My Questions:
1. Alternative satin nitro cellulose brand available to North East Ohio?(pigmented color match)

2. How can one go over a nitro cellulose with a conversion or Precat lacquer.

3. Other than pie in the sky theorizing, has anyone beat the microbubble plague by any means other than to jump brands?

My problem specifics.

I have been using Nitro cellulose lacquer for the past 3 decades, no problem.

Now I just shot Lenmar Nitro cellulose Satin pigmented on a bunch of cabinet doors, and I can't get lay on a coat without microbjbbles.

The primer laid out like glass, and the finish lays out like glass, but you can watch a ton of microbjbbles form at the 10 minute mark.

I tried everything from thin film to thick, to thinning with 25 lacquer retarder, xylene, different guns tip, fast dry, warm 60F dry, force dry, cold dry down 15 F, always strain pain, never shake mix, even lowering and raising humidity (the most credibile tech support was that humidity was too low and I need to add humidity so the outer layer does not skin.

Google tells me to switch brands but I cannot find any nitro cellulose sold anywhere. Sherwin-Williams only sells five gallons lots $500.

So, does anyone know of a seller of an alternative brand to nitro cellulose? Or, anyone figure out a micro bubbling solution other than charging brands?

Most importantly, is there a way to go over my nitro cellulose with a a Precat or conversion varnish. Tech support says it is impossible.

My spray area is poorly insulated and space heaters and kerosene does zero to warm up the shop. I can only turn on a torpedo heater for a few minutes after spraying to warm me up and blow out the fumes that my point of capture air suction system did not suck out side and through a carbon filter. I have easily sprayed cabinets down to 11F, here in North East Ohio, maybe even sub zero as I recall doing. The doors dried fine overnight to a hard satin finish.

1. Alternative satin nitro cellulose brand available to North East Ohio?(pigmented color match)

2. How can one go over a nitro cellulose with a conversion or Precat lacquer.

Trust the tech support, they are the chemists that developed the products.

Conversion varnish,forget it!

Pre-cat?
Mmmm, maybe if you sand back what you have and then use a vinyl primer/sealer first?
Personally I don't know why you haven't switched to a pre-cat or CV long ago

So far, this is what I am reading and being told:

It looks like on the sds that Precat Magnalac lacquer is just nitro cellulose with 1 percent epoxy and formaldehyde for a little extra crosslinking. It looks like they took out the toluene and xylene for a variation of naptha, according to the sds. It is said to be less flexible, less fixable (scratches, dust, minor transportation/drying issues/dry spots are easily fixed on nitro cellulose by hitting with retarder), needs higher temperature to apply (I have used nitro cellulose in really cold Temps), more likely to chip off, and if you get more than 4 coats on it there's a fear of the entire film popping off. (Strip?)

Precat is said it is harder to apply than nitro cellulose, as it has windows and does not melt into a single coat. Sanding lines with 320 grit do not melt away and are seen under a coat. The nitro cellulose (according the mlk Magnalac sds) have easier to sand sterates (likely just the nitro cellulose primer, which they are warning using under the petcat) .. Nitro cellulose covers like a dream in one coIf you need to, you can go over Precat with nitro cellulose, but not the other way around.

Precat is not harder to apply. It goes on and flows out just like traditional lacquer. You do have to know you coat thickness, but that does not make it harder to apply. I don't consider Precat nor nitro cellulose as acceptable kitchen or bathroom acceptable. There are much better finishes available for wear and long term water resistance. The main reasons the industry went away for both of those finishes decades ago. Furniture is a different story.

