Clear fog from overspray in booth causing dots in last coat of clear??

2

20mercury

Promoted Users
Question please but first much thanks to everyone on this super forum for the help and ongoing education on auto coatings!!! Best forum anywhere!!!

I just finished the last of 4 coats of Euro on my 72 Corvette and have a fairly large number of what I would call tiny dots (not bugs we know them in South La) not trash? I think it really looks like clear droplets?? Maybe??? Hoping this will cut and buff out. This is only on the horizontal surfaces; hood, tee tops, rear deck. Sides look great to me only very very minor trash. Where is this coming from? Euro overspray fog?

More info:
*Euro 2020 4:1:1. 4 coats 30 min+ between coats
*Clear gun Sata 5000 RP1.3 28psig @ gun 1 3/4 turns out
*Base was great IMHO 600 smooth tacked before clear with some base dust cleaned off
*Base was Diamont shot the day before w/SataNR2000 1.4
*Booth harbor freight tent with a/c blower w/ booth filters in homemade plenum positive pressure
*Turned blower off 30 sec after last clear coat
*cleaned and cleaned as I got a lot of trash in my 1st paint job on a 68 corvette about 6 months ago and wanted to try to do better

So looks like the Sata 5000 RP1.3 atomizes super but also I generated a lot of clear fog laying down clear. Had to stop, get out and start again after blower cleared it out. Is this norm? Or lacking enough air flow? And can settling or clearing out "clear" fog leave these dot imperfections?? Any thoughts are appreciated.
 

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Difficult to tell on a phone screen but usually tiny droplets could be water in airlines. Looks like trash to me tho. Almost too large to be water . Trash floats around in the air as long as fan is running and keeping it from landing on those flat surfaces. Vette looks nice btw. Friend had blue 72 t-top back in the 80s.
 
Hard to tell from the pics. My WAG is it may be water. Hate to disagree with Elwood but it's too even to be trash IMO.

What is your compressor and air line setup like? Looks like a lot of water going through the lines. Either that or really bad solvent pop. What speed reducer and activator? How warm was it there in LA when you shot it?
 
My best guess (GUESS)
It looks like oil and water vapors
Is it coming from the airline?
If you have an oil coliester and desiccant maintained, it can't be, and im wrong.
All you can do is sand out sand with 1000 wet, then 1500 to convert and buff.
The easiest way would be 800 and reclear, but if it is the filtration system, than that would be fruitless.
 
Chris_Hamilton said:
Hard to tell from the pics. My WAG is it may be water. Hate to disagree with Elwood but it's too even to be trash IMO.

What is your compressor and air line setup like? Looks like a lot of water going through the lines. Either that or really bad solvent pop. What speed reducer and activator? How warm was it there in LA when you shot it?
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Hi Chris and thanks for the response. Used 885 reducer and 80 85F when shooting clear so I would think ok. Compressor out goes thru a vertical serpentine (homemade) cooler with a column of desiccant at the end then 50ft 3/8 hose to diaphragm reg at gun. Only regulator is at gun. I have a couple of drain valves with collection pockets at the bottom of the serpentine bends. The first drain sometimes drains out a few tablespoons depending on humidity 2nd valve usually nothing. Dry day on clear shot.

Dumb question but what does solvent pop look like?

U right dots or flecks uniform on horizontal surfaces only sides look great me thinks
 
elwood said:
Difficult to tell on a phone screen but usually tiny droplets could be water in airlines. Looks like trash to me tho. Almost too large to be water . Trash floats around in the air as long as fan is running and keeping it from landing on those flat surfaces. Vette looks nice btw. Friend had blue 72 t-top back in the 80s.
Click to expand...
Much Thanks! 72 Bryar Blue one year color.
 
Barry said:
My best guess (GUESS)
It looks like oil and water vapors
Is it coming from the airline?
If you have an oil coliester and desiccant maintained, it can't be, and im wrong.
All you can do is sand out sand with 1000 wet, then 1500 to convert and buff.
The easiest way would be 800 and reclear, but if it is the filtration system, than that would be fruitless.
Click to expand...
Hi Barry and thanks for the response.
What does not make sense to me is why is this on horizontal surfaces hood/tee top/deck and at the same time the sides look good???
My nimrod guess is I am not getting enough air flow across front to back sweeping away this excess Sata RP5000 1.3 "fog" and some of the "fog" droplets are settling back on the horizontal surfaces but not the sides even though the fan is running?? BTW, I am spraying the hood first closest to air in and working away from the blower.
The clear fog is worst from the Sata 5000RP1.3 only and I have to evacuate and wait until it clears to resume. Base using the SataNR20001.4 is a little some fog but not nearly as much.

So how do you tell sufficient air flow absent fancy equipment??? If I take a cigar and watch smoke plume what kind of trail would you expect to see???

Had this problem on the 1st 68 Corvette paint job with same setup plus beaucoup trash and it cut and buff ok. So hope will be OK. I have learned buffing the s@$t out of the clear helps my boo boos a lot ha ha!
 
