Question on how Pressure Regulators work?

The Harbor Frieght compressor you have is a low power model that cannot sustain pressure higher than 20 psi at full throttle, 0.5 CFM. I don't understand the purpose of your second regulator. Can't you just adjust the pressure to 20 psi using the regulator that comes with the compressor on the bottom of the filter?

The second regulator is for haveing a handy one next to me while I paint, and if I dont have to turn the compress over to mess with the screw on the bottom of the regulator if I want to spray less than 20 PSI.  Plus later on I will get an small air tank so the compressor doesn't have to run as often.

 Thanks
Jon

Greasy wrote:

The Regulator 2 is set to 20ish PSI.  I would expect to get 20 PSI to the airbrush but pumps up to about 40.  I use a double action so I can hold down the trigger and pressure will drop to about 20 PSI and stay there, but I thought a regulator would not let it go past 20.  Am I wrong or did I configure my options wrong?  Or are they cheap parts? Thanks, Jon

That's the sign of a cheap (no good) regulator. had the very same situation here, the exact same "regulator" and I have a 10 gal tank large compressor. set for 40, dropped to 20!!

So, one day I was on ebay, and saw a regualtor, with moisture trap and figured what the heck I will take a chance on it.  Glad I did. It works 100 % MUCH better than what I had for a 2nd regulator. (my compressor and factory regulator is on the other side of the garage)

here is what I got, and it's scale is very good/readable in the low pressure range:

it drops maybe a few psi at most, from airbrush off to on.

from global auto accessories, here is a link, hope it copies and paste works for you:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWNX:IT&item=110285769460

Greasy wrote:

OK I have completed my setup of adding an addition regulator to my compressor/airbrush.  It works and I am able to use but here is my question.  Here is a link to my setup (plus a review) http://www.happinessismandatory.com/misc/Tools/Compressor.htm but basically here it is Compresser-->regualtor1 (60psi)-->hose-->regulator2(20psi)-->hose-->air brush Regulator 1 is set to 60 PSI and it pumps up to that and auto shuts down.  The Regulator 2 is set to 20ish PSI.  I would expect to get 20 PSI to the airbrush but pumps up to about 40.  I use a double action so I can hold down the trigger and pressure will drop to about 20 PSI and stay there, but I thought a regulator would not let it go past 20.  Am I wrong or did I configure my options wrong?  Or are they cheap parts? Thanks, Jon

first thing I'd think about is the volume of air plus the overall pressure overcomming the smaller regulator which is now used as a pressure reducing valve. Regulators do not work all that well as a pressure reducing valve, and you really want a dedicated valve for this function. They will cost a little more money as well because of the way they work. My suggestion is for you to buy a Wilkerson colescent filter with a built in regulator (the colescent air filter is the best moisture trap made unless you want to invest in a true air dryer). and then downstream add a pressure reducing valve (buy a good and forget it). Another problem is when working in small pressures most regulators just don't meter well, and the need beomes necessary to have what is known as a precision regulator. Otherwise the second regulator will do two things. First restrict airflow greatly, and secondly actually make the first regulator nonfunctional.

    here's a couple things to check out before running out to buy something else (stay away from the Chinese junk). On the second valve look for the vent to see if it's blocked (did you add the little bronze outlet filter?). Make sure you have the airflow going in the right direction! This is the most common mistake. The do the samething on the first valve. If all looks good then try it with the drain on the bowl opened up. If that solves the problem then the second regulator is usually the problem (too small and maybe not hooked into the system right). Also make sure you installed the gage in the correct port! I've done that one more than once. I built machinery for a living for more years than most of us have been on this planet, and air systems (low pressure and low volume) can be tricky. Your problem acts like a blockage somewhere between the pump and the second regulator.

gary

bspeed wrote:

Without a Air tank, I wonder if the 1st regulator is doing anything....?? just passing gas, maybe!

well two things to remember here:

* anytime you add anykind of a valve, you also add a restriction in the air flow. But when you want to further reduce presure downstream from the main regulator you want a pressure reducing valve not another regulator. This valve works off the actuall PSI in the airline feeding it.

* all regulators have a flow rate, and he may well be putting out too much CFM as well as PSI for the valve to handle it

gary

Passing Gas ---- good one.

