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Thread: HVLP...Do You Thin?

  1. #1

    HVLP...Do You Thin?

    I've been using GF HP water based poly and don't thin, but now I'm wondering if that's what I should be doing? If I should thin, should I use water to thin? Also, I just got a new HF Spectrum HVLP and want to know what to use as a cleaner before I use it? Thanks.

  2. #2
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    With lots of water based poly, you can spray straight but really depends on the individual product so check with the manufacturer. Needle size is more important I think - consider viscosity. You can thin with alcohol and I've heard of using water also. I clean up with lacquer thinner. Just some basics there as I'm not a spraybooth monkey by any stretch but I get by ok.

  3. #3
    I have not used that gun before. In general I try not to thin if I can help it.

    You can clean that product from your gun with soap and water.

  4. #4
    I have not used that gun before. In general I try not to thin if I can help it.

    You can clean that product from your gun with soap and water.

    I like using the 3m pps cup system because it saves me having to clean the cup.

  5. #5
    Thanks. For the first cleanout and oils and stuff, what do you like to use? I don’t want to destroy any internal parts by using the wrong solvent.

  6. #6
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    Quote Originally Posted by Derek Arita View Post
    Thanks. For the first cleanout and oils and stuff, what do you like to use? I don’t want to destroy any internal parts by using the wrong solvent.
    I'd likely use DNA for that.

    As to thinning, I prefer not to thin. With waterborne products, the water is just the carrier; it's not the solvent. So when you add water, you're separating the actual finish molecules more and more and your coating quality can suffer when you get beyond a certain point. Most products say not to thin more than 5-10% max. I prefer to setup the gun and use the finish as-is or with a little extender if thinning and/or extending dry time slightly will help the finish lay down nicely. (Like Prashun, I use a gun with the 3M PPS system which when combined with the correct N/N sprays nearly anything beautifully with very little or no thinning required)
    --

    The most expensive tool is the one you buy "cheaply" and often...

  7. #7
    Cool. Thanks. I’ll use DNA for the initial cleaning. I also use the 3M system, however I do clean and reuse the cups just cuz I’m cheap and they are not.

  8. #8
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    GF's High Performance has a viscosity of about 65 seconds through a #4 Ford cup. With my gravity feed HVLP gun I used a 1.8 mm needle and thinned it 6% with water. It was about the easiest stuff to spray. Since I upgraded to a pressure assisted gun, I use a 1.3 mm needle and no thinning, and it still sprays great. There's no harm in thinning up to whatever the manufacturer says is OK if that's what it takes to match the viscosity with your gun/needle. Most manufacturers say it's OK up to 10% water. I often thin WB paints 10% even with my pressure assisted gun and have never had a problem beyond an increased risk for runs and sometimes the need to spray an extra coat.

    If you are concerned about a new gun having oil, etc. in it then clean it with lacquer thinner or Naptha. When spraying WB products the only thing you need to clean the gun is soap and warm water, and sometimes a little ammonia added to it. I admit, however, that I often soak the spray cap in lacquer thinner to dissolve over spray.

    John

  9. #9
    I reuse the cups too but at least you can clean them easier than the guns cup.

    I don’t use ethanol anymore to clean my gun. Soap and water and a long rinse in the sink gets it clean.

    The gf poly should not require a solvent rinse.

  10. #10
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    Quote Originally Posted by Derek Arita View Post
    I also use the 3M system, however I do clean and reuse the cups just cuz I’m cheap and they are not.
    I think I'm on my 3rd cup liner in more than three years...with waterborne finishes, I see zero reason to dispose of them unless they get damaged.
    --

    The most expensive tool is the one you buy "cheaply" and often...

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