Advice on this gun

[LDO]

I picked this one up for primers....

https://www.northerntool.com/shop/to...4729_200324729

[MARTINSR]

Originally Posted by LDO

I picked this one up for primers....

https://www.northerntool.com/shop/to...4729_200324729

That is a little big, you need to watch out using that big of a tip on urethane primers and sealers as you can trap solvents. It's really pushing it to polyurethane primer use with that 2.0 tip.

Now I just used a 2.0 tip on my epoxy primer inside the cab, but it was because of the guns design that I used it. And it PILED on that primer! http://67-72chevytrucks.com/vboard/s...d.php?t=765811

I WILL NOT be using that big of a tip on the outside or dash or anything that needs the primer applied properly.

Now understand, you can get away with it, if it's warm out, if you have fast gun movement, little overlap, a bunch of factors can keep down the film thickness and solvent being applied so you don't trap it. So you can get away with it, I just grab a different gun to solve the problem.

Solvent entrapment is the number one, NUMBER 1 cause of paint failures hands down. So you want to do anything you can to avoid it.

Brian

[LDO]

Martin,
what does it mean to trap solvents?

Maybe I could get a 1.8 or 1.7 tip for this gun?

[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

[MARTINSR]

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”.

[scott123]

I'm split between buying the FLG 4 and the FLG 5. The FLG 5 gets much higher reviews for a lesser price.

I have painted a number of trucks over the years. Most of my trucks have been daily drivers. I can't drop 3-4-5 grand on paint and then head to the fields, bushes, ponds, etc. etc. So I spray myself on these.


I'm still debating on the next gun. I had a 72 K5 some years back and knocked it out of the park with a Binks Model #7 siphon gun. That gun was used to shoot everything from primer to paint and used to stain wood cabinets and then glue for formica tops. It was a beast in its day.


Like the above posted, it is nice to have a great gun, but a great gun will not make a great painter. I'm an amateur and I still practice on old panels.


Post what you think as an amateur with the FLG-4. I'm interested as I am still 'in the market'.

Scott