Results 1 to 10 of 10

Thread: Paint problems

  1. #1
    Join Date
    Dec 2012
    Location
    Providence, RI USA
    Posts
    1,339

    Default Paint problems

    Hello Forum,

    I think I may be having my first experience with amine blush. I got through my last build with no blush issues.

    So I decided to paint the inside of my CB trunk a light color so I could better see in there if there was a problem in the future.
    I had glassed the inside, and after the epoxy had cured, I noticed that if i ran my fingers along the (dry to the touch) epoxy surface,
    i would see and feel a slight "smear."

    I figured this must be the fabled "amine blush," so I washed with water and a Scotch-brite green pad. Seemed like the blush was gone.
    I applied a coat of TotalBoat gloss white using roll and tip method. I've used this paint many times with no problem.
    After a week of curing time, though dry to the touch, the paint gums up sandpaper and is a bit sticky. When I went to wipe the sanded area down with Lacquer thinner to remove the dust, the paint came off down to the epoxy as shown in upper left of first pic.

    I figure that at the least, I need to get all this paint off, since it has not bonded to the epoxy. What then?

    It's weird, because I had done the CB the week before with no problem. Second pic.

    Should I abandon the paint idea and do another layer of epoxy and graphite?
    How should I prep the surface in either case?

    Thanks!

    Mike

    [IMG]IMG_1317 by Michael Owen, on Flickr[/IMG]

    [IMG]IMG_1318 by Michael Owen, on Flickr[/IMG]
    "near it, a small whale-boat, painted red and blue, the delight of the king's old age."

  2. #2
    Join Date
    Jun 2007
    Posts
    616

    Default Re: Paint problems

    Regardless of whether you paint or re-epoxy you need to get the blush off. Epoxy will not adhere to surfaces contaminated with amine blush. Assuming your epoxy is really cured I'd go at it with Scotchbrite, water and dishwashing detergent. If that doesn't work, white vinegar. Still not working? Acetone but all traces must be removed before recoating. If the epoxy didn't really cure then it must be removed.

  3. #3
    Join Date
    Apr 2014
    Location
    Anchorage, Alaska
    Posts
    259

    Default Re: Paint problems

    Check out this article...
    http://epoxyworks.com/index.php/minimizing-amine-blush/

    Note the paragraph that says, "​Blush is water soluble and can be removed with an abrasive pad and water, after the epoxy has cured hard. 3-M Scotch-Brite® General Purpose Hand Pads or similar abrasive scrunge pads work well for abrading and dulling the shiny surface. Detergents and solvents are not required or recommended for removing blush."

    The poxy must be cured hard. Otherwise blush continues to form during subsequent curing. There is a misconception out there that scraping soft poxy removes the blush.

    Most poxy disaster stories begin with "I wiped the surface with [detergent/solvent/ammonia/vinegar]"

    Your issue may not be blush...it may be poxy mixing, ratio and/or curing.

    Also check out
    http://epoxyworks.com/index.php/avoi...contamination/




  4. #4
    Join Date
    Nov 2011
    Posts
    5,204

    Default Re: Paint problems

    Read this (way too techy),

    http://www.huntsman.com/performance_...20-%202013.pdf,

    or just this;

    Amines form on the surface when epoxy resin is exposed to CO2 and/or moisture in the air.

    There are ways to avoid this;

    Don't use a heater that produces CO2 as a byproduct of combustion, such as a kerosene burning "salamander" heater.

    Don't apply epoxy when the relative humidity is high.

    Apply epoxy in a very warm environment. The heat will accelerate the curing and lower the relative humidity. The more quickly the epoxy cures the less time there is to react with CO2 and/or humidity.

    Allow as much "induction" time as possible before applying the epoxy. Induction time is the time the mixture is allowed to begin it's cure in the mixing container where there is a much lower ratio of CO2 and moisture absorbing surface area to volume than when it is spread thinly on a surface.

    Not confirmed in the above link, but it has been shown many times that adding citric acid to the water to clean off amine does help. White vinegar contains acetic acid, which many say works as well. While any acid residue will affect the bonding of subsequent applications of epoxy, minute amounts (wash it off with pure water and a clean rag) don't appear to affect the bonding of paint and varnish.

    Amine continues to form on the surface until the epoxy is entirely cured. Heat it, keep it heated for 2 or 3 days. Wash it with water and a scotchbrite pad. The scotchbrite scratches the surface and provides tooth. Alternately, use wet or dry paper and water. Either way, rinse it well once it has been scrubbed.

    I suggest that you sand off any paint, heat the work for a few days, then clean it well and paint it.

  5. #5
    Join Date
    Mar 2010
    Location
    Woodinville, Washington
    Posts
    60

    Default Re: Paint problems

    I am not at all familiar with the brand of paint you mentioned, but do know that laquer thinner is a terrific paint stripper. It will dissolve some kinds of paint nearly instantly. So maybe you are dealing with two separate issues: Amine blush, and a reaction to the thinner.

  6. #6
    Join Date
    Dec 2012
    Location
    Providence, RI USA
    Posts
    1,339

    Default Re: Paint problems

    Thank you all. Lots of good info here.
    "near it, a small whale-boat, painted red and blue, the delight of the king's old age."

  7. #7
    Join Date
    Apr 2015
    Location
    St. Helens, Oregon
    Posts
    1,044

    Default Re: Paint problems

    Another question would be; what kind of epoxy did you use inside the CB trunk? Some seem to blush more than others. I'd also check the tech guys at Jamestown Distributors and see what they have to say. I'm just starting to try some of the TotalBoat stuff, so I'm watching with interest

  8. #8
    Join Date
    Dec 2012
    Location
    Providence, RI USA
    Posts
    1,339

    Default Re: Paint problems

    I used WEST. Same as I always use. It's what I first started with and i'm too superstitious/set in my ways to change!

    After reading the above, I think temperature might be the culprit. That, and I may have used the slow hardener that I had on hand.
    I did clean off the blush, but maybe not enough.

    Thanks to Mo'poxy for the link to "Epoxyworks."

    Mike
    "near it, a small whale-boat, painted red and blue, the delight of the king's old age."

  9. #9
    Join Date
    Dec 2012
    Location
    Providence, RI USA
    Posts
    1,339

    Default Re: Paint problems

    P.S. I used TotalBoat paint on my other build and it was fine.

    [IMG]profile by Michael Owen, on Flickr[/IMG]
    "near it, a small whale-boat, painted red and blue, the delight of the king's old age."

  10. #10
    Join Date
    Nov 2011
    Posts
    5,204

    Default Re: Paint problems

    "I used TotalBoat paint on my other build and it was fine."

    Understatement.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •