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Thread: Tips on first Spray-finish job?

  1. #1

    Tips on first Spray-finish job?

    I have finished many products by hand, but have decided to invest in a Fuji mini-mite 3 HVLP for my current project, which is a quarter-sawn red oak secretary desk. Wondering if anyone had some good tips on do's and don'ts for my very first spray-finish job. I will be staining with General-Finishes waterborn stain, and then High Performance for the top coat, as I am trying to stay away from VOCs as much as possible. I did get a respirator, which I plan to use.

    From what I've seen in research (you-tube, here, etc.), it seems like it should be fairly straight forward, as long as I do some testing on spare wood to dial in spray pattern, speed, & etc. I got the 1.0mm tip for the stain coat, and have the 1.3mm that it comes with for the high performance, which according to the Fuji website should be about right (though I will check with the viscosity cup, of course).

  2. #2
    Join Date
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    Your 1.3 N/N should work well with HP Poly, though you may have to thin it a few percent. HP Poly sprays very easily and is a good choice for your first spray project. That said, practice on scrap first. Can't emphasize that enough.

    John

  3. #3
    Tip: All dust you didn't clean up will end up in the finish.
    Practice. Sanding sealer is good for practice. Make sure your stance, positioning of the work piece, and handling of the gun are comfortable. Hearing protection can make the work less taxing. Be sure to clean up right after you finish spraying.
    Chris

  4. #4
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    Waterborne finishes "raise the grain". That's just the nature of the beast. Be prepared to de-nib. I usually do it after the second coat. De-nibbing is very light sanding. It is surprising how little sanding changes the surface from rough and nasty to nice and smooth. I use 800 grit.

  5. #5
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    Having just gone through this learning curve, my advice is that getting the stain even and not streaky will be the tricky part. I wasn't using stain, but garnet shellac, and getting a nice even color took some practice. Practice (a lot) on some scrap, and spray light coats; it's very hard (at least for me) to get even color when spraying a heavy coat. You can always do another pass with stain if you want more color.
    --I had my patience tested. I'm negative--

  6. #6
    Quote Originally Posted by Jamie Buxton View Post
    Waterborne finishes "raise the grain". That's just the nature of the beast. Be prepared to de-nib. I usually do it after the second coat. De-nibbing is very light sanding. It is surprising how little sanding changes the surface from rough and nasty to nice and smooth. I use 800 grit.
    I’m pretty sure that is the same sprayed vs hand finished! I don’t have a spray booth, so will likely be spraying outside, and just sand down any dust nibs. The wb poly is supposed to set up fairly quick when sprayed.

    Actually, I was planning on stealing an idea from the wood whisperer and make an initial pass with just water to practice and get the grain raising done and sanded out before my wb stain goes down.

    I will be doing some samples and practice this weekend while the last of the desk gets clamped and dried.

  7. #7
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    You can pre-raise the grain with distilled water and then knock down the fuzzies before putting your first coat(s) of finish on. You will still need to de-nib after that initial finish application as there will still be a little bit of grain raise. Even with shellac, there's a need to do this very lightly because wood is wood and it wants you to work for your end result.
    --

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

  8. #8
    It took me a little while to get used to spraying color and the overlapping. Practice, practice, practice. I found using some large pieces of cardboard work well. I still prefer to wipe the stain by hand - I just feel I have more control.

    The one thing that helped me get a handle on how thick I was spraying the clear coat, was picking up a mil guage. Once I figured out what a 2-3mil thickness looks like when spraying, it helped me dial in the spray gun and be more repeatable.

    https://www.amazon.com/TCP-Global-Th...a-794176278679

    I have the same Fuji spray system GFHP is really nice to spray and does a great job. Have fun with it - it really changed my outlook on finishing. I cant wait to get to the finishing stage now.

  9. #9
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    Having just gone through this on my first project, I'd say budget a gallon of finish and a couple spare sheets of plywood or other material for test runs and practice. I hung up sheets of rosin paper that made my spray pattern easy to see. There are a variety of parameters you'll want to adjust, and it seemed to me that the optimal settings on the gun changed as I picked up a little experience. Several days of practice and fooling around, a few minutes of application to the actual project and it came out OK. Doing it every day for a month would be ideal in terms of developing technique and muscle memory, but there's no way I can make that much stuff.