My guess is pervasive contamination from some kind of silicone containing material such as Armor All or tire shine having been used in the vicinity of this job.
 
my guess is solvent pop or you are dry shooting it and spraying over dry overspray .

after blowing up the pics you are dry shooting it . way too many dry spots so you need to practice on your gun handling. not enough there to buff as most of it went into the air. open up the gun until you get a nice wet pattern.
 
shine said:
my guess is solvent pop or you are dry shooting it and spraying over dry overspray .

after blowing up the pics you are dry shooting it . way too many dry spots so you need to practice on your gun handling. not enough there to buff as most of it went into the air. open up the gun until you get a nice wet pattern.
Click to expand...
 
Hi Shine! Thanks for the response and the feedback. OK this is helpful, need to be laying down a nice wet pattern. Maybe moving gun too fast plus more than 5-6" from surface? Hard to follow these body curves consistently. Soooo, at this point can I scuff and shoot more clear?? In what time window? And why do the sides look good I wonder?
 
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sides your shooting 90 degree , top your at 45 or so creating dry spray and thin coat. gun discipline is all important . set up your gun first. stay 90 degrees , and stay 4-6 inches off panel .
a run is much easier to fix than a thin dry panel.
 
Positive pressure just does not work in homemade booths. You really need negative pressure to evacuate the overspray as fast as possible. I’m a front yard hack and I use a negative pressure set up.

From the pictures your clear is going on really dry. I can see dry spots just in the thumbnails. This is prob from poor lighting and visibility once the room starts to fog up, and maybe overspray settling on the wet horizontal surfaces. It will probably help to change your set up and then just work on better gun control and overlap—-REALLY easy to say and hard to do.
 
Curious why you based with a 1.4 and cleared with a 1.3 ? Unless Euro is 'ok' with a 1.3,haven't used it,but would went 1.4 with everything personally.
The 1.3 was contributing to the dry spray as well imo.
Another question is,
What was the Humidity of the air your pumping in for the 'booth ? You said S. LA....
And, Filtration of it ?
And,
Another reason I have a Devilbiss bulb Air Filter At the Gun Inlet instead of a regulator,which is at the Gun hose supply end. I've screwed up a Lot of stuff but Never from contaminated compressed air thanks to a 5 buck lifesaver.
 
MikeK said:
Curious why you based with a 1.4 and cleared with a 1.3 ? Unless Euro is 'ok' with a 1.3,haven't used it,but would went 1.4 with everything personally.
The 1.3 was contributing to the dry spray as well imo.
Another question is,
What was the Humidity of the air your pumping in for the 'booth ? You said S. LA....
And, Filtration of it ?
And,
Another reason I have a Devilbiss bulb Air Filter At the Gun Inlet instead of a regulator,which is at the Gun hose supply end. I've screwed up a Lot of stuff but Never from contaminated compressed air thanks to a 5 buck lifesaver.
Click to expand...
No expert here, nimrod doing 2nd auto paint job. However, from doing some digging the Sata NR2000 is good for base 1.3 or 1.4. The 1.4 is said to be better for metallics and this Bryar Blue OEM color is a metallic. The Sata RP5000 1.3 is said to be a great gun for clear and as I understand it, is supposed to spray clear a little different than the usual 1.3 gun. Just passing along what I learned. My base did lay down great this time which I was happy about. The 5000 atomizes the clear big time and I have not figured it out just yet I think.

I did not check humidity but it was a clear early dry fall day for south Louisiana, 80 or 85F.

Filtration: I used paint booth filters (9) in a homemade plentum before an a/c blower I had into the tent booth. So a positive pressure setup which I thought would be better. Might try setting up some fans as Lizer suggests to get the overspray out as quick as possible which sounds directionally correct to me.

Interesting on the Devilbiss bulb air filter. Might try that for next time.

Thanks for all the responses and helpful feedback from everybody. I really like this auto paint work and will keep working to get better. This second one is better than the first, LOL's, so it is possible to improve ( I hope!)
 
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RosharonRooster said:
So u got 1 squirrel cage fan clearing out the overspray?
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Yep, 1 squirrel cage blower out of my 5 ton a/c unit when the a/c guy changed out the inside evap setup. I wired it up for lowest speed as I was thinking it might be too much air flow plus the plenum filters choke it down some.

If I held a cigarette smoke in the middle of the booth, what kind of plume would you like to see with the right amount of air flow? And the air flow might not be the issue anyway after talking with Barry today. But curious about what air velocity is considered good?
 
Well I'm not pro and I paint in a "paint room" in my backyard, but I've learned all kinds of ways to get good results. That is not enuff air moving. Reminds me of when I painted a car using 1 box fan. 29 psi clear, after about 15 seconds I couldn't see what I was doing. I've upgraded exhaust and now it clears out in 15 seconds or less. Best results for backyard paint jobs are going to happen when the sun comes up. Around 6am. I like to be spraying base no later than 7am. And clearing around 10am, Like others have said, alot of dry spots. When I spray I don't stand behind the gun, I stand about 45 degrees from the gun so I can see the clear hitting the panel. Small droplets filling in. (Learned that on here) that's alot of car to paint at one time without a booth, and better lighting, throw in inadequate exhaust and there's alot of room for error,...could cut and buff out maybe start on one of the headlights. 1000 grit. Sand it and buff it all the way thru and see the end result. If it don't fix it. Then 800 the whole thing and 2 more coats and will slick out much easier. And quicker. I recently flowcoated my first panel and was blown away how the clesr laid and looked like glass after 1 thin coat. Backyard hack disclaimer.
 
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