Look for microfoaming solution

[usatu]

Hi- I am spraying tinted Kem aqua plus white and added the enduro extender by about 5%. Viscosity cup from fuji hvlp measured @25 seconds with extender added while @35 seconds without. It has a lot of microfoaming going on.  I am trying to find out the root causes and fix the problem. Any suggestions are really appreciated!

 

[tjbnwi]

What air cap set do you have in the gun?

Tom

 

[usatu]

I used the 1.3mm air cap set.

What air cap set do you have in the gun?

Tom

 

[tjbnwi]

Did you just shoot this?

How close are you, I find 8" is pretty good for KA+.

Shooting over Surface or bare substrate?

Tom

 

[usatu]

Tom-Yes, I just did today. I sprayed around 6-7 inches? I didn't warm it today as I thought it is pretty thin @25 secs. Am I wrong? Room temperature is 65 degrees. Can you please let me know your settings? My fan setting is about 6 inches and 3 turns for fluid control from close. It is over surfacer which I put on a few days ago and sanded on last Saturday.

BTW, I tried to get 3 mils in one pass but can't so I shoot in different direction second times to reach 3 mils. Is that also problematic? I see micro-foaming regardless whether I do that or not.

Thanks so much!

 

[tjbnwi]

Your distance should be okay, try backing off a little see if it helps.

Viscosity should be okay.

I find wet over wet to be an issue. You're better off going with an extra coat.

I use a 1.0 air cap set, 2-3 turns from seated.

Tom

 

[wptski]

All I can add I asked Fuji a while back how turns from seated is full open on a Gxpc gun and they stated, three turns.  I etched a witness mark on mine but its full seated position does change with each tip/nozzle set.

 

[usatu]

Thanks all. Actually I put a dot on the knob so I can know how many turns I did Fully open takes 5-6 turns probably.

Should I adjust the fluid knob to reach 3 mils in one pass? Somehow if I set to shoot for 3 mils and get runs and drips for vertical surface. Maybe overspray gets on the surface? It is very hard to control. Will I be Ok to get between 2 and 3 mils and do an extra coat after flashing? I do see a hint of orange peel in certain angle.

 

[tjbnwi]

How are you checking the wet mils?

If it is running/sagging you're probably over 4 mils.

I overlap approximately 50% on each pass.

Tom

 

[usatu]

I got a mill gauge to measure it. I sprayed on a sample board flat and then put it up to test.
Any good solutions to fix the pin holes in the base coat? Can I use the toothpick to dab a little KA+ white into the holes and then sand it? Thanks

 

[tjbnwi]

How about a few pictures?

Tom

 

[usatu]

How about a few pictures?

Tom

The worst one so far in first pic. The ones I sprayed wet on my wet have less problems.
Also would you think that is orange peel（pic 3 and 4） and need redo？

 

[JCLP]

The first photo looks like air getting trapped and popping through. I'm having the same problem and I was told to reduce the amount of air and back off from the surface. Also, you should be doing one pass when laying down paint, as I was told.
Cheers,
JC

 

[tiralie]

Hi- I am spraying tinted Kem aqua plus white and added the enduro extender by about 5%.

Curious why are you adding extender? Do you need to thin the Kem Aqua? Which Fuji system/gun are you using to spray with?

Any good solutions to fix the pin holes in the base coat?

Sand the whole panel and respray.

Can I use the toothpick to dab a little KA+ white into the holes and then sand it? Thanks

You have nothing to loose trying it. Likely will have to respray any way.

Also would you think that is orange peel（pic 3 and 4） and need redo？

It looks like from the photo, you have sprayed it too thick and the surface is drying and then crazing (surface film is cracking) as the lower portions dry. Sand and redo.

 

[usatu]

I just tried again with 8” distance and slightly less air time presuure. This time I got pin holes directly instead of bubbles. What will be the way to solvle this？ Go further？I dont understand [crying] Thanks so much！

Toothpick trick works fine but takes a lot of time. Can I fill the pin holes while paint is still wet？

 

[usatu]

The second coat is even worse. I fill the pin holes and wet sand andwith 400 grits and wipe ckean with water added DA. any step is messed up？ Please help！ I tried different distance and air flow ， but it doesnt make much anddifference. Out of clues now.

 

[JCLP]

I use to get that when I sprayed on too thick. It will be interesting to see what Tom and Tim have to say.

As well, make sure the coat underneath has dried completely. If you sanded the previous coat vigorously, the heat created by the friction of the sandpaper may have soften the previous coat in some areas, thus causing contamination. I learned my lesson a lot time ago, and now I sand lightly.
Cheers,
JC

 

[junk731]

I would start with a fresh piece of material, apply a SW primer, let dry and sand with 320P to knock the nibs off. Blow the piece off to remove the dust.  If you are stirring do so by hand and let set for at least 15 minutes before using. Make sure you're spraying at between 65 and 70 degrees. If you have to thin use water, 10% max. Spray a coat of top with no extender. This is my standard procedure for almost everything, the only disclaimer is I don't use a turbine gun, strictly compressor gravity PPS guns or AA and have very few issues.

John

 

[tjbnwi]

That is not micro foaming. Micro foaming is very, very tiny holes across the entire surface.

Best guess looking at the pictures you are spraying to heavy.

Don't wet sand, unnecessary. Sand between coats with 240 or 320 Granat. I use the ETS 125, DTS and RTS to sand between coats.

Just shot these. KA+ White Mid Gloss, tinted to match BM Navajo White, thin 2% by volume with GF Enduro Extender. T-70 bottom feed, 1.0 mm air cap set, can't tell you how many turns out on the needle, I set my gun by sound. Shop temp is somewhere around 65ºF.

Tom

 

[usatu]

The coat is @ 3mils. When you say too heavy, how do I get 3 mils without heavy coat? Should I thin the material little more or turn the fluid down a little? What kind of sound should I hear  [smile]?

I will sand (should I do 220 then 320 or just 320 will be fine) and recoat tomorrow.