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Car Painting - Spray-gun Basics

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http://web.archive.org/web/200702122...dcoat/app1.htm

 

This is a link to PPG's website that I believe would very helpful in getting some basic knowledge to help with your painting.

 

It describes:

 

atomization

fluid at gun adjustment

provides spray gun parts and function in a schematic drawing

Show correct and incorrect spraying techniques

 

Just to name a few!

 

Moderators - would it be possible to make this a sticky please?

 

Thank you!

 

Ernie/RacerX

Edited by Drax240z

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Guest MyNew3oo

You do not know how much this is going to help me when I paint my bumpers and hood.

 

(Quick question and you can re-direct me if this is the wrong thread.)

The clear is coming off my 300zx on the hood. I want to bring it down to the paint, without harming the paint. If you could give me a few tips that would be great. Also, if you know of a good clear coat that does well with being washed, and waxed, that would be awsome.

 

Im new to the Zeds but I love my car ten times more then the E30 I had.

Any help is good Help.

 

Thanks Ty

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Just thought i'd help revive this sticky.

 

I have personal "backyard" experience with PPG DBC (Deltron Base Coat).

 

Here is my personal story on painting a very large bodykit on my Lexus LS400. It took some time but I managed to complete the painting. This was all done in the backyard in HOT, DRY weather (in San Diego).

 

I purchased my basecoat paint at Tri-City (they have a website). I gave them my paint codes and they mixed the paints on the spot. I had no idea what I was in for. The counter guy asked me what kind of paint I wanted and I said PPG. He was like...ok... and I told him that I was not familiar and he was more than happy to help. So we ended up choosing DuPont PPG DBC. I also purchased Wax and Grease remover and a mask. I went away spending about $150. on 1 qt base, 1 pt base, 2 bottles of reducer and the W&G Remover and mask.

 

I ordered my primer and clear from SPI (Southern Polyurethanes). I purchased regular grey primer they sell and their Euro Clear. This set me back about $200 for everything including reducer.

 

So i have everything paint-wise now. I purchased a stirrer from harbor freight. I'd recommend at least 3 stirrers. 1 for each color/clear/primer.

 

Application:

My gun is a cheap purple HF gun. Do a search loads of info.

Scuff the surface (in this case FG) with 400 grit.

Clean thoroughly.

Apply primer.

Wetsand Primer.

Apply more primer.

Wetsand primer.

Repeat till happy with primer coat count.

Let dry overnight.

Clean thoroughly before applying base.

Apply base.

DO NOT WETSAND.

Apply base till coat count is to your liking. *This isn't really important because it's really all about your clear.

Let base cry for about 30 minutes.

Apply Clear.

Let dry to tacky.

Apply clear.

Let dry to a dry touch.

Apply clear.

keep going through the motions.

Let sit for 1 week.

Westsand with 2000 grit.

Polish with buffer using a ~2000 RPM spin and Turtle Wax rubbing Compund. Careful with burns on edges and corners.

Follow up all with Turtle Wax Polishing Compound.

 

This is a quick rundown. I did it and my paint came out almost as good as OEM. I will tell you that it truly is all about prepping.

 

Chris

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What Grit do you wetsand your primer coat with? and with your base coat, if you end up with a drip or obvious imperfection, can you sand it out if you're going to spray another base coat over it? How long between base coats should be waited?

Edited by Drax240z

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I wetsanded the primer using 1500 grit. Also, kept it wet with a spray bottle of water/soap. You can sand down all imperfections in the primer. I would not recommend wet sanding the base coat.

 

Wait time between base coats depends on the paint. Look at the data sheet to find out that info. The sunnier and drier the weather, the faster it will "flash".

 

Hope that helps!

Chris

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I had a paint shop tell me that if I brought my car in primered that I should sand it lightly at 300 grit so they had a surface that the paint could adhere to.

 

LMAO at this very bad idea. You need to avoid that paint shop if you want any type of quality work done.

 

Base coat (three stage) is applies only as good as the surface it is applied to. You will see all the imperfections (sanding marks) in the primer underneath the base coat paint. I understand if you scuff the body metal with 300 grit. Usually a high build primer can cover those sanding marks.

 

Unless the body shop is going to spray house paint over the primer, I don't recommend scuffing it with 300 grit.

 

Chris

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wet 600 by hand is okay on a primer as long as there is a pad between your hand and your paper to avoid grooves your hand can make while sanding, a stiff foam block works best, your local paint store will have a few different types of these. if using a DA (dual action sander) with an interface pad 400 grit dry works too. IMO 1500 is over kill, on a 2K primer you'd be there for days trying to flatten that surface. I paint B/C over DA'd dry 400 grit primer every daynwith no problem and have terrific turn outs. Avoid dry sanding by hand on primer though, your hand creates heavier pressure on the primer and digs deeper into the primer and you will see those scratches in the basecoat.