What a mess... First off is, it must be understood that all Nitro cellulose finishes are not equal.! in fact the only thing they have in common is the fact that they contain Nitrocellulose.! Nitrocellulose, in and of itself, has terrible coating properties as to creating a durable adhesive film that has good protective qualities on it's own.! It has poor gloss, poor adhesion, and on it's own is to brittle to be of any use as a wood or other substrate that contracts or expand to any degree at all..!!
The "main" reason it became so popular starting in the late twenties to early thirties, as a new coating, was it's incredible ability to Quickly shed or release the aromatic hydrocarbons and other used solvents or thinners that were needed to put in into solution.
It took years to actually formulate a coating that had all the great properties that any coating should have, especially for production work.
Without going into pages of further explanation on this subject, and it's first usage on cars and then furniture etc., you must know that it was never "intended" to be sprayed at low temperatures, though it is sprayable at almost any cold temperature, it is subject to cold checking, case hardning, and loss of it's intended overall properties it has when used within the chemist/company's guidelines for use.!
Most finishers do a lot of things sucessfully from time to time and get away with it, but normally, at some point, those same methods and means come back to bite them in the a*s.! Just a friendly warning.
What I can point out from your description of this so called micro-bubbling, and what you stated the MSDS sheet states, is that for whatever reason they decided to move away from the traditional use of alkyd resins which have been the standard other resin/oil used from the begginings, in the formula, (whether for cost or safety restriction reasons placed upon them by the government, )
which when used require the use of aliphatic hydrocarbons, such as toluenes, naptha's, etc.!!
Which prices are ever increasing. To instead use Epoxies/polyesters, with formaldehyde as a catalyst/hardening method.
You also state that this bubbling is not happening with the clears or primers, correct.?
So I need to know first off if all 3 products being used are from the same coatings manufacturer.??
If they are, then I would surmise that their is a reaction taking place between either both or one of the catalyst components with one or more of the pigments being used in the opaque coloring of the coating.! But I would have to have both components and the pigments to test and see if this is the ghost in the attic for sure.!
If by chance you are using different coatings from more than one manufacturer for your projects, which is a no no, it could have something to do with it also, but in this case I believe it is the opaque coating that's the real culprit.!!
As to further advice, given in sincerity, I would look into finding a heating system that can be installed in and above your booth to be or act as a heated air makeup system that will allow you to spray at proper temperatures that all finishes are recommended to be sprayed at.!! Coatings Manufactures do not post these temps for the hell of it, and if not followed, can cost you dearly usually at a time when you least need it or can afford to deal with it.!
Last note...
I would recommend other excellent nitro coatings manufacturers to you, but these days they all are expensive and with shipping charges on hazardous materials through the roof would be no better than what you could get from SW locally.
Hope this is of some help..sorry if it's not...
Reguards,
Chemmy

Most of the responses are greatly appreciated, especially since I will go with a Precat on the next job.

To Chemmy, I will add that my first attempt, I shot all of the doors' topcoat, 31F to 60F outside, but after shooting each door, I put the door immediately in a temperature controlled box and immediately turned on my torpedo heater to the right of my spray table ( above the table was a 2x5x1 insulated box with a heater. Down wind of my heater, to my left, I built a series of drying racks that hang from the rafters to where the heat from the torpedo will go. The torpedo heater helps clear the air of solvent fumes (in exchange for a touch of carbon monoxide), to help the point of capture air evacuation system that comes down from the rafters and constantly sucks. ... The microbubbling happen in the cold, in the warm, any gun, with 25 percent lacquer retarder. The primer and problematic finish was Lenmar. I need to pull the sds on this product and call the technical support to see how they have improved this formula over previous generations of nitro cellulose.

For anyone interested, yesterday, after a week of wrestling, reading, and trying everything - - I finally solved the microbubbling issue after a week by adding 10% to 20% acetone to the spray cup!!! My theory was that it was most likely h2o coalescing from the air, the pigment, or the lacquer paint. Water is heavier than the lacquer or any of the solvents so was not magical rising out of the horizontal paint film. ( I spray and dry the doors horizontally, as I found I could get the best build, best leveling, and the zero possibility of any run developing, except for the occasional run on the less visible lip/door edge.)

