Afew First Time Spraying Questions

[Woodsy]

Excuse the messy garage, getting stuff ready for a garage sale.

Looks alot smoother etc now but as you can see its more a matt black than a gloss black, its meant to have a great gloss off the gun. Nothing like its pressure pack relation though which is great out of the can.

 

[Flyboy]

Looks good to me, looks pretty smooth to, bet that will transform into a really glossy finish once you lay down the clear.

 

[Woodsy]

thanks flyboy, i still want to give it afew more coats tomorrow i'm pretty happy with it tonight though!

 

[Guest]

Keep at it Josh, that should come up nice

My base colour looked crap finish wise until I got that clear going, just like Stan's saying now, so don't sweat it.

 

[twotimeGSr]

If you want a cheaper (than a new compressor) way to help extend your paint times buy a secondary air tank and hook it inline. You will not get any more flow from your compressor... but you will get a longer spray time in each shot.

 

[Woodsy]

Actually i'm not having any problems with the air supply, which i am quite surprised about.

Going to give it a block down this morning then depending how it comes up i'll either clear straight over it or do another coat or 2, but i have been told to get a really deep shine to mix the colour and clear 50/50 then thin it down as normal, then put more clear coats over that while its still wet. a good idea or should i just stick to my original plan? Any difference with spraying clear to spraying colour?

 

[Homie]

Wow, a lot of variables here! Most compressors have a low and high output rating somewhere on the data label. So many CFM's at 30psi and so many CFM's at 90psi, etc. The gun should have a so many CFM's at such and such pressure somewhere in the instructions. Newer High-Volumn-Low-Pressure (HVLP) guns require more air flow than older high-pressure guns. The compressor has to at least match the gun's requirements.

Generally speaking, a 1/4" line is too small. It will give you too much of a pressure drop along the line. A 3/8" line is the way to go. Don't put your primary water trap on the compressor. The air at the compressor discharge is still warm and the water vapor hasn't fully condensated out of it. I run a 25' length of hose from my compressor to my primary water trap. It gives the air time to cool and the water vapor to condensate before it gets to the trap. Always add a disposable water filter at the gun inlet.

The gun tip is determined by the viscosity of the material you're spraying. 1.2, 1.3 would be for thin laquers; 1.8, 2.0 for heavy high-build primers or latex; and a 1.5 for medium enamels and urethanes.

Then there is the paint itself. With today's modern paints SPYUG said it best:

You should get a product sheet with the paint that will give you all the info you need to set up your equipment, spraying and recoating times etc. Always refer to that.

Always, always, always refer to the product sheet. It gives you everything you need to know to spray that particular paint. It tells you how to prepare the surface and the paint, setup your gun (tip size and spray pressure (pressure at the air-cap, not at the compressor or gun inlet)), and spray it. It will also tell you the recoat time. If you are using a base / clear paint (and sounds like you are), some basecoats have to be cleared within a certain amount of time after spraying the basecoat. And speaking of basecoats, I don't know what color you're spraying, but if it's a metallic, sanding the basecoat can really screw up the appearance of the metallic flakes - it could make them look all splotchy and mottled.

 

[Woodsy]

Okay, went out this morning and sanded the tank down, it was abit rough in spots. I gave it 3 wet coats of gloss black again as the instructions say to do and it is looking realllly glossy now. It is still textured and not a smooth finish so what do i do now.... wet sand it to 100% then clear over the top? Or lots of clear straight over it as is, or my last option, wet sand it and then polish it without a clear?

 

[Homie]

Okay, went out this morning and sanded the tank down, it was abit rough in spots. I gave it 3 wet coats of gloss black again as the instructions say to do and it is looking realllly glossy now. It is still textured and not a smooth finish so what do i do now.... wet sand it to 100% then clear over the top? Or lots of clear straight over it as is, or my last option, wet sand it and then polish it without a clear?

If the finish is coming out rough and textured, here are some of the most likely causes: a) gun air/fluid control knobs incorrectly set - too much air and not enough fluid; b) holding the gun too far away from the work while spraying; c) too fast of a reducer/solvent for the temperature - paint starts drying before it can "flow out"

The narrative of your progess is a bit confusing to me. What exactly is the type of paint you are spraying? If you are spraying a basecoat of a basecoat/clearcoat system it shouldn't get glossy at all. It should only get to a nice satin lustre before you spray the clear. We all assumed you are spraying a modern catalyzed basecoat/clearcoat urethane. Or is it something else?

 

[Woodsy]

It is Jet Black Acrylic Lacquer, always has been.

 

[Homie]

It is Jet Black Acrylic Lacquer, always has been.

