Question about pressure on a compressor.

[Exist2Resist]

I bought a compressor from Amazon, and it does not have a tank. It's a pasche branded one.

The reason I bought one without a tank is because prior to doing so I watched a video of the owner from Badger saying a tank is not necessary.

Now mind you I'm no expert, and so far I've been only practicing lines, dots, and shading in black. Doing this over the last few days I noticed that my pressure had been dropping below 20 PSI. The reason I noticed this is because if I'd do a continuous spray/line it would get lighter to the point of disappearing, even though my distance from the paper does not change. When I looked down at the PSI gauge it would drop below 20, and I set it to 40 in order to work with 30 PSI. There is a bit of a drop of when I start the airflow.

When I was working today I also noticed that I'd have breaks in my spray.

I'm using Aztec airbrush paints, I try and keep the tip clean, and I have yet to buy tip juice/lube.

My question is is this due to the lack of tank, or could this be due to something entirely different?

 

[markjthomson]

I expect so - I'm not sure about the paschee but the high quality tankless ones are expensive to get good working ones. Even a small tank is better than none. Perhaps you can set a small one up.

 

[Amra]

I watched that video and Ken is partly right...

One of the reasons people wanted a tank in the past was because they would find the airbrush "pulsed" when hooked directly up to the compressor. This was because older compressors ran at a lower speed and typically had a larger diaphragm. With those older compressors, the air coming out of the nozzle of the airbrush would often have a constant fluctuation when used without a tank. This is what most older people are referring to when they talk about the air pulsing without a tank.

However most modern compressors use pistons and higher speed motors. These newer compressors are more than capable of keeping up with the CFM demand of the airbrush, and the hose itself is usually enough of a buffer to prevent pulsing, keeping the air coming out of the nozzle at a fairly constant pressure. So when he says there is no need to have a tank because the air doesn't really pulse, hes mostly correct.

However, modern compressors are not without their flaws. The biggest reason I recommend having a tank is the consistency of air at the moment of pressing the airbrush trigger.

Modern compressors usually pump up to their preset pressure, then release the pressure in the head of the compressor (known as unloading) They do this because one of the flaws of compressors (new and old) is that if the pressure inside the compressor head itself is too high, it will act against the motor, pressing against the diaphragm/piston and holding it in the down position, and the motor might not be strong enough to restart if there is 60-100psi pressing down on the shaft of the motor. By unloading the compressor the head has no pressure, meaning the motor can move freely and get a running start, as once in motion it has inertia and angular momentum to assist it when the pressure starts building (some low HP motors will still stall if the pressure in the head gets too high).

Because of this, when you first press the trigger of your airbrush, the pressure in the line is quickly released, dropping the pressure and signalling to the pressure switch to turn the compressor on, but it takes a few revolutions of the compressor for the pressure build back up and stabilize. Meaning every time you press the trigger of your airbrush, there is a burst of air, then a sudden drop of pressure, then a slight delay followed by a spike of pressure. so every time you press the trigger you have to wait a moment for the pressure to stabilize before using the second action of your airbrush.

Having a tank eliminates this issue, and is one of the main reasons I prefer to have a tank.

Another reason people like a tank is that it allows the compressor to 'rest' more often, as you are using the air in the tank, and the compressor only refills the tank as necessary. This means the compressor tends to run less often, giving it time to cool off a bit between refills, which might increase the life of the compressor. Without a tank, every single time you press the trigger of your airbrush the compressor starts running and runs non-stop, so if you paint for several minutes at a time the compressor will get extremely hot.

That is the second reason I like having a tank. There may be other reasons, but those are enough for me.

 

[haasje dutchairbrush]

When I was working today I also noticed that I'd have breaks in my spray.

That sounds more like an airbrush or reduction problem than one with the compressor (just blow air into your hand a while to see if it "pulses" as that, I think, is the only way in whicht the compressor could cause that.

 

[jagardn]

That sounds more like an airbrush or reduction problem than one with the compressor (just blow air into your hand a while to see if it "pulses" as that, I think, is the only way in whicht the compressor could cause that.

I agree. A tanks is always more consistent than not having one, but yours sounds like a reduction or maintenance problem.

 

[Exist2Resist]

That sounds more like an airbrush or reduction problem than one with the compressor (just blow air into your hand a while to see if it "pulses" as that, I think, is the only way in whicht the compressor could cause that.

Reduction problem?

 

[Exist2Resist]

I agree. A tanks is always more consistent than not having one, but yours sounds like a reduction or maintenance problem.

I filed a return with Amazon, for $50 more I can get a generic compressor with a 3L tank and dual compressors.
I'm going to pick that one up next week.

