Pressure Pot-Priming the spray gun

[wptski]

I haven't found one set of instructions for any pressure pot on the market that explains a procedure for priming the spray gun.  Some do outline a procedure for checking flow rate and adjust by +/- pot pressure which does prime the gun.

I have two different pressure pot systems but both have material supply that plastic and somewhat clear.  You apply pressure to the pot, depress the trigger and watch the material come up to the gun.  Once the line is fill, apply pressure to the gun and away you go.

Many PP systems don't use somewhat clear plastic hoses so one can't see the material filling the line.  I'm sure the PP users here have a procedure they use, care to share?  Or do you check flow rate?

 

[tjbnwi]

I don't understand the issue????????

The fluid is placed in the pot, the pot sealed, pressure applied, gun trigger pulled (you do not need the turbine on the get fluid to the nozzle/air cap), fluid exits nozzle. It's not a closed system, no need to prime/bleed.

The PPS is not used when the gun is connected to a pressure pot, the fluid hose from the pot is connected where the PPS adapter would be. My pot to gun hose are black high pressure hoses.

You do prime/bleed an airless pump because it is a closed system positive displacement pump.

Tom

 

[wptski]

I don't understand the issue????????

Yes, you don't.

The fluid is placed in the pot, the pot sealed, pressure applied, gun trigger pulled (you do not need the turbine on the get fluid to the nozzle/air cap), fluid exits nozzle. It's not a closed system, no need to prime/bleed.

What do you think you are doing when the trigger is pulled?  You are bleeding air from the line and/or priming the gun so to speak.  If you had a clear material line you'd see what I mean.  If there weren't any leakage in the material line from the pot to your gun the material would never ever get to the gun by just pressurizing the pot.

The PPS is not used when the gun is connected to a pressure pot, the fluid hose from the pot is connected where the PPS adapter would be. My pot to gun hose are black high pressure hoses.

Never mentioned PPS in my post.

You do prime/bleed an airless pump because it is a closed system positive displacement pump.

Yep where the pump and gun are separate.  A handheld airless system for which some have a PP has two lines from the PP to the gun, one for material and the other is a return line.

 

[tjbnwi]

I don't understand the issue????????

Yes, you don't.

The fluid is placed in the pot, the pot sealed, pressure applied, gun trigger pulled (you do not need the turbine on the get fluid to the nozzle/air cap), fluid exits nozzle. It's not a closed system, no need to prime/bleed.

What do you think you are doing when the trigger is pulled?  You are bleeding air from the line and/or priming the gun so to speak.  If you had a clear material line you'd see what I mean.  If there weren't any leakage in the material line from the pot to your gun the material would never ever get to the gun by just pressurizing the pot.

The PPS is not used when the gun is connected to a pressure pot, the fluid hose from the pot is connected where the PPS adapter would be. My pot to gun hose are black high pressure hoses.

Never mentioned PPS in my post.

You do prime/bleed an airless pump because it is a closed system positive displacement pump.

Yep where the pump and gun are separate.  A handheld airless system for which some have a PP has two lines from the PP to the gun, one for material and the other is a return line.

Again what is the issue and why the question?

There is no mystery or magic to this, you pull the trigger.

You're asking how to prime the gun? There is no priming, you purge the line of air or what ever cleaning fluids may be in the line. You're not priming anything.

I don't need a clear line, I know exactly what is occurring when the trigger on the gun is pulled if it is connected to a charged pressure pot, fluid is moving from pot to nozzle.

None of my airless (including hand held) units have a return line from gun to pump, it is unnecessary.

I misread your PP for PPS.

Which pressure pots do you own? Brand and model.

Tom

 

[tiralie]

I have two different pressure pot systems but both have material supply that plastic and somewhat clear.

What kind of pressure pot system do you have that has this type of material supply line?
Difficult to advise unless we know.

You apply pressure to the pot, depress the trigger and watch the material come up to the gun.

