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Paint gurus- DuPont Centari questions

Discussion in 'The Hokey Ass Message Board' started by xlr8, Jul 22, 2008.

  1. xlr8
    Joined: Jun 26, 2006
    Posts: 700

    xlr8
    Member
    from Idaho

    I'd sure appreciate some expert advice, I wanted to paint my son's '63 Pontiac in the original light aqua color. Went to the local paint supply place and told the gal there that I wanted a paint that would be safe to paint with a respirator as I dont have a full booth or air supplied mask, and she fixed me up with Centari. She scanned the color and came up with a Mazda color that is a metallic, apparently with a little bit of iridescent. The color looked spot on, but it seemed like there was a dark blue tint that didn't mix in no matter how long i stirred it. So I sprayed it today and sure enough, it goes on and looks pretty good then all of a sudden it shows up too much of the dark tint and leaves a blotchy or tiger stripe look to it. So what now? Am I an idiot or was this paint mixed wrong or is this just how this stuff is. I'm no painter, most of my experience is doing tractors and heavy equipment, never seen anything as hard to paint as this stuff. Also, to finish up some overspray and other minor glitches, is it better to buff or color sand Centari? Any help would be much appreciated.
     
  2. 31aBoy
    Joined: Sep 17, 2006
    Posts: 634

    31aBoy
    Member

    does it look like zebra stripes?
     
  3. 37fordtruck
    Joined: Jan 28, 2006
    Posts: 157

    37fordtruck
    Member

    It has been way too long since I've delt with Acrylic Enamel paint. As I remember my boss shooting it, he would put about an inch or two of mixed paint in the cup and then fill with reducer. The pressure was turned up and additional 20 or so pounds and the gun was held about 2 feet or more away from the car, then he would go over each panel in a random way. This would "flow out" the metalic. When the car was dry it looked great.
     
  4. xlr8
    Joined: Jun 26, 2006
    Posts: 700

    xlr8
    Member
    from Idaho

    31aBoy, yes, it's kind of a zebra stripe effect, and in some places more of a fisheye type appearance.
     

  5. bumpybigblok
    Joined: Feb 26, 2008
    Posts: 247

    bumpybigblok
    Member
    from Midwest

    Centari is not for beginners. I hope you bought the hardner. Centari will krinkle if you redo without hardner. To avoid tiger stripes , spray 50 lbs. at the gun with wide fan setting. Spray 3 medium wet coats then add some reducer to the mix,(25% more) and fog it. Back away to 18ins.
     
  6. 53chieftian
    Joined: Aug 13, 2005
    Posts: 611

    53chieftian
    Member

    The stipes are easy to end up with and a pain to get rid of! But it happens often with metalic paints.
     
  7. xlr8
    Joined: Jun 26, 2006
    Posts: 700

    xlr8
    Member
    from Idaho

    bumpy, I've sprayed Centari some with pretty good luck, but I've never done metallic. I thought it would be a learning experience, but I think I'm learning more than I wanted to, lol. I didn't use hardener, so what do I do now?
     
  8. publicenemy1925
    Joined: Feb 4, 2007
    Posts: 3,187

    publicenemy1925
    Member
    from OKC, OK

    My rule of thumb is never shoot metallic single stage paint. The thin and fog method over a semi wet coat works good. Going back over your last coat the opposite direction to blend out the stipes. Rule two, Always shoot with the hardner.
     
  9. BigChief
    Joined: Jan 14, 2003
    Posts: 2,084

    BigChief
    Member

    Metallics are the hardest paint to do correctly and require some specialized and well practiced techniques to avoid mottle and zebra striping ESPECIALLY with single stage acrylic enamels....as you've just learned. The modern base-clear systems work so, SOOOOOO much easier with metallics its not even funny. Without the hardener you'll need to let it sit and cure, seal it and reshoot it. I shoot PPG so a Dupont guy will have to chime in on the bloody details but I'd suggest spending the bucks on a base-clear if your going to stick with that particular color.

    The dark swirlly you describe while mixing the gallon of paint is common with metallics. Keep, keep mixing. The swirl following the paint stick doen't usually totally go away, its the nature of the beast.

    Good luck with it.

    -Bigchief.
     
  10. bumpybigblok
    Joined: Feb 26, 2008
    Posts: 247

    bumpybigblok
    Member
    from Midwest

    I'm not going to stick my neck out here and tell you what to do now, cause your in a touchy situation. Go to your Dupont supplier and ask their advice. They could have a sealer that might save you from pulling all your hair out when the redo blows. I haven't shot enamels in years so I'm not your best advisor. I use urethanes in single, twostage, and tri-coat systems and prefer PPG products.
     
  11. Skrayp
    Joined: May 31, 2008
    Posts: 197

    Skrayp
    Member

    If you buff a metallic single stage paint you're gonna change its look, because you will be cutting into the metallic. Like these other guys are saying, it's a good idea to over reduce it a smidge and/or use a slower reducer so your dry spots flow out. You want to use hardener to catalyze the paint, leaving it hard and somewhat impermeable by fresh paint or solvent laying on it. I you don't harden it, the underlying paint will re-wet or "re-flow", causing it to wrinkle. If you're gonna have to repaint it, I would seal it first. Try a test area to see if it will hold up. I always used Velvaseal underneath it or the Nason version. Its more or less lacquer, but I never had a problem with it. Or you could step up to prime n' seal, its epoxy.

    When you do an overall with a single stage metallic, the best way to lay it out is to walk the entire length of the car for your pass. It takes a steady hand and a lot of patience, but by the third coat you should have it straightened out. Like these other guys are saying, keep the fan as wide as you can without having a dead spot in the middle. The old Binks model 7's and 62's were ideal for this old paint but they are pretty wasteful. I like to mix it in the old formulation, which is 2 parts color,1 part reducer, and 4 oz of hardener to every unmixed quart. You can use either 793 Dupont hardener or Mar-Hyde "Wet Look". I wouldn't water it down until your third coat or maybe even for a fourth. You want to lay down a tack coat on the first, a cover coat or medium wet coat for the second, and a gloss coat for the third.

    Just study the car and strategize your passes. Plan out where you're gonna start and where you're gonna bring it all together. Concentrate on getting the metallic right first, then worry about the gloss. They do make clear kits for centari if you have to buff it. It can be done, it just takes practice. They used that stuff for many years. If anything you'll get an appreciation for the old schoolers that had so little to work with and could get the same results.


    ........OR you could take it back to the woman that mixed it for you , give her a little shit,and tell her to mix this color in Chromabase (premier if you can afford it) and some 7900 clear.
     
  12. docauto
    Joined: Dec 1, 2006
    Posts: 789

    docauto
    Member
    from So Cal

    I use a Binks 62 for single stage metallics. like everyone else suggests, use as wide a fan as possible, the spray pattern is causing the zebra stripes, not the paint.
     
  13. kustoms2
    Joined: Dec 10, 2006
    Posts: 127

    kustoms2
    Member

    Skrayp has very good advice and I would have to agree with it. If you use a metallic single stage and you plan on sanding and buffing it you will need to clear it or you will be sanding the metal flakes that are mixed into the paint and it will change the effects of the flake. If you are going to clear it I would stick with base clear it is easier to work with unless you are trying to restore a car back to original. Man no hardener that sucks! :(The woman who sold you the paint didn't do a very good sales job.
     
  14. pimpin paint
    Joined: May 31, 2005
    Posts: 4,937

    pimpin paint
    Member
    from so cal

    Hey,

    As directed above, you should have used a different method to shoot
    this paint. I've only ever shot Centari with a standard cup gun (Binks
    #7/36SD Tip) fan adjusted to 10''-12'', 65 pounds at the gun. A slow
    temp. reducer for the last pass, with chris-cross triggering patterns to
    unify the metalic.
    DO NOT ATTEMPT TO SPRAY A SEALER OR URETHANE OVER THIS PAINT
    JOB! An old type enamel such as Centari, when shot without hardner, will
    remain soft below the surface for months, if not a year. If painted over
    prior to becomming completly 'cured', will lift, wrinkle, sandscratch swell,
    and or all the above!
    Either remove all of the paint back to the primer or let the job dry out
    and cure for 6-12 months. Sand completly, providing the paper doesn't
    clog (this would tell you the paint hasn't cured/dried and should not be
    painted over) and reshoot with a paint that includes a hardner in it.
    DO NOT SHOOT ANY PAINT WITHOUT A PROPER MASK, FILTERS DESIGNED
    FOR THE PRODUCT YOU ARE USING, AND ATLEAST PAPER COVERALLS FOR
    PROTECTION!