 

[haasje dutchairbrush]

Reduction problem?

The less likely of the two, but:
-too thick paint could build up and block a bit till pressure forces it all out
-paint not mixed propperly or with a reducer that doesn't mix, blotches of paint followed by water/reducer giving the impression the paint doesn't flow constantly

Another thing that just came to mind, water in the airhose (although that would probably result in a more "splatter" effect)

 

[jagardn]

Reduction problem?

Paint reduction ratio.
If not reduced enough, you can have inconsistent spray issues.

 

[Exist2Resist]

The less likely of the two, but:
-too thick paint could build up and block a bit till pressure forces it all out
-paint not mixed propperly or with a reducer that doesn't mix, blotches of paint followed by water/reducer giving the impression the paint doesn't flow constantly

Another thing that just came to mind, water in the airhose (although that would probably result in a more "splatter" effect)

Paint reduction ratio.
If not reduced enough, you can have inconsistent spray issues.

I'm using TESTORS Aztec Acryllic paint meant specifically for airbrushing. I'm not reducing the paint at all.
I also checked the needle last night after my paint session when I was cleaning the airbrush, and it seems fine there is no friction nor does it look bent... I thought that might have been an issue as well, but doesn't seem like that is the case.
As for moisture my compressor has a moisture trap on it.
I'll keep practicing with this setup until my new compressor arrives week after next, hopefully a tank and two compressor units will give me a more consistent result.

 

[Nessus]

What size needle/nozzle does your brush have? I've used Aztek paints, and while they do flow pretty well out of the bottle, IMO they still need reduction if you're using a smaller needle/nozzle. They spray OK out of the bottle with my .35 Eclipse, but with my .2 SOTAR, they definitely need some reducing.

 

[RebelAir]

If you need a water pump, use one without a tank LOL...The heat buildup Amra mentioned is my issue, especially in my environment..A tank as mentioned isn't necessary but bloomin helps as it allows the air to cool a bit and better match the ambient temp outside prior to entering the line..Its cheaper if you just need a little quieter compressor to build a silencing box for a standard tanked compressor..mines as quiet if not quieter than any "Silent" Compressor bought for 2-3 times the price..Silent compressors are imo only useful for sitework...They can do the job but just don't do it quite aswell..I often run both compressors at the same PSI and I find the silent will skip and hesitate a lot, chuck the same airbrush and bottle of paint on my big compressor and suddenly the issue reduces...The pulsation even if minor or not noticeable (You will barely hear or feel a 2-5 psi drop unless already working really low) and the interrupted flow Amra describes is enough to breakdown the venturi if only for that cple of seconds..Fine maybe if you spray at 10-20 psi but give me a "real" compressor any day LOL

 

[JackEb]

Judging by your intro thread you're using a Paasche V series side feed. I can't find any detail on needle size but it states it's a 'detail brush' so I'm guessing the paint might need reducing /thinning, rather than straight out of the bottle.
Don't forget to mix and strain the paint before using it. A piece of stocking over the neck of the bottle assists in keeping lumpy bits out of the airbrush.

 

[Mr.Micron]

studio compressors were designed for folks who just need to add a bit of color to a rendering. While they state max psi is 40 or 35 spray pressure is more like 15 to 20. So they would not really work for things like t shirt work where you want 60 psi.
Some buy the tankless compressor due to them be quiet . But they heat up , create moisture and cause headaches when you are trying to do a lot of airbrushing .
For things like model cars , possible xbox /PS controllers a tankless compressor would work fine.
So Ken is 100% correct in that you do not always need a compressor with a tank But a tank is a storage area. 0 gallons of stored air = no air.
1 to 500 gallons of stored air = AIR
The little pancake compressor you find at wal-mart and places like that you will also see at job sites, They are a lot more quiet than say the craftsman brand compressor
David Monnig of Coast Airbrush has a really good video about compressors http://www.coastairbrushtv.com/Comp...pressor-maintaining-your-compressor_p_57.html

 

[Exist2Resist]

What size needle/nozzle does your brush have? I've used Aztek paints, and while they do flow pretty well out of the bottle, IMO they still need reduction if you're using a smaller needle/nozzle. They spray OK out of the bottle with my .35 Eclipse, but with my .2 SOTAR, they definitely need some reducing.

Good question I'll have to have alook at the manual when I get home. They are size 1 and 2 from Paasche, I think it's .25 and .66 mm respectively.
I base that on this search result.

Judging by your intro thread you're using a Paasche V series side feed. I can't find any detail on needle size but it states it's a 'detail brush' so I'm guessing the paint might need reducing /thinning, rather than straight out of the bottle.
Don't forget to mix and strain the paint before using it. A piece of stocking over the neck of the bottle assists in keeping lumpy bits out of the airbrush.

Noted, I will have to buy some pantyhose, that will be an interesting purchase. Needle size is .25 mm and .66 mm as per search results on amazon. I actually got a full refund for the airbrush today, and I'm returning the compressor. The reason I got a refund is because, one, the operation of it was not consistent enough, and two, because I noticed I can't find parts for it very easily. I'm going to grab a Iwata or Badger brush instead and get a dual head compressor with a tank.

studio compressors were designed for folks who just need to add a bit of color to a rendering. While they state max psi is 40 or 35 spray pressure is more like 15 to 20. So they would not really work for things like t shirt work where you want 60 psi.
Some buy the tankless compressor due to them be quiet . But they heat up , create moisture and cause headaches when you are trying to do a lot of airbrushing .
For things like model cars , possible xbox /PS controllers a tankless compressor would work fine.
So Ken is 100% correct in that you do not always need a compressor with a tank But a tank is a storage area. 0 gallons of stored air = no air.
1 to 500 gallons of stored air = AIR
The little pancake compressor you find at wal-mart and places like that you will also see at job sites, They are a lot more quiet than say the craftsman brand compressor
David Monnig of Coast Airbrush has a really good video about compressors http://www.coastairbrushtv.com/Comp...pressor-maintaining-your-compressor_p_57.html

This was the compressor that I picked up...
http://www.amazon.ca/Paasche-D500SR...1452186729&sr=1-2&keywords=paasche+compressor
which I am now returning for one with a tank....
http://www.amazon.ca/dp/B014OK9IPY/...TF8&colid=1CUPNKRMKEVBX&coliid=I29NXTKUBQXXOJ

What do you think of the Pro Twin compressor?

 

[Mr.Micron]

Good question I'll have to have alook at the manual when I get home. They are size 1 and 2 from Paasche, I think it's .25 and .66 mm respectively.


What do you think of the Pro Twin compressor?

I can not give an opinion on the tanked mini compressors mainly because I have only owned a tankless one.
But at least with a tank it has storage space for air which will allow you to get better than 20psi at the business end .
I also understand has some type of budget (I called it I can stand to lose budget) if I get into a hobby and find that it is just not for me.
If you do not have one make one.
But great thing about a compressor it has a lot more uses like air tools , inflate tires or just knocking dust off a work area

 

[Greg Geilman]

I noticed a California Air Tools 5510 for another 75 cents. Seems like a much better deal.

 

[Exist2Resist]

I noticed a California Air Tools 5510 for another 75 cents. Seems like a much better deal.

Yeah I was looking at that and was wondering if it would be ok for airbrushing. This could be a good household solution looks like it goes up to 120 PSI.

 

[RebelAir]

If still keen to have one inside, don't judge it on the tank size etc, even a tiny tank helps and you can realistically attach a spare tank to any compressor..What you want to look for if needing it for inside is Db rating..You won't find this information on all adverts because many silent compressors are not silent-Mildly noisy instead I would suggest to ******** loud for others LOL (most are in the realm of 50 Db or higher). but the expensive ones will advertise Db as there the only ones that can get down to about 30 Db which is in the realms of standard talking and not too irritating for others in your house or your next door neighbour.

One thing I soon learnt about a silent compressor and its not often you hear it mentioned in this way and prob the best reason for a decent tank on it is its the storage herb mentions..0 gallons =constant running and constant noise..Doesnt matter how silent they are when the constantly run, they will eventually irritate you or those around you..Thats more annoying to my wife and kidlet than my bigger 25 litre shop compressor because I can paint on that for about 15-30 minutes, maybe more maybe less pending on my PSI need and how often I'm pushing the go button..So even a small storage solution although better for reducing pulsing and such will still be seeing that compressor still kicking in near constantly..

Now the bigger the reserve the more time running in true silent mode of zero Db..I'd suggest to all thinking about silent compressors to only do so if you need a mobile solution or can afford the higher end models, once you get to about $600-700 your probably in the realm of a decent silent option..if you have a shed and can run a 15 meter hose or build a good quality silencing box and attach a decent reservoir, you can literally paint for an hour or two pending on its size, not quite as mobile but can be set up much, much cheaper than a decent silent compressor and can also be done with a silent compressor also so consider this option if you want to save money in the long run constantly searching for silence and may only need to recharge the res two or three times a night and thats much more beneficial to those around you..But best of luck with what ya decide and what ya get...as long as it pushes air you can enjoy airbrushing and truely thats all that matters....but I like my silence