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Painter dudes,, Humidity and priming

Discussion in 'The Hokey Ass Message Board' started by Von Rigg Fink, May 25, 2011.

  1. Von Rigg Fink
    Joined: Jun 11, 2007
    Posts: 13,418

    Von Rigg Fink
    Member
    from Garage

    Looking for advice from the painter crowd

    on Humidity and priming of raw (new) steel

    with the typical automotive primers, is there issues with trying to lay down some primer in high humidity? I forgot the name of the product but its a typical high build sandable automotive grey primer

    all we have been having the past 2 months have been rain, and today was no different..seems like 3" of rainfall in just the past few hours:eek:

    what say you?
     
  2. Biggest reason I have a window AC unit for the shop. Not to cool the shop (crazy insulation, so it stays pretty cool) but to decrease the humidity in the shop.
     
  3. Von Rigg Fink
    Joined: Jun 11, 2007
    Posts: 13,418

    Von Rigg Fink
    Member
    from Garage

    Im well insulated, but i dont think that helps much with the amount of precipitation we have had..its just crazy wet up here
    I have a humidistat in the shop..im afraid to look at it

    should i just go for it? does primer behave badly in high humidity?
     
  4. theHIGHLANDER
    Joined: Jun 3, 2005
    Posts: 10,245

    theHIGHLANDER
    ALLIANCE MEMBER

    I say this...heat the garage and dry it out. That way you have no issues. It was a bigger problem in the days of lacquer primers but trapping moisture is never good. I forgot what your exhaust plan is but with temps near 60deg you should heat up fairly fast. Get some air movement to go with that heat and you'll be fine. You have a propane torpedo heater, right? And a wood burner too?
     

  5. Von Rigg Fink
    Joined: Jun 11, 2007
    Posts: 13,418

    Von Rigg Fink
    Member
    from Garage


    Oh hey thats a great idea..

    I could fire up the wood burner..and paint in my shorts:eek::D

    the humidity is up around 78 to 80% at this point even with my over head fan on all week

    so the possibility of trapping moisture in the primer is a concern?
     
  6. I think I'd be more worried with top coat. We've primed near 80% humidity before. Never noticed an ill effect. Highlander has a great point/thought though. Dry it out some with the wood heat!
     
  7. theHIGHLANDER
    Joined: Jun 3, 2005
    Posts: 10,245

    theHIGHLANDER
    ALLIANCE MEMBER

    You want it warm anyways bro. You're probably shootin a "4 to 1" type of urethane primer, right? 4 parts primer, 1 part hardener (catalyst). That shit doesn't really like cool temps and it may "skin over" and trap solvents if it's not warm enough. 65 degrees MINIMUM. It's what, 55 outdoors right now?
     
  8. Von Rigg Fink
    Joined: Jun 11, 2007
    Posts: 13,418

    Von Rigg Fink
    Member
    from Garage

    Yeah boss, yer right.
    The Temp. sure did drop after that front went thru..and its not warming up again up here until next week..than it will go from 55 to 85!

    I was able to shoot it in my shop in the winter , but temp. was my only issue, and that was an easy one with my wood burner.

    Shit now most of my dam wood is wet:mad:

    guess its time to go score some propane
     
  9. Von Rigg Fink
    Joined: Jun 11, 2007
    Posts: 13,418

    Von Rigg Fink
    Member
    from Garage

    Thanks for the advice man
     
  10. theHIGHLANDER
    Joined: Jun 3, 2005
    Posts: 10,245

    theHIGHLANDER
    ALLIANCE MEMBER

    Nuttin to it bro...
     
  11. VOODOO ROD & CUSTOM
    Joined: Dec 27, 2009
    Posts: 1,287

    VOODOO ROD & CUSTOM
    Member

    If you are priming bare metal, make sure that your Primer is Direct to Metal, otherwise, give it a good coat of Epoxy Primer . After 2 hours, pour on the 2k primer. Humidity
    doesn't play a big role in priming. Air flow, temperature and dry time are the important
    factors. Air flow across the car will "wick" the moisture out. I hope this makes sense.

    Good Luck,
    VR&C.
     
  12. Back in the day when I was shooting laquer I always ran the heat to burn off the moisture. I ran it up to 80 or 85 degrees and I didn't run exhaust fan till all primer or paint was on the vehicle. Then I'd give it about 5 or 10 minutes and hit the exhaust fan. If you run the exhaust while you're still spraying then you are sucking humidity right back into the shop.
     
  13. Von Rigg Fink
    Joined: Jun 11, 2007
    Posts: 13,418

    Von Rigg Fink
    Member
    from Garage

    I pulled off of it guys, after the weather went thru, the humidity went up to 100%..at 62 degrees. and i didnt feel like heating up my shop to sweat like a june bride while priming..

    thanks a ton for all the advise and ways to work it

    maybe tomorrow
     
  14. i have found that urethane paint and primer actually dry faster in higher humidity. never can get it to really flow.
     
  15. Clik
    Joined: Jul 1, 2009
    Posts: 1,965

    Clik
    Member

    They say the dumbest question is the one never asked, so, excuse the dumb question from a guy that has never painted with anything but a rattle can: Hopefully I'll be painting my car soon and I live in really high humidity area between the Pax River and the Chesapeake Bay. I've noticed water based paints being used more lately and wonder if that would be a good way to go in high humidity. After all if your spraying water...
     
  16. snopeks garage
    Joined: May 25, 2011
    Posts: 556

    snopeks garage
    Member
    from macomb MI

    bare medel MUST have etch primer sprayed on first. then a 2K primer over that. its Fin primer humidity will only effect the flash time in between coats. spray it on let it tack (when you toutch it with your finger its sticky like tape) and spray another coat or just read the proper flash times for tempitures on the applacation guide that you can ask for if your buying quality primer at a REAL paint shop. no need to get tec. with primer your sanding it after just get proper flash times and your golden dude
     
  17. with the newer paints, it is more important that the air in your spray hose be dry. use a water separator and a inline dessicant dryer.
     
  18. Bondoboy
    Joined: Apr 14, 2005
    Posts: 648

    Bondoboy
    Member

    use an etch primer first (the transparent green stuff that stinks), let it flash and then 2K urethane primer. If you have bare metal it has flash rust on it whether you see it or not, and really should be etch primed, its designed just for that. You can use epoxy over the metal then prime but it doesn't adhere nearly as well as etch primer, and etch is much more forgiving to apply..
     
  19. djust
    Joined: May 31, 2006
    Posts: 1,230

    djust
    Member
    from Oklahoma

    Progress is good.
    Doing the same thing myself now.
    Media blasted, 2 coats Epoxy, Filler, 2 coats of Epoxy, 2 coats of high build 2k Primer sanded to 220 grit.
    Only a few small imperfections that showed up blocking the 2k.
    I need to work on those and shoot on more 2K then paint.
    Never done any of this before temp was around 80 degrees not sure on humidity but its all pretty forgiving so far since it gets sanded on anyway.
    Primer is very easy to shoot comes out thick and orange peely but sands easy.
     

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