 

As for wet sanding basecoat... never dry sand B/C....NEVER. You can WET sand an imperfection (i.e. drip, run, large dust specs, bugs (yes I've run across this) etc.) with a minimum of 1200 grit sand paper. 3m Trizact paper is an amazing friend when you run into an imperfection, but always wet and be sure you try not to burn through the b/c and when repainting the sanded area fog the b/c out far around that spot to blend the b/c back together. a word of caution, metallic b/c is much harder to fix an imperfection on than a solid base, but it is very do-able.

 

hope this helps any who read.

 

cheers

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Yes, ALWAYS use a backing pad or sanding block. You dont want to finger **** your bodywork. 600 grit sanding of primer is fine. basecoat will cover 400 grit but to be on the safe side wetsand using 600. DO NOT SAND BASECOAT, especially if there is metallic in it, you will cut the metallic flakes and it will look terrible. I like to do 3-4 coats of clear with a wetsand and polish at the end. Wetsand using 1500 grit and a multi stage cut/polish system

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Yes, ALWAYS use a backing pad or sanding block. You dont want to finger **** your bodywork. 600 grit sanding of primer is fine. basecoat will cover 400 grit but to be on the safe side wetsand using 600. DO NOT SAND BASECOAT, especially if there is metallic in it, you will cut the metallic flakes and it will look terrible. I like to do 3-4 coats of clear with a wetsand and polish at the end. Wetsand using 1500 grit and a multi stage cut/polish system

 

 

 

 

yes sanding metallics cuts the flake and yes it will look horrible if you leave it but i wrote to repaint backover it and blend it back out to bring it back and then continue and if done correctly its a no harm no foul correction. by no means sand it and clear it...

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how much money does one save painting their own car approximately as opposed to bringing it already prepped to the paint shop?

 

Sorry I did not see this sooner.

 

It basically comes down to how much is your time worth? After doing my body kit and not having the proper facility, I decided that next time I do this I would get it done by a pro. This is exactly what I did. I needed two fenders and a front bumper painted recently and the shop (San Marcos Collision Center) charged me $300.00 for all three panels. The parts were done in ONE DAY. I brought it in Monday morning and I picked the parts up Tuesday morning.

 

So in all, if you want the "experience" then DIY. If you don't want to go through the troubles, then take it to a shop.

 

Money saved is dependent the shop that does it. For me, San Marcos Collision (in California) was the best quote. Other shops were charging roughly $125-$175 per panel.

 

Thank you

Chris

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The fluid control knob will allow you to adjust the distance that the fluid needle will travel back, away from the fluid tip, with each pull of the trigger. By setting this control all of the way open, you are allowing the full amount of fluid that the fluid to pass through the nozzle opening. To set the fluid adjustment, start by unscrewing the fluid control almost completely. Next, pull the trigger back to the full open position, and screw the fluid control in until you feel a force from the back side of the trigger. Setting the fluid adjustment in this manner will allow full-fluid volume to exit your spray gun.

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I painted my first car last fall, it turned out much better than I expected. All said an done it took about 80 hours to complete and around $800 for the gun, paint and misc. supplies (sandpaper). It was a Corvair Convertable so it's about the same size as a Z. The car had old laquer paint so I stripped it to bare metal to avoid adheasion problems. Here's a few things I learned;

 

1. Dust control

2. Dust control

3. Bug control

Almost all the visable flaws I have came from dust or bugs.I swept my garage twice then put up plastic sheeting on all surfaces and taped and stapled all joints then vacuumed the floor yet I still came up with some dust in my finished product. It must have come from the car itself or from my clothes (I didn't wear a tyvac suit). After my second clear coat I noticed a giant mosquito stuck to my hood! I painted at night and the lights in my garage drew bugs in.

4. Ventalation

I had a box fan with a furnace filter upstream set up to blow air into my paint booth. It was not enough. While I was clear coating a dense mist almost obscured my vision. Next time I will rent a ventalator or two like they use to dry wet carpet, they move a lot of air.

5. Practice

Watch a lot of utube videos and practice on whatever you can. I had an old washing machine that is now a nice silver/blue semi metallic.

6. Don't do a metallic for your first paint job.

The counter guy chuckled at me when I told him my paint code and it was my first time. It turned out well though, a little 'tiger stripe' on the hood where my coverage wasn't perfect ( I'm the only one that sees it). Refer back to #5.

7. No paint can cover poor prep.

Prep is where 70 of the 80 hours went.

8. Beer will NOT prevent paint job issues, only ease the pain once it's done :icon7:

 

I will definely paint more cars, the diy pride is really worth the work. I crused the local Maaco holding area and their work looked flat and lifeless where mine shines. 

 

 

 

 

post-33376-0-61892600-1367806733_thumb.jpg

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