Acrylic Lacquer? Really? Okay, somehow I didn't pick up on that. Can't hardly get that stuff here in the States anymore thanks to the EPA (Environmental Protection Agency). Well then, from the sound of things, it seems as if things are progressing quite normally. Lacquer won't gloss up on its own. You have to carefully wet "color-sand" it smooth and then buff it to make it shine. The buffing is what makes it shine - you don't have to put any clear over the top of it if you do it right.

Remember, lacquer is very "thin" - it has practically no build and shows every little sand scratch. The more coats you put on it the better - if you don't have enough coats on it you can easily sand through an edge while color-sanding. After each coat you want to scuff it down smooth. When you have put your final coat on it then you have to progressively color-sand it down to at least 1500grit or finer. When you are done with that you buff it being extremely careful around any sharp breaks or edges where the buffer could "burn through" the paint. It should shine up like a diamond. When you are done, you can clear it if you want to. The clear will add "depth" to the shine and help protect the lacquer.

 

[Woodsy]

Here is the finish on it, as you can see its pretty textured, i did sand between coats too, Bonus is its glossy, which it should be. I dont know wether to sand it again and give it afew more coats or to wet sand it as is and polish it in afew weeks.

 

[Nessism]

Your spray is too dry. Possible solutions include adding more thinner to the mixture, tweaking your gun to shoot more material, and adjusting your spray pattern (gun movement) to throw more paint down on the surface. I'm not sure which is necessary in your case, but I'd play around more with the spraying and paint mixing process until you get the paint to lay down smoother. If you are using lacquer, you can just shoot more paint on top of what you have with no risk.

 

[Homie]

That's a pretty rough looking texture! Dry spray for sure. Paints not getting a chance to flow out before it starts setting. Gonna take a lot of sanding to smooth it out. To quote myself.......

If the finish is coming out rough and textured, here are some of the most likely causes: a) gun air/fluid control knobs incorrectly set - too much air and not enough fluid; b) holding the gun too far away from the work while spraying; c) too fast of a reducer/solvent for the temperature - paint starts drying before it can "flow out"

Nice thing about lacquer is that it's easy to fix. Sand that puppy down smooth using progressively finer sandpaper. Don't try and hog it all off at once - you'll wind up with noticeable sand scratches that will show. Once you got it as smooth as a baby's behind, start over again adjusting your gun, technique and thinner to produce a nice "wet" coat. I'd rather be too wet than too dry. If you get a run or drip its no biggie. cut it down with a nib file and sand it out. Sanding out a run or a drip is a lot easier than sanding out a tank full of dry spray.

 

[Woodsy]

Thanks for your help fellas it is much appreciated.

Tank was sanded down this morning, still cant get the gun setup right, paint i am using is mixed 1 part paint to 1.5 parts thinner, for use between 50-72psi, i had the paint adjuster wound all the way out and was still getting dry spray, so i played with the air pressures and spray pattern and was starting to get runs in the paint, so i'll adjust my speed and distance and go from there, the weather has now turned bad so no more painting today, going to try and find another larger nozzle for this gun, but getting them for any spray gun around here is quite hard, its probably easier to buy another gun.

 

[Homie]

For lacquer a 1.3 tip is ideal but you can probably get away with the 1.5 tip. You know the Hawaiian "shaka" hand sign with the thumb and the pinkie extended all the way out laterally? Hold the gun that distance (tip of your extended thumb to the tip of your extended pinkie) from the object you're painting. Adjust the fluid knob out a couple of turns and then the adjust the air knob to get a good elliptical pattern as tall as your "shaka" and a third to half as wide as it is tall. On your test panel, once you think you got it right you should be able to fully hold the trigger down for a full second and form a good wet pattern without it running on you.

I don't know if you're using a siphon cup gun or a gravity feed gun. If you're using a siphon cup gun a problem that I encountered once that resulted in dry-spray was the cup vent orifice that was clogged with dried paint. With the cup vent clogged no air could enter the cup to equalize the pressure which resulted in diminishing paint flow being drawn up the siphon tube and hence the dreaded dry-spray.

 

[Woodsy]

Okay i finnnnalllly had some luck spraying, paint was going on wet and realllllly glossy, i am still going to wet sand and buff it then the white line will either go down the middle or i might paint the sides of the tank white above the crease if that makes sense?

 

[Guest]

That looks much better... I think.

I'd still go the white line... but that's just my opinion

 

[Woodsy]

yeah i think once i have the white suzuki stickers on it will look abit less black

 

[Woodsy]

okay, laid afew more coats down, i think this is the best i'm going to get it off the gun.