What is advantage of spray system that comes with turbine vs. using air compressor?

[Daniel Berlin]

I would agree that the system you have is more than enough to do the finishing you need to do, I would not get rid of it. And yes you can add the PPS system to it and I would.
HVLP is High Volume Low Pressure, these are systems that push less than 10psi, they use a turbine, not a compressor. Conversion guns work with compressors with an extra gauge that allows you to dial it down to the pressure you want. Usually these are still set to about 25psi which is way above HVLP qualification. I like the compact size, constant airflow, clean dry air and ease of cleanup that I get with my HVLP system.

You seem to misunderstand how conversion guns work. HVLP conversion guns, like HVLP turbine guns, produce 10psi (or less) at the aircap. The aircaps use restriction (or other mechanisms) to convert High Volume High Pressure air into High Volume, Low Pressure air. Reducing the pressure expands the volume of air dramatically. The finish is not atomized or propelled using high pressure. They are "HVLP qualified". In fact, the first HVLP guns were *not* turbines, they were compressor based guns. It wasn't until about 10 years later when Apollo got into the business that turbine based HVLP started.

[John TenEyck]

I think everyone goes through this when they decide to get into spraying. But you, the OP, already went through it to some degree, but you appear to be second guessing your decisions or hoping for something better. You have both systems, turbine and compressed air driven. Pick one and go with it. If it were me, I'd sell the turbine unit. I'm perfectly happy with my cheap compressed air driven, gravity feed, HVLP gun. I don't plan to spray at a remote location, and I already had a compressor, so the decision was easy. Oil contamination has never been an issue for me. I use nothing more than the coalescent filter that came with the regulator on the compressor and a screw in oil/water filter at the gun. I've sprayed gallons of WB products and never had a fisheye. I don't/won't spray solvent based products, except shellac; I just don't see the need when such excellent WB products are now available. Cleanup is a non-issue and really doesn't take much longer than cleaning a brush. The only thing that does take longer is setting up my temporary spray booth and thinning whatever I'm spraying so that its viscosity is correct. But to me these are minor inconveniences compared to the quality of the finish I can achieve compared to brushing. And the larger the project, the more benefits there are with spraying.

[Will Blick]

Dan, thx for all that clarification, very helpful.... even though lots of the benefits of the Fuji are not beneficial for my use, interesting you suggest I keep it as my spray system, it must be a good system. THANK YOU for the input of the 3M system. I was deceived, as the 3M EZ listing of spray systems they are compatible with, a few pages long, did NOT list the Fuji, your link cleared that up.... Matt mentioned all the benefits I wanted to enjoy with the 3M system, specially spraying upside down.

Its funny, the first few jobs I sprayed with the HF $19 spray gun, came out pretty well...tweaking wasn't too bad, just hit a test piece till it was right. A little common sense tweaking, and I was amazed how good a low cost gun was....of course, prob. because my water based poly was "spray friendly". They were relatively small pieces...which needed several coats, as I often finish with poly and then hand buff the poly down to glass smoothness, so I require a thick coat, typically 3 coats, light 600 grit sanding between coats to assure adhesion of the next coat. My experience was, the spraying took 5 minutes, the setup and clean-up between coats was 10-20 minutes (based on several factors of course). Since I use disposable brushes, spraying seemed a waste of time.... more time, more hassles, and no real benefits. But I will be doing some large pieces and need to get comfortable with a spray system...and with the addition of the 3M system to the Fuji, some of these tasks will become faster.

Sam, thx for the clarification of the HVLP issue, as it seems all these guns (compressor type and turbine type) are called HVLP.... I guess through marketing and changes in technology - the definitions have gray areas.... but basically its a pressure zone which pushes a system in the "LP" category... about 25 psi, good info.

So if I want to spray higher viscous finishes, such as some water based paints, is this one of the areas where the the LP becomes "less desirable" vs. the higher available pressure for the compressor type guns, where you have that added "higher pressure tool" available when needed vs. the Fuji? Or is the Fuji just as well suited for the higher viscous finishes as the compressor type guns? If not, I wouldn't object to buying a mid tier compressor type gun if its better suited for the heavier viscous finishes. As I assume I would not have to tweak the viscosity as required with the Fuji? I have a few small furniture projects coming up that require a glass smooth paint finish, like a piano.... any input on that would be appreciated. TYIA...

[Will Blick]

John, I had cross posted, and just read your post...

We seem to be doing similar finishing (WB only for me) and shop setups. Your suggestion of selling the NEW Fuji was what I thought Dan was going to suggest.. I realize both systems would work, specially now that that I learned the Fuji is compatible with the 3M EZ.

