Going insane trying to spray GF HP Poly & GF Enduro Clear Poly...

[Dustin Brown]

Hey guys, I'm about at my whits end trying to spray this stuff. I don't know what else to try. I've talked to general finishes and fuji as well as many hours of reading everything I could find on the net and threads on SMC. So many conflicting causes and solutions, yet I'm unable to get a smooth finish. There's no way this can possibly be so hard.

I'm spraying with a new Fuji Q3 turbine setup with the T75G gun and the 3M PPS cups. Using the 1.3mm nozzle. GF and Fuji both confirmed that is the proper nozzle, though I do have the 1.0mm set I haven't tried.

This all started when I was doing my first spraying with general finishes high performance poly. I was always getting orange peel, and sometimes I would get air bubbles if the finish was laid on too thick.

I decided to get a can of the enduro clear poly and try that instead. Now I'm getting orange peel and bubbles no matter what the thickness is. I'm using plywood and the board I was spraying the gf high performance on after sanding perfectly smooth. I've wiped it clean with a dry cotton cloth and I've also tried wiping it with a 50/50 mix of DNA and water.

I've tried spraying very thin coats, medium coats, thick coats. Checked with a wet film gauge and I've read 1 thru 5 mil in my different tests, GF advises 3-5mil. I've adjusted the air up and down(hose is straight as possible). I've adjusted the fluid more and less. I'm sure I'm getting a very fine atomization. I've gotten close to the work, further away from the work, smaller fan width, larger fan width. Goes on as a finely atomized mist. Tried it where it slowly starts to flow out all the way to where it quickly flows into glass. After several hours and even days later the orange peel is still present.

I also just tried spraying glass with the GF Enduro Clear Poly and I get orange peel and bubbles.

The GF HP viscosity measures 20 seconds through the fuji cup(said to be a ford #4) which is strange because they advertise 35-45 seconds. The can has a date of 8/28/14.
The GF Enduro Clear Poly measures 23 seconds, which is also weird because they advertise 40-50 seconds. The can has a date of 3/2/15.

Both cans are unthinned. I find it strange to think they could both be bad cans being so recent and from 2 different unaffiliated local stores. I did try thinning the GF HP by about 10% with the extender which didn't help.

Not using stearated sandpaper, everything cleaned with denatured alcohol or RODI water. Tried on glass, plywood, poplar, walnut, with and without zinnser sealcoat. The guy at Fuji says with my setup and water based finish, the only possible cause is too thick of a coat, yet I have tried coats so thin the mil gauge doesn't register all the way up to about 6 mil.

I'm am absolutely lost and extremely frustrated with this. Never in my entire life with all the things I have done, have I EVER had even a fraction of the difficulty I'm having with this. If anyone can share some insight, things to try, solutions, I would be eternally grateful.

EDIT: Forgot to add, doing this in my climate controlled shop, 75 degrees and 46% humidity.

[Jamie Buxton]

How far is your gun from the wood? Too far leads to orange peel. Something like 6-8" does it for me, and my rig is pretty similar to yours.

[Dustin Brown]

I've tried 3" all the way to 10". Almost always about 6" other than for testing. About a 5 or 6 inch fan pattern at that distance.

[John TenEyck]

Wow, those two products spray like a dream for me. Your viscosity readings are way off compared to a #4 Ford cup, however. I measure Enduro Clear Poly at about 45 seconds, right where GF says it should be. HP Poly I consistently measure at nearly 60 seconds, however, even though GF says it's 35 - 45. I have no clue why, but that's what I measure. And I have to thin HP Poly with 6% water to get the viscosity down to 45 seconds so that it will spray well with my 1.8 mm gravity feed HVLP gun. So unless your gun has a pressure assist there's no way it will spray well through a 1.3 mm orifice. GF's literature lists a 1.3 mm orifice but what they don't say is they used an air assisted HVLP gun.

At 45 seconds viscosity both those products spray beautifully; doesn't matter if I spray thin or thick, they flow out nicely with no orange peel or air bubbles. I typically spray at 65 - 70 F and 40 - 55% RH.

