Better to aim for lower or higher end of tip range for HVLP spraying?

[QuailRider43]

I've been experimenting with my HVLP, still getting a feel for dialing in all the variables, so please forgive the newb question.  When two tip sizes will work for a material, or a range is stated in the recommendations, is it better to aim for lower or higher tip size?  For example, with my gun waterborne polyurethane sprays out well using either 1.3 mm or 1.5 mm tips.  I find I have to open the fan width and flow rate knobs more with the 1.3 mm, but in the end both tips seem to yield roughly similar finish quality.  Is there a rule of thumb when faced with a choice of two tip sizes?

 

[sancho57]

Though Im no expert at spraying. There are others here that are far more experience with spray equipment then I am. If it were me and I was getting the same results from either N/N sets it wouldn't matter to me. I was at Mohawk today discussing the HVLP I just picked up and it has a 1.0 nozzle. They told me that my set up was good for about 90-95% of the products they carried including General Finishes Enduro.

as long as it sprays well and my results are good. Im happy.

 

[wptski]

Use a paint film thickness gauge and go by the product's TDS.

 

[tjbnwi]

No, if given a range of tip sizes use the one you have in that range.

Spraying is often a moving target unless you have total control over the product and environment. The talent in spraying is learning how to adjust for the variables we cannot control.

Tom

 

[JCLP]

I agree with Tom. Use what you have. Is one needle size better then the next. Probably, but remember that at the end of the day if you are happy with the final coat then you are doing it right.

By the way, with my Fuji Q5 dialed down to about 3/4 power, I use a 1.0mil needle for Poly and Lacquer and I also use 3M PPS pressurized cup with my T70 gun. I very happy with the final results, therefore I must be doing something right.

Cheers,
JC
BTW I do spray General Finishes Poly as well.