I have not ruled out the possibility that the microbubbling wasn't caused by the lacquer formula, because I did try using a chip brush application on a 7 inch round plastic lid, and the microbubbling still appeared, which indicates environmental, brand of lacquer, or pigment cause. (I have used this base for years, sprayed cabinet doors in the same environment for years, tried 3 guns, tried xylene (high and low percentage) and 25 percent Lacquer retarder, I varied the temperature up and down, and humidity up and down, I did try tinting a quart of the same brand with ppg pigment rather than Benjamin Moore, I tried letting my paint cool overnight, I tried using paint warmed to 80F, I tried thick coats, thin coats, I tried straight unthinned lacquer paint, I tried lowering and raising air pressure, I switched brands of water separator at the gun to a desiccant and left the oil water separator at the compressor as the metal clear type. I did not notice the clear separation filter getting foggy like times in the past where microbubbling was never an issue-this made me wonder if it was doing its job.)

I ran into an old forum post from a guy who successfully topcoated his nitro cellulose lacquer with a Precat Lacquer by mist coating, 320 scuff sanding, another mist coat, another 320 scuff, then full topcoat of Precat. I am tempted to clear coat the set of doors with a Precat to better protect the finish, on the front of the doors. (I am being told that the Precat does not expand and contract like the nitro cellulose, and might crack. However, I was told, in 1991,the same thing about porch floor paint, and I was not supposed to prime, because primers were flexible. I learned by 2001, that porch floor paint lasted longer if I used a high build flexible paint under to act as a buffer, because wood expands and contracts a crazy amount. If you think about it wood swells and skrinks something like 10 percent, depending on the humidity, and the miniscule flex of a base coat is nothing in comparison. In fact, it might help buffer a less flexible topcoat from a wildly expansive, flexing base wood substrate. We see hard inflexible top coats cracking after 6 decades, but they also crack and checker when they the base coat. I am not convinced of cracking risk, especially when the people who warn against have never tried it, nor do they apply the coatings for a living and having at least a few decades to witness the various phenomena in the field. I will only trust a first hand witness, not urban myths, as proven by the Discovery Channel Series called Mythbusters.)

For others Googling this problem years from now, I also tried spraying all the doors with 3:1 lacquer thinner to retarder, and straight retarder to melt out the bubbles, but they did not budge. Even sanding, then hitting with the retarder. I also tried clear coating with a lacquer to see if the bubbles became less noticeable, to no improvement in appearance. If these were mere air bubbles melting with a retarder would have fixed the problem. It had to have been hard core water or mineral spirits bubbles - some incompatible liquid, which the acetone was able to bind to and carry up the surface, as acetone is going to be the first, lightest thing to flash off. Acetone is used to dry out beakers in a chemistry lab, and has at least some water solubility I was told by a chemist or two. Most likely the paint somehow had some water getting into it, or was pulling water into it from the air, and the acetone carried it out. Else, the last day and a half was a fluke. Yesterday, I shot all the doors, outside air was 28F, no bubbles with the acetone. I skipped the climate controlled warm box, as I wanted slow drying, incase that might help with the bubbles. So they just had the benefit of me cycling on the torpedo for 2 minutes after each door. But really, the acetone, seemed to be the ticket. I would open and stir up paint on the assumption that the acetone would rise and separate in the cup after every 1 or 2 door sides, and I periodically added more acetone on the theory it would be quickly evaporating through the tiny hole in the top of spray gun and out of the tiny hole on side of the plug, plus every time I stirred. I was too much of a coward to shake my cup for a likely unfounded fear of making the very bubbles that I was trying to prevent.

So, rather than switching brands, in solvent materials, perhaps, adding acetone might be something that can be reproduced by others with this problem. Unfortunately, it will be someone 7 to 10 years from now, and the thread will be closed, and I & others will be deprived of their valuable and sought after input.

So, theories about too thick of film, and other straw grasping seems to be incorrect. The occurrence in Emerald Urethane water borne spraying is like due to a different cause-the surface tension lowering agents needed to avoid goose bumps, beads, caused by the higher surface tension of water.. This solution would not apply to water based materials.

