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PostPosted: October 7, 2014, 11:59 pm 
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Joined: June 8, 2010, 8:02 pm
Posts: 621
Location: White Rock, BC, Canada
Hey guys,

So I've been fooling around with painting my car lately. I've never sprayed a car before and, as always, I made it difficult for myself. In this case by choosing a flat black (closer to satin really). So I'm 3 coats in now and while it's better, it's still patchy and has some stripes. So, assuming I am unable to get it to work out...... can you wet-sand and polish a flat/satin black and have it come up even? I realize it won't be flat anymore, but I'd rather even-looking semigloss black than patchy flat black. I worry that I wouldn't be able to polish the edges without burning through and having it still be uneven.

I will spray a test panel and give it a try first, but was hoping someone would be able to give input as to whether it's feasible or not. Paint is PPG Delfleet Essential flat black and is a single stage.

Thanks for the help.
Cory

PS: Do patchy spots even out over time? I'll probably wait until next winter to try polishing if I go that route.

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PostPosted: October 8, 2014, 2:54 am 
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Joined: July 2, 2010, 1:13 am
Posts: 431
Location: Phoenix arizona
I have been painting cars and doing bodywork for over 20 years and flat black is a pain in the donkey.You need a gun with a wide fan pattern and you need to overlap your coats.As for polishing it , no ..it wont work.My suggestion is sand it down and put black basecoat on then add a flatening agent to some clear and it will be much easier to get a non stripey blotchy paintjob.


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PostPosted: October 8, 2014, 10:07 am 
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Joined: July 6, 2009, 11:50 pm
Posts: 177
I have unintentionally polished satin black to a gloss. Last year I painted my zx6-r satin black, and after about 8 months of riding without a tank pad my jeans had polished the end of the tank to a gloss. There's probably a better solution though.


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PostPosted: October 8, 2014, 11:57 am 
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Joined: September 3, 2012, 10:48 pm
Posts: 336
Location: Hamden CT.
years ago I was a BASF paint rep . so being PPG is a totally different CO I will explain what works and does not as a BASF .

1st thing you should always do is read the TDS on the product your looking to use .
this will tell you just what fluid cap , needle and nozzle most of the time a 1.3 is best for low gloss colors .
the 1.3 is best because you want to atomize the paint droplets as small as you can to avoid stripping .
then your hardener and reducer is also very important .
you should go with a slow or very slow if the temps are about 70 F degrees . the reason why the gloss will tend to look different is one of two things most of the time . 1st the temps were different when you sprayed the two panels and the other is how wet you put the material down .
by spraying a little more of a little less material this will change the flash and dry times also changing the gloss . that leads into the speed of the hardeners and reducers and again how long it takes to flash off and dry .
if the cause was that the temps were different and you sprayed the same amount of product down in 6 months to a year the gloss will end up being dam close to one another as it gets to full cure .
when temps are talked about it's more panel temps the your air temps as when taking the temps you should take the temps of the panels and not so much the air temps .

when your getting stripping your getting it from a inconsistent over lap of your patterns on the panel .
I found a 60% over lap of my patterns works best for my gun speed and fluid at the tip of the gun .

in reality low gloss is very ez to spray ! there are just things a average sprayer will be doing wrong with all there spraying that shows up when doing candies , pearls and low gloss finishes .

when painting low gloss you spray the same way as you do with the pearls and candies . you start off the panel and work right off the other end never stopping of changing the line across the panel . you keep your gun speed the same and you do not change the distance from the gun to the panel .


as for trying to color sand and buff the panels it will not do anything but waste your time .
again because it's low gloss and it has a matting agent in it time will dull back out to the gloss you picked . and because it will not shine to a full gloss even after you buff it the stripes to just stay or come right back in no time .

the best thing to do is because your thinking of sanding it to buff it just resand it with 600 or 500 grit and spray another 2 to 3 coats over every thing again . this time spray every thing at one time and make sure your spraying technique is the same on every panels using the same hardener and reducer for the panel temps your spraying in .
things like if your spraying a panel from the side of the car do not lay it flat on a stand hang it as it would sit on the car .
often people will lay one side panel from the car flat on a stand and the panel that bolts up next to it will be hanging off the stand . then they go to paint the panel laying flat will get more material sprayed on it then the panel hanging off the edge of the stand they go to bolt the panels on the car and they have two different looking glosses or colors . this is because people tend to spray heavier coats on a panel laying flat then they do on a panel on it's side .
so orientate your panels as they should be on the car to paint them .


