hello all, I normally lurk over @ breaktime, but I figgrd I’d tap the wealth over here if y’all don’t mind. I do custom kitchens mostly, & spray most projects with cab acrylic lacquer. Started using cab acrylic to avoid yellowing on light colors & liked the end product enough to use it on everything. Now venturing into the pre-catalyzed realm for the sake of durability. Anybody with either pros or cons on the subject?
thanks for your time…
greg
Edited 5/17/2007 2:50 pm by gbwood
Replies
Greg,
I use CAB-Acrylic for all my lacquer finishing. I also started using it because it does not yellow maple. I love pale, blond maple. I REALLY dislike yellow maple.
I have used CAB-Acrylic for kitchen cabinets and I'm very pleased with the results in the kitchen. No durability problems to speak of. But my experience is with only one kitchen. I consider the fact that repair will be easy if I ever have to do it a plus. I haven't had to (yet). I have found CAB-Acrylic to be a little more durable than Nitro-cellulose.
But catalyzed lacquer would be much more durable. The trade-off is trickier repair if, and when needed. I haven't had the time to practice doing that. But if I got comfortable with it, I think I would use only catalyzed in a kitchen or any other environment where durability is the first consideration. If I made my living doing kitchens, I would definitely become proficient with it and wouldn't hesitate to use it over CAB-Acrylic
Rich
Thanks Rich-
I'm not aware of the repair difficulties you speak of...
greg
What the other guys said.
All the more durable finishes have the issues of repair. Only Shellac and Nitro Lacquer are easily repaired.
If you want the ultimate in durability, clairity, and ease of application look at conversion varnish. Catilysed lacquer and Pre Cat are very close but they will yellow a little; enough to be noticed on a unstained light wood.
Pardon my spelling,
Mike
Make sure that your next project is beyond your skill and requires tools you don't have. You won't regret it.
I'll ditto Mike here too. Precat is much easier to repair than Conversion Varnish, but the trade-off is that it's not as durable. Of course "repair" is a hugely vague term because it very much depends on what kind of damage needs fixing and what your experience level is. For example, there are several companies that make shellac-based repair products which will work on most any finish. But they require a definite skill to do it flawlessly and at least some knowledge of the repair products to even avoid making a small repair task into a larger repair task.
It might interest you to know that my Sherwin Williams rep recommends using CAB lacquer to do minor field repairs on S.W. Conversion Varnish. If you went that route then you'd already be familiar with the recommended repair product.
The big downside to conversion varnish is that it has a pot life measured in days once it's been catalyzed. Whereas precat lacquer's shelflife is measured in months.
PS. I'll just add that I used to use precat for almost everything and then a couple years ago I switched over the a vinyl conversion varnish that I'd had to use on a specific job because I found that I really liked it. But I've just recently (read: earlier this week) started switching back over to Sherwin Williams' new high-build precat. Largly because it's the easiest finish short of straight nitro to work with and almost all the same tricks (sometimes with slight modification) work with it that work with nitro.
Edited 5/17/2007 11:34 pm by Kevin
I hadn't heard about using CAB as a repair on CV, Ill remember that. I like conversion varnish because it has a longer shelf life than PreCat. I only catalyse one pot at a time. I think that once catalysed the pot life is 30 minutes, or something like that. What ever is left over (not catalysed) will last for a year. Once you leave the store with your batch of PreCat I believe that the shelf life is 30 days. You can buy it in the catalysed version where you add the acid to each pot like with Conversion Varnish.
My Sherman Williams rep told me that a lot of people use the vinyl as a stand alone finish. I still haven't used it. Also if you have not used the Conversion Varnish for solid colour jobs, you will be amazed. I can get an automotive quality finish with that stuff. Of course it is not cheap either!Pardon my spelling,
Mike
Make sure that your next project is beyond your skill and requires tools you don't have. You won't regret it.
The shelf life of their standard precat is 9 months. The new high-build precat has a shelf life of 4 months. Of course as you know it's all about trade-offs... but I like the convenience of being able to leave precat in my pressure pot for a week or a month if I feel like it and all I have to do is stir it up and start spraying.
The S.W. vinyl conversion varnish I use, which is not the same as the vinyl sealer or another vinyl conversion varnish they make, has the longest pot life of any of their conversion varnishes at 5 days after being catalyzed. In a production shop that is a definite advantage over a pot life of a few hours. I can leave varnish in my pot over the weekend and still use it the following Monday.
