found out the mistake later and doesn't want to be honest about it But what if the finisher is used to working with brand "A" that takes 10% catalyst and now using brand "B" that takes 3% catalyst and made an honest mistake and over catalyzed? Asking the question may get an honest answer if it was an honest mistake. I don't always avoid asking a question because I think I may not get the truth. But then again, I tend to give people the benefit of the doubt until they prove me wrong.

1) It will always be the fault of the finisher/s that a coating has failed unless the finisher/s log and are witnessed by a neutral third party on their procedures.

That's often the case. But that's why stuff gets sent to a lab when there's a problem. The lab is supposed to do more than say the layers look okay; they're supposed to find out why the finish failed. The lab that tested this finish apparently didn't do a very good job. They should be able to say exactly why the finish failed unless they just don't have the capability.

2) Finish failure due to film thickness should not be associated with the final films thickness alone, Two heavy double coats as sealer and cured could and should be thought of as excessive dry film thickness even though thickness has been sanded back.

I don't agree. There are guidelines to film thickness for each coat, but that goes to preventing runs and sags as well as cure/re-coat times. And if the individual coats were too thick, the overall thickness would be too great. And if the lab did that portion of the testing/examination correctly, they said "the layers were okay."

3) Is there a difference for finish failures between a small shop and a large one?

I was just thinking of the equipment the smaller shop probably didn't have. Another cause of crazing is pre-mature or excessive baking during the curing process. Most small shops don't have a heat room/curing oven and Elizabeth said they had to shut down the shop when they were spraying which I took to mean they were not very well equipped to even deal with dust.

4) Moisture content and lifting of finish/veneer are not the only result of this imbalance in substrate.

I'm not sure what you mean by this either. I said in my previous post that I'd expect the finish to separate from the wood if the moisture content was too high; that's a common occurrence in my experience. Certainly the wood would have shrunk quite a bit in the 1.5 years it's been in a climate controlled house if it was wet when finished. Maybe no one has picked up on this yet because they haven't been looking for it? And that's also why I asked about the crazing depth. If it goes all the way to the wood, then moisture content could have played a role in the failure.

The Original Questioner stated in her response that "... this is probably an application error, more than a product error." I'm not sure where that information came from, so it's hard to say how reliable it is. It's true that you can occasionally get a bad batch of finish; I know it's happened to me a couple times and it's a nightmare when it does happen. But it's not very common and seems less likely considering that re-work has been taking place over a period of time and different batches of finish should have been used. There's no mention of the coating rep in this whole scenario which seems odd. You'd think someone would have brought up the point that the finish might be bad and that the coating manufacturer would have it checked into it. And if the shop was having trouble with that product, you'd think they'd let her know.

To come to the conclusion that entire job would have to be ripped out rebuilt/finished and re-installed due to cost factor is incorrect in my estimation.

In my experience, it's a lot more time consuming to strip and refinish wood than it is to start fresh. Now add to that the fact that the finish is CV, the work is all onsite and it has to be done very carefully to avoid damaging household items, the time adds up very quickly. And from the description, this is one big job. Time is the most expensive part of finishing; the materials are negligible in comparison. That's why I said "...it could be more expensive than ripping out all the bad work and starting over." If I were paying for the work, I'd get estimates for both repair and replacement. I wonder who is paying for this?

One of the main reasons I posted earlier with the summary of what seemed pertinent was to bring some clarity to the subject, for myself as much as anyone. It is right on the money saying that the important point is finding out the best course of action to correct the problem. Someone is paying for this re-work and I'm sure they'll want to do it in the way that costs the least and guarantees the problem is solved. My guess is that some of the work will simply be replaced, and the least possible will be done on-site.



From contributor R:
I think moisture content is a very good possibility. When we get VGDF here in Reno it almost always is around 18% MC. Fortunately we have our own kiln and dry our lumber until it is 6 - 8%. I don't know which shop did this work but I know there are some shops who are more concerned with getting things done fast than they are with getting them done right. This could very well be one of those situations.


From Paul Snyder, forum technical advisor:
In the Original Questioner’s first post, she said "Some cracks are in all directions and about 1/4" in length, others are more vertical and slightly longer in length." To me, that does support the high moisture content theory since the wood will shrink more in one direction that the other. But I'd also expect to hear about some finish peeling and wood cracking/checking/warping (besides the veneer). But I don't know fir that well and maybe it doesn't split or check when it dries like other woods.

Whoever goes to do an on-site inspection will have the best opportunity to make a better judgment and work out a plan to fix the problems.



From Paul Snyder, forum technical advisor:
I think the need to find an answer for the cause is a normal reaction from finishers and explains all the "off-topic" discussion. From experience, we expect everyone to lay the blame at our feet whether it belongs there or not and so the first reaction is to look for the other possible causes. It's just the nature of the job/work. Figuring out who's going to pay for the repairs is no small matter and tends to be the primary focus until it’s resolved. Getting a quote or three is always a good idea.


