HVLP, LVMP, and Conventional Air Caps the Advantages and Disadvantages of Each
Conventional Air Caps
Conventional air caps allow for the best atomization – heavy body materials are easily broken up with conventional air caps. However, conventional spray guns only have about a 30 percent transfer efficiency meaning you have significant paint waste. Additionally, if you are under watch for excessive emissions conventional guns will cause higher emission of VOC’s due to the lower transfer Efficiency. They are the most affordable of spray guns costing about 1/2 the cost of higher quality HVLP Spray Guns. They use a lot higher pressure which allows them to atomize a wider variety of coatings.
HVLP Air Caps
HVLP air caps are highly efficient with up to 65% of your paint hitting its intended target. They use a high volume of air at a low pressure to break apart coatings. They allow for great savings on your coating use and help with emissions reduction. However, they are not able to atomize heavy body coatings such as epoxies, heavy glues, or zincs as well as conventional caps .
LVMP Air Caps
A LVMP spray gun allows for spray finish quality similar to conventional guns, it atomizes your coating more thoroughly but will not atomize heavy bodied coatings as well as a conventional gun. LVMP air caps have a mid pressure which allows them to atomize a bit finer than an HVLP cap, this makes them a great choice for wood finishes where a finer atomization is desired. It is also more efficient than a conventional spray gun at about 60% efficient.. With so many positives why is it not the only spray gun air cap used? Mainly because if emissions need controlled the LVMP air cap will not meet regulations for emissions restriction requirements in painting in many states. However, if you are not under emission restriction, need a fine finish, and can sacrifice slightly on transfer efficiency an LVMP air cap is a great option.
General Summary – Conventional excels at breaking apart heavy materials but is not as efficient as LVMP and HVLP. HVLP is the most efficient of spray guns and will waste the least paint. A LVMP spray gun allows for high transfer efficiency with a bit of a finer breakup than HVLP.
Ultimately which of these caps is the right for your application will come down to what you are spraying, your goal for the finish, and if there are any regulatory concerns about your emissions. By knowing this information you can best match your air cap for your spraying needs and achieve the best finish you desire while not wasting excessive paint.