This is the way I do it. It's like me, simple.
Unless the coating is very viscous, the pressure in the pot has pushed the material to the gun and it's ready to go by the time I am ready to spray.

Once the line is fill, apply pressure to the gun and away you go.

What does "apply pressure to the gun" mean? How do you apply pressure to the gun?
Tim

 

[wptski]

Again what is the issue and why the question?

I asked what do you do.

There is no mystery or magic to this, you pull the trigger.

Pulling the trigger is bleeding the line.

You're asking how to prime the gun? There is no priming, you purge the line of air or what ever cleaning fluids may be in the line. You're not priming anything.

The act of priming is bleeding air from the material.

I don't need a clear line, I know exactly what is occurring when the trigger on the gun is pulled if it is connected to a charged pressure pot, fluid is moving from pot to nozzle.

Yes, once the air is removed.

None of my airless (including hand held) units have a return line from gun to pump, it is unnecessary.

Are you sure about your handheld?  Don't you have to prime/bleed air somehow?  With your cup removed, you have a material pickup tube.  Isn't there a hole or maybe a small protruding piece?

Which pressure pots do you own? Brand and model.

A one gallon pressure pot for a Graco Truecoat Pro II which has two line fused together which has a 9V battery powered pump(10psi) mounted on the tank/pot.  A Fuji 2 quart which doesn't use anything but the turbine.

On larger airless systems the pump starts/stops to maintain pressure.  The Graco PP for some of their handhelds has a return line because the pump never shuts off so when the guns trigger is released the pressurized material goes back to the tank.

On a handheld, when you prime/bleed, you normally flip a lever that opens the return line to the cup, run for a bit to remove air from the material, flip the lever back and your ready to spray.

What handheld to you have?

 

[tiralie]

A one gallon pressure pot for a Graco Truecoat Pro II which has two line fused together which has a 9V battery powered pump(10psi) mounted on the tank/pot.

I am not familiar with how these units work so I cannot advise you on this. Doesn't sound like a pressure pot but more like a bag with pump.

A Fuji 2 quart which doesn't use anything but the turbine.

I don't believe the turbine provides enough pressure to move heavy viscosity waterbourne coatings through the fluid line to the gun so I use a compressor driven pressure pot system. Without the help of gravity (gravity gun) or siphon (bernoulli siphon) the pressure from a turbine is not sufficient to adequately move heavier viscosity coatings through a fluid line.
Tim

 

[wptski]

What kind of pressure pot system do you have that has this type of material supply line?
Difficult to advise unless we know.

Fuji 2 quart has a hard plastic line that you can see the material coming up from the pot.  This stuff is so stiff I ordered some 6' lines that are for a DeVilbiss and my first thought was, I can't see the material flow anymore!  I have a pressure pot for a Graco Truecoat Pro II that has a fiberglass enforced clear lines also.  I have a modified setup of the Graco for HVLP usage(return line plugged).

This is the way I do it. It's like me, simple.
Unless the coating is very viscous, the pressure in the pot has pushed the material to the gun and it's ready to go by the time I am ready to spray.

So if the material is thicker, you have to wait a bit?  Your higher pressure pots probably pushes the air from the line much quicker.

What does "apply pressure to the gun" mean? How do you apply pressure to the gun?

Start the turbine.  I use a wireless remote.

 

[tiralie]

So if the material is thicker, you have to wait a bit?  Your higher pressure pots probably pushes the air from the line much quicker.

That's the idea. It's intuitive. Like I said, simple like me.

Start the turbine.  I use a wireless remote.

Seems like it works for you.
Not sure what your problem is.
Tim

 

[wptski]

[/quote]

I am not familiar with how these units work so I cannot advise you on this. Doesn't sound like a pressure pot but more like a bag with pump.

It's heavy plastic tank/pot with a pump.

I don't believe the turbine provides enough pressure to move heavy viscosity waterbourne coatings through the fluid line to the gun so I use a compressor driven pressure pot system. Without the help of gravity (gravity gun) or siphon (bernoulli siphon) the pressure from a turbine is not sufficient to adequately move heavier viscosity coatings through a fluid line.

