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I think I figured out my painting problem? Help with PSI


Hemi Killer
07-03-2012, 02:39 PM
I had another thread about my painting woes. No matter what I did, the paint or clear would never settle and flatten out.

I started messing with my compressor and airbrush. I have a badger compressor. Its entry level. No switch, just turns on when its plugged in. I had to buy an aftermarket regulator for it also. So Im thinking is a cheapo, not sure what I paid for it.

anyway, I set the dial to 12 for Alclad, 20 for other stuff, etc. No matter what I set it on, when the button is depressed, it never had more than 15 PSI.

Im wondering if this could be the cause of my painting problems. I know most people spray this stuff at 20-30 psi


thanks

MPWR
07-03-2012, 03:34 PM
Increasing your spray pressure is not going to help to flatten out your paint. It's more likely to do the opposite.

If your pressure is too low, it will usually result in unreliable atomization of the paint. You'll be able to tell because the airbrush just doesn't feel like it has enough power to consistently feed/spray paint. Generally you want to spray with the lowest pressure that the airbrush and paint will spray at, and increasing the pressure much beyond that can cause orangepeel.

But if your compressor now won't generate above 20 or so, you may have a bit of a leak somewhere. Teflon thread tape (plumbing section of your local hardware store) is very useful for mounting regulators on compressors.

You might try adding more thinner when you paint, and spraying in light, wet mist coats. I hardly ever spray anything with more pressure than 15-20.

Hemi Killer
07-03-2012, 06:06 PM
Thanks for the help. The airbrushes have been spitting and sometimes every 3 seconds or so there is a break in the air. Theres no power switch im just kind of iver it. I have two identical paasche airbrushes so i know they arent the problem. Theres no leak i yhink its just a bottom of the barrel compressor.

I just got a good deal in a Grex i just picked up drom the LHS. Max psi is 60. Maybe thia one fix my painting issues all together but it will eliminate all yhe other annoyances. Ive had it six years So the upgrade is justified

stevenoble
07-03-2012, 06:35 PM
If it's the same Badger compressor that I started out with then its junk. It never used to get up to a good pressure and also when you sprayed the pressure would drop because it had no storage tank for the air. It used to use air as it was produced and it couldn't make it fast enough. I used to find myself waiting for the compressor to catch up all the time. Bought myself a better compressor soon after and it was the best move I ever made..

Hemi Killer
07-03-2012, 07:06 PM
If it's the same Badger compressor that I started out with then its junk. It never used to get up to a good pressure and also when you sprayed the pressure would drop because it had no storage tank for the air. It used to use air as it was produced and it couldn't make it fast enough. I used to find myself waiting for the compressor to catch up all the time. Bought myself a better compressor soon after and it was the best move I ever made..


brand new the compressor was no more than $70-$80. Thats what it seems like, it never produces enough air.

Archetype123
07-03-2012, 09:43 PM
I had the same sort of case...

I bought a sort of 'airbrush in a box' kit. It was a Testors setup... It was horrible to say the least.

But, what sold me on it was that it came with a compressor. Nothing fancy... Much the same as yours. Plug it in, flip the switch and it was 'on'. No regulator, no nothing. I thought this was the right way to do things. It was my first time holding an airbrush. The only thing I knew about airbrushing Tamiya acrylics is that I had to thin them. LOL.

This thing would shoot out what felt like 100PSI at times, it was brutal. My skills sucked a big one, the airbrush it came with was garbage, and I felt totally discouraged/disheartened.

Let me tell you this, this DEFINITELY the case of the bad equipment. The operator can only be so good before what you're working with just seems like trash. I bit the bullet... Got myself an Iwata HP-C Plus and an Iwata Smart Jet compressor.

With proper pressure settings on this bad boy, my results were night and day to my crappy old Testors piece. I don't want to say that spending the kind of money I did on an AB setup made me a better painter, but man, I really can't deny it. Results speak for themselves, and there's nothing like fighting with crummy equipment.

