Inline Air Pressure Regulators Questions :help:

[gm280]

I know there has to be a lot of boaters that use inline (or at the gun) air pressure regulators on these forums. I have a few of them myself. And it seems that they worked well initially and now lock up and won't allow any air through. And this seem questionable since taking them apart, I can't see or find any reason for them locking up. And so I usually have to go through three or more to get one working correctly to use when spraying primers or paint. Anybody have any ideas what makes them quick working. I mean there is basically nothing to them? Here is what they look like...basically;

Yes they are cheap (plastic body and knob), but what causes them to block the air flow after a few uses? I mean they are all built basically the same and I can't see what blocks them. I can turn the knob from one end to the other and nothing comes through. I take them apart and can't see anything as a problem. And then install them again and for a very brief period it might works and then stops cold again. :noidea: :help:

 

[Grub54891]

Hmmm... Do you have a dryer inline before the regulator? I've had my 2 current regulators for 10 years, still working, but I only use them about 12 times a year. Can't remember the brand as they work and I don't look at them to hard.

 

[gm280]

Yes Grub, I do use a water trap before the regulator at the gun. But these worked fine and all of a sudden, they stop up like something is blocking them. But disassembling them you can see there is nothing plugging them up. I mean they really are quite simple in design, but stop flowing with zero air going through. I have one working unit out of three presently. I would buy more, but if they are that finicky, there has to be a better setup. :noidea:

 

[dingbat]

When it comes to regulators you get what you pay for...

I designed pneumatic controls for radioactive source holders for a number of years. Regulator failures, unless physically damaged, are almost unheard of. Then again, we only used name brand quality components. The filter and regulator on my compressor in the garage is over 20 years old.

Stick with name brands. I prefer Ross Controls but Festo makes good quality components as well.

FWIW: The typically failure point of a regulator is a ruptured/leaking diaphragm. The failure isn't apparent unless pressurized. Plastic housing are notorious for this.

 

[bruceb58]

I like Iwata which isn't super expensive. The regulator in the picture looks like one of the cheapies you would buy at Harbor Freight or Northern Tool.

 

[mla2ofus]

A good friend just put a 1/4" tee on the gun connection w/ a gauge in the tee and a small 1/4"(your choice of style) valve w/ the quik connect in the tee. Pull the trigger, adjust the valve to the pressure you want and start painting. Simple and almost bullet proof.
Mike

 

[bruceb58]

A good friend just put a 1/4" tee on the gun connection w/ a gauge in the tee and a small 1/4"(your choice of style) valve w/ the quik connect in the tee. Pull the trigger, adjust the valve to the pressure you want and start painting. Simple and almost bullet proof.
Mike

That won't work unless you have a pressure regulator upstream of the valve.

 

[gm280]

Ha, thanks everybody for the suggestions and responses. Yes, these regulators are the "el cheapo" types but they came with the HVLP spray guns. The only one presently working is the one that came with the Devilbiss kit I bought, and it is metal, not plastic. I have a IR 270G HVLP gun as well and it was a middle line gun. And it too came with one of those el cheapo regulators too. I do have a pressure regulator on the output of the compressor. but I usually lower that one to about 75psi and then set the gun regulator to 28-30psi. And that is because at that ~30psi input to the gun, I get 10psi at the tip cap. And that pressure is what you're supposed to spray most auto paints at. Any more then that, you waste too much overspray. However, disassembling these cheap regulators, there is no diaphragm involved. A spring and some "O" rings is about it. And nothing looks damaged, but they stop flowing any air. :noidea: I'll just buy new ones and toss these plastic ones.

 

[bruceb58]

I used to have a really nice DeVilbiss gun and it had a pressure gauge at the gun. I would just adjust my up stream regulator so that I had the correct pressure at the gun when I pulled the trigger. That way the pressure drop between the upstream regulator and the gun was accounted for. I used to paint cars and having the correct pressure was critical. Wrong pressure and the color would be either too dark or too light.

 

[mla2ofus]

That won't work unless you have a pressure regulator upstream of the valve.

If you have a pressure regulator upstream then the valve isn't necessary.
Mike

 

[bruceb58]

If you have a pressure regulator upstream then the valve isn't necessary.
Mike

The problem is if you don't have a pressure regulator at all and your tank pressure varies from lets say 125 down to 100 because the compressor is cycling, the pressure after the valve will also vary along with the tank pressure. That's just simple physics.

 

[gm280]

Since I have two pressure regulators inline, yes I know I don't need two, I don't get any varying pressure issues. And with an added drier as well at the gun inlet, the paint sprays perfectly. Thanks again all for the replies. It was just interesting to disassembly these cheap regulators only to see there is near nothing inside, but they stop working. :noidea: