My high capacity DIY hvlp sprayer

[MMI Enterprises]

Felt a need to boost my stain, laqcuer, and urethane paint spraying capacity to 5 gal. so I used some existing parts to create a true commercial level pressure pot/hvlp sprayer.
What I realized first in going up in capacity was that anything available retail above 2.5 gal was gonna be pricey..i.e. Binks...
Second thing was I don't really need an agitator...so I thought what's left to do and quikly realized geez all I need aside from existing parts on hand was some 1/4" hose to keep down the amount of stain in the line and then to figure out the correct fittings needed.
The thread fittings go as such... The air regulator (off a gravity feed gun) side is standard npt to compression fittings of regulator. The air 'in' fitting of the firestone soda premix tank is a proprietary type quik connect that happens to be of different post size underneith compared to the liquid 'out' fitting of the tank. The tanks are stainless 130 psi so they serve well the purpose of a pressure pot. That is what they are actually. Since the 'in' is air you can use the standard plastic type found at home brew beer stores without worry. The 'out' has to be converted to all metal though for using solvent/oil based stuff is my feeling. The posts underneith except flare type threads to create a compression type result but they can be hard to come by in all sizes. Had to saw the nut of the bottom nut in the closeup pic as it must compress down onto post after removing the quik connect. So but anyways, you can see it is female to female flare and then goes to npt. These fittings can be had at an Ace or True Value. Just remember the post sizes are different between in and out. Got my tank at yard sale for like $5..the spray gun part is part of the under $50 two quart kit at Harbor Freight.. the 1/4" hose was $15 each for two 100'. You should be able to tweak and use their two line welding lines also.
I like the simple 'insert lid and flip' of the tank as compared to tightening down all the wingnuts of the commercial offerings. I have a donut type stand I stick it in so it don't tip over. That is advantage of the low profile Binks type...although they don't get hurt if they do fall over.
For those that don't understand hvlp... the gun gets both air and spray product discretely. This makes for just about unlimited adjustment. Often all it takes is about 20lbs to atomize the product and you get no cloud of death as in an airless. The air does this at the tip after the product come out. Transfer efficiency is something like 98% compared to 80 something with higher pressure stuff. I do still use the shurflow type for big flat areas. This for me is mainly for overhead work, railings, picket fences, trailer and car painting, decorative concrete lacquer spraying... but you could theoretically use it to spray some chems..
Simple hu?....enjoy!!




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Other fitting options-- http://www.brewersdiscount.com/productCat15954.ctlg
The 3/8 would be the 'out' and the 1/4 the air 'in' under the poppet plug thingies.

----------------------FEEDBACK FROM OTHERS-----------------------

[quote author=Chris link=topic=2208.msg25793#msg25793 date=1185980727]
I had purchased 4 of the soda kegs off ebay last year and tried to find adapters for them. They are like 19mm metric threads that are not tapered like pipe threads so you need an o-ring, compression fitting (like how you cut the threads down) or the quick disconnects from a supplier or dealer.
That is a really good idea on the sprayer. How is it working out for you?
Is it producing good spray like if it was an
HVLP rig?
I have an extra keg that I am not using so I might give that a try. Do you have to have the HVLP gun or will a regular airless gun work?
I have 2 Graco paint stripers that I have an extra gun for so I was thinking of using that with the soda keg.
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OK, I re-read the post. It is a HVLP gun that you are using.
It looks like the air is coming in, regulated, t'd (part going into the tank and the other part is going to the gun) and the liquid is coming out and going into the gun. You are using welder's dual hose (one side for air and the other for liquid) and both are meeting in the gun.
Is that correct?
That is a good idea.
----------------------------------------
Any problems with using 100' of hose?
Have you tried longer hose? 200'?

Chris,
Yes it is true hvlp gun...no problems with the 100'..not tried longer hose..no need. Air pressure loss is minimal at about 10lb between compressor and tank and then likely same between tank and gun. Some put a regulator at the gun too. About 35 starting at compressor works fine for me and even then I still turn down the gun both air and product. Can soak a deck with gallons and gallons or just one if it were yer perogative. There are plenty of web links with techniques to adjust hvlp systems. As example, when air is off at cap the product shoots straight out like 0 degree tip and you set for like 3 or 4 feet then add yer air till you start to get an inverted oval..
Airless likely not work less you were to boost air way way up and then ya loose the whole idea of very low overspray...they atomize by way of pressure.
These guns called a conversion gun (like a Capspray) and are different than a standard spray siphon type or a gravity fed. The air comes in after and sprayed out the cap without being mixed with product in the gun. The harbor freight ones can be had all day on Ebay if that suits ya. The hose pictured is not their welding hose. It is their roof hose series and very tough but lite..is like 250psi. Only tried the 100' worth and as I said I went with 1/4" for to keep down amount oil stain in line. Being these systems work off air pressure pushing down on the liquid inside tank you can almost spray all product out the lines though unlike your shurflo or airless as they rely on the product itself to push. Once their prime is gone at the pump it's done in those type. (btw, being able to spray all chems in a line is something I like about air operated diaphragm pumps to spray chems also.)
Although there are different brands and perhaps fittings on them I would think the thread sizes are that mentioned earlier. Yes yer right they not tapered pipe thread. You need no washers after you remove the poppet plug thingies. The flare thread or whatever that Hotshot link shows will compress down and make the seal. They are not compression threaded. I sawed my nut and not my post...lol

[Tmrrptr]

Great pot Kevin !
I just bought a 2 1/2 pot from Harbor Freight for 39 bucks to use for staining concrete. I use a Capspray gun, and turbine. Use a small compressor to drive the pot.

The shiny metal air hose connectors at Harbor are junk... they leak, and compressor doesn't get to shut down. gonna return em.

BTW, the gun you show here is a conversion gun.
The conversion is all about changing the cone at the gun to approximate hvlp.
Maybe 50-60psi from compressor to gun, reduced at gun to about 20 - 25psi to atomize product with the conversion cap used on the standard gun.

Capspray IS hvlp.
My 9100 4 turbine Capspray puts out all of 8 - 10psi but has volume.
Turbine to gun hose is 3/4 diameter.
Internal passages in gun are larger, to pass bigger volume of air efficiently.
The gun can actually be converted to a constant flow setup for higher production rate by switching around the feed point for airflow.
Capspray gun also has available projector sets... Set has needle & tip & the cap. 1 - 5 for different viscosity fluids. Comes w #3 as standard. I use #4.

I WOULD like to have an agitator for the stains I am using so result is uniform from start of the load, to end. All we can do now is kick the pot as we pass by it, from time to time. We use 25ft feed hose from pot to gun.
Turbine to gun hose is 30ft.
r

[MMI Enterprises]

Rich,

Conversion guns can be true hvlp with low psi and high flow. The term is not limited these days to the turbine method of air delivery and the 'conversion' does not refer to the spray pattern or cone persay. It pertains to the conversion within the gun of the high psi into high volume via the large passage ways. The specs on the gun pictured is not of that higher level of psi you speak of. I start around the 20lb. at the pot and it surely way lower at the cap. ..Regardless to the debates that can be seen in the spraying industry between turbine or compressor they both got one over and above an airless...lol.

ps- the lacquers for crete can get heated too much from the turbine is what I hear. You gonna stick to the acrylics on the crete?

[Integrity.PSI]

That looks great. I do not know enough about this to build one myself. What should I buy to be able to stain decks with true hvlp as apposed to airless?

[MMI Enterprises]

High cfm compressor or turbine, hoses, hvlp gun, maybe a pressure pot like Rich said or a Binks down at Sherwin. Be prepared to spend mucho dollars though if your not making your own.

This one is 5gal but you can piece together the harbor frieght 2.5 gal pot kit and their sprayer to your compressor and be up and spraying in no time for a little over a c note.

[Tmrrptr]

OK Kevin, what gun has internal passages the size of what the capspray does?

The only thing that CAN be converted is the cap, itself.
There is an adjustment tool to set pressure/volume properly... it attaches to the gun in place of the cap, you make your settings, then remove it and install cap. Never tried it though, myself.

I rarely spray lacquer. Just clean w thinner.
I'm not real happy using acrylic on concrete and would like to use some of the superior products available, but they were out of budget consideration on the projects I had.
Suppose it won't be too long before I learn abt strip & maintain.

I like hvlp a lot, but it just doesn't have the capability of moving as much product as airless does.

The FFgraco with air assist seemed to be a boost, but only tried it for a minute at a demo thingy... it was neato... but expensive, once again.
r

[MMI Enterprises]

No idea Rich on which brands do or don't have same size as capspray...but 1/2 rings a bell for some reason. Don't see it mattering though as whatever result there after I am sure they done took into account all the factors that differ between a turbine supply and compressor supply and designed the passages to end the user with the appropriate specs out the cap.
Why do you say conversion is only the cap when the air flows in and expands into the passages and smooths out before it going to the cap air sprayers? Beats me.. but that what I thought conversion was..

[Integrity.PSI]

Is this roughly the same thing that you made?
Harbor Freight Tools - Quality Tools at the Lowest Prices

[Tmrrptr]

Scott, That's exactly what Kevin made...

Except his is larger.
And I expect he'll see more solids "dropout" because of that 5 gallon dump in one shot, gravity within the tall cylinder, and bottom pickup with no agitator.

I have found it's cheaper, by far, to buy something like the chinese pressure pot, than track down all the components and purchase them individually.

I mix the 5 each time I make a gallon or so dump into the pressure pot to insure the blend of solids at least remains close to what I started with.
My guess is it probably drops out somewhat.

... one of the problems w the chinese rip-off stuff is the quality is just not there, as in Binks, or the other well known brands.

...adjustment threads are coarse, regulators vary while being used, etc...
and gaskets... the wear item... may be different enough from the original they copied so that you can not get a replacement if needed.
r

[Tmrrptr]

Originally Posted by MMI Enterprises

No idea Rich on which brands do or don't have same size as capspray...but 1/2 rings a bell for some reason. Don't see it mattering though as whatever result there after I am sure they done took into account all the factors that differ between a turbine supply and compressor supply and designed the passages to end the user with the appropriate specs out the cap.
Why do you say conversion is only the cap when the air flows in and expands into the passages and smooths out before it going to the cap air sprayers? Beats me.. but that what I thought conversion was..

Kevin, bottom line is your rig works well for you!
If it makes money, it's all good!

Let me sort out a presentation you can understand clearly.
r

[MMI Enterprises]

Yes Scott in essence it is a 5 gal. stainless steel pressure pot able to take 130psi. There hasn't been any issues with it so far mechanically and in use it turns out to be a major step up with both the capacity and the cleanup involved. Did a monster of a pergola with it this morning in 3.5 hour nonstop. Didn't bother stirring product as any drop out there may have been would have been coming right out the gun.
Cleanup goes fast with not a bit of mess and the collumn diameter helps if anything to steer the product right to the uptake tube inside.
Goes as such....ya pop air hose off, pop the air release valve built into lid, flip lid off real quik and dump excess product via funnel back to container. Then you close it up and turn your air off at gun and spray a straight stream from the hose into container till hose is clear and all ya got is air coming through product line. Open it back up and pour in maybe 2 cups of spirits and spray that though into an empty jug. Yer done....
Used only one rag today for cleanup and so I'm happy with that. I don't like to have the fire hazzards associated with numerous oil soaked items if I can help it.
I have this tomato cage type wire mesh thing with a bottom flange that makes it real stable on any surface. Can either drop tank right in or if I place the cage over the tank it would take the hoses to the ground preventing any tip over situation. With the 100' worth of hose I got no problem with pulling on it though at all. Turns out since the cage thing sticks up past top of tank it holds them big wide mouth red funnells from Ace perfect for filling tank. They got a screen in the bottom that prioveds a little prefiltering. Still haven't stuck a filter down inside the tank on the uptake tube. Not sure if I want or need to...

[Integrity.PSI]

Originally Posted by MMI Enterprises

Yes Scott in essence it is a 5 gal. stainless steel pressure pot able to take 130psi. There hasn't been any issues with it so far mechanically and in use it turns out to be a major step up with both the capacity and the cleanup involved. Did a monster of a pergola with it this morning in 3.5 hour nonstop. Didn't bother stirring product as any drop out there may have been would have been coming right out the gun.
Cleanup goes fast with not a bit of mess and the collumn diameter helps if anything to steer the product right to the uptake tube inside.
Goes as such....ya pop air hose off, pop the air release valve built into lid, flip lid off real quik and dump excess product via funnel back to container. Then you close it up and turn your air off at gun and spray a straight stream from the hose into container till hose is clear and all ya got is air coming through product line. Open it back up and pour in maybe 2 cups of spirits and spray that though into an empty jug. Yer done....
Used only one rag today for cleanup and so I'm happy with that. I don't like to have the fire hazzards associated with numerous oil soaked items if I can help it.
I have this tomato cage type wire mesh thing with a bottom flange that makes it real stable on any surface. Can either drop tank right in or if I place the cage over the tank it would take the hoses to the ground preventing any tip over situation. With the 100' worth of hose I got no problem with pulling on it though at all. Turns out since the cage thing sticks up past top of tank it holds them big wide mouth red funnells from Ace perfect for filling tank. They got a screen in the bottom that prioveds a little prefiltering. Still haven't stuck a filter down inside the tank on the uptake tube. Not sure if I want or need to...

Its impressive that you made that. I have not used this tupe of sprayer before. I will ask some questions that most will find quite novice:
1. Doy you put an air hose from a compressor on a valve to pressurize the tank?
2. Do you need to back pad, or back bush?

Thanks for taking the time to help me with this. I have an oldschool paint sprayer, and a sureflow type. I assume the pot type with a gun would come out like a can of spraypaint?

[Tmrrptr]

Originally Posted by MMI Enterprises

Why do you say conversion is only the cap when the air flows in and expands into the passages and smooths out before it going to the cap air sprayers? Beats me.. but that what I thought conversion was..

The government determined HVLP is all about 10psi, or less, measured at the cap. Gleem Paint has the two gauge device listed on their website.

Apollosprayers in vista CA just won a green award for their TrueHVLP conversion gun that has a chamber opened up, at the tip, where the cap attaches.

So it would seem you are correct, conversion is all about driving a gun with a compressor, and setting the control low so there is only 10psi at the tip.

HVLP cap is described as 4-6 small holes for atomization as regular gun, and also a large hole around the center, at the tip of the nozzle, for improved atomization at the lower pressure.
r

[MMI Enterprises]

Originally Posted by Integrity.PSI

Its impressive that you made that. I have not used this tupe of sprayer before. I will ask some questions that most will find quite novice:
1. Doy you put an air hose from a compressor on a valve to pressurize the tank?
2. Do you need to back pad, or back bush?

Thanks for taking the time to help me with this. I have an oldschool paint sprayer, and a sureflow type. I assume the pot type with a gun would come out like a can of spraypaint?

With old school sprayer the air and product is mixed within the gun and sprays by way of pressure through a tip after it is gravity fed from top or sucked up from bottom pot. Spray cans have no air mxed in but are like a pressure pot with air pushing down to force pruduct up through a tube..still relys on a tip to make atomization. Airless also relys on tip to make spray pattern and but is fickle due to it's selection and product being pressurized..there is no air involved and just like the sureflow type, once the prime is gone at pump you got no pressure..makes for horrible cleanup issues.
Then now you got hvlp that does it's spray pattern and atomization after the gun by way of streams of air blown in from both sides of the stream...
The product volume and it's psi coming out is fully adjustable via main pot pressure regulator, projector tip within the gun, or the gun on/off knob. Yes you may not get as much volume as an airless but that would require more air volume/gun design/compressor cfm to make the pattern than you would care to have.
The air volume and it's psi coming out to form the spray is also fully adjustable but note air comes by way of excess bleed off through the "t" in this design. You can change things up anyway you like and add air regulators at key spots to make it so the air line and the product line does not rely on one another...product line settings are aka the pot pressure and the setup presented here has the max presure of one line being the max of the other.

But anyways..to answer your questions:
--You need a compressor but no adjustable valves for the air..the quik connect on end of air supply hose is your valve that keeps the line pressurized when you unplug for cleenup like in the back or side yard or in trailer. Where you keep sprayer depends how far the object to be sprayed is of course. I like putting down a small piece of cardboard along the side yard walkway for it to set on and do the filling over. As I may have said earlier I have a few hudred feet of air supply on a reel so I can get out to about 400' if need be with this setup.

--- Back pad or brush depends on the product you use along with wood your using it on. No back brushing with the paraffinic RS type products.

--No it don't come out like a spray can due to all the design related things described earlier.


I plan to add quik connects at the gun so that I can use the product line alone for high volume tip type spraying as that of a sureflow or airless but with the added advantages of the easy cleanup and quik pressure adjustments. When I unplug the air line it wll be sealed off and keep pressure in system. Realize I mainly made this for railings and fine work and that swinging the arm all day with no extension wand ability is not what I want on large open decks. I have my bucketster setup already with a few wanding options that I'll just throw on the end.

[Stuart Nabors]

I don't think I'm enought of a DIY'er to make a sprayer like Kevin's, which looks great. But have you guys tried a remote cup setup with your hvlp? I use sealing pads to do the horizontal stuff, but like everyone else am looking for a more efficient way to do the verticals, and I've done a fair amount of research. I don't think I need something as big as a pressure pot for what I'm doing (and I'd also be concerned about more difficult portability and not having an agitator). Would you advise me to go with a cheaper (I've seen a couple for under $200) turbine-driven unit with a regular one quart gun, or a remote cup setup with two-quart cup and conversion gun--probably a $700 investment for a decent one with cost of compressor included. An advantage of the remote cup setup seems to be that I don't have to worry about the angle I'm spraying from, but it's more expensive and probably more difficult to clean up. Thanks!