I thought having the added Turbine unit to deal with was an unnecessary hassle vs. the compressed air which is always charged up and ready to go. And from what you wrote, it seems I have to tweak the viscosity with either system. Your post made me think.... a big advantage of the turbine system (or manufactured supplied air supply unit, regardless of what its called) ..... is when using oil based finishes, as the water in a compressor tank would not bother a water based finish, but can create problems with an oil based finish. Is this a fair assessment? If so, less value in the Turbine for me :-)

added:
I do realize an oil based compressor "can" introduce oil into a WB finish, but the volume of oil is so small, and cheap filters seem to solves that issue based on your input.... Water in compressed air tank is the big variable....as my tank can go from having virtually no water in dry desert climate, to loaded with water when certain conditions present themselves (high humidity, then lower ambient temp. after air is compressed). But since most WB finishes are not effected by the addition of small amounts of water, I would think blowing out the water in the tank before starting (I set-up blow-out valve at bottom of tank), the added water will be consistent enough where it becomes a non-issue. agreed?

[Scott Holmes]

Will,

Your requirements and mine are similar...

I have a high end Air Assisted Airless unit that will spray anything I put in it. Cleaning it is a pain, so is the 50' twin hose. For small jobs using a 1/2 gallon of finish to get it to the tip of the gun is foolish. It uses a 1-1/2" pick-up tube like an airless spray painter, so to do small jobs in the shop it not worth using it. When I'm on a job site the AA airless is the tool of choice. It will outperform any HVLP system out there.

You can get a much better conversion gun for the same money as the HVLP package system...

I'm looking at a few different conversion guns now for small stuff in the shop. I'm leaning toward the gravity feed gun that Jeff Jewitt sells at Homesteadfinishing.

[Will Blick]

Thanks for that feedback Scott... the Fuji keeps the finish at the gun, not dragging it through the hose, so I don't think that comparison is applicable, unless I am missing something. But your point about a better conversion gun for what the new Fuji can fetch new, is what I was thinking...
But I would feel better if Dan blesses this strategy.... :-)

I will check out Jewitts site...

[Daniel Berlin]

John, I had cross posted, and just read your post...

We seem to be doing similar finishing (WB only for me) and shop setups. Your suggestion of selling the NEW Fuji was what I thought Dan was going to suggest.. I realize both systems would work, specially now that that I learned the Fuji is compatible with the 3M EZ.

I would suggest that if you were going to be a high volume auto shop user , but your not, so it's not really worth going and getting a different setup when you've got a fairly high end one already.
Don't get me wrong, compressed air based systems are great. But this is not a "A > B" situation, it's a "both work fine for most users" situation.

If you sold your Fuji and got $800 for it, you could certainly buy whatever compressor based HVLP spray gun setup you wanted, but i'd have to say it is fairly unlikely you will get better finishes or spend less time cleaning up after spraying for it, so it just seems like a waste of time to me for your needs. Certainly you could go get a pressure feed gun with the new pressurized PPS system and spray whatever you wanted. In reality, most people don't spray a wide variety of stuff, they spray a sealer, a single finish (pigmented or not), and maybe some dyes or stains (which if you want to spray, you'd actually want a separate smaller gun setup).

I'll tell you what, if you find you are actually unhappy with the turbine system, i'd be happy to trade you one of my high end conversion gun with a 3m pps setup for it. I have both small and large cups for it

You should call Jeff Jewitt, and ask him. He's a good guy, but i'm pretty sure he'll tell you what I just told you.
Basically you are asking if you should sell your high end luxury car to get a different manufacturer's high end luxury car when all you want to do is drive to the grocery store 3 times a month.

You should definitely do what is going to make you happy, and to be honest it sounds like you want to do a conversion gun because you think its better. In that case, I can tell you that some guy on the internet telling you it isn't better, just different, isn't going to make you stop "wondering" when you use your Fuji.

I thought having the added Turbine unit to deal with was an unnecessary hassle vs. the compressed air which is always charged up and ready to go. And from what you wrote, it seems I have to tweak the viscosity with either system. Your post made me think.... a big advantage of the turbine system (or manufactured supplied air supply unit, regardless of what its called) ..... is when using oil based finishes, as the water in a compressor tank would not bother a water based finish, but can create problems with an oil based finish. Is this a fair assessment? If so, less value in the Turbine for me :-)

added:
I do realize an oil based compressor "can" introduce oil into a WB finish, but the volume of oil is so small, and cheap filters seem to solves that issue based on your input.... Water in compressed air tank is the big variable....as my tank can go from having virtually no water in dry desert climate, to loaded with water when certain conditions present themselves (high humidity, then lower ambient temp. after air is compressed). But since most WB finishes are not effected by the addition of small amounts of water, I would think blowing out the water in the tank before starting (I set-up blow-out valve at bottom of tank), the added water will be consistent enough where it becomes a non-issue. agreed?

Yes.

[Will Blick]

thx Dan... from the start you were clear, either will work fine for my small needs.... if this was gun A vs gun B, I would have no issues...

My only issue with the Fuji being ideal for me.... the added burden of the turbine, when in the end, its just another thing that can fail, storage, bring it in/out, etc., with what appears to be very little or no benefits in my case... specially that you confirmed the water in the tank for WB finishes negates that potential problem (vs. OB finishes). Your input educated me on the value of an all-in-one type system, thx for that...

Since you have a lot of experience at this, if you were to buy a new compressed air gun today, knowing it was going to work with the 3M EZ, any models you suggest?

