Junk in Base Coat – Assistance Needed.

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  • January 25, 2010 at 4:45 am #18895

    Hi Guys,

    I’m going to need a little help with this one. I’ve been struggling with an old hood that I’m using on my car project. It was sitting outside under a tree (where I bought it from – I’m not that dumb) and I’m having one hell of a time getting all the junk out of it. There was a bunch of rust/paint chips etc, so I fixed all that up and epoxied it. I’d blasted it out, pressure washed it, blasted again and no matter what I do there is still junk coming out of the crevices. After the epoxy, I hit it with some UPol 2K primer (dam that stuff is thick) and finish sanding it. More junk. I took it back to the car wash and blasted the hell out of it again.

    Then one final clean and a blow off with my gun when I tacked it up for the sealer. Everything is golden with the sealer coat. No junk in the sealer. I’m doing a little dance :exci . Then after the sealer dries, I hit it with my base coat and wouldn’t you know it – I’ve got junk (pieces/chunks of crap) in the flaming base coat (SW Dimension) :cens .

    So now I’ve got to sand it off and blend it in…right? I’m sure it will happen again, but I’m mostly worried about the sanding of the base and the re-application. What do you do when this happens? I should have posted before, but thought I had it licked.

    Here are a few shots of today’s progress.

    I had just enough paint (a liter) for two medium coats. How much should I get to do the outside…I’m not that good at estimating paint volumes and since switching to the Iwata, I’m using a lot less paint.
    [img]http://www.calgaryvolvoclub.com/gallery/d/19392-1/bottom_hood_base.jpg[/img]

    Here’s the engine bay.
    [img]http://www.calgaryvolvoclub.com/gallery/d/19394-1/engine_bay_base.jpg[/img]

    Little stuff turned out great – here are the hood hinges and the rad support. The rad support back side is getting painted off the car as it would make putting the engine in a pain if it were installed and I’ll have to figure out what to do with the bolts etc on the top side of the rad support when I get it installed. I’m thinking some new bolts would probably be in order.
    [img]http://www.calgaryvolvoclub.com/gallery/d/19396-1/hood_hinges_rad_support.jpg[/img]

    The paint store made a mistake and mixed me a liter of the colour in single stage…so the trunk got done as well. I’m very pleased with the finish, but it is difficult to take a picture of this area in the garage.
    [img]http://www.calgaryvolvoclub.com/gallery/d/19386-1/Trunk-1.jpg[/img]
    [img]http://www.calgaryvolvoclub.com/gallery/d/19388-1/Trunk-2.jpg[/img]
    [img]http://www.calgaryvolvoclub.com/gallery/d/19390-1/trunk-3.jpg[/img]

    January 25, 2010 at 5:03 am #18896

    Just trash in your base coat?
    Just level the trash out with 800 and throw another coat on.
    You can either lightly blend out the area. or just throw another coat on the whole thing.

    You get more, wait at least 30 minutes (Or longer depending on temp/film build, yada yada yada) hit it with 800 and base it again… (Be careful. the edges of your paper will put ruts into the soft surface.)

    Now if this is single stage.
    Choose rather your a picky bastard. and if you are, hit it with some 2000 and buff it out.

    I’ll tell you now. Don’t go too far in your engine compartment.
    You’ll only screw it up during reassembly. Murphy’s law… :S

    For some reason if you let a few boo boo’s slide. it doesn’t seem to get scraped up as much during reassembly… Call my crazy, but that’s how it works for me.

    January 25, 2010 at 5:09 am #18897

    Another thing to mention is if you’re getting a ton of shit in your basecoat. You’re probably hammering it on too wet. It isn’t clear. it doesn’t need to be a lake.

    Once you learn not to put your base on so heavy, the trash becomes minimal to non existent in your base.

    Just remember, never leave trash in your base if you plan to buff. If you can physically feel it to the touch, You’ll cut right through the clear on the high spots while buffing.

    January 25, 2010 at 5:44 am #18898

    I only used a liter for all you see there (hood, rad core support, hinges and engine compartment) – so I think I was OK for film thickness. I’ll hit it with 800 and get it done tomorrow. It’s looking good so far and I won’t be polishing out my engine compartment (done it before and I did hit it with the engine on the way in…you speak the truth :rofl .

    So there is no problem with going straight over the base with a third coat after drying over night at 20 degrees C (sorry I don’t know F…about 70 ish?). I’ll probably wipe over the entire area with 800 just for giggles. Then let it dry of a day and clear it. Sound like a plan?

    What about product volume? Am I going to be OK shooting the entire outside (including jams) with around a gallon of base (including my 3 rd coat outside). Then I have to clear the entire car. I’ve got a gallon of clear ( with hardener I think it is 5 liters sprayable).

    Craig

    January 25, 2010 at 6:55 am #18901

    For an overall (Including jambs) I always buy a gallon (3.78 liters) of the main color. And I usually use about 3.5 quarts (3.31 Liters) of it.

    Your car is a little smaller than most things I’ve painted.
    I would say 3 quarts (2.8 liters) is probably do-able.
    But I would buy the gallon anyways. Always better to have too much than not enough.
    And the worse thing you can do is run out of base and get another quart mixed. They’ll never get the mix identical and It is always a shade off. (Been there done that…) :whistle:

    And having a little extra gives you room to make some errors. and redo some parts, and even have some left over for down the road.

