Why does this happen to me when I spray paint?

It does not matter if I use spray from a can or if I use my sprayers (I have a CommandMax and an HVLP with a compressor) but I always get spots that come out shinier than others. I spray in both directions and I try to make sure that I overlap each "pass", yet I still get spots that appear shinier than others. I am at my wits end as to why this happens to me...anyone have suggestions as to what I could be doing wrong?
  6 answers
  • Shari Shari on Aug 26, 2012
    When I use my airless sprayer, I experience this occasionally too. I typically apply multiple light coats and it seems the more coats I apply, the more even the finish becomes. Recently I read (but I can't remember where) that it can happen when the paint mist is very fine and it more or less "dries" in mid-air before it touches whatever you are painting. I don't know if that is really true but it seems to make sense, I suppose. We both live in hot climates so perhaps our weather is contributing to the problem.
  • Spray painting can be a bit of a challenge at times. If the final finish is part gloss and part dull, a few things can cause that. 1 The surface of the object your painting was not properly prepped. 2. The paint being applied is drying to fast because of uneven coats. 3. The method of application or mixing of the paint to accept the HVLP sprayer was incorrect. 4 all of above. What type of paint is it that your spraying? Latex, Enamel, Lacquer? Oil base? Remember gloss is determined by drying time as well as thickness of the finish. If the paint drys really fast, it does not have time to flow to become smooth enough to become glossy. Putting on to much paint at one time can cause runs, but to little can cause it to dry and not flow properly. Some manufactures put additives in their paint to increase gloss such as found in hand held spray cans. Some provide a additive that you can put in yourself to help with this finish. All is determined by what it is that your spraying and what your spraying with. The trick is to do a thin tack coat. Let it set up for a few min then one more heavy coat, just enough to cover the surface, but enough to allow it to flow. The tack coat or first coat will help prevent some of the runs one gets when trying to put it all on in just one pass. Also with a HVLP sprayer, you need to have the adjustments set just right. If the thickness of the product is to heavy, then you need to push more air into the gun to make it spray out. The result is that the air flowing is drying the finish even before it comes into contact with the surface. So play with the thickness of the paint. There should have been a special tool shaped like a V that came with the gun. This checks the viscosity of the paint so you know if you have properly thinned it or not. After some use you will begin to get a feel and see of the paint just by watching it run off of the paint stick stirrer
  • Terri D Terri D on Aug 26, 2012
    Thanks so much for the replies. it seems there are many factors that are possibly causing my problems! It makes a lot of sense that heat is a big factor. I am using latex paint that I did thin a little for the sprayer. I am also guilty of doing heavier costs. Eddie multit thin coats. patience is not my strong suit!
  • Terri D Terri D on Aug 26, 2012
    sorry, that should be "versus multiple thin coats"...darn spellcheck!
  • Woodbridge certainly covered everything that I would have guessed. Spraying is not as easy as one would think. It takes a practice and being able to adapt or almost "feel" the product and your equipment.
  • KMS Woodworks KMS Woodworks on Aug 27, 2012
    About the only spraying I do is some occasional clear lacquer, My shop is not heated so during the winter I need to run my propane heaters...I have found temp to be a critical factor is how the finish performs. Too hot and the finish can get spotty. I also find that "over spray" can really be much worse. When working a large horizontal surface I like to get some good low angled "rakeing light" and start spraying in the foreground and work may way "away" from where I started. This prevents over spray from landing on the finish.
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