sata mini jet 4 hvlp questions.

[eugene thomas]

I have a sata mini jet 4 hvlp spray gun. It came with a 1.2 tip set. when i spray big projects like kitchen cabinets even when thin way down so get good flow the finish not alwice look good. Do i need to buy some different tip sets or ???? I have plenty of air and already played around with the air pressure. hard to exsplain how looks. maybe have to go out to shop and post pic of the less than steller look.

thanks all eugene

[Mark Kornell]

What kind of finish are you spraying?

[eugene thomas]

i generaly use pre-cad satan laquer finish.

[Nick Sorenson]

i generaly use pre-cad satan laquer finish.

Well the first thing you'll have to do is get satan out of the mix, that may be part of your problem sorry couldn't resist. What you're saying is "Satin".

Anyways it's hard to say what the problem could be without seeing what the piece currently looks like, the technique, and the product your spraying. Here's my technique for spraying almost any product:

-Not always necessary but I recommend reading the data sheet on the product. If you don't have it, it's usually on the manufacturers website if you search. If it's Sherwin Williams Pre-Cat, it's most likely there and it'd be called the PDS. You want to see equipment what they recommend to apply the product. Some products are made for Airless, some for Conventional, some for HVLP. Usually you can thin whatever it is to make it spray reasonably well if it's too thick out of the can. I like around 14-18 seconds out of a #4 Ford viscosity cup for my air powered HVLP guns.
-Set the air pressure in the range between 30-60 psi. Higher pressure gives better atomization, but you don't always want that because it also blows the wet finish around on the piece if it's too high. My guns like 30-35 psi, and a touch-up gun like your Sata might like even less.
-Set the fan to medium-wide to wide (too narrow and it'll blow the finish around and look uneven) and too wide and it's hard to get a wet coat. I usually set it in the middle or to just shy of the widest.
-Set the fluid control to where it gives you a wet coat (as in you can see reflection of the lights above the workpiece) without runs or trapped solvent pop bubbles. You can get too much lacquer on the workpiece. You just want a wet coat while moving the gun at a rate you're comfortable with. Too dry and it won't flow or look good and too wet and it will run or solvent pop. Adjust exactly to where it gets a nice wet coat and maybe a hair more, but not too much more though; you don't want runs.
-If I can't easily get a flowing wet coat as described, I thin the product. I find 50/50 works good for many lacquers through conventional air powered guns. Sometimes you can get away with using it right out of the can but I don't find most products to work like this.

Beyond that it should go just fine. How old is the lacquer? Pre-Catylized products have a Pot Life. If it's more than a few months old I'd check into this. Again, read the Product Data Sheet if you can get it.

Lastly, I should add that your Minijet's 1.2mm is sort of a touch-up size needle/nozzle. I've used small guns for spraying clear and it works but it's slow progress. If I'm in a hurry or if time is more important than money, I'd get a regular sized gun and maybe between a 1.4 to 1.8 tip size. I like to have around a quart cup and if the project is big I like to have a few gallon pressure pot.