I've never worked with their solid color varnishes because I have a full DuPont automotive paint system in my mixing room. I actually use that far more often then I do any of the wood finish materials. But I don't doubt that S.W.'s stuff works well. They make some great products.
Kevin,
If I may ask, which specific SW conversion varnish are you using with the 5 day pot life? The one I use has a 24 hour potlife as printed on the back label. It is V84 F 82. I believe the 82 is the code for medium rubbed sheen.
Thanks,
Lee
Edited 5/18/2007 1:13 pm by mapleman
Lee,
It's Super KEMVAR "M" T77F48, which is a Vinyl/Alkyd hybrid rather than a modified Alkyd which the varnish you are using has. They also make a Super KEMVAR "C" Vinyl C.V. which I have used a few times. I believe it's just Vinyl without the Alkyd added. It only comes in one sheen and is a specialty finish designed to replicate the look of an oiled finish but with all of the durability benefits of a C.V. finish. The "C" has a 3 day potlife.
It is V84 F 82. I believe the 82 is the code for medium rubbed sheen.
If it's the standard C.V. then then it would be F 62. If it's the compliant water white C.V. then it would be F 87. Both are V84 varnishes, use the same catalyst and have a 24 hour potlife.
I suspect that the C.V. I'm using gives up a little durability compared to the regular stuff. But the extended potlife is more than worth the trade-off IMHO.
Kevin, I never knew any of those others existed. I will talk to my local SW rep the next time I get into the industrial coatings store (the local SW guys don't have a clue about any of this stuff).
My can definitely has V84 F82 printed on the label.
Lee
I'm not at all surprised that your local S.W. guys don't know these products. They really do treat their commercial coatings division almost as a separate company.
If you can talk them into it, you might try asking for a copy of the S.W. Commercial Coatings Guide. The most recent one was published in 2001 and doesn't have the few new products like the new high-build precat lacquer. But it's got all of the other stuff from finishes to industrial paints to powders. It's an extremely handy reference.
PS. I forgot to mention earlier that the one hallmark of the vinyl C.V. I use is that it's easily the most chemical resistant finish S.W. makes. I don't know of a wetcoat finish made by anyone that has better chemical and solvent resistance than the KEMVAR "M" has. It also reportedly has exceptional cold check resistance... meaning that it'll stand up to uber cold conditions without cracking. But... I use it because I can use the same witch's brew solvent blend with it that I use with lacquers. None of the other S.W. conversion varnishes are compatible with these solvents as far as I know.
Edited 5/19/2007 10:30 am by Kevin
Kevin,
Thanks for the tip on the Comm. Coatings Guide. I will definitely try to get a copy of that next time I am in the industrial store. I find the SW web site a little hard to navigate sometimes.
By the way, here is a link to the product data sheet for the CV I am using from the SW web site: http://www2.sherwin-williams.com/chemicalCoatings/datapages/CC-F24.pdf
Now, if I may, I would like to ask you a few questions about the CAB Laquer: (because I have never given it a try)
How does the CAB compare in thickness to the CV? The data sheet says to lay the CV down in 4-6 mil wet coats. 6 mils is twice the thickness of a heavy duty contractor trash bag! So I hose it on, and it looks like a million bucks. I like the fact that I can spray 1 coat of vinyl sealer and 1 coat of CV and the wood looks like it has had a zillion coats of nitro. Most of the jobs I do are large (30-50 cabinets) so I don't really want a product that I would have to put numerous coats to get the build I get with the CV.
It seems to dry relatively fast, maybe in 5-10 minutes I can handle it lightly and move it out of the booth to spray the next batch. I do on occasion get a some little flecks of trash that settle in it. As Mike said, I always aim for a perfect finish also. The CV levels out extremely smooth. I don't mind the short pot life, it's a minor inconvenience to me. I mix a few quarts at a time, so I don't have a ton left over at the end of a job.
Does the CAB dry faster in your opinion? I know that the solvent (thinner) you use can affect the dry time - but do you think that the CAB dries sufficiently faster to warrant using it when trying for a blemish-free finish? It's been a long time since I sprayed any nitro, and that is really the only other thing I have sprayed in any amounts. I never felt like I could get a great looking finish with the nitro, but it seemed to dry very fast, almost instantly.
This may be a naive question, but is CAB and CAB Acrylic the same? I hear people refer to it different ways so I want to make sure we are talking about the same product.
