Spray guns

[cheapdouchebag]

ive been doing some automotive painting for a while. nothing special just tryna make bang for my buck. ive had a few failed attempts on spraying my own car in a few areas (doesnt relaly matter i only have sprayed real screwed up areas so i cant make it any worse) and ive painted a few of my friends car body parts (like bumpers, lips, etc.)
my car has the oem metallic B63P - harvard blue pearl found on many eg/eh sedans. and ive got a plentiful supply of paint and thinner leftover. its an acrylic based.

the problem is when i spray it on it always gives me a deep dark blue colour without any shine, even if i decide to use a real generous ammount of thinner. but when i spray my friends parts, it always comes out great (not A+++++ 10/10 rating, but real decent). their colours are usually a basic colour (black,white, red etc. nothing metallic)


ok enough introduction information, heres my question. i was wondering if anyone could agree/disagree with my theory and reason with any better approach.

ive been using this gun with my air compressor
http://www.northerntool.com/images/product/images/4598265_lg.jpg

im led to belive that because of this gun, my metallic flakes getting slapped onto the car's body because once i gave up, i couldnt be bothered emptying out the leftover paint mixure in a mixing container. few weeks later i managed to peel off the paint like a big chunk of jelly and noticed all the metallic flakes sunk down to the bottom. so on top of this chunk was a big dark blue area, and at the very bottom was a very shiny and metallic light blue. i think this is the reason why the paint that has been sprayed on my car lacked any metallic shine and was the deep dark blue colour.

was just wondering if i use a gravity feed gun, would this enable me to spray on with a way better matching colour?
http://www.northerntool.com/images/product/images/4519000_lg.jpg

your help is appreciated.

thanks.

[ekcoupe]

are you using a clear coat after spraying the paint? because metallic paints need the clear coat after to get the shine/glossy look or you can let the paint sit for a few days then light sand it, then use a cutting compound an rub that into the paint a few times an then polish an wax it, mine came out great

ive never used a spray gun so i dont know much about them

[cheapdouchebag]

yes im using everything i need. W&D various gritts, buffing compund, cut and polish compound. the whole lot.
the only problem is the colour is incorrect. even thoe i have taken my fuel tank lid off and had let the blokes run it through the scanner and my colour code to mix up my paint.

[ekcoupe]

hmmm thats weird, sorry im not sure maybe someone else could help.

good luck mate:thumbsup:

[Giraffe]

maybe your not mixing it properley .. look on the internet for a good mix ratio

[androo]

Not really related but what compressor are you using? Power? etc? Thanks man.

[cheapdouchebag]

cant remember the specs anymore, its been collectin dust from living in the garage for a few years now but yeah it is enough to spray my friends cars n shits.

[aznstyler]

use a garvity free gun

[Zilli]

^ you mean a gravity FEED gun right? can you elaborate your answer?

[gee-aye-dee]

pretty sure that when you spray colours with flakes/metallics you have to continuously keep the paint in the gun mixed i.e regular shaking/swirling. also are you mixing the paint long enough before you put it in the gun

[tiksie]

Okay.

Need to know the PSi your using and how many Litres the air compressor is, do you lose pressure over time ?

If you go to your compressor now, you will see what setting its on.. Usually count back 20-30 psi of what it's on, and that would be your spraying pressure as it drops when you open the nozzle of your gun.

After spraying anything, you should make it a habit to clean it thoroughly with thinners and make sure you release the moisture in the trap which is located usually under the air compressor, it will be a dial which you could spin in a anti-clock motion and it will release all the moisture that has accumulated.

Make sure you open up your gun and clean it thoroughly, also invest in a gravity fed spray gun, it will cost you about $100 for a decent one which will give out decent results.

It seems as if you are not prepping your surfaces properly, its best to take photos and let me know what steps you are taking (or not taking), that way its easier to pin point what you are doing wrong.

[cheapdouchebag]

well, im mixing in the measuring cup for about 2 mins with a screw driver, then in the spray gun and then im shaking it fairly hard with my finger covering small lid hole for about a minute as well.
yes it does loose pressure over time, because i dont think i know how to use(or if it does have) settings on my air compressor. it basically generates untill it hits maximum, then it stops.

thats when i spray onto the bumper.

and after it dropps to a certain psi, still fairly high, it automatically turns itself on and continues to generate the compressed air.
but still, usually i can get a coat done before it drops.

its a bit late, ill have a look at what psi it stops generating at, and where it dropps till and then continues generating. but my compressor is 2HP, i know its not recomended but i know it can be done.

what do you mean by im not prepping properly?

ive tried touching up once, ive researched that feathering is the only real way to have any hope in blending. so i have feathered the area

my definition of feathering - sand the area in the middle down a plentiful layers, sand down a few less layers on the edges.

i saw a few videos, that when people touch up, they dont bother masking the panel, allowing overspray.
i didnt, i just masked off the area and went painting a few real thin coats, and then it eventually stacked up and was too dark, with no shine, looked fricken opaque, shine a torch into it i cant see any metal flakes at all.

yes i do clean my spray gun all the time.
every time i use it before i slap on the paint i usually run straight thinner through the gun. and spray it. into the air dont worry im well aware of the risks breathing it in

