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Epoxy primer under body filler?

Discussion in 'The Hokey Ass Message Board' started by rustyironman, Aug 16, 2012.

  1. LOL just wait until you price out the paint. You might want to read through this thread.

    http://www.jalopyjournal.com/forum/showthread.php?t=694175&highlight=paint+costs
     
  2. shadams
    Joined: Mar 16, 2011
    Posts: 1,492

    shadams
    Member

    Yea I read that. But it doesnt really sink in until you are about to start on it yourself. I went back and re-read it and yea, its gonna suck....Its no wonder rr's and patina are so common...
     

  3. I tell everyone that will listen. When it comes time for body and paint materials, expect it to cost around $2k. Could even be more depending on what colors and paint style. A solid color will be cheaper than a candy or a flame job etc.

    I know it is expensive, and I am not for a minute going to try and justify it. But when you stop and think about it. The cost of body and paint is usually around only 10% of the cost of the rest of the build. And yet, it is the first thing people will see and judge your car on.
     
  4. HighSpeed LowDrag
    Joined: Mar 2, 2005
    Posts: 968

    HighSpeed LowDrag
    Member
    from Houston

    I like a couple coats of DP on the bare metal. I let it sit a few days, I block the DP with 180. See the low spots and hammer/dolly/shrink/stretch as needed to get metal closer. Block the DP again. When it's really close, I scuff the DP and shoot another 2 coats of DP. Then 2 days later I will scuff the DP with a scotch brite and shoot 3 coats of primer/surfacer. I block the primer out with 180 and apply filler as needed.

    My thinking, right or wrong, is that the DP under the primer and filler acts as a moisture barrier. Keeps my primer and filler from getting moisture from the back side. I also shoot a coat of DP as a sealer before the base coat.

    Just my way.
     
  5. Schmidy
    Joined: Mar 1, 2011
    Posts: 58

    Schmidy
    Member
    from Minnesota

    I would find a local supplier if you are going to be buying alot, they should be able to help you out on price. I tell people, on a complete paint, you can look to spend around $3000 in liquid products. If you want to do it the right way. I went to school for this, been doing it for 11 years, on regurlar hours I can have the PPG rep on the phone with any questions I have. A lot of times a person will blame the product for failures but most of the time it is because the operator did something wrong. I have made a lot of mistakes in my years and most of them were my fault and if you are not making mistakes you are not learning.

    I will stand behind the DX1791 then DP90LF. They are good products when dome right. Get the product data sheets when ever you get a new product. My cars would sit in bare metal for a long time before I would get to filler and that is just not good, flash rusting starts very quickly with temperature change.

    Also, I would like to point out if you prepared a panel months ago and it sat for a period of time you have to resand that with some 80 grit before you DP it. Also, clean the metal with a wax and grease remover first and where gloves, there is alot of oils and salt in your hands. CLean is the name of the game.

    So in short, Clean 80 grits sanded metal, wax and grease remove, tack it, DX1791 wash primer, 2 coats of DP90LF, Filler work, recoat with DP90, then if there is big filler work I use a Slick sand or feather fill from evercoat, or you can go to a DPS3055 surfacer, I really like this surfacer. This surfacer can not be put over bare metal. So if there is a bare metal spot before surfacer, DP the spot.

    And yes, this stuff is expensive.
     
    Natypes likes this.
  6. Schmidy
    Joined: Mar 1, 2011
    Posts: 58

    Schmidy
    Member
    from Minnesota

    I see this statement very often "do not put filler over primer". DP90LF is a epoxy primer. BP is not a primer for filling, it is not a surfacer. The product is made to prevent corrosion. They make other products for block sanding.
     
    Natypes likes this.
  7. CutawayAl
    Joined: Aug 3, 2009
    Posts: 2,144

    CutawayAl
    Member
    from MI

    The product sheet for DP talks about using it for high build. At least it still did as of about three or 4 years ago. I have used it for high build many times. When doing that it's important to allow sufficient cure time between coats, and to let it fully cure a minimum of a week and preferably several weeks. If not fully cured there is the possibility of shrinkage issues, and, it won't sand well.
     
  8. 1949*john
    Joined: Jul 27, 2010
    Posts: 57

    1949*john
    Member

    Hey Rusty ! I learned at a very young age to listen to every body and pick out the things that make sense . so please pay attention to what I'm going to tell ya .

    the best job is to use The P.P.G. , DP90 and wait at least 24 hours before doing anything , give it a chance to harden . just make sure the surface is wicked clean .

    now just do a little experiment . after your panel has set for 24 hours . lets say its a fender mix up a little evercoat filler and don't apply it directly to the panel , just hold
    the squeegee above the fender and let a little filler drizzle onto the fender , don't squeegee it , and let it set for a while and then try to flick it off with your finger nail
    the only way you can get that off is to sand it off .
    Than is called a chemical bond .

    If you could magnify the surface of bare metal many many times you would see something like little fish hooks and that is where the dp90 works better than body filler , and this is called a mechanical bond

    I have been doing restorations for a long time and this is the way i do it .

    one job comes to mind ,about 1980 34 five w the sheet metal was pitted pretty bad so after i got done sandblasting ( 60 lbs air pressure ) i gave it 2 coats of dp90 waiting a day in between and then applying the filler .

    ok , visualize this , again magnify the pitted sheet metal many times and ask your self which would fill these Pitts better , by spraying of by trying to squeegee the filler in to them .
    and as far as media blasting you can use dp90 but here again it's gotta be clean clean clean , re sand if you have to but get rid of the residue left behind from the media .

    i have had panels in the back room for 6 months and just revive with a squirt of dtl16
    will bring it back.

    dp90 can be used as a sealer also but you reduce it a little ,, 10% i think

    check the car out on you tube at hardcorehappenings .
    white 5 w
     
  9. 1949*john
    Joined: Jul 27, 2010
    Posts: 57

    1949*john
    Member

    the LF on the dp90 stands for lead free .
     
  10. CutawayAl
    Joined: Aug 3, 2009
    Posts: 2,144

    CutawayAl
    Member
    from MI

    I think it really stands for: not as good as it used to be.:D

    It's still a great product, but it was better before they removed the lead and revised the formula to make it less deadly. With a little thinning it sprays more like the old stuff, but that increases shrinkage and reduces build. When not painted over LF doesn't protect the metal like the old stuff did. At one time guys from MI were bringing in the old stuff from Canada, where it was still available. I understand that's over because all they have in Canada now is LF.
     
  11. blowby
    Joined: Dec 27, 2012
    Posts: 8,661

    blowby
    Member
    from Nicasio Ca

  12. In the trade for over 40 yrs. Yes you can put filler on over roughed up epoxy if its real thin. I still like to grind the bare metal with a 36 grit for the bondo to adhere to and put the filler on after a fresh grind. I've seen to many panels with hair line splits after a few years because it really doesn't adhere well enough. The key is trying not to load up with a bunch of product under the paint. especially incompatible products.
     

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