The little 9V 10psi pump on the Graco was enough to push material to my Fuji Gxpc(no straining or thinning) that kept on plugging up my Graco Truecoat Pro II which saved the day for me.

Can't judge the Fuji pressure pot because I haven't used it yet. 

 

[tjbnwi]

I pull the trigger until the product arrives at the nozzle.

I don't look at purging the line as bleeding, I apply the word bleeding to a closed system.

There fluid moves from pot to nozzle, the air has no affect on it getting there.

I believe this is the Graco backpack you have;
http://www.graco.com/us/en/products/contractor/propack.html

Does it pressurize the vessel or is it a pump that moves the product to the gun? I've never used one and the site is not clear on this.

It appears as if the Fuji does not have a return hose.

Pro Shot Fine Finish II. There motor shuts off once a set pressure is reached. I've never used it with a backpack, so no primer line.

Why does it matter if you can see the material? It will get to the end of the line, it's an open system once the trigger is pulled.

The highest I recall running my pot is 18-19 psi. Through a 25' hose a wait time of 2-3 seconds max. Once the fluid is at the nozzle wait time is zero when cycling the trigger.

The air in the line is not an issue with my pot. I flush the line, then let air from the pot run through it to dry it.

Tom

 

[wptski]

Seems like it works for you.
Not sure what your problem is.

I don't have a problem, yet!  Just asking about your procedure but the terms I used weren't understood.  I'm a retired mechanic not a cabinet maker, etc.

 

[wptski]

I pull the trigger until the product arrives at the nozzle.

I don't look at purging the line as bleeding, I apply the word bleeding to a closed system.

There fluid moves from pot to nozzle, the air has no affect on it getting there.

I believe this is the Graco backpack you have;
http://www.graco.com/us/en/products/contractor/propack.html

Does it pressurize the vessel or is it a pump that moves the product to the gun? I've never used one and the site is not clear on this.

It appears as if the Fuji does not have a return hose.

Pro Shot Fine Finish II. There motor shuts off once a set pressure is reached. I've never used it with a backpack, so no primer line.

Why does it matter if you can see the material? It will get to the end of the line, it's an open system once the trigger is pulled.

The highest I recall running my pot is 18-19 psi. Through a 25' hose a wait time of 2-3 seconds max. Once the fluid is at the nozzle wait time is zero when cycling the trigger.

The air in the line is not an issue with my pot. I flush the line, then let air from the pot run through it to dry it.

Tom

If you took a straw, put your finger over one end and try to pour water into it, would it fill the straw?  It can't because it's filled with air.  Same goes if you took that same straw and put it in a glass of water.  No water will go into the straw till you remove your finger.

Air has to be forced from a line in order for the material to take its place.

Yeah that's what I have.  It pressurizes the pot to move the material to the gun.

I can't find the name of the handheld you state but is it on this page?  Does it have a lever on the pressure setting knob?

 

[tjbnwi]

I pull the trigger until the product arrives at the nozzle.

I don't look at purging the line as bleeding, I apply the word bleeding to a closed system.

There fluid moves from pot to nozzle, the air has no affect on it getting there.

I believe this is the Graco backpack you have;
http://www.graco.com/us/en/products/contractor/propack.html

Does it pressurize the vessel or is it a pump that moves the product to the gun? I've never used one and the site is not clear on this.

It appears as if the Fuji does not have a return hose.

Pro Shot Fine Finish II. There motor shuts off once a set pressure is reached. I've never used it with a backpack, so no primer line.

Why does it matter if you can see the material? It will get to the end of the line, it's an open system once the trigger is pulled.

The highest I recall running my pot is 18-19 psi. Through a 25' hose a wait time of 2-3 seconds max. Once the fluid is at the nozzle wait time is zero when cycling the trigger.