You also talk about the solvents that are compatible - what do yo know about the various solvents for the different CV's and CAB's? I only know what is printed on the label, so I am wondering if what I am using is what's best.
Sorry for the essay and # of questions - but you seem to be the first person other than the rep at the industrial store I use that know about a lot of this - and you may know more than him ;)
Lee
Lee,
I see the source of confusion now. Apparently S.W. has either slightly reformulated the "compliant" water white varnish, has simply renamed it or a bit of both. As I mentioned before, the commercial coatings guide is slightly out of date and doesn't include this specific PDS.
I think you've misread the specs on wet mils for the varnish. It's showing a recommendation of 2.5 to 4.0 mils wet. However if you're getting away with putting it on heavier then I see no inherent problems with it. It'll just cure out slower due to the heavier coat. The CAB PDS shows a 4.0 to 6.0 wet mils spec, but it's got significantly lower solids than the varnish you're using. So, it's going to build quite a bit less quickly per wet mil. Now, according to the relevant PDS's, applying the CAB at the higher wet mils is supposed to yield a slightly higher build once the coat has dried. But you're already putting on a lot heavier wet coat and there's no way that the CAB is going to match what you're doing on a per coat basis.
Keep in mind that the Conversion Varnish is a self-sealing system. You obviously can use a vinyl sealer if you wish, but it's not necessary. The varnish itself will perform quite well as a sealer coat and most likely will actually sand better than the vinyl at the recommended dry times. The one thing that I've never liked about vinyl sealers is that they don't sand worth a damn unless they are thoroughly dry - which always takes longer than the spec sheet says, in my experience. They've come out with a hybrid nitro/vinyl sealer which is supposed to sand better on shorter timelines, but my experience is that even that doesn't sand well at the specified dry times. So I quite using vinyl sealers several years ago and now just use the finish as a self-sealing system.
That said, I do still use vinyl sealer... as a washcoat to lock in dye stain in a multi-step color process. For that task it works as well as anything I've ever seen, and better than all but shellac. Also, bear in mind that the different vinyl sealers (there are several) are not interchangable under conversion varnish! That's because they don't all use the same catalyst. You're only supposed to use a vinyl sealer which is catalyzed with the same catalyst that the conversion varnish uses.
As for dry times... CAB isn't going to dry any faster than the varnish you're using. They're roughly comparable as far as dry times go. The PDS seems to indicate that CAB might be ever so slightly slower, but you're putting on heavier than recommended coats of the varnish. So my guess is that for your purposes there would be no advantage to using the CAB over the conversion varnish... the dry times are essentially the same.
The one advantage to CAB is that, like nitro lacquer, because of it's solvent compatibility it can be manipulated, in terms of how it behaves while wet, to a much higher degree than the conversion varnish can. It can be made to level out every bit as nicely as the conversion varnish, but doing so involves using a retarding solvent which would make it less competitive in terms of dry times. I just don't see any real advantage for your situation. I think the conversion varnish is meeting all of your stated criteria in spades and there's nothing that CAB brings to the table that offers any meaningful advantage as far as I can tell. Had you stated repairability as a primary criteria then CAB would offer a distinct advantage because it's vastly more repairable than any conversion varnish. But if you don't need it to be easier to repair then I would say stick with what you've got.
CAB and CAB Acrylic are one and the same thing. CAB is just easier to say (or type).
As for solvent selection... I too go by what the PDS and the label say, especially with conversion varnishes and post-catalyzed lacquers. Each conversion varnish is different, so there is no general approach that will work for all of them. However, there is always some wiggle room to work with within each stated solvent system.
I like to blend a "hot" solvent with a "cold" solvent rather than use a middle-of-the-road solvent or solvent blend. I've had finish reps tell me that my approach makes no sense because the hot and cold solvents are counteracting each other. But that is precisely why I use them. The hot solvent flashes quickly, thereby thickening the wet coat quickly... which enables it to hang much better, while the cold solvent flashes slowly and gives me a longer open time... which translates into good leveling behavior.