I liked it so much, I got myself an Iwata Revolution BCR to take care of spraying bodies (0.5mm needle/siphon fed).

Anyways, HK, I hope you solve your painting woes sooner than later. We've all thrown some kits in the trash (I'm guilty of it... double digits.:banghead:), but practice makes perfect. Best of luck. :wink:

MPWR
07-03-2012, 11:36 PM
The airbrushes have been spitting and sometimes every 3 seconds or so there is a break in the air.

That does sound like insufficient pressure could be your problem.

I bought a Badger diaphragm compressor like this-

http://images.craigslist.org/5I95K35Hf3Fc3oe3Hbc5k5f67ce582315122a.jpg

-many years ago. Well over two decades later, it is still going strong. I can't say it is the only choice or necessarily the best choice, but it has always been entirely sufficient for all of my airbrushing needs (once I added the regulator).

Hemi Killer
07-04-2012, 12:12 AM
one of the biggest problems was RIGHT at the end of painting my F40 for the second time, literally right before I stopped, it sputtered and shot chunks out. The cup wasnt empty. Its made more work for me many times, so Im happy to be done with it. The new one is setup and I will use it tomorrow.

CFarias
07-04-2012, 01:14 AM
When buying hobby style compressors it is important to get one that exceeds the pressure you would normally spray at. This is because you will loose pressure within the hose, the airbrush, from the paint and thinner, and especially through the regulator and water trap. A compressor that is rated for 25 psi may pump out 15 to 20 psi at the airbrush because of these pressure losses.

So it is a good idea that if one is going to buy a hobby compressor that a medium to high end model is selected and one that says right on the box what the pressure should be. I would recommend getting one that is rated for at least 100% more pressure than what one would expect to spray at. For example, if 30 psi is the desired airbrush pressure then a compressor rated for 60 psi should work.

As a side note...the pressure ratings for compressors are at the compressor outlet with no load put on them from an airbrush. And, the regulator is telling you how much pressure is going through it and not how much pressure the compressor is putting out (more than what the regulator says) or what the airbrush is putting out (less than what the regulator says).

Hemi Killer
07-04-2012, 01:49 AM
yeah this one is rated at 60 PSI.

With the brush held open constantly, it maxes out at 20 PSI, but if I feather it as I go side to side (like a spray can) it maintains pressure and only takes about 1 second to bump the pressure back up.

th regulator is built in. It also has an auto shutoff when it reaches the set PSI, it has a small reserve of air.

I need to work on my technique, once I get that down I think this compressor will be perfect.

CFarias
07-04-2012, 02:15 AM
Good luck and I hope things work out for you.

There are other options for hobby compressors if it comes to that. The home-garage style compressors that you'd find at the hardware store usually come with a tank, and almost always pump out at least 90 psi. These are great as they can be used for airbrushing and around the house for air tools and footballs and such, but they make more noise and are heavier to move around and are inconvenient for apartment dwellers. Still, they almost always come with a regulator and moisture trap and often times can be in the same price range as a hobby compressor.

I opted for a CO2 system. It is the ultimate in quietness since there is no compressor. A charge of CO2 lasts me two years and costs about $25 to replace. Also, there is no need for a moisture trap. It is heavy, but you can get smaller, lighter, CO2 bottles. A typical setup can cost less than $150.

stevenoble
07-04-2012, 06:06 AM
That's all good advice and I would agree to always buy a compressor that will give more pressure than you will ever need, simply because the compressor is not working as hard to produce the pressure you spray at if it can produce double or more the pressure that you need...