It controls the auto turn off on the compressor.  Once it gets to 60 PSI the compressor stops running.

 I think I am going to swap out that regualtor for this one
http://www.lowes.com/lowes/lkn?action=productDetail&productId=221026-1126-KBA10700AV

Hopefully that wil be a little better.  I look better anyways.  Its also pretty heavy so it should be durable.

 Thanks

Greasy wrote:

Passing Gas ---- good one. It controls the auto turn off on the compressor.  Once it gets to 60 PSI the compressor stops running.  I think I am going to swap out that regualtor for this one http://www.lowes.com/lowes/lkn?action=productDetail&productId=221026-1126-KBA10700AV Hopefully that wil be a little better.  I look better anyways.  Its also pretty heavy so it should be durable.  Thanks

instead of Lowes I'd go to Granger. Better quality stuff.

gary

I don't believe I have one local.  I just have a lowes and Home Depot.

 Thanks though.

squeakie wrote:

instead of Lowes I'd go to Granger. Better quality stuff.

Granger is too expensive and by mail order only. Lowes is both expensive and mediocore quality. You don't really need industrial grade regulator/filter for airbrushing because the pressure is low. Search for "regulator" at the Ebay Airbrushing section. You will find some diaphram regulator with glass (not plastic) filter casing. They are very good buy for the money if you get it with free shipping. It has very fine control of the pressure.

You can replace the pressure gauge with a larger diameter/lower pressure range for easy reading. There are plenty of cheap choices on Ebay too.

The Sparmax and Iwata compressors are designed to allow users to put the regulator next to him/her. You can do the same with other compressors by disconnecting the regulator from the compressor. There is no reason to use two regulators.

I purchased my Paasche DA400 compressor without the filter and connect the compressor to my regulator/filter by a 25-feet plastic hose from Harbor Freight. The hose has 1/4"-NPT on both ends and costed $5.

keilau wrote:

squeakie wrote: instead of Lowes I'd go to Granger. Better quality stuff. Granger is too expensive and by mail order only. Lowes is both expensive and mediocore quality. You don't really need industrial grade regulator/filter for airbrushing because the pressure is low. Search for "regulator" at the Ebay Airbrushing section. You will find some diaphram regulator with glass (not plastic) filter casing. They are very good buy for the money if you get it with free shipping. It has very fine control of the pressure. You can replace the pressure gauge with a larger diameter/lower pressure range for easy reading. There are plenty of cheap choices on Ebay too. The Sparmax and Iwata compressors are designed to allow users to put the regulator next to him/her. You can do the same with other compressors by disconnecting the regulator from the compressor. There is no reason to use two regulators. I purchased my Paasche DA400 compressor without the filter and connect the compressor to my regulator/filter by a 25-feet plastic hose from Harbor Freight. The hose has 1/4"-NPT on both ends and costed $5.

I doubt that you'd believe just how many cheap regulators and valves I've tossed that were brand new. Probably well over a thousand pieces. The lower the airflow (cfm) as well as the lower the operating pressures the better a regulator you have to have. It's just an unwritten rule of the thumb. I didn't say anything about Ebay for two reasons. First he wanted to goto a dealer, and second he didn't say anything about Ebay and a lot of what they sell is used junk that wouldn't work for them in the first place. I mentioned Wilkerson as I think it's the best without spending a ton of cash (there's much better stuff and a much higher price). Remember you almost always get what you pay for.

gary

squeakie wrote:

keilau wrote: I doubt that you'd believe just how many cheap regulators and valves I've tossed that were brand new. Probably well over a thousand pieces. The lower the airflow (cfm) as well as the lower the operating pressures the better a regulator you have to have. It's just an unwritten rule of the thumb. I didn't say anything about Ebay for two reasons. First he wanted to goto a dealer, and second he didn't say anything about Ebay and a lot of what they sell is used junk that wouldn't work for them in the first place. I mentioned Wilkerson as I think it's the best without spending a ton of cash (there's much better stuff and a much higher price). Remember you almost always get what you pay for. gary

I agree with you on the general principles. Buy cheap, buy twice. It used to be true for the compressor that one cannot get a decent one without spending hundreds of dollars. It changed a few years ago when Iwata and others started importing compressors made by Sparmax in Taiwan. Today, even some of those produced in China are good money values. It is always prudent to do the homework and buy from a reliable dealer because there are still so many cheap garbages out there. But I don't think that buying industrial grade component is the only way to go anymore.