For the C.V. you are using, the listed recommended solvents can be arrayed from hottest (fastest) to coldest (slowest) in terms of how many minutes each takes to flash: toluene (4), butyl acetate (8), xylene (11), MAK (25) and high-flash naphtha (40) - (these are all listed in the front of the commercial coatings guide I mentioned). So rather than just using one of those solvents, you can mix and match at different ratios to modify the behavior of the C.V. as it flashes off. So that if using just toluene doesn't give you enough leveling then you can either switch to a slower solvent or blend a slower solvent with the toluene to eliminate the poor leveling characteristic. This is very handy if ambient conditions change enough that you have problems day to day or even week to week with how the C.V. behaves. On a hot day, using straight toluene or straight butyl acetate might be problematic because with the elevated temperatures it is drying too quickly. You can either change to a slower solvent (which means that your over-all dry times are longer) or you can blend enough of a slower solvent with a hot solvent to eliminate the behavior problems without sacrificing as much dry time between coats or steps.
Personally, I like to pick one of the hotter solvents (but not the very hotest) and one of the slower solvents (but not the very slowest) and and mix them together into a single reducer for a given finish material and then just adjust the ratio of those two to meet whatever conditions I need to deal with. When working with a new finish I'll typically start with a 50/50 blend and then go from there based on how the finish material is behaving on the wood.
Edited 5/20/2007 2:53 pm by Kevin
Kevin,
First of all, thanks for an informative, in depth answer to my questions. I really appreciate the time you took.
I did re-read the data sheet, and you are right, it says 2.5-4.0 - however, I think either it says 4.0-6.0 on the can (don't have one at the moment) or it said 4.0-6.0 when I started using this stuff a little over a year ago. I did notice about 6 months back they printed a slightly different label for the 1 gal cans. Who knows, maybe they changed it or maybe I just completely goofed. I'm not sure what approx mil I am laying it on, don't know if there's a way to test that?
As for the vinyl sealer, here is how I came about using it: I started off on the advice of the local SW guy using the CV as a self sealer, just thinning the first coat down about 15-20%. Did that up until about 3 months ago, when I needed a special color mixed (all of my jobs had been stain & clear up until that point) and I had to go to the industrial store in New Orleans to have that mixed special. (funny the local guy never mentioned the industrial store before that)
That guy seemed way more knowledgeable about the chemical coatings. I was asking him for a tinted conversion varnish, told him what I wanted to do. He said that would work, but a better way to do it would be to tint vinyl sealer, spray 2 coats, and topcoat with CV like I had been using. That worked amazingly well for the paint job.
He was amazed that I had not had adhesion problems with using the CV as a self sealer (I don't see what the big deal is, it says on the can that is an acceptable way of doing it) and recommended sealing with the vinyl sealer, and topcoating with the CV.
As for the vinyl sealer - the SW data sheet for the CV I am using states it is ok to use T67F3,F5,F6,or F7 under conversion varnish, but they must be catalyzed. ( I am using T67F3) T67F3 uses a different catalyst than the CV I am using does. Could you double check the info about using a vinyl sealer with the same catalyst as the CV for me, I don't want to have any major problems down the line. T67F5 is a high build vinyl sealer, and it uses the same catalyst as the CV. So I could switch vinyl sealers if I had to - but now I have a ton of the different catalyst.
This is all getting a bit confusing, kind of like an episode of "Soap" ;)
As for the sanding, I find the vinyl sealer dries faster (shorter) to sand, and clogs the paper much less than using the CV as a self sealing system. It seems like that first coat raises the grain ever so slightly, and the CV is so tough, even thinned down, that it makes it harder to sand smooth. So I think I will stick with the vinyl sealer, hopefully you can shed some light on the catalyst confusion for me.
Thanks again for all of your time Kevin, hope I haven't been a pain.
Lee
Lee,
I would definitely go with what the PDS says on relevant vinyl sealers/catalysts. They're the experts on the relevant organic chemistry. What made me think that the sealer had to have the same catalyst is that the vinyl/alkyd C.V. that I use can only be used over one particular vinyl sealer and that sealer happens to use the same catalyst as the C.V.... and I drew what seemed to be a logical conclussion. But you are right, the PDS for the C.V. you are using does list a bunch of acceptable sealers and they don't all use the same catalyst. Ultimately it all comes down to organic chemistry. There must be some specific issue with the C.V. that I use that precludes use of all but one of their vinyl sealers.
If you ever have problems that you can't seem to narrow down then try switching to the sealer that uses the same catalyst and see if that cures it. Otherwise, I'd just keep doing what you're doing. I've talked to several S.W. lab guys and they are extremely competent. If they say that it's okay then I'd bet a lot of money on it being okay.
