Author Topic: Look for microfoaming solution  (Read 9078 times)

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Offline usatu

  • Posts: 121
Look for microfoaming solution
« on: January 16, 2017, 07:06 PM »
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!

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Online tjbnwi

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Re: Look for microfoaming solution
« Reply #1 on: January 16, 2017, 07:49 PM »
What air cap set do you have in the gun?

Tom

Offline usatu

  • Posts: 121
Re: Look for microfoaming solution
« Reply #2 on: January 16, 2017, 07:54 PM »
I used the 1.3mm air cap set.
What air cap set do you have in the gun?

Tom

Online tjbnwi

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Re: Look for microfoaming solution
« Reply #3 on: January 16, 2017, 07:58 PM »
Did you just shoot this?

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

Shooting over Surface or bare substrate?

Tom

Offline usatu

  • Posts: 121
Re: Look for microfoaming solution
« Reply #4 on: January 16, 2017, 08:07 PM »
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!
« Last Edit: January 16, 2017, 08:33 PM by usatu »

Online tjbnwi

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Re: Look for microfoaming solution
« Reply #5 on: January 16, 2017, 09:41 PM »
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

Offline wptski

  • Posts: 443
Re: Look for microfoaming solution
« Reply #6 on: January 16, 2017, 10:22 PM »
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.
Bill
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Offline usatu

  • Posts: 121
Re: Look for microfoaming solution
« Reply #7 on: January 16, 2017, 10:57 PM »
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.
« Last Edit: January 16, 2017, 10:59 PM by usatu »

Online tjbnwi

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Re: Look for microfoaming solution
« Reply #8 on: January 16, 2017, 11:19 PM »
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

Offline usatu

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Re: Look for microfoaming solution
« Reply #9 on: January 17, 2017, 08:26 AM »
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

Online tjbnwi

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Re: Look for microfoaming solution
« Reply #10 on: January 17, 2017, 08:34 AM »
How about a few pictures?

Tom

Offline usatu

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Re: Look for microfoaming solution
« Reply #11 on: January 17, 2017, 11:27 AM »
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?
« Last Edit: January 17, 2017, 11:47 AM by usatu »

Offline JCLP

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Re: Look for microfoaming solution
« Reply #12 on: January 17, 2017, 12:26 PM »
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

Offline Tim Raleigh

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    • Oakville Cabinetry
Re: Look for microfoaming solution
« Reply #13 on: January 17, 2017, 01:04 PM »
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.

Offline usatu

  • Posts: 121
Re: Look for microfoaming solution
« Reply #14 on: January 17, 2017, 04:05 PM »
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?
« Last Edit: January 17, 2017, 04:08 PM by usatu »

Offline usatu

  • Posts: 121
Re: Look for microfoaming solution
« Reply #15 on: January 17, 2017, 05:19 PM »
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.

Offline JCLP

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Re: Look for microfoaming solution
« Reply #16 on: January 17, 2017, 05:24 PM »
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

Offline kcufstoidi

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Re: Look for microfoaming solution
« Reply #17 on: January 17, 2017, 06:48 PM »
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

Online tjbnwi

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Re: Look for microfoaming solution
« Reply #18 on: January 17, 2017, 07:07 PM »
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

Offline usatu

  • Posts: 121
Re: Look for microfoaming solution
« Reply #19 on: January 17, 2017, 07:45 PM »
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.

Online tjbnwi

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Re: Look for microfoaming solution
« Reply #20 on: January 17, 2017, 07:57 PM »
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.

That wet film looks heavier than 0.003" (3 mils). Shoot as you normally do, test the wet film, take a photo of the test area with the comb visible.

Don't thin the material, if anything go a little more viscous (thicker).

Best guess, decrease fluid to the nozzle.

Can't describe in words what it should sound like.

320

Tom

Online tjbnwi

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Re: Look for microfoaming solution
« Reply #21 on: January 17, 2017, 08:21 PM »
This is what you should see when you test the wet film.

5 marks, the base mark on the far right, 4 notches to the left off the gauge base. This panels wet film is 4 mils (0.004").

Back to the sound---if you have ever welded, your ears tell you when you hit that sweet spot with the settings for the medium and material.

Tom

Offline usatu

  • Posts: 121
Re: Look for microfoaming solution
« Reply #22 on: January 17, 2017, 09:22 PM »
I can't say enough to thank you for your inputs. I will restart tomorrow till I get this right  [smile]

About sanding, I found my surfacer probably sprayed too thick/ thin and orange peel showed. Can I get away by sanding with 320? The entire surface should look even and dull? Now I found dull and shinier spots are blended together. Don't want to overkill it but am afraid that I might not sand enough.

Online tjbnwi

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Re: Look for microfoaming solution
« Reply #23 on: January 17, 2017, 09:37 PM »
Surfacer is one of the easiest things to spray. You want it to go on evenly, each coat can be hand sanded very easily. Make it smooth to touch. The second coat will be pretty smooth on its own.

If you want a really nice pure white, Surfacer with KA+ clear over it.

Tom

Offline usatu

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Re: Look for microfoaming solution
« Reply #24 on: January 17, 2017, 09:54 PM »
I sanded the surfacer very smooth to touch. Why it still looks like orange peel from certain angles? What does it suppose to look like? Glass without shine? I will post pictures tomorrow for diagnosis.  This group is so friendly and helpful.
« Last Edit: January 17, 2017, 09:57 PM by usatu »

Online tjbnwi

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Re: Look for microfoaming solution
« Reply #25 on: January 17, 2017, 09:58 PM »
I sanded the surfacer very smooth to touch. Why it still looks like orange peel from certain angles? What does it suppose to look like? Glass without shine?

Should be flat.

Waterbourns need at least 12 hours to tighten up.

Tom

Offline Tim Raleigh

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    • Oakville Cabinetry
Re: Look for microfoaming solution
« Reply #26 on: January 18, 2017, 07:46 AM »
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

I agree, you are spraying to much paint! Do not box coat Kem Aqua it flashes off too fast. Dial back the fluid delivery knob.

When you spray too little you will get a dry spray or a very sandy gritty surface after the paint has dried.
« Last Edit: January 18, 2017, 09:36 AM by Tim Raleigh »

Offline wptski

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Re: Look for microfoaming solution
« Reply #27 on: January 18, 2017, 08:28 AM »
I'm confused which the norm for me but how did the OP spray too heavy if a wet film gauge was used, misread it somehow?
Bill
Most Confused!

Online tjbnwi

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Re: Look for microfoaming solution
« Reply #28 on: January 18, 2017, 08:56 AM »
I'm confused which the norm for me but how did the OP spray too heavy if a wet film gauge was used, misread it somehow?

Believe it or not I had someone tell me they thought that the proper amount of wet film would fill the vertical space between the 3-4 mil notches. Look at your gauge, imagine trying to get a puddle that thick.

Looking at the posted photos, my guess is he's at 8+ mils. The pocks are at least 4 mils.

Tom




Offline wptski

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Re: Look for microfoaming solution
« Reply #29 on: January 18, 2017, 09:20 AM »
Believe it or not I had someone tell me they thought that the proper amount of wet film would fill the vertical space between the 3-4 mil notches. Look at your gauge, imagine trying to get a puddle that thick.

Looking at the posted photos, my guess is he's at 8+ mils. The pocks are at least 4 mils.

Tom
I think the first time I used my Graco Truecoat Pro II handheld it was that thick!  [eek]  It was 1x6's supported to do both sides and started to paddle wheel fling the paint.  [big grin]
Bill
Most Confused!