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  • Sprayin Black Paint

    I have recently made my first attempt at spray painting. In the 1960's you could buy lacquer spray cans and I used to 'dabble' when I was a kid but those days are over so I need to find another means fo doing my own frames, hubs, brackets, etc. I have no intention of becoming a body guy nor do I aspire to becoming a professional painter, so I'm only looking to become proficient enough to properly spray my own black.

    I recently purchased a single-stage acrylic enamel system from a New Jersey company (Trinity1945) through a web site; www.paintforcars.com. I prepped a knucklehead headlight bracket and a panhead seat tee and had at it with my new HVLP touch-up gun; a $250 unit. My results were a little disappointing. After mixing the primer and paint to the correct proportions each coat went on quite well. I sprayed two fairly heavy coats of primer and let the parts set up for 24 hours. No drips or sags. I sprayed three lighter coats of black, hung the parts in my basement and went away on vacation.

    The cured paint looked great. The seat tee looks like a true factory-coated part; a shiny but un-rubbed finish. There was a little orange peel, but I'm told that this is almost unavoidable with the newer paints. The headlight bracket looked equally nice. As these were test pieces, I also decided to experiment with rubbing this paint out, although the factory rarely, if ever rubbed out these black pieces. I used different grit wet paper and varying buffing techniques and screwed up the finish on part of the seat tee. But once I got it down, other areas of the tee polished up quite nicely. BUT..., I am having adherence problems with the top coat. In fitting up the headlight bracket I found that the black does flake off of the prime coat a lot easier than it should. However, the primer is very well anchored.

    I sprayed the parts outdoors over two 50 (+) degree days and brought them into my warm basement after applying the last coat of the day. I used all of the manufacturer's recommended products and was very careful to mix them to the recommended proportions. I also used the recommended pressure for the HVLP gun, measured at the gun. I emailed the Manufacturer's help site but received no useable assistance. They do publish a phone number in N.J. which I haven't tried yet.

    I don't know what I did wrong, but I do believe that the paint is quite good and the Manufacturer does appear to be responsive, but I'll know how helpful they are after I call them directly. I do believe that the problem is most likely due to some novice mistake by the applicator (me). But I think is really cool to be able to do your own black, and do it well. So, I'm going to continue the learning process when the weather warms up. In the meantime, any and all constructive criticism and all recommendations are more than welcome! Thanks...
    Last edited by billpedalino; 11-28-2013, 08:49 AM.
    Bill Pedalino
    Huntington, New York
    AMCA 6755

  • #2
    Hey, Bill. Happy Thanksgiving! Did you sand the primer before you applied the black? If it is a catalyzed product, it will have hardened up too much in 24 hours for the top coat to stick. Even an un-catalyzed primer (like lacquer primer) should be sanded before top coating. If it is a "wet on wet" system, you can apply the black in a short time but 24 hours is too long. Good luck! Painting can be very fun and it is always nice to stand back, look at a nice job, and say "I did that!" Dale

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    • #3
      Dale,

      Thanks so much for the reply and Happy thanksgiving to you and yours as well!

      The primer and paint use a hardener so this is a catalyzed system. I asked them (through email) about the drying times and they stated that the 24-hour drying time for the primer is sufficient. However, they did not state that the primer should be sanded. I guess that they assumed they were communicating with a knowledgeable paint and I didn't ask the right questions. So the sanding that you suggest makes perfect sense. What seems to make more sense is your suggestion that black be applied while the primer is chemically active so it bonds chemically rather than relying on the mechanical bond of the fully cured and sanded primer.

      Do you think that an hour after the last prime coat would be enough time to allow a proper bond for the black and prevent sagging?? On previously primed parts, is 350 paper (sanded dry) too fine a finish for the black coats?
      Bill Pedalino
      Huntington, New York
      AMCA 6755

      Comment


      • #4
        I always sand primer before paint because it is an opportunity to see surface problems like dents, scratches, and imbedded bugs, or dirt. I always block sand the primer, and use 400-600 wet/dry. I also use a good reducer, or thinner to wipe the part down and I think that softens the primer enough for the paint to get a good grip. At least I've not had a problem yet I agree with Dale that painting can be fun, and it sure is cheaper to do it yourself. Also, no one is going to take the time and care to try and do a job as well as you will on your own stuff.
        Eric Smith
        AMCA #886

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        • #5
          Bill, You are spot on about the chemical bond vs. mechanical bond. Eric has the system dialed in very well, also. What I would do is, like Eric, take advantage of the opportunity to sand the cured primer to remove any defects and start with a smooth surface. I would use 400-500 wet/dry. Get your hands on a red Scotch-Brite pad to scuff up the edges and the nooks and crannies where the paper won't go. You want to avoid sanding through the primer on the edges so go easy or just use the scuff pad. Wipe it down and apply the black. With the primer completely smooth, you will be amazed at how well the black will lay out! Dale

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          • #6
            Eric; Thanks for the suggestion - I will sand the previously-primed parts and using the reducer makes sense as well. From your experience, it looks like 400-500 paper will leave enough of a profile for the color coat to anchor to.
            Dale: On the next batch I'm going to try applying the black right at after the primer starts to set. As I asked previously, is there any rule-of-thumb for when to apply the color coat after priming ? - Do you think that 30 minutes or an hour after the last prime coat would be enough time to allow a proper bond between the prime and top coats and to prevent sagging??

            I have done my own (and customers/friend's) motors, transmissions and everything else ever since I started working in the field starting in the 1960's. While I had moved on to another career years ago, I've always kept my skills up and thoroughly enjoy being able to continuously use and hone those shills. The only thing that I never got into with any seriousness is painting. I've dabbled with spray guns over the years, but now that I'm older (and a lot more patient) I would like to do my own black correctly.
            As far as doing it myself, it's as much as a convenience thing as it is the pride in accomplishment. Where I live on Long Island, automotive painters seem to consider themselves Michelangelo even in applying the most simple coatings like the black that we've discussed. We're not talking about seasoned, expert craftsmen like John Pierce; these local guys are normal run-of-the mill painters. Furthermore, what they charge is an insult and the time that they take is yet another poke in the eye and I will no longer tolerate it. This stuff isn't hard at the level that I wish to perform, so it's worth the time to learn and tweak a technique that works for me and the product I'm using.
            Thanks again for the input.
            Bill Pedalino
            Huntington, New York
            AMCA 6755

            Comment


            • #7
              Bill, Products that are intended for "wet on wet" applications are referred to as primer sealers as opposed to primer surfacers. That's not to say it can't be done. I don't think there is any set rule of thumb for how long to wait. It would all depend on the product and the "speed" of the hardener. I would give it at least 30 minutes if you are not in a controlled environment. You should be able to see the surface begin to haze up or dull out slightly. Be careful though, you don't want to lay the primer on too heavy or you could trap solvents and lose some gloss retention in the topcoat. If I had to guess, I would probably give it a maximum window of 3-4 hours. Hope this helps! Dale

              Comment


              • #8
                perfect timing for this thread. My kids are looking to buy me a Christmas present and I said I want a spray gun. I am interested in painting (eventually) my fenders and other bits and pieces, is the HVLP touch-up gun mentioned by Bill acceptable for fenders? (I may have to settle for a similar item as I am in Canada) I as well am only interested in doing black.
                Bob Beatty
                AMCA 19209

                Comment


                • #9
                  Dale,
                  The primer that came with my paint system is a Primer-Surfacer and is mixed at 8 parts primer/2 parts reducer/1 part hardener. Can I assume that the 3-4 hour set-up time prior to the application of the top coat that you suggest above would still apply for this primer? If not, I guess that I'll have to plan on always letting the primer set and sand before applying the top coat and rely on the mechanical bond. I'm not adverse to sanding, but I would rather use that time to wet sand between color coats. Also, is there anything that I can do to minimize orange peel when applying the black coats?
                  Bob;
                  My wife bought me my spray gun last Christmas from an online source. It's a 3-gun HVLP kit (Aeropro G7000) and its a real cheapie (I checked the price - about $100). I've only used the touch-up gun so far but it seems to work fine. I am worried about replacement parts though, if I should need them.
                  Last edited by billpedalino; 11-30-2013, 05:49 AM.
                  Bill Pedalino
                  Huntington, New York
                  AMCA 6755

                  Comment


                  • #10
                    Originally posted by Bill Pedalino View Post
                    Dale,
                    The primer that came with my paint system is a Primer-Surfacer and is mixed at 8 parts primer/2 parts reducer/1 part hardener. Can I assume that the 3-4 hour set-up time prior to the application of the top coat that you suggest above would still apply for this primer? If not, I guess that I'll have to plan on always letting the primer set and sand before applying the top coat and rely on the mechanical bond. I'm not adverse to sanding, but I would rather use that time to wet sand between color coats. Also, is there anything that I can do to minimize orange peel when applying the black coats?
                    Bob;
                    My wife bought me my spray gun last Christmas from an online source. It's a 3-gun HVLP kit (Aeropro G7000) and its a real cheapie (I checked the price - about $100). I've only used the touch-up gun so far but it seems to work fine. I am worried about replacement parts though, if I should need them.
                    Any decent paint or primer should have available a manufacturers tech sheet to guide.Starting with the basic mix ratios,recoat window times,suitable undercoat and topcoats etc.Im using PPg single stage concept,and their tech sheet is the place to start,available from jobber or online.Your brand should have the same info available.
                    Tom