As a reminder, I am still waiting for replies on the possibility of clear coating with a Precat clear, especially using the double premise method. As well as figuring out if it is even necessary.

I have been doing cabinet doors for a condo and apartment complex for years with this Lenmar product (working through the management), and have no complaints yet. On residential repaints, we mostly used water borne urethane and alkyds, which seems to inferior to the Lenmar lacquer. I watched a builder from 2003 to Dec 2008 use this same Lenmar on all the trim, and thought it was superior to any oil that I could apply, at least for the first 6 months to a year as my finish cured. I got into catalyzed 2k urethanes in 1996 and quickly got away from them as they were nearly impossible to keep from running and dirt to get into the film=unsuitable for the typical nitpicking client...

I have some black doors to shoot and will need to test my hotbox and acetone. If this combination escapes the microbubbling issue, it will allow faster drying and limit the stray dust that plagues the slow drying... Typically, in the winter, I would shoot 30 doors, 20 would dry perfectly but 10 would have some flaw from a dust spec, or my error when moving to the drying location, etc. So I would need to fix 10 doors, and reshoot. Then, nearly always 3 doors would have some imperfection and I would need to redo, leaving me with 1 door that didn't turn out. 2/3rds of the time I can just redo that door and have it perfect. So 30 doors is really 30+10+3+1=44 doors. I was really hoping a dust proof warm box that I could set them in for 15 minutes while I prep the next door would eliminate the random dust problem. If successful I planned to build it capable of drying 4 doors at a time. Hopefully, this would mean 40 minutes before allowing a door to exposed to the non hermetically sealed environment.

Pouring heat directly over a freshly sprayed door will flash off the solvent on the surface immediately and any level of orange peel will quickly result. I'd also worry about the dew point from moving items from hot to cold in the shop. Do it too fast and you may get blushing. It will also slow the cure deeper in the finish. I don't mean drying, I mean curing. But I have a feeling my advice won't sway you much.

Rich, my observation is that 40 minutes is the typical dry time for lacquer under normal conditions. I have not seen it dry more quickly.

I have seen overnight for lacquer to dry. I have tried to paint in new million dollar ohio houses that barely was kept above freezing (one furnace, likely locked at 40f, plus I have had far colder lacquer jobs.

I can keep a heated box at any temperature using a diffuser system and temperature monitoring until I know the cycle time or upgrade to a thermostat, I suppose. 1500 watts of heat is nothing and is the max that 110v circuit can put out. But in a box, 1500 watts may only need to run a few minutes per hour. My torpedo heater is over 100k btu and the heat immediately escapes, which is probably good for carbon monoxide. I tried 2 kerosene heaters, a 1500 watt electric infrared heater pointed at the drying doors and a propane infrared pointed at me. But these had little effect on the temperature of the area. But I did find that the torpedo makes a good space heater for heating me up and the immediate area. But it became ridiculously expensive to keep buying diesel or kerosene to attempt to raise the entire area temperature. However, I do not think it is remotely necessary to heat the entire shop, so long as lacquer has fast drying solvents. Anything water based, polyurethane, or mineral spirits based would shut everything down for 6 months per year, as the system would not dry for days, else freeze, even with a hot box.

Indeed getting the heat into the box with effective results and not over doing it, while keeping even distribution, is another engineering trick.

I mainly used it yesterday as a dust shelter during the initial dry phase before putting it on the drying rack. No heat inside the box.

I haven't yet ever achieved orange peel with a lacquer. Lacquer always comes out like glass for me, so far. And the nitro cellulose sands unlike anything else I have seen, including easy sand oils. This is one reason I have been scared to switch to a Precat.

Of course, my questions remain, as to whether anyone here has had real world, boots on the ground experience putting a Precat over a nitrocellulose (I only found 1 guy who did it on a closed thread in 1996, by 2 mist coats of Precat, scuff, then top coat.). My question remains as to the exact cause, because I ruled out environment reasons, water in the air, base lacquer as the culprit, air in the film. I did switch from Benjamin Moore pigments to a PPG pigment; however, these are sister stores, I am constantly being fed incorrect information by paint salesmen, and due to raw material shortage PPG and BM could be buying a common pigment from the only currently available source.