John18d
07-04-2012, 04:17 PM
Hemi killer - I live in an apartment and I use a 1/3 hp compressor with a 3 gallon tank that I got from "Harbor Freight" tool for about $50 on sale - it came with a built in regulator - a water/moisture trap cost an extra $14 with a pressure regulator built in - I've been using it now for about 5 years and it works great - it's not that noisy - none of my neighbors have said a thing or ever complained - they don't even know I use it as far as I know. The tank holds enough air at up to 100psi so that the compressor doesn't run that much - the tank has sufficient air supply to paint most things before the air supply runs out. two things to consider with any air spraying system is "pressure" and "volume" they are not the same thing - many people by those little "hobby" compressors, but are soon disappointed - the compressor runs full-time and the "air" spurts out of the airbrush "gun" in rhythm to the compressions of the compressor. The air pressure is neither "constant" in volume or pressure. Thus the results are poor. With my system which is really a cheap system The compressor runs briefly - fills the tank - the auto systems shuts off the compressor and I spray off the supply in the tank. When tank pressure drops to 50-60 psi it switches back on and fills the tank again. in most all cases I'm finished spraying the object "model" before the compressor turns back on. I get a nice steady constant stream of air plus I use a "micro" inline regulator right before the airbrush to make small changes to the air delivery rather than changing the line pressure at the tank regulator which is set to 40psi and I never change. pm me if you want to discuss any of this further - John

Hemi Killer
07-04-2012, 07:02 PM
Thank you John. I have a large compressor in my garage. I am not willing to set up my airbrush stuff in the garage because its 110+ 3-4 mnths out of the year here.

this is what I bought. It was an early Bday present from my wife.

http://www.grexusa.com/grexairbrush/products.php5?id=AC1810-A

John18d
07-04-2012, 11:10 PM
Hemi Killer - not to slant you, but I don't think you'll be happy with what you have. those type of compressors with no storage tank will not provide adequate "cfm" to produce overall quality finishes on the surface of a model. It will be satisfactory for spraying "very small" areas "one or two pulls of the trigger" but it will not be sufficient to spray a car body with paint or better yet clear. I may me mistaken, but the compressor that you have is more for a "nail polish" salon type use. The hp of a compressor will determine the psi it can achieve, but "cubic feet per minute" is a measure of volume and that has no bearing on the compressor's hp - when you pull the trigger on the compressor type you have the psi and cfm will fall to zero because it cannot maintain a constant "cfm". This is true of all small compressors and in general any "home/garage" compressor without a storage tank. Where the storage tank comes into play is it holds enough "volume of air" so that when you pull the trigger to spray a "car body" with paint or clear you will be able to pull the trigger 20-30 times before the psi starts to fall because the "cfm" volume has decreased. 20-30 pulls of a trigger has been plenty of "volume of air" to paint something in the modeling world and I have worked on models up to 1/8 scale without any problems. Give your unit a try, but I feel you'll be returning it if you want a compressor for general use for airbrush application. I understand your not wanting to spray in your garage - I used to live in Laughlin NV for many many years - very often the hottest place in the USA during the summer - and even here in Tucson our average summer day is 105 degrees Fahrenheit. I don't spray outside either, but for me my small unit with tank works indoors and I vent the over-spray thru my paint spray hood out the window vent so the apartment doesn't fill with fumes. I spray mostly "Zero" paints and 1K and 2K clears. I also use Tamiya "enamel" flat and gloss paints that I get from Japan. Hemi Killer - have you considered running a hose with a manifold containing a regulator and water/moisture trap into the house where you work on your models?? You could turn on your garage compressor when you wanted to use it and then turn it off when not in use, and this way you can work indoors? You will still need to vent the over-spray and VOCs as your house will become inundated with toxic fumes - especially if you spray anything like 2K clear or paints that use any type of catalyzer to harden the paint. Most all these types of finishes use cyanoacrylate "super glue" for the hardener and that is not good for the lungs. Hemi Killer PM me at your leisure and we can discuss this more after you try out your compressor. - John

Hemi Killer
07-04-2012, 11:39 PM
the compressor in my garage is on wheels. Certainly portable but way too large to go in and out of the house with. My garage is attached, but you cannot go from the garage to the house, you have to go outside, then in the front door, it's very annoying.

This Grex compressor has a small "storage" capacity. It takes a few seconds of full, constant trigger pull to get the compressor to click back on. If I feather the trigger, or pull the trigger as I go along the car body, then relase, then pull again to go down the car body the other way, that split second of trigger release is enough for the compressor to load back up. Does that make sense? Like when you use a spray can you dont hold the trigger all the way down, like spray left to right, then release, right to left, then release. That release allows the compressure to max out pressure, it's really quick.

