Picking the correct tip and size is essential for a quality finish and ease of use. This may seem a bit confusing or complicated at first but once you understand it, picking the right tip is not rocket science and can save you time and money. To help answer the question: "what tip do I use?", please read on for recommended tip sizes for airless sprayers.
Be sure the tip you want to use is not too big for your pump. If you do not know for sure, check your manual for the maximum orifice size. The paint won't atomize if the tip is too big.
Generally, light / thin coatings are sprayed with smaller *orifice tips and thicker materials use a larger orifice tip. Many coating manufacturers list recommended tip orifice and/or recommended tips on the container.
In this case it is the hole in the spray tip that the paint passes through
The size of spray tips has two components; the fan size and the orifice size. Lets use the LTX515 as an example as it is one of the most common tips for spraying latex paint.
The fourth character, first number (5 in this case) is used for the fan size. If you multiply it by 2 the result is the approximate fan size when the tip is about 12" from the surface being sprayed. So this tip has an approximate 10" fan when the tip is 12" from the surface to be painted.
The last two digits are the orifice size in thousands. So this tip has a .015 (fifteen-thousandths) opening for the paint to go through. Orifice size is directly relational to how many gallons per minute of material will be passed through the tip.
A significant measurement used to determine the ability of an airless sprayer is its "GPM" or "Gallons per Minute". How many gallons per minute a sprayer can deliver determines what the largest tip size is that can be used with it. Also consider that when a tip wears, the orifice gets bigger so in nearly all cases you will select a tip that is one size below what the pumps maximum rating is so as not to go beyond.
If a pump is rated for a maximum tip size of .021 (twenty-one thousandths) you would not want to use a tip lager than a .019
Here is a table of some flow rates
Contrary to what some believe, airless tips actually do wear out!
Tips, like brakes on a car, wear out after a given amount of use, and there are a lot of variables that affect that amount of time; quality of material sprayed, the grittiness of the material, the pressure used etc. Also, how often, how well and with what, the tip is cleaned with (solvent type, nylon or wire brush etc) is a factor. Graco tips should last anywhere from 15-135 gallons when spraying latex. They may last longer with oils and stains and may last up to a few hundred gallons if spraying a thin water like material with no grit. See detailed tip info.
Something else to consider is that when a tip wears out the spray fan changes from a tight long thin rounded corner rectangle to an oval and when it is completely worn out it sprays a circle. This wear reduces the fan width which means you will have to make more passes to cover the same area. Also as a tip wears out the opening gets larger so you are spraying more and more material.
At a point it becomes much less expensive to buy a new tip than to buy more paint and pay your help more to apply it not to mention the quality of job suffers, becomes poor. When a tip has lost 25% of the original fan width it is time to replace it. Example; a new tip that has a 12 inch fan pattern is considered worn out when it is reduced to a 9-inch fan. That tip is now outputting 40% more paint on 25% less area so not only are you using more paint than necessary you are also working harder.
Lets say your paint costs $10.00 a gallon, your employee costs $18.00 an hour and that individual sprays 5 gallons an hour.
If that person is using a worn tip, say a 12 inch fan worn down to 9 inches, you will spend an additional $24.50 in wasted paint and labor each hour. Assuming 8 hour days, that's nearly $200 a day! You could have bought 7 tips for that. So in reality it would be cost effective to supply a new tip to your airless paint sprayer every 1-3 days (depending on quality / grittiness of material).
Here is a general guide for airless tips as far as orifice sizes go as compared to the material being sprayed.
A basic rule of thumb is to use smaller orifice sizes for thin / low viscosity materials such as stains & lacquers then for heavier viscosity coatings use larger orifice sizes.
You may want to go down one orifice size when using some higher quality and/or higher gloss latex paints or when using narrow fan sizes.
These recommendations are based on typical 12" distance from surface being sprayed with an 8-12" fan size.
This is only a guide, the actual tip size(s) needed will vary depending on actual material to be sprayed.
*Fine Finish tips recommended. Graco RAC X Fine Finish Tips are green, start with "FFT" and end in even numbers. Some popular finish tips are; FFT310, FFT312, FFT410, FFT412 and FFT210
|Varnishes (before low VOC)*||.009||-||.011||thin materials|
|Lacquers, clear coats*||.009||-||.011|
|Stains - transparent||.011||-||.013|
|Water sealers (thin, clear)||.011||-||.013|
|Tung Oil (pure thinned)||.011||-||.013|
|Lacquers, water borne*||012||-||014||medium|
|Acrylics 100%, latex int||013||-||015|
|Varnishes (low VOC)*||013||-||015|
|Stains - solid||.013||-||.015|
|Enamels - oil-base||.013||-||.015|
|Latex paint - interior||.013||-||.017|
|Latex paint - exterior||.015||-||.019|
|Primers - latex||.015||-||.017|
|Primers - oil||.017||-||.019|