The air in the line is not an issue with my pot. I flush the line, then let air from the pot run through it to dry it.

Tom

If you took a straw, put your finger over one end and try to pour water into it, would it fill the straw?  It can't because it's filled with air.  Same goes if you took that same straw and put it in a glass of water.  No water will go into the straw till you remove your finger.

Air has to be forced from a line in order for the material to take its place.

Yeah that's what I have.  It pressurizes the pot to move the material to the gun.

I can't find the name of the handheld you state but is it on this page?  Does it have a lever on the pressure setting knob?

Depends on how you pour the water in it, yes it can be filled with your finger over the end. The second example is a closed system.

I consider this purging the line not bleeding, again I view bleeding as a process in a closed system.

Yes, the lever is the priming lever. The hand helds are airless sprayers with positive displacement pumps, not HVLP's with a pressure pot. Once the pump is primed no fluids bypass back to the cup (or bucket), the motor shuts down at the set pressure, same as my stand airless sprayers.

Tom

 

[tiralie]

I don't believe the turbine provides enough pressure to move heavy viscosity waterbourne coatings through the fluid line to the gun so I use a compressor driven pressure pot system. Without the help of gravity (gravity gun) or siphon (bernoulli siphon) the pressure from a turbine is not sufficient to adequately move heavier viscosity coatings through a fluid line.

The little 9V 10psi pump on the Graco was enough to push material to my Fuji Gxpc(no straining or thinning) that kept on plugging up my Graco Truecoat Pro II which saved the day for me.

Please note my comments were not addressing your Graco/Fuji set up but the Fuji Pressure pot set up using the turbine.
Other than in name, one is not the same as the other.

Can't judge the Fuji pressure pot because I haven't used it yet.

Please do and let us know what you think of it.
I would be interested in how well it works getting paint from the pot to the gun in a reasonable pattern.
Tim

 

[wptski]

I don't believe the turbine provides enough pressure to move heavy viscosity waterbourne coatings through the fluid line to the gun so I use a compressor driven pressure pot system. Without the help of gravity (gravity gun) or siphon (bernoulli siphon) the pressure from a turbine is not sufficient to adequately move heavier viscosity coatings through a fluid line.

The little 9V 10psi pump on the Graco was enough to push material to my Fuji Gxpc(no straining or thinning) that kept on plugging up my Graco Truecoat Pro II which saved the day for me.

Please note my comments were not addressing your Graco/Fuji set up but the Fuji Pressure pot set up using the turbine.
Other than in name, one is not the same as the other.

Can't judge the Fuji pressure pot because I haven't used it yet.

Please do and let us know what you think of it.
I would be interested in how well it works getting paint from the pot to the gun in a reasonable pattern.
Tim

I made the comparison of the two different systems because of the same published pressures.

It'll be sometime before I have the need for the 2 quart Fuji.  I just tried it with water to test for leaks.

 

[wptski]

I pull the trigger until the product arrives at the nozzle.

I don't look at purging the line as bleeding, I apply the word bleeding to a closed system.

There fluid moves from pot to nozzle, the air has no affect on it getting there.

I believe this is the Graco backpack you have;
http://www.graco.com/us/en/products/contractor/propack.html

Does it pressurize the vessel or is it a pump that moves the product to the gun? I've never used one and the site is not clear on this.

It appears as if the Fuji does not have a return hose.

Pro Shot Fine Finish II. There motor shuts off once a set pressure is reached. I've never used it with a backpack, so no primer line.

Why does it matter if you can see the material? It will get to the end of the line, it's an open system once the trigger is pulled.

The highest I recall running my pot is 18-19 psi. Through a 25' hose a wait time of 2-3 seconds max. Once the fluid is at the nozzle wait time is zero when cycling the trigger.

The air in the line is not an issue with my pot. I flush the line, then let air from the pot run through it to dry it.

Tom

If you took a straw, put your finger over one end and try to pour water into it, would it fill the straw?  It can't because it's filled with air.  Same goes if you took that same straw and put it in a glass of water.  No water will go into the straw till you remove your finger.

