General Question: Viscosity & Air Caps

[Mike Goetzke]

I've been spraying about 4 years now. I started with popular HF 43430 conversion gun, then purchased a used 4-stage turbine system w/5-air cap assemblies, and recently (see my other post this section) bought a new Fuji Q4 Pro with 4-air cap sets.

First: I was wondering why in the Fuji manual they tell you to measure the viscosity of the finish but don't reference a needle size or air cap color set to use. They say to use your own experience and keep records.

Second: Why would you dilute a finish if you could just use a larger diameter needle instead?

Thanks,

Mike

[Michael Pyron]

one measures viscosity for uniformity...let's say you figure out that 24 seconds in a zahn #2 cup is what works best for you....you simply make it so that every product you shoot is to that viscosity...

my system will shoot lacquer easily with either a 1.2mm or 1.4mm tip...I prefer the 1.4mm tip...

as far as diluting a finish, well I don't care what the labels say, I like to reduce the stuff I use because it makes it flow out better and gives a much smoother finish...there are also various types of thinner for lacquer with varying evaporation rates...I use fast for things on a wall, and medium or slow for things like table tops....

there is also a substance called retarder....use it sparingly and ONLY when you HAVE to (i.e. it is too humid to not use it as it will prevent blushing)...I've heard plenty of people say to use it all the time...yeah...right...bleh...retarder is a 'bad' substance that changes the curing time of a product and if too much is used you will be waiting literally months for the lacquer to harden properly (don't ask me how I know this..)

[Jon Dieterlen]

I have a Fuji Q3 that I have used to spray conversion varnish, both clear and pigmented. I used a #4 tip and air cap. I'm not sure what the actual size of the orfice is. If you call Fuji (the Canada #), the guy there is very helpful.

One thing I'll tell you is, get a pressure pot. It makes a huge difference in the amount of material you can get out of the gun. You can spray more viscous material easier. I was spraying clear conversion varnish straight from the can in the summer, getting excellent results. In the winter I would thin 5-10%.


I use an air-assisted airless now. It does a better job than the Fuji, but mostly because it can lay down more material per coat.

Unless you are spraying latex (yuck), the #4 set should work fine.

Jon

[Mike Goetzke]

Michael thanks for the info - I have a lot to learn.

Mike

[Mike Goetzke]

I use an air-assisted airless now.
Jon

That's an oxymoron!

Thanks for the hints. I bought a pressure pot from HF but haven't used it yet. I think I need to c/o the pressure regulator that came with it. Maybe it's no big deal but it's the kind that doesn't bleed off air if you reduce the pressure.

Mike