[John TenEyck]

Let me say again that I've never had any trouble with water or oil from my compressor causing problems with either WB or solvent based finishes. I only spray WB in my basement shop, but I have sprayed solvent based paint in my garage. Draining the compressor tank prior to use for spraying together with the in-line filter seems to be enough to keep anything from reaching the gun. I've sprayed more than a gallon of finish on some days and still never saturated one of those filters. It doesn't sound like you either do or want to spray every day. If that's the case, there is no need to spend a lot of money on a high end gun, IMO. Pros can justify the $500 or more for one because they work flawlessly for weeks, months, years, with minimal maintenance. But the lower end guns will work for years of occassional use with minimal maintenance, and I can't see any difference in the quality of the finish they lay down. I bought 3, gravity feed, HVLP guns for about $120, a 1.0 mm touch-up gun, a 1.4 mm gun that I use for stuff requiring only minimal thinning, and a 1.8 mm gun for thicker stuff like most paints. They all spray great. With the filters, gun regulator, etc., I have less than $200 invested and don't see a need to spend more. Because the cups sit on top of the gun there's no wasted finish and clean up is easy. Dump whatever is unused back in the thinned container, take it to the sink and wash it out, then spray an ounce of alcohol to remove any remnant water. 5 minutes max., done.

The key to spraying is getting the viscosity adjusted correctly. OK, technique counts, too, but the stuff coming out of the gun has to be right, first. I got some guidelines from Jeff Jewitt's website, bought a cheap viscosity cup and use it religiously with every new finish. I've sprayed little boxes with clear coat, a kitchen full of doors and drawers, and painted large china cabinets with these guns with no complaints on finish quality. Hey, you can spend as much as you want, but my experience shows me that you don't have to spend a lot to get very high quality.


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[Howard Acheson]

Will, there are two types of HVLP systems. One is based on the use of a turbine for the air supply. The second uses a conventional compressor as the air supple. Both are HVLP.

Most professional finisher, including Jeff Jewitt, like compressor HVLP systems better. The guns produce a finer spray and the air is not heated as happens with turbine systems.

[Will Blick]

Thx John, nice post...
I understand the viscosity issue.... you thin the finish, if required, to work within the guns viscosity specs. Some thicker finishes and paints possibly can't be thinned enough to meet the guns spec, and the finish makers spec of dilution, so what is the fix? Can you change the spray tip diameter, to widen the viscosity parameters the gun can handle? The gun I used had a 1.2mm diam tip, which just happen to work great, prob. dumb luck the few times I used it.

Howard, so HVLP definition widens even further.... I will get Jeff J's suggestion on gun on Monday... he has quite a line-up on his web site, thx for tip...

[Daniel Berlin]

Thx John, nice post...
I understand the viscosity issue.... you thin the finish, if required, to work within the guns viscosity specs. Some thicker finishes and paints possibly can't be thinned enough to meet the guns spec, and the finish makers spec of dilution, so what is the fix? Can you change the spray tip diameter, to widen the viscosity parameters the gun can handle? The gun I used had a 1.2mm diam tip, which just happen to work great, prob. dumb luck the few times I used it.

Howard, so HVLP definition widens even further.... I will get Jeff J's suggestion on gun on Monday... he has quite a line-up on his web site, thx for tip...

Yes, you can change needle/nozzle sizes, and if you tell Jeff what you want to spray, he can tell you exactly what tip sizes go with what gun.

As for your earlier question, the 3m system works well with almost all guns you can find.

For your needs, my guess (without knowing anything about your compressor other than it's 60 gallons), i'd say the QS-600WB would probably be a good choice. I can't imagine your compressor doesn't have the output to handle it, it sprays nicely, it won't break your bank, etc.
They are actually LVLP guns, which means they will output finish a bit slower than HVLP guns, but you won't care

[Will Blick]

Dan, thx for gun suggestion..... I assume you are suggesting a LV gun since I don't finish much, and therefore speed is not an issue... I am curious, what are the benefits of LV vs. HV? better atomizing?

I have a basic CH Borg type 60 gallon compressor.... Its set up with filters, water drain cock etc. How does the compressor specifics effect how the guns perform? Thx again for all your input....

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[Daniel Berlin]

Dan, thx for gun suggestion..... I assume you are suggesting a LV gun since I don't finish much, and therefore speed is not an issue... I am curious, what are the benefits of LV vs. HV? better atomizing?

Better Atomizing and it can output the more finish in less time. The fan pattern may be wider as well.
LVLP has a bit higher transfer efficiency than HVLP however.

I have a basic CH Borg type 60 gallon compressor.... Its set up with filters, water drain cock etc. How does the compressor specifics effect how the guns perform? Thx again for all your input....

The only effect is whether they can enough air to keep up with the gun's requirements or not. It otherwise doesn't matter at all.

[Will Blick]

Dan, can you explain transfer efficiency? I assume it means more finish makes it onto the surface vs. being wasted from over-spray?

I would be stunned if this compressor can't keep up with that gun, at least at the pace and volume I do :-)