Quote:
Originally Posted by Jrainman
traping solvents ,in a nutshell he is saying that the chemical make up of the product needs to release gases as it changes from its liquid state to a dry material
|
Not so much the "Chemical makeup" being that could remain the same and the solvents can be trapped or not depending on how it is shot, "wet" or "dry."
Now the true definition of "chemical makeup" could be something different than what I picture being my degree is in cardiology.
, double
In a nut shell, it's the solvent (reducer, thinner, what ever) that is designed to LEAVE the film once it's applied....doesn't leave!
Product applied too heavily, for instance, the top surface of the film flashes off with the solvents leaving fast enough to "harden" up a bit (be it "drying" or be it "curing"
*) and then the solvents that are down in the film under that hardened layer get "trapped." This is the cause for "die back" when the gloss is lost a few weeks after the thing was painted and buffed and drove off with a beautiful shiny paint.
Trapping solvents can occur when too slow of reducer is used for the temp of the metal and shop, or over reducing trying to get it to "flow" (a BIG no-no) or too much overlap, too many coats, too short of time between coats...get the picture?
Spray it as per the tech sheets, and it's going to work for you.
Brian
* From the "Basics of Basics" on Paint technology:
“1K” This is a product that uses no hardener, catalyst, activator, etc. It may have an added solvent, but no hardener or activating reducer. 1K products like RTS
dry with the evaporation of solvents and are soluble, meaning that they are could be wiped off with a rag soaked with lacquer thinner. They could in THEORY be scraped off and put in a can with solvent and stirred back to a sprayable condition. Of course ALL RTS products are 1K. Examples: All lacquer products, some synthetic enamel products, and some acrylic enamel products. Because of the low VOC regulations the 1K product options are getting scarce, with most limited to “specialty products” like adhesion promoters.
“2K” or “Two component” is any product that uses a hardener, activator, catalyst, etc. It may or may not use a third component in the form of a solvent. 2K products don’t “dry” like a 1K. The 2K product “
cures” by molecules linking together to form a whole new compound. Most high quality 2Ks are insoluble after a full cure and will not soften when exposed to solvents like thinners or gas. Examples are urethane under coats and top coats. Epoxies, ISO free products that use a hardener, etc.
Basic tip, ALL 2K products should be mixed as accurately as possible. As a rule 2K products need a minimum of 55 degrees to cure with an ideal minimum of 65 degrees. MIX THEM AS DESCRIBED BY THE MANUFACTURE. They have spent hundreds of thousands, possibly millions of dollars developing the product, they WANT it to work as BEST it can. Do as they say, don’t become a “Junior Chemist”.