  10. #10
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    Make a spray booth. I just had a thread on the one I built, my second but first in my new home.

  11. #11
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    Amount of overlap depends on the shape of your fan. An oval shaped fan that is wider in the middle, and tapered out on each end is easiest to do nice overlaps. You can see from a sample spray of your fan in one place (like in a recent thread I posted about adjusting a spray gun) what you are dealing with. With that ideal, for me, fan shape, you can overlap almost half, and put about the same amount of material over any spot. It might actually not be quite half.

    Spray you fan shape, and then drop down beside it, on your test cardboard, to see about where you can do your overlap, and not load any part of the next pass more than anywhere else.

    Don't fan the fan! If the fan is not held the ideal distance from the surface, the finish may partially dry before it hits, and you end up with bumps all over the surface. The goal is to get it all to flow out flat, and level. Fanning the fan means that at the ends of the pass, the fan is too far away from the surface. Your gun manufacturer should tell you what the ideal distance is. Learn it.

    Start off the surface, and finish off the surface. Maintain the gun perfectly perpendicular to the surface. Tilted up moves the top of the fan too far from the surface, and the same the other way if tilted down. Learn to feel like your arm is a robot painting arm.

    Make sure your foot path is clear for your next pass. The hose can make you stumble.

    Practice on something that doesn't matter. Practice makes perfect. Without practice, your first project will be guaranteed to take WAY more time that it would if you have everything dialed in to start with. A quart of the finish you want to use ends up being cheap practice.

    Watch youtube videos of pros painting cars. The same techniques apply.

  12. #12
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    I am in the same situation as Evan with the same equipment. This discussion is spot on for me and I will use it as soon ass I recuperate from my recent knee surgery. Thanks for posting!
    Rustic? Well, no. That was not my intention!

  13. #13
    Quote Originally Posted by David Utterback View Post
    I am in the same situation as Evan with the same equipment. This discussion is spot on for me and I will use it as soon ass I recuperate from my recent knee surgery. Thanks for posting!

    Welcome to the party, we'll have to keep each other up to date. Did you splurge on the 3M PPS? I decided that since I had lots of interior & vertical surfaces it was worth the extra $100. Last thing I want is to be worried about spitting air when I'm doing odd angle stuff.

  14. #14
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    Evan, I honestly don't consider the PPS system to be a "splurge" after having been using it for a year and a half plus. Not only does it permit spraying things well that are very hard to spray with many guns, that "I don't care what the position of the gun is" since it's pressurized is a darn valuable feature. I have ZERO regrets putting out the $385 I did for mine because of the functionality as well as the fact that I'm getting much better results.
    --

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

  15. #15
    Quote Originally Posted by Jim Becker View Post
    Evan, I honestly don't consider the PPS system to be a "splurge" after having been using it for a year and a half plus. Not only does it permit spraying things well that are very hard to spray with many guns, that "I don't care what the position of the gun is" since it's pressurized is a darn valuable feature. I have ZERO regrets putting out the $385 I did for mine because of the functionality as well as the fact that I'm getting much better results.

    That's what everyone said in the billion reviews I read - and why I got it. It sounds like experienced sprayers can live with out it (but love it) - but it'll be even better for novice sprayers. $385 must mean you got all the sizes and both H/O cups up front? I managed to get Adapter ($25), 6-midi liner starter set ($25), and Midi H/O Cup ($50) from amazon - more than enough to use for the 1st project. If I have to refill the cups a couple times, I'll live with it. The ability to spray in any direction is /exactly/ why I thought it would be totally worth it.

    I got a couple of sample boards stained today, and went ahead and stained my loafers (which I will need to clear coat, and then mask off when I do the rest of the desk). Everything is looking fairly good so far, though I decided that doing a full coat of stain, and then wiping it off, was giving me a much better / more even look than trying to spray it lightly enough that I didn't have to wipe.
    Last edited by Evan Van Dyke; 10-11-2020 at 4:26 PM.

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