If this doesn't work, I will move on to a small automotive compressor.

Its much better than what I had so it will work for a while. If worst comes to worst, I have an 8ft bench next to the compressor. I can bring a body or two out there and paint.

My wife's hobby is baking , so if I dont end up sticking with this one she can use it for airbrushing her cupcakes and stuff.

I appreciate everyone's input

John18d
07-05-2012, 12:05 AM
Hemi Killer - glad you can see the up side - give it a try, but with respect to your garage compressor - you don't have to bring it in the house just run a hose into the house and put a manifold with a pressure regulator and water/moisture trap on it and then you can use the air in the house with the compressor in the garage - do you understand?? - do you have a door from the garage to the inside of the house? you'll figure things out - if not just ask - John.

Hemi Killer
07-05-2012, 03:25 AM
Hemi Killer - glad you can see the up side - give it a try, but with respect to your garage compressor - you don't have to bring it in the house just run a hose into the house and put a manifold with a pressure regulator and water/moisture trap on it and then you can use the air in the house with the compressor in the garage - do you understand?? - do you have a door from the garage to the inside of the house? you'll figure things out - if not just ask - John.


yeah i got it. I'd probably have my electrician buddy route the hose right through the wall. After thinking about it I think the compressors (garage and hobby) share the same common wall. Might be perfect.

John18d
07-05-2012, 06:18 AM
There you go Hemi Killer - now you're considering options - I could be completely wrong about your new little hobby compressor and it will work just fine. I used to paint "real" cars and my superbikes that I raced here in the USA under CCS and AMA sanctions - the one thing I learned is you want a compressor that has the most hp that will generate twice the psi you will spray at, but what is more important is the cfm rating and if that is low then you need an air storage tank. - Best of luck to you - I know you have had several painting concerns lately. Also did you see my postings stating that Mac at Mac's Modeling is going to distribute "Zero" paints? He has already taken the first set of orders from people here in the USA as a test on the process and to figure out the shipping issues with FedEx - John

F1-Fan
07-07-2012, 11:42 AM
Since you guys are talking about compressors, PSI and paint issues, I would like to ask a question in regards to PSI.

Considering that you have a compressor with an air storage tank, which PSI I should use for each different paint?

Acrylics, enamels and lacquers?

I don't have a lot of experience painting with airbrush, I did acrylics using around 20 PSI and recently I did for the first time enamel with 40 PSI. In this one I had some orange peel and I will need to take care of the OP.

What do you guys recommend?

Thanks!

John18d
07-07-2012, 01:34 PM
f1-fan - everything depends to a point?? what type of spray gun "airbrush" are you using - gravity feed - siphon - single action - dual action - ambient air temperature etc - you really need to experiment with what you have - even the length of the air line has a bearing on the psi used. You need to experiment by trying different viscosities "thinness of paint" - distance from the object you are trying to airbrush etc. There are a few things I can advise you on - first needle and jet size on the airbrush has to do with the viscosity of the paint you are using no other reason - it is not to spray a "thinner line" for example. Second the air pressure at the gauge on the compressor is different than than at the airbrush when you pull the trigger you lose psi because when the air travels down the hose -it has friction against the "wall of the hose" and pressure drops. siphon type airbrushes require a little more psi because the air rushing out the airbrush nozzle has to also suck the paint up from the bottle. Gravity feed brushes work best in my opinion- I have both types but almost NEVER use the siphon type anymore. some people like the big bottle that holds the paint in a siphon type but I have gravity feeds with replaceable cups and I have cups up to 25cc which I have not needed to use yet. I generally spray at 10-15 psi for AlClad paint because I have found that excessive psi makes the metalic shine "blush" and look dull. I spray Zero paints when applying to something like a car body at 20-25 psi and when I spray 2K clears I spray about 30 psi because it is a little thicker and if I don't use enough psi it will splatter the clear out instead of a nice atomized droplet. Another thing to consider is that the psi is set so that the material "paint" you are spraying reaches the object before it dries. If you have paint buildup at the nozzle the material is drying to fast and you need a little more psi. Too much psi just wastes material "paints" as it blows around as overspray. It really is an art to master - there are books about airbrushing if you think that will help. In general you have to practice to gain experience - PM me if you want to discuss things more - I don't want to bore the rest of the forum readers - John