All said and done, unless your gun is air assisted you need a larger orifice. Maybe you should try a cheap gravity feed HVLP conversion gun like I use.

John

[Dustin Brown]

I'm not sure why the readings are so low. Fuji states it's a ford #4 cup that comes with it, I guess I need to find the dimensions and measure it to be sure. I start the timer as soon as lift the cup out of the finish and stop the time when I see the first break in the stream. Plain water runs through in about 8 to 8.5 seconds.

The Fuji T75G cup is pressurized. Maybe I'll try the smaller 1.0mm tip and see what happens, it's about the only thing I haven't tried yet.

A lot of people seem to report these finishes as being super forgiving, I really don't understand what I could possibly be doing wrong after trying so many things. I've read just about every thread on the internet concerning hvlp and water based finishes, including just orange peel and hvlp in general. Read nearly every manufacturer's website, internet guides, articles. I even bought the book/video by Jeff Jewitt. If I wasn't worried about who would answer my request, I would post an ad on craigslist to pay someone to show find out what I'm doing wrong. Either way, I've got a feeling I'm going to feel pretty stupid when all is said and done.

[Prashun Patel]

I just purchased the Fuji Semi Pro 2 stage and last week sprayed Enduro Clear Poly with it. My gun came with a 1.3mm needle. I did not thin. I was largely successful. I found I almost had to work at it to get it to orange peel.

Are you getting the orange peel on even the thinnest of coats? Or are you getting it only after you've applied many thin coats?

[Dustin Brown]

If I apply thin 2-3 mil coats it will show up by the 2nd or 3rd coat. If I spray a 4 mil coat it will show up after one coat on a perfect leveled surface. GF states to apply 3-5 mil coats.

Figures I would ruin something so easily, I always was an over achiever.

[Dustin Brown]

Here's my latest test. This was with the enduro clear poly thinning about 10% with the enduro extender. I also dialed down the airflow by about 40%, needle is about 3/4 of a turn out, moving about 6"/sec at 6" away. I did what the fuji tech said and sprayed a very light coat and 5 minutes later did a thin coat at about 4 mil. Seems to have leveled out much better, you can only see the orange peel around bright reflections but it's very light. I'm guessing I need to thin it down a little more, but I still get the air bubble marks. It looks like they develop shortly after spraying but not during. I'm guessing it may not necessarily be that the material is too thick to level out, maybe it's drying to fast with the dry air in my shop?

Still doesn't explain the problems I had testing the hp poly, I tested everything including thinning. Always ended up with worse orange peel or air bubbles, wth the enduro clear poly both at the same time. I don't know how so many people have no issues at all, thick or thin coats. Maybe I'll try another sample tomorrow and take some pics as I'm doing it, maybe someone can see what I'm doing wrong.

SprayTest-1.jpgSprayTest-4.jpgSprayTest-2.jpgSprayTest-3.jpg

[Jason Roehl]

That looks like "dry spray" to me. Too much air and too warm of air. There's no need to get super-fine atomization. What happens is that the tiny droplets start to dry before they hit the surface and can't coalesce as well into a smooth film, and excessive air can also cause the orange peel from pushing on a nearly-dry finish. In my experience with waterborne materials, 75ºF is pretty warm to start, but I suspect your bigger culprit is the turbine air--I've even heard of guys adding a second hose and coiling it up in a large cooler filled with ice water. At any rate, try turning down your airflow so that you get LESS atomization.

[John TenEyck]

I agree with Jason; it looks like your finish is drying too quickly, before it has a chance to flow out. Lower air flow and lower temperature air should both help. Adding some humidity to your shop would help, too, if you can.

Just so you know it is possible, here's what Enduro Clear Poly Flat looks like through my 1.8 mm HVLP conversion gun:

IMG_3451.JPG

John

[Dustin Brown]

I tried thinning it a bit more, probably about 15% now. Also cut the air down a bit more. Almost perfect leveling, but the air bubbles are worse...