We usually airbrush at low psi. Cheap regulator with small gauge does not resolve the adjustment well at the low end and is usually useless. The reason that I specifically called out diaphram regulator with glass casing filter is that they represent better design and good for we we want to do. It usually costs more. I have seen a few on Ebay for under $20 and free shipping. Yes, the Ebay is full of pitfalls. You need to know what to get and what to pay for when buying there. That is why we have this conversation here.

You must be in the air tools business to "throw out well over a thousand pieces of cheap regulators and valves". Regards.

While I agree its not best to buy cheap (My dad drilled that into me for years).  From working in the computer field for 20 years I have learned you don't have to by the best just as good as you want.  Also being a novice if I buy local I can return parts (huge advantage) and carry them in to test and see if parts fit.  I returned a ton of plumbing bits do to not thinking it out correctly.  Online I usually can't and I lose shipping.  Where I live we have Lowes and Home Depot maybe a few mom and pop stores if I look, unless I know specifically what I want I have to  just look and see what they have.  I did return my regulator today and got this one instead http://www.lowes.com/lowes/lkn?action=productDetail&productId=221026-1126-KBA10700AV&lpage=none
I don't expect it to be exact but as long as I can get within 2-3 PSI of what I want it should be fine.  I am no great modeler.  I just want a tool that will make things a little easier.   I will update my website with a review of differences, and I will post them here as well. 

I do want to thank everyone for the advice, and I did take it to heart.  If I ever get to where I need better tools, I will defiantly keep a copy of this thread.

Thanks,
Jon

Jon,

Let me make a guess. Your new regulator from Lowe will make absolutely no difference than the original Harbor Freight one. Let me know how good or how bad my guess is.

It works much better and swaping the regulator was a great move.  Below is the text that I added to my review, but if you want to look at the pictures here is a link to the review
http://www.happinessismandatory.com/misc/Tools/Compressor.htm
It is basicly the same price only a few dollars difference and the new regulator is so much better.

TEXT FROM MY WEBPAGE

The older setup had a problem with the regulator.  The gauge would not change when you change the pressure gauge.  When you had it set to what you want and the compressor turns on it would go over the pressure setting.  But it would run at the pressure it was set to once it runs down.  I knew enough to know that was not right.  So after some talking on the net I updated to a better regulator.  This one works so much better.  I can turn the dial and the pressure changes to match what it is set to.  It does not over pressure, and runs at what it is set up.  The Mini Pressure Regulator is only 5 bucks more than the other one, and you don't need one of the couplings saving a dollar or two so the price difference is only about 2-3 dollars.  I would defiantly buy this set up instead.

This is the current list of Items you would need
Kobalt Mini air regulator 19.94 221026
Watts
2 A-738 Pipe Hex Brushing 1/4" MIP X 1/*" FIP 17000738
1 A-732 Pip Coupling 1/4"FIP  17000732
1 A-717 Brass Pipe Nipple 1/8" MIP x 2" 17000717
Great White Threading sealer
Teflon Tape

The only thing that may be an issues is the 1/8 hole.  The little plug that comes with it is a bit small so you would have to use a threading sealer and Teflon tape.  I put the threading sealer on did about 4-5 wraps in Teflon tape.  Since I already had it, it was not a big deal.  You may be able to eliminate one more adapter but you would have to buy a 1/4 cap to plug the other hole.  Here is a picture of the trouble spot.  But it was not a big deal at all.  The leak was very slow but I did not want any at all.

Just bought a Pasche single piston compressor with tank. The gauge on the regulator is bleeding air proportional to the pressure I set at such a rate that the compressor never shuts off. Any ideas?

Hello!

Do you mean you have an air leak there? In such case you might want to unscrew the gauge and re-seal the threaded connection using either teflon tape or better yet natural fibre - wicking or tow. This way you have a chance of stopping the air leak.

I hope this helps, good luck with your compressed air system and have a nice day

Paweł

The age-old way of locating leaks is to mix up some soap and water, then brush it on the suspected connexions and look for the bubbles spitting.