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PostPosted: October 8, 2014, 9:59 pm 
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Joined: July 2, 2010, 1:13 am
Posts: 431
Location: Phoenix arizona
We could give advice till the cows come home , but the bottom line is your going to need at least an iwata lp400 or satajet paintgun to get even half decent results, oh and more liquid to practice with, none of this is cheap.


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PostPosted: October 9, 2014, 8:14 am 
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Joined: September 3, 2012, 10:48 pm
Posts: 336
Location: Hamden CT.
I don't agree with the need of a high dollar spray gun to get the desired results .
it is very important to have a good spraying gun but more important is the tip size of the gun .
the biggest you can really get away with is a 1.3 once you get into 1.4 and larger the material will not atomize as it should coming out of the gun .

in my body shop we get all the low gloss finishes for 3 BMW dealers . they have there own body shops but the problem is that because low gloss finishes are not some thing the average sprayer runs into they then to screw things up . the fact that most painters/sprayers will only come across a low gloss finish at most once every 5 years they just don't get the time under there belts spraying the products.
there is nothing wrong with the average painter not knowing the in and outs of low gloss products they just don't come across them all to often .

things like when you buy a low gloss product you have to use it in a timely manner . if you spray some of the product when you 1st get the can of paint and then let the can sit for 3 plus months before you use it again you will not get the same gloss as you did the 1st time you sprayed it .
this is because the matting agent and even being not catalyzed it will still affect the gloss in the can .
so you have a very small window from the time you open the can to the time you have to get every thing painted out of that can . low gloss products are time sensitive .

in reality there are just some very simple things to know and then spraying and getting very good results is ez with low gloss products .


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PostPosted: October 9, 2014, 10:52 pm 
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Joined: June 8, 2010, 8:02 pm
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Location: White Rock, BC, Canada
Thanks for the input guys.

I was spraying with a 1.4 tip, which falls exactly in the middle of the suggested range. I wouldn't argue the finer tip would be easier. A much more experienced friend came over and hit the last couple panels for me last night. He ended up doing 3 very light coats to even out and compensate for the cheap paint gun. Those panels are as good as you could ask for a flat/satin job that was: sprayed in a barn, with a cheap gun/regulator, in what was effectively the dark (not near enough light).

I will drive it as is, and maybe next year spray it again with a gloss black or something that I can wetsand/polish my mistakes out of. I've gotten enough practice wetsanding now to be good at it ;) . I think I could spray something gloss that would look good enough for me now.

Thanks again.

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PostPosted: October 10, 2014, 8:56 am 
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Joined: October 19, 2012, 9:25 pm
Posts: 3365
Location: Summerville, SC
I'll never paint a car black. It shows EVERY imperfection in your body prep and paint skill.

Now white, green, or yellow, I'll rock those out on the lawn.
The MGA was my 4th open air, paint it on the grass job.
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PostPosted: October 10, 2014, 12:20 pm 
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Joined: September 3, 2012, 10:48 pm
Posts: 336
Location: Hamden CT.
this is the TDS for the 22 line (single stage ) glasurit low gloss black .
it has very little to do with PPG but the spraying of the two should be close .
it's always a good idea to get a TDS with the products your thinking of using . this way you can go thru the does and don't .

there is also another product we use allot and that the SEM rust-shield .
it Blows the POR products away by far at a much lower end user cost .
there are many good thing about it like it comes in colors . if your looking for a low gloss buy the flat black and then add in the hardener to it will then become a semi gloss black . we use a lot of the rust-shield most of the time on chassis as it's a top coat and under coat all in one so there is no need for priming . a Gal plus the QT of hardener will run you around 140 dollars . it's a one to two coat coverage it lays down very lice and is very user friendly . so it will not want to stripe like other low gloss blacks do . being a undercoat and top coat it also save money on the long run because of the time your saving no spraying many products but also the money on the products .
it will go right over aluminum and steel you can do your finish sanding in 180 or 220 .
we also use it allot on the insides of the race cars after we build a cage in the car. I tend liking to paint the insides of the cars gray because if they are black it's hard to see things and they are hotter . gray white and black are colors that will go with any other color so gray will also go with any out side body color and white is just to bright and gets to dirty to fast .
we have used the Rust-shield on the out sides of many race cars also and it does hold up real well !
when the car gets damaged we do our body work and spray two coats of the RS over it and that's it .


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