[mocchi]

pressure depends on the gun. what type of gun you using? hvlp, lvlp, or just the old 40-50psi gun
you need a pressure regulator that screws on the gun, then shoot empty air and adjust the pressure while its open.

doesnt really matter abt the psi, its the cfm/lpm is what really matters. 17cfm+ should give good atomization. FAD. not cfm rating in piston.
your 2hp is probably only 8cfm max.

you cant see the flakes because it sinks at the bottom when you use suction feed. make sure you stir them properly before use?
and every time you wanna refill the gun, stir the paint again real good.

btw, dont sand metallic paint? my test panel didnt show any flakes after sanding and polish

[cheapdouchebag]

pressure depends on the gun. what type of gun you using? hvlp, lvlp, or just the old 40-50psi gun
you need a pressure regulator that screws on the gun, then shoot empty air and adjust the pressure while its open.

doesnt really matter abt the psi, its the cfm/lpm is what really matters. 17cfm+ should give good atomization. FAD. not cfm rating in piston.
your 2hp is probably only 8cfm max.


you cant see the flakes because it sinks at the bottom when you use suction feed. make sure you stir them properly before use?
and every time you wanna refill the gun, stir the paint again real good.

btw, dont sand metallic paint? my test panel didnt show any flakes after sanding and polish

how much is a entry-level pressure regulator (im talkin about maybe one of quality that WILL break down if used constantly unlike those that would be used by a panel beater)?

i have no idea what gun im using, just one thats lying around my garage. its suction fed and the pic i posted up gives a good look-alike. im under impression this came with the compressor as a kit.

and i dont sand metallic paint, only the clear coat. ive got a riddiculious test square of paint on my really crude bumper (dont worry, if i was to spray the whole bumper it would look a hell of a lot nicer than if i didnt do anthing at all). i will only W&D the acrylic clear coat

cfm shouldnt be a problem in my case i think.. my old man had his hands on diy on this car as well, he sprayed the roof without mixing thinner and by the time he knew he screwed up cuz the paint came out stringy he just clear coated and left it at that. i tried to fix it by sanding it down untill smooth and applies plenty of this 'fire-glaze' polish/buff compound and it really brought the paint up alot nicer (not the best, but acceptable and almost as good as oem paint). i think it just down to taking your time with painting and cfm wont be a problem. my theory i belive is true, but if im wrong please dont hesitate to correct me.

thanks for your help however i dont think enough information/education is in me before i try again.
still wondering about my theory of metal flake sinking being correct or not. could it possibly be beacuase ive thinned the colour too much that theres not enough viscocity in the paint to keep the metal flakes all over the paint pot? leading to all heavier particles (metallic flakes) sinking quickly

[mocchi]

how much is a entry-level pressure regulator (im talkin about maybe one of quality that WILL break down if used constantly unlike those that would be used by a panel beater)?

i have no idea what gun im using, just one thats lying around my garage. its suction fed and the pic i posted up gives a good look-alike. im under impression this came with the compressor as a kit.

and i dont sand metallic paint, only the clear coat. ive got a riddiculious test square of paint on my really crude bumper (dont worry, if i was to spray the whole bumper it would look a hell of a lot nicer than if i didnt do anthing at all). i will only W&D the acrylic clear coat

cfm shouldnt be a problem in my case i think.. my old man had his hands on diy on this car as well, he sprayed the roof without mixing thinner and by the time he knew he screwed up cuz the paint came out stringy he just clear coated and left it at that. i tried to fix it by sanding it down untill smooth and applies plenty of this 'fire-glaze' polish/buff compound and it really brought the paint up alot nicer (not the best, but acceptable and almost as good as oem paint). i think it just down to taking your time with painting and cfm wont be a problem. my theory i belive is true, but if im wrong please dont hesitate to correct me.

thanks for your help however i dont think enough information/education is in me before i try again.
still wondering about my theory of metal flake sinking being correct or not. could it possibly be beacuase ive thinned the colour too much that theres not enough viscocity in the paint to keep the metal flakes all over the paint pot? leading to all heavier particles (metallic flakes) sinking quickly

acrylic should be abt 60% paint 40% thinner. cfm is very important man, low cfm-high psi will get your paint to dry before it goes on the car giving dry sandy grainy finish or like fluff. low psi - high cfm gives you really nice spray (like hvlp guns that require 15+cfm @ 10psi) it makes lotta difference. try look at youtube and find SATA spray guns / patterns. then you'll know how important is cfm.

but still for budget like you, just paint whatever and sand the clear and buff it. should work fine.
as for flakes, make sure you stir.

[cheapdouchebag]

ive been going half half. maybe thats my problem. ill give it a go ill let keep this thread updated on how i go. thanks for help.


low cfm-high psi will get your paint to dry before it goes on the car giving dry sandy grainy finish or like fluff. low psi - high cfm gives you really nice spray (like hvlp guns that require 15+cfm @ 10psi) it makes lotta difference

on a last note, to beat the problem with low cfm- high psi, i can beat that by aiming closer to the panel and to prevent heavy coat n sag i need to spray faster than usual huh? ive never had the problem with sandy grainy finish but