HVLP question

[Jon Grider]

I'm considering purchasing the Fuji Q3 orQ4 HVLP system. My question pertains to the guns; What are the relative advantages/differences in the gravity fed vs. pressure pot guns? I will be using it primarily for furniture work with some trima nd large surface painting as well. Thanks in advance for any help.

[John TenEyck]

Gravity feed guns are quick and easy to clean. They are more unbalanced than a pressure pot gun and are more difficult to get into tight interior spaces. Pressure pot guns are smaller, have better balance, and are easier to maneuver into smaller spaces and can spray at any angle, even upside down. You can spray and spray until the pot is empty. You also can spray higher viscosity finishes through a smaller orifice than with comparative gravity feed guns. Cleanup, however, is another story and is a lot more involved than with a gravity feed gun, and you will lose significantly more product during cleanup. IMO, gravity feed is better for low volume work while pressure pot guns are better suited to high volume work.

John

[Mike Henderson]

John covered it well. A pressure pot gun is very nice but they're expensive compared to gravity feed guns and they are a mess to clean up. They're excellent if you're going to be doing a lot of spray work of one kind (where you don't have to change the product).

I don't know if you're getting your first HVLP gun, but if you're just getting started, let me recommend a conversion gun - assuming you have an air compressor. They're much less expensive because you're using your own air compressor. If you go that way, get one with an air regulator at the gun. That way you can leave the compressor set to high pressure.

But if you need to take the whole set up to a customer location, something like a Fuji is a good way to go.

Mike

[John TenEyck]

Just a follow up to Mike's recommendation to get a conversion gun if you already have an air compressor. And you don't need to spend very much money to get very good results. I recently tried one of HF's HVLP guns, bought it on sale for $12.95 mostly as a lark, and it sprays shellac and WB topcoats beautifully. Here's a photo of a project I sprayed with it; shellac then EnduroVar.

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John

[Jon Grider]

Thanks for the input John and Mike. This is my first foray into the HVLP world. I do have a compressor,but it's a small pancake unit and I'm not sure if it has the capacity to run the HVLP gun from HF. That was an option I thought about after reading the good reviews on this forum and others about the HF gun. I see from John's photo the beautiful results obtainable with that gun. So what size compressor do you use with that gun, John? Besides occasional use of the finish nailer that came with my PC kit, I don't use air powered tools much, and instead of purchasing a bigger compressor, I'd rather put the money into the Fuji system. If, however a pancake is enough compressor to use the HF gun, that would be a good starting point for me.

[Mike Henderson]

I've used a pancake with a conversion gun. But there are a couple of problems. One is the noise - most pancakes are LOUD (if you can put the pancake outside and run the hose through a mostly closed door, it helps). The second is that the pancake may not be able to keep up with the air needs of the conversion gun. That's not a problem if you don't have really big things to spray. You can spray a bit, then wait for the compressor to catch up.

But with the gun I used with my pancake, the pancake was able to keep up. I can't say whether your compressor would be able to keep with with the HF unit but at the cost of the HF unit it would be worth a try. It might keep you from having to spend close to $1,000.

Mike

[John TenEyck]

IIRC, that gun needs about 4 - 5 CFM @ 40 psi, but I only run it around 20 psi at the gun so I think it actually needs even fewer CFM. I have a 60 gallon compressor that puts out 10 CFM at 40 psi so it's not an issue for me. BTW, I bought it used for about $300 more than 4 years ago and it runs great. Anyway, I've used my 3 gallon nailer compressor in a pinch and it worked OK as long as I waited for it to catch up when it kicked on. You could add a 20 gallon air tank to it for not much money and that would give you a lot larger reservoir to draw from and longer spray times before the compressor cycles. If you don't spray too often, it could be an acceptable route, at least to start with. Most projects don't need more than 1 or 2 minutes of air to spray a given part, a table top, for example.

John

[John Huds0n]

Are you going to be spraying any latex paint?

I think one of the main advantages to the pressure pot is you can turn up the pressure to the pot to force the fluid to the tip of the gun - instead of having to thin it out excessively.

Also, I don't really think cleaning one of these is any harder than a gravity fed gun. Depending on the size of your pressure pot, you can actually use a container inside of the pot. (I sometimes use 1 pint wide mouth mason jars for example). With a 5' line set, it takes less than 2 ounces to fill the line, and most of that will drain back into the container when you disconnect the gun. When using water based products, I drain the fluid line back to the pot, connect the end to my faucet and proceed to flush the line and the gun - which is the bulk of the work

The main drawback is portability compared to a turbine powered system and I did not like trying to spray with basically a garden hose attached to your gun

[Chris Merriam]

Back to the original question, did you mean to ask about gravity vs. a pressure pot or vs. a siphon-feed gun? Because your options with the normal Fuji units are gravity or siphon. I think you can buy an add-on pressure pot, but it would be an extra 300.