Some info on water cure CARC

[ida34]

For those using the older water cure solvent based one part carc I have a little advice. The biggest problem with this stuff is the water in the air will start the curing process so Shermin Williams recommends using the whole gallon at once. Once thing the manager at the store told me was to vent some argon into the container. It would displace the air and the moisture with it. I had heard about this before so I had an old regulator for my mig welder so I connected a hose to it and used my argon mix for the job. When I was done pouring out some of the paint I ran the hose in and filled the container with the argon mix. I started using a gallon back in March used it of and on for a few weeks working my cucv. I used it again a couple of months ago to paint my new troop seats. Again I used the argon mix. Yesterday I took it out to paint my deuce fender and the new winch. I was initially skeptical because I could not pry the lid off. It took a lot of work to get the lid off and I destroyed the can. Even so the only chunks were dry stuff from the top that fell in. I had put in a pour spout top that pops out like on five gallon buckets. The chucks came loose when I would take the top off. I could not get it off this time so I just took the top off. The paint had obviously separated but I wanted to manually stir it up before putting it in the paint shaker. After about a minute of getting the solids to move I was able to get it to an even consistency. I used a paint strainer funnel to help get the chunks out and poured all the paint left into a smaller virgin container for the paint shaker. After 10 minutes in the shaker the paint was just fine. There was no skin on the top of the paint at all. Putting the argon in regular paint cans will prevent the paint from skinning also.

 

[Nonotagain]

The single component CARC, Mil-DTL-53039, does not need moisture to cure. It will react to moisture and create carbon dioxide gas.

The new three part CARC, (base, catalyst, water) Mil-DTL-64159, uses water that is mixed into the paint to act as a thinner as well as to aid in the cure process.

When I set up our paint line for CARC in 1988, I specified using Argon as the shield gas so that we could leave the paint in a pressure pot. Back then we generated Argon for our titanium welding processes, so Argon was reliably available. Today we use Nitrogen for all of our critical paint operations.

Any polyurethane paint will react to moisture and bond the lid on the container. I end up rejecting about 20% of the paints that are sent to me for overage retesting due to the lid being bonded in place.

 

[ida34]

Taken directly from the Carc Data sheet from Shermin Williams. The full version is also attached.

MIL-DTL-53039B, Type I coatings are 3.5
VOC single component moisture cure
aliphatic polyurethane camouflage
chemical agent resistant coating
(CARC) for military equipment. They
conform to MIL-DTL-53039B, Type I composition
and performance specification.
They can be effectively decontaminated
after exposure to liquid chemical agents.

 

[Nonotagain]

ida34,

I read the Sherwin Williams data sheet but I think they are incorrect in the terminology used.

Attached is the mil-spec for this material. You will find no references to moisture being needed or wanted for cure.

The previous version of the mil-spec required you to use Mil-T-81772 thinner that was a urethane grade product due to moisture in I believe the type 1 thinner.

 

[ida34]

It is not like they say add water to make it cure. Milspec sheets are not paint data sheets. You are comparing apples to oranges on this. The milspec sheet tells suppliers what they want the paint to do and what they expect of the paint. The contractor then works up a paint to match all the specs. Unless the military specifically wanted or did not want "moisture cure" then it would not be addressed in the milspec documents. The milspec sheet says what the military wants. The paint data sheet describes the actual product. You are really still going to argue this when the people that make the paint clearly state "moisture cure". This is not just on the Sherwin Williams data sheet. I have seen it described a "moisture cure" elsewhere also. I have a feeling a rebuttal will be posted but if posting the data sheet was not enough to rebut you argumentative post then I have a feeling we will just have to go our own way on this.


I guess the only thing we can agree on it that argon will help the shelf life of opened paint and this was the main point of my post. It was not to point out that this particular carc is moisture cure. My point in describing this as moisture cure was to make sure people did not confuse it with waterborne carc.