spraying problem

[brooker2008uk]

hi i want to spray gates and railigns and when i do im having a problem. i am using a sealey gold edition with a 1.4mm nozzle. the paint is quite thick and if i thin it 20% it gets stuck and comes out in blotches and in dribs and drabs. i have to thin it down well more than 50% but when it dries you can easily scrape the paint off with your finger. would i need a bigger nozzle to reduce thinning down so much or what should i do .the biggest available nozzle i can get for the gun is 2.0mm and i do not know wether it would help or not.

the spray gun i am using is Spray Gun Professional GOLD Series Gravity Feed 1.4mm Set-Up Sealey S701G

also just out of interest what black paint would be as close to powder coating match

 

[malcolm]

If you can scrape the paint off with your finger it's likely to be a paint or preparation problem. Which paint are you using and which primer?

If the paint manufacturers recommend 20% thinners for spraying it's possible your pressure is a bit low, or the paint isn't properly mixed. Or that it's just too damned cold out there. Nozzle size is mostly a CFM thing - bigger nozzle would need more CFM and would get things done more quickly.

 

[irondarren]

To get close to powder coating you will have to put it on the thick thats for sure which means minimum of a 1.7mm nozzle or better still 2.0mm

 

[jaykay]

use a primer and finnigan's smoth-rite.they do a thinners for it,but i always use cellulose thinners.never had a problem with it.

 

[Chipper]

I've got that gun though now use it for primer. 1.4 I'd use with 1k paints, the 1.7 with 2-pack, 2.0 for high-build primer but there's no hard 'n fast rules really. Needle and cap sets are cheap for 'em, like £7-£8 each.

Crucial thing though is what paint are you using.

 

[brooker2008uk]

ok so i would not need any bigger than 2.0mm then because if i do i would have to get another gun. also how do i get a real good thick coat on it so it would not scrape off so easily e.g the lock and the drop bolt. i have seen so many paints at the min and want to know which would be the best one to use so it would be chip resistant and also be a nice finish like powder coating

thanks

 

[brooker2008uk]

also i would also like the paint to be hard but not easily chipped and rub off round the drop bolt

 

[jaykay]

i think you will be over the top with 2.0 tip that shifts paint very fast and thick.
as for hard paint it will be more liable to chip,unless its powder coating.

 

[brooker2008uk]

but i can adjust the amount of paint coming out and also the only reason i need it is because the paint is thick e.g vinylast and on my 1.4 it gets clogged up and jams

 

[irondarren]

You will be extremely hard pressed to find a paint that doesnt wear off moving parts such as drop bolts etc. I have been doing it for years and havent found one yet.

 

[Chipper]

What he said. Maybe leave it with v.thin or no paint where the bolts go, and give a brush over after they're done up?
Looked up that paint, it says it's sprayable, so worth asking the manufacturer about setup - they should be able to give the % thinning and approx gun setup (bit different for HVLP and conventional so watch that).

 

[jaykay]

a old trick is to heat paint up,it thins it with out lossing the density.
do not heat it over a flame. stand it in boiling water.

 

[brooker2008uk]

ok the prob is still here and i am at my wits end what to do. im still using the sealey gravity fed gun and running the 100ltr compressor at bout 80 psi. the prob is one bit of the gate is all nice shiny and smooth and others are really dry looking and sort of rough and matt effect. if i was spraying a rail starting on the uprights and went from left to right, and when i go to do the other side the same way. one side is nice and smooth and the other is matt and rough and real dry. also if i sprayed onto the flat bar bits which were already sprayed, the bits which i spray down the round bars and hit the bits of flat it meets. these bits are nice and shiny and got gloss look but then makes the rest of the flat bar look duller and matt. i have an air filter and all on the compressor and water trap so its definately not water. i have not a clue why it is happening. i am using a 2mm nozzle and needle and spraying with rourkes vinylast paint gloss. can someone please help me

 

[brooker2008uk]

what i think the problem now is that when i spray one side of the rail it is drying too fast and so when i go to the opposite side it is depositing over spray onto the dried side. any suggestions on what to do or how to slow it from drying too fast

 

[brooker2008uk]

anyone????

 

[jaykay]

i would talk to paint manufacters my self.
how big are these railings?
i have found that more presser can dry paint out to fast.

 

[scarecrow]

ok the prob is still here and i am at my wits end what to do. im still using the sealey gravity fed gun and running the 100ltr compressor at bout 80 psi. the prob is one bit of the gate is all nice shiny and smooth and others are really dry looking and sort of rough and matt effect. if i was spraying a rail starting on the uprights and went from left to right, and when i go to do the other side the same way. one side is nice and smooth and the other is matt and rough and real dry. also if i sprayed onto the flat bar bits which were already sprayed, the bits which i spray down the round bars and hit the bits of flat it meets. these bits are nice and shiny and got gloss look but then makes the rest of the flat bar look duller and matt. i have an air filter and all on the compressor and water trap so its definately not water. i have not a clue why it is happening. i am using a 2mm nozzle and needle and spraying with rourkes vinylast paint gloss. can someone please help me

80 psi sounds very high for a HVLP gun. I don't know much about the paint that you are using is it a stone chip paint something like gravitex with these paint the proper thinners is vital and even then its hard to spray the only success I have had spraying this paint was with an cheep piston pump sprayer from Aldi

 

[Mr_Caine]

If the gun is HVLP which I think it is it should be running about 30PSI at the gun. At the 80 PSI that will be way too much air! Your gun instructions should tell you the correct gun air pressure. High air pressure = dry paint finish.

Get a bit of metal, lean it up against a fence, set the air pressure; a mini regulator at the gun is good for this. The spray a test onto the piece of metal, just an on off spray and check the shape and for any runs, adjust the amount of paint and fan shape accordingly, then move onto spraying your item.

If you're spraying synthetic it generally only requires 20% thinners (80:20 paint:thinners). I'm pretty sure Hammerite is a type of synthetic paint but check specfic requirements if using that. Heating it up is also good for helping flow but don't set it on fire! The type of paint you've got sounds like a synthetic and will benefit from thinning before going through the gun. Cellulose will tend to be 50:50 paint:thinners. 2K paint tends to be 2:1 paint:hardner but you could also add 10% thinners.

I've used standard kitchen all purpose cleaner to degrease parts, in a fairly concentrated mix with water, costs about 80p for 1.5l from Tesco. Abrade the item before painting to give it a key.