Which airless paint spray system should you buy?
Hundreds of different airless spray machine models available, all with varying pricetags, so which airless sprayer do you need to buy?
Generally most airless paint sprayers are capable of achieving static pressures anywhere between 3000 and 3500 psi, approximately 200 bar.
So most airless sprayers have the same pressure what is the real difference? Motor size? Yes but not a good comparison method.
Consult the specifications for airless paint sprayers and you will notice that most specifications from reputable manufacturers and suppliers will include the output, or flow rate and maximum tip size capability.
This is where the main difference lies between small airless paint sprayers and large airless paint sprayers. As the airless machine increases in size the output capability increases meaning it can maintain better pressure with higher flow rates.
Basic physics cannot be avoided and as the flow of a pump increases the pressure must decrease. An airless paint sprayer achieves pressure by having its flow restricted, or decreased, by the airless spray tip.
If there is no restriction such as an airless spray tip fitted to an airless spray pump allowing the flow to reach maximum there will be no pressure.
Quickly check out this airless spray tip flow guide to see approximate flow rates at typical spraying pressures for different sized spray tips.
What this means is, lets say you purchased an airless spray machine that was capable of supporting a 0.015 inch spray tip. A 0.015 inch airless spray tip that is brand-new should flow approximately 0.72 of a litre of water at 1500 psi. As this 0.015 inch airless spray tip wears the flow rate of the tip will increase and the pressure will begin to decrease due to the output capability of the 0.015 inch maximum airless spray tip machine being exceeded.
For example if the maximum flow rate of this airless paint spray machine was actually 1 litre per minute then theoretically when the spray tip becomes enlarged through wear to a little larger than a 0.017 inch spray tip then maximum flow capability will have been reached and theoretically there should be zero output pressure.
If an airless sprayer had a maximum tip size rating of 0.021 inch and a 0.017 inch airless paint spray tip was being used theoretically the airless spray paint machine would be operating at 50% of its maximum capability.
Similarly an airless paint sprayer with a maximum tip size rating of 0.027 inch airless paint spray tip being used with a brand-new un-worn 0.017 inch spray tip would theoretically be operating at a third of its maximum output capability.
Purchasing an airless paint spray pump and using it at and above its maximum output design capability will result in high wear of components and early replacement of the entire airless machine can be expected. Purchasing a larger airless paint spray machine and using it at 50% or even 25% or less if the machine has a high output capability generally means that if the machine is maintained and stored correctly that long service life can be expected.
Always try to purchase the airless paint spray machine that has the highest output in flow and the highest maximum tip size capability that can be afforded above the maximum airless paint spray tip size that will be used to ensure there is a buffer to cater for tip wear and to avoid operating the airless paint spray pump at continuous maximum output.
Beware of claimed maximum airless spray tip specifications if a pressure attainable with that size airless spray tip is not stated!