    Swankey Devils C.C.
    "Meanwhile, back aboard The Tainted Pork"
     
  15. chopolds
    Joined: Oct 22, 2001
    Posts: 6,208

    chopolds
    Member
    from howell, nj
    1. Kustom Painters

    IF, IF, IF, IF
    you used hardener in the Centari....wait a couple days, sand it out with 600 wet, then lightly recolor the Centari, one full coat, then a mist coat or 2 to even out the metallic, then coat with Centari clear.
    And don't use single stage metallics any more! (except for "car lot" work)
     
  16. overspray
    Joined: Jan 14, 2003
    Posts: 1,417

    overspray
    ALLIANCE MEMBER

    Mark is right---and since you didn't use hardner, same advise-wait a couple days, sand it with 600# wet. Then I would leave it in the sun fo a couple days--maybe more--lots more--it depends.. Opening the "coat" with 600# wet sanding will help release the solvents faster and MOST Centari formulas will cure pretty well without hardner---but it takes longer, and it is not as even a cure. Give it some time in the sun--Oh yeah--unmask it before you wet sand and don't sand in the sun or if the paint surface is real hot. You can check the progress of the cure by using your fingernail to try make a dent in the paint film. If it is soft enough to "dent" with your fingernail, it will surely be sensitive to a recoat and will probably lift. It still may have sensitive areas after it firms up and doesn't "dent" with the fingernail test, but by using a recoat sealer(clear sealer would be nice) and respraying on a nice 70-75 degree day with fast and maybe a little medium reducer, you should be able to save the job. Too slow of a reducer will penetrate the paint film, on the respray, and could cause lifting or wrinkling. Get it ready the night before and paint early in the AM.

    Maybe chopolds remembers the recoat sealers numbers or names. I'll see if I can find them, also. This paint technology is 30 to 35 years old and products and numbers have changed some.

    If you are not comfortable spraying the metallic color, see if you can find an older experienced body man or painter to either spray the recoat or come over and "baby sit" the respray. If you ask around I'm sure you will find a local acrylic enamel expert that will be able to help save the project. Centari is more forgiving (recoating non-hardened paint) in this instance than comparable acrylic enamels in other brands.


    overspray
     
  17. Dads-53
    Joined: Sep 8, 2006
    Posts: 171

    Dads-53
    Member

    What Chopolds said, NEVER USE AN ENAMEL WITHOUT HARDNER, and don't over reduce the last coat to flow out the metalic, what your doing is washing the resion away from the met. and your color will have no gloss in about 60 days if not overnight. Dust the base then clear if you want it to shine and be able to buff at all.
    Don
     
  18. 8flat
    Joined: Apr 2, 2006
    Posts: 1,392

    8flat
    Member

    Do you know a painter that could help you? It's almost impossible for a beginner to shoot single-stage metallic Centari without someone with experienced right there to help you out.....you've been setup for failure. Even after a few years of painting full-time, I still had occasional troubles with it, before we switched to Sikkens products.
     
  19. 8flat
    Joined: Apr 2, 2006
    Posts: 1,392

    8flat
    Member

    I've seen this happen....not a pretty sight.
     
  20. Al Napier
    Joined: Feb 6, 2007
    Posts: 400

    Al Napier
    Member
    from Central CT

    I apologize in advance, but, the striping is operator error; you didn't spray it with the right technique and gun settings. The swirl in the can is normal.

    Don't feel too bad though, it is common and hard to avoid without some experience with the stuff.

    Best thing now is to set it out in the sun for a few days or a week, then get out the sanding block, LOTS of paper and (soapy) water because you will have clogging, and sand it *all* off.

    Anything less is a crapshoot IMHO. Sand it off and reshoot (with hardener) after sealing.

    Sorry for your troubles, it sucks doing over........

    Al in CT
     
  21. overspray
    Joined: Jan 14, 2003
    Posts: 1,417

    overspray
    ALLIANCE MEMBER

    Yup! Make sure the gun is spraying a very even pattern and watch your distance and pressure. Keep the gun perpendicular to the surface, the hood roof and trunk are the hardest panels to keep metallic even.

    I have used this sealer for recoat before.

    http://www.performancecoatings.dupont.com/dpc/en/us/html/prodinfo/oemfleet/1858S.pdf

    It is a light gray enamel sealer ( I couldn't find a clear sealer #) that is compatible under Centari. After wet sanding the color and some good dry/cure time, this sealer will work well. You will have to respray 2 to 3 coats of color and you can use hardner this time around. I would spray this sealer on the night before. It will firm up nice for solvent hold out on the recoat, and small dust nibs can be sanded carefully the next morning before respraying the color. The sealer on the entire car will NOT need to be sanded before spraying the color when left overnite. Just lightly nib sand any specs and lightly tack off the surface.

    Painting tips: 3rd video shows "cross coat" technique for wetting the paint for flow. This also works to even out metallic. Wait till the 2nd and 3rd coat to do this. After the first pass on the roof hood and trunk, keep going on to the next 2 or so panels, which gives the flat areas a couple minutes to flash, then come back to the flat panels and do the "cross coat" about 4 inches farther away to even out the metallic. You can also drop the pressure on the "cross coat" about 15-20 psi to about 35 to 40 psi. Spraying the "metallic evening coat" at a higher pressure will usually deposit more metallic on the top and lighten the tone, sometimes significantly. Increase the gun to panel distance and lower the pressure a little and move faster on your passes. Watch it flash and see how the metallic lays. It may not be perfect on the second coat but you should be able to get it even on the 3rd coat. The first coat is the foundation for gloss and is not critical for metallic layout. Some metallics will be easy to get even from the first coat on, but usually it's the 2nd and 3rd coats.

    http://www.jalopyjournal.com/forum/showthread.php?t=225633&showall=1

    Also check out the "King's" advise on technique and spray pattern adjusting.


    overspray
     
    Last edited: Jul 23, 2008
  22. xlr8
    Joined: Jun 26, 2006
    Posts: 700

    xlr8
    Member
    from Idaho

    Thanks for all the replies, I knew I could get answers here. I talked to the DuPont sales rep this morning, she said let it dry a couple days, sand it out with 600 or maybe even 800, let it dry a couple more days and then it should be ok to respray it. I guess after I sand it I'll have to make the decision about whether to seal it, she said it shouldn't need it in this hot weather but it would be necessary in colder temps. I've done some painting and like most guys on here I was trying to expand my abilities a little bit and learn something new, but this experience has kinda sucked. Thanks again for the answers, the best thing that happened is that I got on here last night and asked and didn't just go respray it this morning or I would have had an even bigger mess.
     
  23. Hate to hear your problems, but there's a lot of good advice here!
    Let me mess you up some more---:eek:
    20 years ago, when I was still spraying enamel all-overs, I learned this technique from my PPG jobber---he shot his first two coats to color and cover, placing the metallic as best as possible. Coat 3, he mixed half color/half clear and "cross-coated" like overspray referenced. The last coat was straight clear. Ideally, you end up with a slick ,deep, uncompromised finish that you can 'lightly" sand and polish if you NEED to.

    Just more food for thought ;)
     
  24. cleatus
    Joined: Mar 1, 2002
    Posts: 2,277

    cleatus
    Member
    from Sacramento

    I used to spray single stage Centari metalic a lot. I actually really liked Centari as I could always get it to gloss out better than anything else I've used since.

    I'd be pissed that she didn't sell you hardner with it. I'd start by going back to that paint store and ask what you are now supposed to do with a paint job that won't cure hard enough.

    If it had hardner it would be fixable with additional coats in multi directions (after a light sand), but I'd be afraid of adding coats to something that will remain soft indefinitely.
     
  25. gas pumper
    Joined: Aug 13, 2007
    Posts: 2,957

    gas pumper
    Member

    Geeze, I must be getting old, I remember when Centari was a new product and was SO much easier to use than DuLux.

    And everyone is right about the counter girl should have insisted on adding the hardner. Years ago hardner was optional. But the better results with it make it mandantory now.

    I'd done Centari jobs where i'd only add the hardner in the third coat, cause I was cheap, and gotten good results, no defects. Now I put it in all layers. Paint is so expensive now, a little more $$ don't seem to matter.

    But I just paint for me.

    Frank
     
  26. SlowandLow63
    Joined: Sep 18, 2004
    Posts: 5,958

    SlowandLow63
    Member
    from Central NJ

    Thats the way I do all single stage jobs. Helps to even everything out as well as bring out the gloss and depth. Just make sure the clear is compatible and when you mix it, mix the color, then mix the clear, then mix the 2.

    I still would never use a single stage for a metallic.
     
  27. sik_kreations
    Joined: Jul 14, 2008
    Posts: 436

    sik_kreations
    Member

    heres a tip that i was taught with ss metallic.
    slick ur first coat, meaning flow it out, almost like glass.

    let it flash off. spray ur second coat a medium coat., dont go to heavy, right after ur done, drop coat the side hood or whatever ur working on, meaning back away a little and spray it, criss cross if u want. this will even it out, and u dont have to add reducer or anything.

    heres the last ss metallic i did, it was for a buddy who is a desert racer
    [​IMG]
     
    Last edited: Jul 24, 2008

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