                    Comment


                    • #11
                      Great point, Tom! I've been painting a lot of years and still keep a technical reference manual handy. As far as orange peel, Bill, there are a lot of factors involved. First, if the undercoat has peel, your topcoat will have peel. Then gun adjustment is important. Open up the fan and cut down the material adjustment for smaller parts. I leave my material adjustment all the way open and then I can "feather" the trigger as necessary. Speed, distance, ambient air temperature, proper reduction all have a hand in this. Air pressure is a big factor. HVLP is high volume, low pressure so make sure your compressor is up to it. Above all, watch how the paint is going on. This may not be a popular statement but I paint by "feel" more than by numbers (air pressure, etc.). Practice like you have and you will get the "feel" also! Dale

                      Comment


                      • #12
                        Howdy chaps,

                        +1 on that compressor and HVLP. An even nominally undersized compressor will heat its air which creates other issues; condensation and unpredictable flow out and flash off if using shop temp based hardeners like those offered by Glasurit. This can challenge recreational painters to get consistent results with more challenging finishes like black and metallics. Though I've moved on to far better Sata products, the machine in my sig as well as many others in the links at the bottom of that site were shot with $50 gravity feed touch up gun at only 28-32 psi. Though my Sturgis shot entirely outside in our back yard, the others done in a single car garage with 5 furnace filters taped up around a box fan and the floor merely wetted. The key was compressed air as close to ambient as possible and that air temp within hardener working range.

                        Will admit though, a touch up gun has met its match when taking on skirted fenders.
                        Cheerio,
                        Peter
                        #6510
                        1950 Vincent - A Red Rapide Experience

                        Comment


                        • #13
                          Thanks again for the replies.
                          I'm using a large commercial compressor capable of over 30 cfm at about 90 psi coupled to a 60 gallon volume tank, so air volume/pressure are not an issue. It also looks like the cheapie touch-up gun I'm using is fine for the frame and small black parts when I learn to get it dialed in correctly.
                          Because I'm am now a engineer by profession (with all the accompanying anal characteristics), I certainly did have all of the product technical sheets with the stated inter-coat and drying times so the information has been available since I started this process and I augmented this information by communicating online with the paint Manufacturer (Trinity1945). Unfortunately, the Manufacturer did not state that the primer must be sanded after waiting the specified 24 hours after priming; an experienced painter would have known this. That's why Dales suggested top-coating right after priming seems so logical (chemical vs. mechanical bond).
                          HOWEVER... It's mostly academic now as I've decided to go with another paint system. Trinity1945's acrylic enamel seems to work fine but I'm turned off by the long term performance and color loss of the enamel. Therefore, as long as I'm in this learning curve I'm going to switch to a single-stage 2K urethane paint. The reason for the single-stage system is that from what I'm reading from professional painters, the urethane clear coat causes a tint or haze when applied over black or white urethane base coats. Also, the clear coat contains most of the Isocyanides, so even though I use proper safety precautions and PPE I would like to minimize my exposure to these VOC's. It seems that as I become older I become more mortal - funny how that happens!
                          I'm now thinking of the DuPont Nason Super Jet Black or possibly a single-stage PPG paint. Unfortunately this will cost more money, especially if I can't use the catalyzed Primer-filler that I'm currently using for the acrylic system (any thoughts on that??). But as long as I'm doing the research and the work, I may as well end up with the longest-lasting coating possible, given my limited experience in painting.
                          Thanks again to you all for all of the pushes in the right direction!
                          Last edited by billpedalino; 12-01-2013, 12:06 PM.
                          Bill Pedalino
                          Huntington, New York
                          AMCA 6755

                          Comment


                          • #14
                            Here's a website with a bunch of painting info and how-to videos by a professional: http://www.thepaintspot.biz/
                            I just met Rick a week ago and he's attempting to guide me through bringing my VL tanks back from the dead. He's not a member...yet, but I'm working on that.
                            Rich
                            Rich Inmate #7084

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                            • #15
                              Thanks Rich. Lots of information on the web, unfortunately much of it is conflicting. I just have to jump in and do it while augmenting my knowledge online.- ThePaintSpot.biz is one of the better web sites. Work on Rich; I'm sure he would become a valued AMCA member.
                              Bill Pedalino
                              Huntington, New York
                              AMCA 6755

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