Hot Rod Forum : Hotrodders Bulletin Board

Hot Rod Forum : Hotrodders Bulletin Board (http://www.hotrodders.com/forum/)
-   Body - Exterior (http://www.hotrodders.com/forum/body-exterior/)
-   -   hazing in the clearcoat? help please (http://www.hotrodders.com/forum/hazing-clearcoat-help-please-168080.html)

richard cash 11-08-2009 05:52 AM

hazing in the clearcoat? help please
 
I have a little issue with my clear and its bugging the hell out of me.

When i clear a car sometimes i get a hazing or fuzzy finish to the clear. Looking at the strip lights in the reflection of say a roof or bonnet it doesnt seem completly flat. Even after vigerous flatting with 1500/2000 and polishing. Sometimes the finish is like glass, others its quite fuzzy. Whats more annoying is that sometimes this wont happen for several weeks or months then it will dull slightly and produce the unwanted finish.

Its not massively noticable and ive never had a complaint from a customer about it but its bugging the hell out of me. Its obvliously more apparent in darker colours but i cant figure out what this is. It doesnt liok like solvent pop, its a much smaller problem than that but happens over the entire area. I thought it could be a water issue in the lines but i use quite a good water trap system. Im completly out of ideas and hope someone can help me out :confused:

oldBodyman 11-08-2009 09:29 AM

"Im completly out of ideas and hope someone can help me out "

have no idea which paint system you're using but will try

1) you're too damn critical, the customer is happy, so be it
2) some colors are formulated that way to match the factory look
3) wrong reducer-hardener-clear combo, read the tech specs for the system
4) mixing cross brand materials, DON'T
5) solvent burn, too much material OR too little flashtime
6) old finish absorbed the solvent and is out-gassing, primer or filler still out- gassing
7) the moon is in the seventh house and Jupiter aligns with Mars :thumbup:
8) it is just a car and it IS going to the scrape-yard, no matter what :evil:

Have tons of fun with it, then grab a beer.

SNTGreg 11-08-2009 09:42 AM

LOL Thats funny I don't care who you are

MARTINSR 11-08-2009 09:43 AM

There is one tip in your description, it happens on the top surfaces.
Some clears are worse than others, but when piled on they get "milky" turning a whitish look. And even if they don't turn white, as time goes by they die back because of all the solvent that is trapped there.

You don't get it on the sides because you aren't applying it as wet and if you did it would likely run all over the floor. But because they are horizontal surfaces you could pour it out of the can and it wouldn't run. So because of this you are applying it super wet.

One of the dead givaways in trouble shooting is admiting what YOU did different where the problem occured.

Brian

richard cash 11-08-2009 11:44 AM

oldBodyman, thanks for the reply. I think that i definatly do number 3 and 4 so will need to stop this.

MARTINSR, i take your point on board but i tend to hang my bonnets. I did a bonnet just last week and i hung it, definatly used the correct flash time etc and it noticed the problem the day after i sprayed it whilst i was polishing it.

BarryK 11-08-2009 12:11 PM

Everyone of your problems is caused by the base-coat and nothing else.

First these problems will always show up first in Dark green, Dark blue or black colors as they are about twice as slow to dry as most colors. A few reds, like guards-red will fall in this category also but only a few.

Cause by:::
*Either you are using a crappy system. (low grade)

*Using improper grade reducer for base-coat.

*Not letting base flash long enough between coats or before clearing.

Take you pick, its one of the three, how to test the theory? Let one of the bases set over night before clearing, that will compensate for a lot of errors.

All your problems are solvent related to base, contraction and traped solvent deep down, that is why sometimes it takes two weeks to show up, usually in first coat of base.

mitmaks 11-08-2009 02:47 PM

did you use 2K sealer? I was thinking maybe solvent in base/clear is reacting with body filler, etc underneath.

richard cash 11-09-2009 02:21 PM

i use 2k primer sealer yes with approx 10% or less solvent. I use 2k HS clear with no solvent. I use a mix of waterbase and solvent basecoat. Come to think of it, the last two colours i sprayed where this was apparent was a royal blue and black, both in solvent. I use the same slow speed reducer for everything.