The nitrocellulos mlk clear top coat did not have any bubbles, while the brush test of straight lenmar tan had bubbles, tells me that the problem was not in the environment, but in the paint. I did not have any problems with the primer. I haven't had issues in the past. I did rule out batches, by using different batches of Lenmar. Unfortunately, both the Benjamin Moore and Ppg tinted lenmar had bubbles, meaning that I can't definitely say that the beige pigments were the problem. It looks a lot like to me, that Ben Moore and ppg use the same tint supplier for at least one of the pigments. I should have paid the commercial sw to test tint my quart, rather than 2 sister stores who have the same owner and both carry Ben Moore and Ppg. I was relying on the word of one old timer sales guy named Todd that he was using a different tint system than BM. So, a bad tint component (possibly due to this year's raw material shortage, so the companies are using something like a Chinese sourced Raw Umber) remains the most likely culprit for the microbubbles... The fact that I could not melt out, or retard out the bubbles, rules out air bubbles or too rapid skin over or the low humidity hypothesis that was the most credible tech support theory. These guys in tech support grasp at every straw they can think of, just so they don't have to consider the possibility that their own products might need to be refunded and damages paid for the lost time and stripping. On the other hand, a painter does not care where the problem comes from, they just want to fix it and learn how to avoid the problem for the future, which will give them an edge over the competition in the future, which may justify the transient cost and distress in the present.

Hey Dennis, just so you know, I am not just a chemist, everything I speak of is from Hands on experience, not from text books or googling info.
That said, I am from Ohio originally, and though my trade was not born there, but in Fl.under my dad's supervision, I later worked in both Ohio and Michigan, in the 70's - 90's as well as several other states. I will not do further commenting on your problems at hand with the bubbling etc.,
I can only say that I agree with many of your comments for having had the same experiences with both coatings companies and sales/Tech reps. And is why I would go back to school and learn as much as I could about organic and inorganic chemistry as I could, especially in the field of decorative and protective coatings, so that no one could bull schitt me about anything.!
From that point on, if problems arose, I would only deal with the chemist and in doing so, using the language of chemistry, find out what was going on or happening by understanding not only the formulation of something, or the application perimeters and boundaries, etc., but also how it could be improved or enhanced to be a better
or more universally useable end product if possible, which almost always is possible.

As to not getting answers on whether you can spray nitro over pre cat or even post cat, or any other coating, as far as that goes, the "simple" answer is " yes".! Your remarks about reading something that told how they went about this is certainly true and I can prove that to anyone.!!
The problem remains, as you yourself have stated twice, that knowing the long term affects of doing such, takes many years to know what will actually happen, for sure down, the proverbial road.!
The problem remains, that even if you spray nitro over any other finish and have success in doing so, once or many times, does not mean that this will always be the case...I know this from my own almost 60 years of hands on experience applying every finish that has come along since 1965, not every brand, but every "type".! and not just for wood but every substrate that has coatings applied to it including plasma coating of jet engines.
Have I personally sprayed nitro over pre-cat.??
Of course, and many other coatings. As a touch up artist and furniture custom repair person or patcher as a factory would call the position, many times I had no choice but to do so.! On the other hand, though I never got a call-back where there was a problem from doing so, I also did not do this on surfaces like table tops or pianos lids, etc., Where I knew there could be a potential for it being problematic.! I do know this...that the "only"way you can ever know for sure how good or effective these test will be, is to make samples, do your own testing, keep one set of samples in the shop, keep another set at home, and another on your dashboard to gather all info you can on what happens over time with your expieriments.! As you yourself have stated...it is time that tells the truth of a matter, not words.! And with that I will end " my words"....
Sincerely,
Chemmy