    Like I said, if you’re getting much trash, just lighten up some.
    All putting base on too wet will lead you to is mottling. (Metallics will begin to float)

    With base you should (Most of the time) be just wet enough that you can still wipe your mild trash out with a tack rag before the next coat. If you’re burying it, just lighten up a tad.
    And to be honest, I’ve never met a painter that didn’t start out putting base on too heavy. It’s just our nature to make it shiny. :lol1

    And you’re using Sherwin Williams DIMENSION Basecoats?
    Nope. just hit your Trash and shoot over it.
    Unhardened base coats are open indefinitely.
    Meaning Solvents will forever be able to penetrate them. And you will always be able to achieve a chemical bond over it.

    But me personally, I would never wait after a few days, base coat becomes too dirty after just a few days and requires an extra coat before going straight to Clear.
    If I was going to scuff my unhardened base. I would see no reason to do it as long as you keep it within the 7 day window.

    With Hardened basecoats I think typically you’re looking at 2-4 days before you have to scuff.

    So you don’t have to scuff your base. Just go right over it with another coat of base, and then clear.

    January 25, 2010 at 9:56 am #18902

    OK, so I just wait the required hour or whatever and hit it with the clear. Sounds like a plan. I’ll lighten it up on the touch up coat.

    Anonymous
    January 25, 2010 at 5:01 pm #18904

    I’ve noticed on some replacement panels the undersides have had a bunch of crap in the e-coat which can make it look like the underside of a panel is completely loaded. Didn’t have time to read the whole thread, don’t know if those are new parts or what.

    January 25, 2010 at 9:09 pm #18905

    [b]Canuck wrote:[/b]
    [quote]Hi Guys,

    I’m going to need a little help with this one. I’ve been struggling with an old hood that I’m using on my car project. It was sitting outside under a tree (where I bought it from – I’m not that dumb) and I’m having one hell of a time getting all the junk out of it. There was a bunch of rust/paint chips etc, so I fixed all that up and epoxied it. I’d blasted it out, pressure washed it, blasted again and no matter what I do there is still junk coming out of the crevices. After the epoxy, I hit it with some UPol 2K primer (dam that stuff is thick) and finish sanding it. More junk. I took it back to the car wash and blasted the hell out of it again.

    [/quote]

    Doesn’t sound like fun :S
    So does it look like the blasting material thats coming out? :unsure: Or is it the dirt and debris from sitting?

    Short of drilling it apart and cleaning it thoroughly about the only thing you can do is keep blowing it out, Me being me I would probably drill a few extra holes and slide a blow gun with a long tube down through the structure on the back side then weld the holes shut after I was sure.

    January 25, 2010 at 9:46 pm #18906

    Screw that, if I ran into a trunk lid that was like that, I’d just masked it and do a clean seam seal job on it… Keeps the shit in and doesn’t look too bad either. :lol1

    January 26, 2010 at 1:27 am #18909

    [b]RatStang wrote:[/b]
    [quote]Another thing to mention is if you’re getting a ton of *** in your basecoat. You’re probably hammering it on too wet. It isn’t clear. it doesn’t need to be a lake.[/quote]
    Until you move to water base of course, when just short of running is ideal 😉

    January 26, 2010 at 1:54 am #18912

    some cars i worked on like Nissan had an under hood color that was achievable by just tinting the sealer. id leave it at that.

    January 26, 2010 at 3:00 am #18916

    Ok, the base is on and went on fine this time. I used my mini gun to cut in the edges and lock the sh!t down. I’m not going to worry about trying to get the clear to go all the way under the edge – so that, knock on wood, should be the end of this fiasco. Thanks for the tips – this base/clear stuff is pretty neat so far (I’m so far behind in paint technology…). Gotta go set up the fresh air system to put on the clear.

    January 26, 2010 at 5:33 am #18921

    OK – here’s the results. I’ve very pleased with the overall finish. There was still some dust nibs in the hood in the end, but I’m giddy about the results. It’s going to be very hard to get an engine in there without screwing something up. Here are some pics.
    [img]http://www.calgaryvolvoclub.com/gallery/d/19398-1/drivers_side.jpg[/img]
    [img]http://www.calgaryvolvoclub.com/gallery/d/19400-1/drivers_side_2.jpg[/img]
    [img]http://www.calgaryvolvoclub.com/gallery/d/19402-1/drivers_side_booster.jpg[/img]
    [img]http://www.calgaryvolvoclub.com/gallery/d/19404-1/hood_corner.jpg[/img]
    [img]http://www.calgaryvolvoclub.com/gallery/d/19406-1/hood_finished.jpg[/img]
    [img]http://www.calgaryvolvoclub.com/gallery/d/19408-1/passenger_side.jpg[/img]
    [img]http://www.calgaryvolvoclub.com/gallery/d/19410-1/rad_support.jpg[/img]

    That’s two coats of clear over the base. I’ve never shot paint this good before (Iwata LPH-400 rocks) – first time at base clear. The second coat of clear is sort of hard to see going on, but I was sort of shooting by feel and used the bottom up technique I learned on this forum so I could sort of see the wet edge. Engine bays are the worst to paint but this one is done. Thanks again boys – now to get the outside done.

    January 26, 2010 at 11:14 am #18924

    Very nice. Get that sort of finish on the outside and I’m sure you’ll be very happy.

    January 26, 2010 at 2:22 pm #18926

    that looks nice and neat mate good job :woohoo: and the best thing about a bay like that is its open at the front so its very easy to get in and out of and to paint.

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