Rough texture when spraying WB Poly

[Tom K]

I've been experimenting with some HVLP conversion guns spraying GF High Performance Satin. I am finding that when I lay down a thin, even final coat I end up with a somewhat textured surface. It feels similar to what a formica countertop - maybe slightly more rough. The area I'm spraying is 42" x 72" so overspray is difficult to control without a more powerful exhaust system.

Is this normal? What is the best way to smooth the final coat? Brown paper bag? Scotch brite pad? Steel wool? How long should I wait before buffing? I've used the paper bag trick in the past but it leaves small scratches.

Thanks!

[AceHoleInOne]

"Thin" coat is your problem. You're dry spraying. Your final coat should be a nice wet coat. The finish will take on a just a little bit of a blue cast to it in a raking light when you have it correct. The finish will come off the gun a little orange peel looking with a bluish tint. Let me see if I can find a picture for ya.

 

-Ace-

[Tom K]

Ace,

I think I know what you are talking about... you start to see a bit of the white in the finish. I have put on some heavier coats and had trouble with the satin flattening agent splotching because the finish wasn't perfectly even. The parts that took a few minutes to flash off were a bit glossier.

At this point is it worth another sand and redcoat or am I better off trying to buff after it has cured?

[AceHoleInOne]

No "white" in the finish should be wet clear/blue.

 

First, STOP what your doing and get a scrap board and practice laying down a full wet coat. The look is orange peel. It will look like crap, as it dry's, it will flow out nice (may take you a couple coats). Scuff with 320 paper between coats that have dried.

Once you get the hang of that, (may take you a day or two). Scuff your project with 320 foam backed paper and clean the surface then lay down a nice full wet coat.

 

-Ace-

 

[Guest]

Ace is exactly right.  It will look like poop when wet, if you are doing it correctly.    I sand with 320 between coats.   Your final top coat should level and not "need" any more work, but you can always rub it out with a 500/1000/2000 sequence if you want to get nutty. 

[Tom K]

Alright well thanks for the advice.

Below you'll see two pics of the orange peel/blue/wet coat and the final result. I also added an extra fan to extract the overspray and wiped the table down again after setting up the gun. I ended up with just a few dust nibs to deal with but it is definitely smooth! 

With the gun I turned the fluid to full and backed down the pressure just above the point where the atomization started to suffer. I also went back over a few areas that were beginning to dry from the excess air while doing the other side of the table.

 

 

 

 

[AceHoleInOne]

Alright, you got it. Looks great. Now get a beer. You deserve one!

-Ace-

[bob493]

That looks great man, good work!

[Tom K]

Thanks.

Previous to the conversion gun I was using a cheapo Rockler turbine which really DID give me orange peel. The thought of having to sand that out had me skittish on laying a heavier coat.

Now to the rest of the table...

[..Kev]

Looks great Tom and great advice from Ace!