Air has to be forced from a line in order for the material to take its place.

Yeah that's what I have.  It pressurizes the pot to move the material to the gun.

I can't find the name of the handheld you state but is it on this page?  Does it have a lever on the pressure setting knob?

Depends on how you pour the water in it, yes it can be filled with your finger over the end. The second example is a closed system.

I consider this purging the line not bleeding, again I view bleeding as a process in a closed system.

Yes, the lever is the priming lever. The hand helds are airless sprayers with positive displacement pumps, not HVLP's with a pressure pot. Once the pump is primed no fluids bypass back to the cup (or bucket), the motor shuts down at the set pressure, same as my stand airless sprayers.

Tom

What are you purging?  If you bleed your car's brake lines you are purging air from the lines.  No liquid can be placed in any container without removing the air within.  Yes, you can dribble water into a straw which forces the air just as slow.  Try to force liquid under pressure into a closed container, you will fail.

After one attaches the PPS H/O cup, apply pressure to the cup, you press the gun,s trigger to purge air from the gun.  Bleeding and purging go hand in hand.

 

[tjbnwi]

Again the difference between closed and open systems.

You can pour water into a glass, your straw is just a glass on a smaller scale. Pick a device to pour from of the proper scale, the water will pour in no differently than pouring the water in a glass with a picture of glasses scale. Would you fill a glass with a fire hose? It is an open system.

A brake system is a closed system. The air is bled from the system to remove the compressible item (air). Once the bleeder is closed you're back to a closed system. The spray units we use are not a closed system.

Some fluid will enter the sealed air chamber, the air will compress and liquid will fill that area.

Nobody is forcing a liquid into a closed system.

Again, I don't understand your question or issue, pull the trigger and spray. There is no other process to purge the system other than that.

Again, I apply the word bleeding to a closed system, purging to an open system.

The definition the dictionary also applies bleeding to a closed system;

• [ with obj. ] allow (fluid or gas) to escape from a closed system through a valve: open the valves and bleed air from the pump chamber.

• the escape of fluid or gas from a closed system through a valve: the amount of air bleed from the compressor.

Your backpack rigged to the Fuji----where did you connect the backpack return line on the Fuji gun? There is no device on the Fuji to allow you to to prime/bleed the Fuji. So how did you make it work with the Fuji gun? (these are rhetorical questions)

Tom

 

[wptski]

Again, I apply the word bleeding to a closed system, purging to an open system.

This is a war or a choice of words.

Your backpack rigged to the Fuji----where did you connect the backpack return line on the Fuji gun? There is no device on the Fuji to allow you to to prime/bleed the Fuji. So how did you make it work with the Fuji gun? (these are rhetorical questions)

That return line wasn't used and was plugged on the backpack tank.  It then became a generic pressure pot.  I'd start the battery pump only, pull the trigger and the material travels up the line.  When the material reaches the fitting on the Fiji gun, I start the turbine and a second later test the pattern.

If one doesn't press the trigger, you are trying to force liquid into a closed line or system, correct?  Does pressing the trigger make it an open system?  By pressing the trigger, you allow air to be forced out, correct?  I'm avoiding to use of bleed or purge, our problem terms here.

 

[wptski]

I don't believe the turbine provides enough pressure to move heavy viscosity waterbourne coatings through the fluid line to the gun so I use a compressor driven pressure pot system. Without the help of gravity (gravity gun) or siphon (bernoulli siphon) the pressure from a turbine is not sufficient to adequately move heavier viscosity coatings through a fluid line.

Rethinking this again.  The viscosity of the material is set or determined by the gun.  Does it really matter if you can pump molasses up to the gun which can't spray it?

Fuji suggests a Q4 or Q5 for its pressure pot.  Pressure pots have a material line length limit as well as there is a pressure drop.  Just like turbines have a line length limit also.  This also changes if you are working off a ladder.