Sherwin Williams actually makes (your rep ought to be able to simply give you one) a stamped aluminum wet film thickness guage. It's really easy to use, although you have to do a test pass on something other than a finished product because using the guage involves placing it in a wet finish film which obviously would mar a finished product.
I would be highly skeptical of the technical competence of any S.W. rep who thinks that using a finish that's deliberately designed to be self-sealing as a self-sealing system would cause adhesion problems. He simply doesn't know what he's talking about! If you read the PDS it doesn't even suggest using vinyl sealer instead. What it says is that you CAN use vinyl sealer if you wish. But default mode is clearly to use it as a self-sealing system.
On the high mil coats of varnish... My boss used to co-own a business making custom rifles and before that he worked for a larger company doing the same thing. He has made and finished lots of rifle stocks and his preferred method involved putting multiple extremely heavy coats of the regular S.W. conversion varnish on and then letting it cure out for 24 hours before proceeding with sanding it. The purpose was to get a totally filled finish. He was putting on much heavier coats than the PDS recommends and never had a problem, other than that the finish took a long time to cure out. Of course he was sanding it way, way back, so he wasn't ending up with a super high build. It was just an easy way to totally fill the grain. So I don't see any inherent problems with you laying it on as heavy as you have. If you're not running into any problems then I'd say just keep on doing what works until it ceases to work.
Hi Kevin,
This all sounds good to me. Thanks again for your time!
Lee
Anytime, Lee.
One quick note in defense of the S.W. guy who raised the adhesion issue... He's wrong. But... vinyl sealer is famous for it's adhesion promoting properties. Very much like Shellac, in fact. So you are certainly not going to sacrifice adhesion by using the vinyl sealer! It's just not necessary in this case. My hunch is that he's well aware of vinyl's truly great adhesion properties and never bothered to educate himself on the self-sealing aspect of the conversion varnish.
Wow,
This has been onr of th emost imformative conversations I have had in a long time. Sounds like I am using a good system. I have used the CV with and without the sealer. I couldnt really see the difference, but I sprayed the first coat of CV (when used as a sealer) very thin so it sanded off easily. I don't think that I will use the sealer any more just to avoid buying two different products.
Pardon my spelling,
Mike
Make sure that your next project is beyond your skill and requires tools you don't have. You won't regret it.
Personally I don't even thin it down for the sealer coat. That way I just have one pot and one reduction schedule. Once I'm done sealing I can proceed to topcoat without having to change anything. Nothing could be simpler. Plus, in my experience it takes too many coats of the thinner sealer reduction to get enough build to prevent burning through into the stain on jobs where I'm staining. So I just don't see any reason to thin it down further just for a sealer coat.
I thin it so it sands easier. If I get it light enough I can go over every thing with 320 and get a perfect surface for the top coat. It seems like the thicker coats would be harder to level. though I havent tried when using the CV as a self sealer.Pardon my spelling,
Mike
Make sure that your next project is beyond your skill and requires tools you don't have. You won't regret it.
Christ just when I thought I had it figured out!! Even the Comercial Coatings guys couldn't tell me all that.
Since you know their line so well ...... I finish about one large project a month, maybe a month and a half. My first priority is that it lay down nicely, and is durable and non-yellowing. I shoot for a perfect finish. What do you think I should use?
Pardon my spelling,
Mike
Make sure that your next project is beyond your skill and requires tools you don't have. You won't regret it.
Well, as I alluded to with Lee, I cheat a bit. I have a copy of the official S.W. Commercial Coatings guide which is a collection of product data sheets for all of their commercial coatings materials along with a bunch of other stuff. It's really very easy to simply look up whatever S.W. products are being discussed here. If you can talk your local commercial coatings folks into giving you one I guarantee that you will find it an extremely handy reference.
As for a recommendation... Although I'm a bit perplexed by the sub-number Lee is reporting for his conversion varnish, I would say that either the S.W. water white C.V. (which is what I think Lee has) or CAB Lacquer would meet your criteria. The C.V. is going to be more durable and the CAB is going to lay down a bit better. So, of those two it's a matter of which is the most important to you.
Greg,
I will agree with Mike (mudman) on this one. I finish all the cabinets I do with conversion varnish. In my opinion, it's the most durable of all - and one coat of C.V. over one coat of vinyl sealer looks like 10 coats of nitro. The C.V. I get from Sherwin Williams is water white, non-yellowing, and has a U.V. inhibitor added.
Lee
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