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Thread: micro bubbles in finish, need help

  1. #1

    micro bubbles in finish, need help

    So, my boss finally got us automated not long ago, we have a small buisness that makes bleacher boards for school gyms, we use the same waterborne poly that is on the gym floor & one of the machines that he got was a older Falconi spray pod & conveyor line, pic below.



    Up till now we have been using an airless system to hand spray the boards, supper flat & very good finish, but this thing uses air & now we are getting tiny miro bubbles in the finish, I have searched online for a solution, we even have our poly supplier looking into changing our mixture, they have now introduced alcohol to it, but still getting the bubbles, I've tried turning down the air pressure, but that just leaves me with to thin of a layer, we have to get a decent build on these, any help would be appreciated, thanks.
    Last edited by Ed Page; 09-19-2017 at 5:55 PM.

  2. #2
    I do autobody work and it sounds to me like moisture from your air compressor system. Either a lack of driers or ineffective driers. Talk to a local compressor installation company.

  3. #3
    Join Date
    Apr 2016
    Location
    Tasmania
    Posts
    2,162
    I have run paint and polish shops for years. Some things to look at are:

    Air incorporated during mixing prior to application. The wrong type of mixing paddle or wrong technique will do this

    Curing too fast. Not enough time allowed for out gassing.

    Contaminated air supply as Bob said - either water or oil or both

    Pinhole leak in the fluid line

    Bad batch of product. Get your local rep to put you in touch with the chief chemist at the factory and talk direct to him. Salesmen aren't necessarily allowed enough technical information.

    Let us know how you get on. Cheers

  4. #4
    Join Date
    Dec 2010
    Location
    WNY
    Posts
    9,648
    Following up on Wayne's point, I've had this problem when I sprayed too thin a coat at very dry conditions. The bubbles don't have time to break before the film dries. I solved it by spraying a thicker coat but I would have added retarder/extender had that not worked or had the coating thickness already been thick enough.

    No clue how adding alcohol is going to help. Maybe it lowers the surface tension, but it would also likely increase the evaporation rate. But I'm no finish chemist.

    John

  5. #5
    Join Date
    Apr 2016
    Location
    Tasmania
    Posts
    2,162
    The alcohol bit puzzles me too. It's why I suggested talking directly to the chemist. Cheers

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