The bonnet i did recently had a reaction with some previous paint and i had to dry flat this and spray the colour on really dry. I managed to get the colour on ok after about 10-12coats of real thin base, then cleared again with no solvent. The day after the hazing effect was quite apparent, probably the most noticable ive ever see it.

oldBodyman, your comments are the most interesting and i will definatly try leaving the base over night to see what happens!

BarryK 11-09-2009 03:34 PM

Yes those colors are the ones that cause the problems 99% of the time.

Remember, contrary to what the cut and paster moderators post on here (just a couple)
Humidity plays a big roll as to how fast the solvents get out, so when the humidity is high, it is very important that the first coat gets extra flash time.

A good rule of thumb is at 70 degrees 50% humidity or more first coat should flash 39 minutes.

Also with the blues and greens they tend to not cover as well and obviously if you now have 5-8 coats of base to cover there is a lot of solvents still trapped.

Worse part is when you see these contraction and hazing problems, they can also lead to poor shone chip resistance and or even de-lamination of the base, if solvents trapped in first coat or de-lamination of clear if just cleared to soon.

Water-base is even more critical.

Countilaw 11-09-2009 10:42 PM

Barry is right, most people rush to get the second and third coats on. What seems like 20 minutes of waiting is usually 5 minutes. You get rushed to get the job done and apply the next coat way to early.

The solvents (reducers) get trapped under the next coat and after 3 coats of base, that's a lot of solvent under there. It works it's way to the clear and clouds the clear. The next event will be delamination.

Frank Cox
[URL=http://www*****************[/URL]

jss 01-23-2013 11:11 PM

is this what we are talking about? I too have this problem

first picture is my problem

http://im1.shutterfly.com/media/47a3...D720/ry%3D480/

second picture is after a wet sand and buff

http://im1.shutterfly.com/media/47a3...D720/ry%3D480/

3rd picture 50/50shot

http://im1.shutterfly.com/media/47a3...D720/ry%3D480/

I am using the sherwin wiliams dementions base and clear.

this problem comes and goes for me. I am trying to narrow it down.

I am thinking to many base coats and not enough dry time.. first problem is the demensions base is so (water down) needs alot of coats to fill colour correctly.

I use to paint with the Sherwin Williams Ultra 7000 which was so great but can't get local no more. so working with what I can

after the clear is buffed etc I too see it come back to a little foggy after a week or 2.

base is mixed 2:1 and clear is 4:1 I am using a med hardner

temp inside is about 15c
its winter in canada so can't do much more in my paint room

TucsonJay 01-24-2013 01:26 PM

The last time I had this problem, I had used some PPG Concept paint that a customer had already bought. I sanded and buffed... but the orange peel and a couple sags came back!!!

I fielded the question about having the clear continue to shink over very long periods... and a guy who used only that system said to let it dry 2-3 months before i sand and buff!!! Screw that!

My own clear reaches a stable finish in 1-2 days, and never ever shrinks again! It might be the nature of your paint system, keeping it from being good for anything but force-drying... or requires a pefect mixture, ideal conditions, and flawless spray technique.

Personally... when a product proves to be too sensitive... I never use it again! }:-(

jss 01-24-2013 04:16 PM

whats a good system to go with for clear these days?

hard to find in my area solvent based stuff these days

AutoGear 01-25-2013 07:50 AM

Southern Polyurethanes Inc

SPI has been mentioned a lot on this forum and I believe they have a canadian distributor now which makes it easier for you. Someone with more experience will chime in shortly Im sure

33Willys77 01-25-2013 08:07 AM

Make sure you have a dry air in the hose when spraying and a good filter. Some high solids clear can actually trap moisture and air when being applied (very thick clear). Is the clear drying to fast? With the amount of orange peel, appears it may be drying too fast and the clear is not laying down flat. I have seen this with some Sherwin and PPG. I now use Wanda paint and I have superior results - plus I lay much more clear than most people do on a car because I am burying artwork. Make sure your flash times are correct - make sure the base is dry. Make sure your air pressure is high enough to atomize the clear.


All times are GMT -6. The time now is 08:42 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.