HVLP Spray Gun FAQ’s

by Patrick Harmon June 13, 2016

HVLP Spray Gun FAQ’s (Frequently Asked Questions)

How Do HVLP Spray Guns Work? – HVLP Spray Guns have different paths that material and air travel through. When material leaves the fluid nozzle air is injected into the material by an Air Cap which then breaks up the material that is being sprayed. HVLP spray Guns use a High Volume of Air at a Low Pressure to Effectively Break apart the coating.
Why Use a HVLP Spray Gun? – An HVLP Spray Gun will have a greater transfer efficiency than most forms of spraying coating including airless and conventional spray guns. For an overview of what is meant by transfer efficiency you can review this article here.
How is an HVLP Spray Gun different than a Conventional Spray Gun – An HVLP Spray Gun requires a higher volume of air than a conventional spray gun. Volume of air refers to the Cubic feet of air that a spray gun uses when being used. All industrial compressors provide similar pressures of air but have varying amounts of air volume that they will provide. An HVLP Spray Gun will therefore typically require a larger compressor though there are a few HVLP Spray Guns that can work with smaller compressors (they usually will be limited though on coatings that they can effectively atomize more so than HVLP’s using Higher air volumes (CFM).
Is HVLP required in All Industries and States? – No it is not required in all industries federally spray gun requirements are based on industries and are set by the EPA. The EPA has a great site with a lot of sources on emissions regulations including spray guns here. Additionally there could be local or state based rules that will require your particular painting to need HVLP, this is something you can check with the state office for your EPA and they should be able to guide you to a proper local contact.
How much Pressure Should I Use? – With HVLP spray guns there is typically a maximum pressure listed on the air cap which allows the gun to maintain HVLP efficiency. The air pressure into the HVLP Spray Gun should be at most the pressure that is listed on the air cap. The less pressure you can use while still achieving a satisfactory finish will help in maximizing your transfer efficiency which will help in keeping your costs down.
Are There Different Types of HVLP Spray Guns – Yes there are two ways which air is supplied to an HVLP Spray Gun and three ways which fluid can be fed to an HVLP Spray Gun.
- Air Can be fed to an HVLP Spray Gun via a turbine unit which uses a series of fans to provide high volumes of air at low pressure to the spray gun. It can also be fed by a traditional air compressor . For an overview of Turbine vs Compressor HVLP Spray Guns here is a good article.
- In addition to how air is supplied to the spray gun there three primary ways to feed fluid to your spray gun via pressure, gravity or suction. Each has their benefits and drawbacks which you can learn more about
Will HVLP Spray Guns work with my Coating? – HVLP Spray Guns work with a broad variety of coatings including stains, sealers, topcoats, enamels, latex’s, and more. The best way to know if an HVLP Spray Gun will work with your coating is to consult your Coatings Technical Data Sheet to see if HVLP is a recommended application method.
Why is my HVLP Spray Gun not working right? – Common problems with HVLP Spray Guns include they are spitting, the coating is not atomizing properly, or you are getting too much/ too little fluid. You can also review common HVLP Spray Gun Problems and their solution
How big of an Air Compressor will I need? – An HVLP Spray Gun uses a lot of air and the more you have the better. However, you will typically always need at least 8 CFM for the lowest consuming air volume HVLP Spray Gun, we recommend a minimum of 30 CFM to prevent issues with the gun not atomizing well and changes in the fan pattern occurring. You can learn more about air compressors for spray guns here.
How Can I Improve the Longevity of my Spray Gun – The best ways to keep your spray gun working well are to ensure you properly clean it and use proper sized fluid nozzles and needles. Additionally, if you are using certain highly abrasive materials like Carc it might be a good idea to consider hardened metal components. If you have to turn your fluid needle in to spray you may want to consider changing to a smaller fluid nozzle as keeping the fluid needle turned in reduces the life of your fluid nozzle and needle. You can read more tips about improving your spray guns life here
Why are HVLP Spray Guns different prices – HVLP Spray Guns vary in price based on the variety of coatings they will be able to spray, the set ups they offer, how replaceable parts are, and other factors. We have a complete guide on the differences in spray guns and why they exist .
Can you Spray Waterborne Coatings with HVLP Spray Guns? – You can spray waterborne coatings as long as
What size fluid nozzle should I use? – A basic rule is the larger the fluid nozzle is the greater volume of paint it will provide. Here is a useful guide on fluid nozzle sizes and choosing the right one for you.
Should I lubricate my HVLP Spray Gun – You should lubricate parts of your HVLP Spray Gun. The key is to use an appropriate lubricant that is non petroleum and non-silicone based.
Why do I get Coarse Texture when Spraying – Coarse texture is typically the result of having too much air press and too little fluid pressure
Why Do I Get Runs and Sags – Runs and Sages are usually the result of too much fluid and not enough air. This could be due to having your pressure pot turned up to high or having to large of a fluid nozzle.
Why Do I Keep Getting Orange Peel – Orange peel is typically due to not having enough atomization air. If you can increase your air pressure without going above the air pressure that is recommended for the HVLP gun go ahead or you may have to try to thin your paint or consider a different spray method. You can review a complete list of other common finish quality problems and there causes here.

Conclusion

By considering these questions, you should be closer to knowing whether an HVLP Spray Gun will work well for your application needs. If your setting up your paint equipment for the first time consider download our free slideshow that covers the most important topics about painting for free here.