Can these defects be fixed by wet sanding? Runs and dust/dot

Discuss anything after that final masking comes off.

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PostPosted: Mon Dec 07, 2015 9:09 pm
Booki wrote:
When I finished putting down my basecoat, I went out of the shed and left it. Would have been a good 15-20 minutes of time between the base and clear.


Did you go over the car with a tack rag before the clear to make sure there wasn't anything on it? 20 min is a good flash time between BC and CC. I stay between 25-30 min.

Booki wrote:Yeah, when I was spraying my basecoat, I saw drops of water, i just blew them off and thought nothing of it at the time, they did not react to the basecoat in anyway. But I assume this must have been what caused the fish eyes, in my clear.


definitely water in the line if you have water coming out of the gun and that was most likely the issue, dirty water contaminating the surface and contaminating your gun on the inside. Did you use a new filter before the APR on the gun? I usually buy a new filter for every car i paint, they're about $3 at HF and work great. Again, next time blow the compressor empty a couple times before painting. Or buy a new air line, I bought a new one because i think my old one was just to contaminated, and old.

Booki wrote:This worries me alot, is there any quick fix's I can do? I would like to keep painting the whole panel too a last resort...its not a show car. If the majority of the fish eyes were removed, I would call it day.


Yea re-clearing can be a pain. If the craters have settled down to a flatter finish, wet sand them out with 2k grit and use some compound and polish on it to restore the shine. if they are even flatter now than the time they were from the picture, shouldn't be to much shaving of CC.

Booki wrote:Live and learn, I could probably get away with respraying the majorly effected area's that will be seen easily, but time will tell if they will come out with a sand.


If you gave it some good coats, 2-3 of CC they should sand out fine.
going to be a lot of sanding for those individual spots.
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PostPosted: Mon Dec 07, 2015 9:15 pm
Thanks for replying again mate.

But to make matters even worse. I think I made a even bigger mistake.

I mixed my clear at 4:1, the tin says 2:1!! **** me I don't think it will cure correctly now.

Now the job has turned into a nightmare!

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PostPosted: Mon Dec 07, 2015 9:28 pm
Well that sure is a bummer! my clear actually mixes 4:1.

i looked up what might will happen if improper clear:hardener is used.

http://www.camaros.net/forums/showthread.php?t=145650

I would think since it has less hardener it would take longer to cure but some say it won't ever fully cure. A pro will probably chime in and let you know exactly.
I don't think your mixing ratio had anything to do with the fish eyes though.

best case scenario, it does cure and you cut and polish it.
worst case scenario, it doesn't cure and you have to re-do the whole thing.
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PostPosted: Mon Dec 07, 2015 9:55 pm
I just got off the phone to manufacturer of the clear, they said even though I mixed it at 4:1 i twill still fully cure, it will just take alot longer then it should.

I was told to wait at a minimum, one week before sanding it, so will probably wait two weeks. Then after sanding it, leave it for another week after polishing to help the gas's escape.

But it will fully cure.

PHEW!

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PostPosted: Tue Dec 08, 2015 6:43 pm
Yes it will cure, just takes longer as they told you.

Just can't believe that such a basic mistake can be made. Above the paint mixing bench in my shop we have charts that I've made up of correct hardeners, thinners and mixing ratios for all the products we use. Within easy reach is a folder with the Tech Data Sheets for every single product. I refer to these regularly.

Anyway, all's well that ends well. It's a good lesson learnt. Not quite as good a lesson as the apprentice who cleared half a car after forgetting to put any hardener in at all. Took hime forever to clean up that mess and start all over again, but he never did it again. :wink:
Chris

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PostPosted: Tue Dec 08, 2015 6:54 pm
I cannot believe I made this mistake as well,

It was such a bad sinking feeling knowing I may have to take it all off because it will not harden! Not to mention just down right embarrassing...Makes me never want to pickup a spray gun again!

Hopefully I can sand out some of the fish eyes, but will be closely inspecting my compressor in the next few days.

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PostPosted: Sun Dec 13, 2015 3:43 am
Bit of a update - The major cause of contamination was what I suspected, my air compressor had some water in the tank. You could hear it sloshing around when I moved it!

Did a a small panel (headlight cover) to make sure it came out OK.

Image



There was approx one or two fish eyes in the piece, is that normal for spraying at home? or should there be none at all?



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PostPosted: Sun Dec 13, 2015 6:11 am
Depends... Fish eyes are usually cause by oils. Cheese burgers, compressor oil, silicone based products. If someone is outside using something and the over spray is sucked into your compressor inlet or fresh air source it can be your problem. Also your water and oil seperTor should be atleast 20 feet from the compressor. You should be able to sand a lot if not all the defects. Your halyards at part will be the runs. If not sanded correctly you will always see a halo of where they where.
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PostPosted: Sun Dec 13, 2015 6:46 am
20 feet??

Well, mine is basically ON the compressor...probably 10-15cm away from the outlet, I also run a small water trap on my gun before my air regulator.



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PostPosted: Sun Dec 13, 2015 8:24 am
Yes when the compressor is running its producing hot air and as it enters the air line it rapidly cools which cause moisture so u need to run it which ever way you can to give it room to cool then seperate the oil and water. If you have the space run it horizontily or multiple vertical runs with a drain at the bottom. Even if you put a drain at the bottom of a horizontal run then your separator is the best way.
Good work don't come cheap, cheap work isn't always good!
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