From contributor C:
Without having a piece of the problem finish in my hand it seems to be impossible to know what caused it. As a finisher and not a chemist the main area is the depth of the cracks. Does it go to the wood or through top layers only? I would want to know this in order to help prevent the problem again in the future. Was it the wood or the finish?

The solution is what best suits your abilities. I would test an area with remover to determine the difficulty of removing the finish. I would remove and replace the wood where that is easier. I would try to get the owner to let me faux finish the areas, fill, sand, prime and faux.



From contributor M:
One thing I do not see mentioned, I may have missed it in all of this, but what was used as a seal coat. I noticed that you said the finisher was not using CV or post catalyzed finishes in their normal applications. Is it possible that they use a nitrocellulose sealer normally and may have used it on some of your work when things started getting behind to speed things up? I have seen some pretty nasty checking in this business when furniture was finished in this manner.


From contributor N:
Here in Phoenix it might get above 25% RH five or six times a year. From April to July it normally is 10% RH. The Southwest (West Texas to So Cal) is very dry. Vegas has the same climate we do. There is a lot of the country that has very low humidity. It's not that unusual. If coatings don't work in 30% of the land mass of the country then perhaps they need to be reformulated so that they do.

Now that I've defended my desert town let's get to the point which is MC of the fir. If this millwork, or the wood from which it was made was made in a high humidity location and trucked to Tahoe that to me is the problem. It can't be dried overnight.

Interesting side story: One day in July I was washing my car and dumped a bucket of water at the top of my 35 foot long driveway down it toward the street. Not a drop of water ever made it to the street, it all evaporated on the driveway prior to ever getting there - no mildew out here.



From the original questioner:
I am definitely interested in the cause (someone wondered why I wasn't chasing after the cause) because I don't want to make the same mistake twice. And the fix is obviously where I need to be headed.

I'll never know the moisture content of the wood (the millwork shop found the supplier, I am just an engineer specializing in wood framed structures in high snow and seismic loads) or if it was sprayed with a sealer, I think that I'll have to find my own lab and send a sample off for testing. Does anyone know a good lab?

With respect to the site, the jobsite was always conditioned with hydronic heat in a slab. This is very even heat. Our humidity is low, but so is Reno's. I almost went with a large, long established shop in Chicago that my father has had a relationship with for 30 years but was worried about the moisture difference from Chicago to this climate. I think if the humidity of the house was really a problem, we would see more problems in our region in general, and all of my woodwork would be suffering from the same problem. But the base and window trim is fine, so I have to go back to application.

Also, if one of the two labs used was the product manufacturer, don't you think it would be weird to send a sample that wasn't their conversion varnish product? Nonetheless I'll probably have this tested just to eliminate that possibility.

I'll be contacting the local people that wrote to me to try and get an opinion. It will be interesting to see what they think once they get to see it.



From Paul Snyder, forum technical advisor:
I came across this article on the Dakota County Technical College website - Repairing a Large-Scale Failed CV Finish - that's very similar to this project. Maybe some of the techniques will carry over.


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

Comment from contributor U:
Some things come to mind. One contributor had questioned the sealer that was used. I would probably follow this path. CV as with all coatings increases surface tension as it cures, and you can watch 1/4 inch material bow crazily as this occurs. A non compatible sealer would have softened up as the CV was applied. During curing, the top CV coat "tightens up" and can pull the sealer from the substrate causing this crazing and haziness.

You should ask the question and have the lab test the sealer. If they went the self sealing route with too quick of a recoat window, lack of sanding or a cold shop, this problem certainly would occur. We use catalyzed vinyl and have not had a problem like this. The flat-line testing using CV on CV at 50-55 degrees and then through the progressive 80-120 degree curing ovens produced something similar. I've been in this business over 20 years and would have to put my money on the finisher who did the work not being very skilled.



Comment from contributor Y:
I don't have a lot of experience with C/V, but I understand this was a large project that you provided drawings for to get a bid if I remember correctly. Also it was said that this shop had to shut down to finish the work. I've had problems with shelf life on catalyst many times in the past.

In particular, I've seen crazing and hazing as a common occurrence with bad catalyst. I wonder if they bought all the finishing materials at once, thus the initial work was done with relatively new catalyst (presumably) and as the job progressed over 1.5 years, the catalyst batch went bad? It sounds like they didn't have much experience spraying C/V, as their operations weren't able to sustain normally without halting other work. That wouldn't work for any shop that wants to stay in business long with finish operations. One other thought, and I know this is out there, but it's happened to me - I've had product delivered that was actually mislabeled. So in effect, I had one part that was incompatible with the other. It all sprayed out fine, but over the course of a week or so, crazing was everywhere. If the crazing did stop, you could try to spray a barrier coat like Ilva's TF-25 isolante.

I'd sand out as much of the crazing as possible without burning through the coat and then put multiple, very light passes of the isolante on so you don't start another chemical reaction. Let it dry thoroughly and then apply a high build sealer that will allow you to flatten out the rest through sanding, then topcoat with whatever you choose. Obviously you’re not going to have the quality of finish that you want, but it may be an alternative. It would allow you to deal with the crazing and the sheen variations. The hazing will have to be dealt with by other means.



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