in my opinion your orange peel was from too high a psi - but it could also you being too close to the object or moving the airbrush across the object too slowly - either way you have excessive paint build up - John

Hemi Killer
07-07-2012, 01:54 PM
John, that single post has been more usefull to me than all the others combined. Not to take away from all the other good info ive recieved, but you put it in terms that make perfect sense to me.thank you

John18d
07-07-2012, 02:18 PM
John, that single post has been more usefull to me than all the others combined. Not to take away from all the other good info ive recieved, but you put it in terms that make perfect sense to me.thank you

glad you got something out of that Hemi Killer - airbrush "speak" can be confusing - I was a 1:1 painter on real items before my accident so I just applied what I knew there to my airbrushing and I have had very good results to date. Still painting of any kind takes practice. I learn something new or a new technique almost every time I do a model - John

F1-Fan
07-07-2012, 03:28 PM
glad you got something out of that Hemi Killer - airbrush "speak" can be confusing - I was a 1:1 painter on real items before my accident so I just applied what I knew there to my airbrushing and I have had very good results to date. Still painting of any kind takes practice. I learn something new or a new technique almost every time I do a model - John

John,

Thank you very much for your response and offer.

As Hemi Killer has posted, you gave us much more in a single post than everything I saw before.

Just to answer your question, I have two Badger airbrushes. A 350 single action external mix that I used to paint with enamel I mentioned before a the other one is a 175-7 Crescendo dual action internal mix that I used to paint with the acrylics. This one has the option to use the bottle or the cup, I used the last one because I was painting small parts.

Hemi Killer
04-04-2013, 12:39 AM
I'd like to follow up with my original issue here.

It turns out that my Paasche airbrush was the problem. Apparently you cannot run lacquer thinner through them or the factory seals can deteriorate over time. I have purchased the Grex compressor and Grex airbrush.

The Grex stuff is so much more effecient than what I had, I think I am just over doing it. I need to tone it down a bit. I have only used it a few times. My problem now is the ZERO base coat is leaving a very rough texture. I was shooting at 30 PSI or so.

I think part of my problem is going straight off everyone's advice as far as PSI. I live in one of the driest parts of the US, with pretty much zero humidity for most of the year. I am quickly finding out, with the proper equipment, that I am having to thin my paint more and use a lower PSI than most people will recommend.

I just ruined a body with 1k clear straight out of the bottle on 30 PSI. It was spider webbing I went back and tested a spare body (I got that backwards huh?) after thinning the 1k 50/50 and lowering to 18-20 PSI. MUCH better but I still need some practice.

This was all done with a 0.3mm needle. I am picking up a 0.5mm needle. Do you think the larger needle will help with my issue of the paint drying too fast? I am having to hold the airbrush close on low PSI so I'm worried about puddling.

Hemi Killer
12-18-2013, 04:13 PM
I wanted to revisit this and thank everyone for their help. I believe I have found the issue and overcome it.

The summer at 115 F definitely doesn't help. I have a Grex airbrush and I bought their inline thumb adjuster. So I basically turn the PSI all the way, then adjust the pressure with the thumb screw at the airbrush. Now I go by sound/feel only, I don't pay attention to the actual PSI. I was so focused on finding the right PSI before, trying to get an actual number, when in reality it doesn't matter. I can now adjust it almost immediately by sound and watching the spray come out.

I have painted the first model ever without anyone issues. I will be starting a WIP soon. 3 coats of paint and 4 coats of clear and it is nearly flawless after practicing a bit.

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