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      dpohunter


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      Post #70209, posted on 06-15-2018 GMT-5 hours    
      Seems most modelers always use flat paints for priming, in that it makes it easier to identify flaws, etc. The one time I used flats, the gloss paint used as the finish coat pulled off with the tape during masking. I've never used flat base paint since. Am I missing something?

      Never put off for tomorrow what can dry overnight

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      Jennings


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      Post #70210, posted on 06-15-2018 GMT-5 hours    
      There are about 2397 variables hidden in your question. What kind of paints? How were they applied? Did you prep the model (ie; wash it) before the primer? Temperature? Humidity?

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      lichtjahre


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      Post #70211, posted on 06-15-2018 GMT-5 hours    
      Bob,
      that is a very good question and probably something many modellers are stuck with.
      Chipping off paint with the masking tape is so very frustrating that it can ruin the joy of modelling!
      So I am trying to summarize how to avoid it once and forever:

      The solution to the problem is all about how much the primer is able to bite into the surface of the model.
      This rules if chipping of paint occurs or not when taping over.

      Every flat paint turns into a silk and gloss paint depending on how much you sand and polish it.

      Make sure your model is absolutely free of fat and oil. Wash it carefully, use acolhol to clean it and even wear gloves when touching it after cleaning.

      If possible, use the rattle can Tamiya Fine Surface Primer (available in white and light grey).

      Now, apply only a faint spray over. So few you almost dont see it! Let it dry!
      The fewer paint the better. Just some fogging! This cant be over-emphasized, because:
      This is the most important step! This is where the primer bites into the surface of the model!
      Too much paint at first is the basic reason for all the paint chipping!

      Apply a second coat. Very thin -- your plastic or resin model surface must still be clearly visible! Let dry.
      Repeat with a third layer (now the model surface becomes invisible) and fourth final layer (what I call the sanding layer) by increasing the amount of paint step by step.

      Once ready, let dry carefully and than sand and polish to the degree you want.
      Few leaves it flat but removes the unwanted orange-skin effect. More sanding makes it silk. Even more gloss.
      Sanding all your paint layers is a must! Dont be afraid of it! Use 4000, 8000 and 12000 grid in that sequence -- always under water and increasingly careful the more delicate your paint layer is (e.g. a cheatline).

      For the white surfaces, this is happily your final paint. Yes, the white surface primer is the final paint!
      When airbrushing other colors do the same, start from very few color and increase the amount slowly.

      Tape material like Tamiya Kabuki brands work great for masking.
      If you want to have it less sticky, apply it to a clean surface before applying to the model.

      With these few steps, chipping of paint will almost certainly never happen again.
      I was stuck with the exact same trouble until I learned these techniques from Kurt.

      Ever since, its so much fun to work with paint that I airbrush all larger surfaces including cheatlines and complex tail colors instead of using decals. Paint works so much better than trying to patch a 2D decal around a 3D surface. Moreover, this allows to sand and polish all color surfaces with different degrees of intensity. This results in that realistic look as on the real plane. That is something impossible to do with decals. This became my basic method for weathering to replicate worn, faded or newly patched colors. The more you sand down a color, the thinner it gets, the more translucent the base color becomes. This looks like a very sun-bleached color. This even allows to apply two different shades of the same color, a darker and a lighter shade. Sanding the top coat until the base coat peeks through makes that "desert airliner" bleaching effect.
      You can use this bleaching and fading effect on the white color as well. Start with the grey primer and add the white primer on top. Sand down to the degree where the grey starts peeking through the white in an irregular pattern! The paint layers are so thin in the end they get that "metal" effect like painted aluminum!
      And dont be afraid of making errors: If you removed too much paint at places just mask that area and patch it by spraying over the original new color. The same method is applied to the real heavy metal jets! )

      For the reasons mentioned above I believe that the "art of decaling" will be the "art of masking" in the future!
      Take Qantas as an example: Neither a white roo decal will work, nor does a huge red tail decal including the white roo will work out! Instead, if decal makers supply us with a precision mask of the roo -- all that is needed is to apply the roo mask, airbrush the red tail, remove the roo mask and there you go! Now, you can sand down the red until color fading effects become visible. A worn roo tail under the Australian sun! )

      Happy modelling!

      Cheers,
      Christian

      PS: As Jennings indicated, yes, make sure to apply different paint types in the correct order to avoid a mess!
      Always primer first, enamel second, acrylics last!

      PPS: I am curious to learn which other techniques are used in our community, its always a great pleasure to improve as nothing can ever be perfect ...

      PPPS: In case you feel that discussing this is interesting and fruitful to many of us, I can open a separate topic on this.

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      NX28388


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      Post #70213, posted on 06-15-2018 GMT-5 hours    
      Sometimes what seems like the surface of a flat coat is more like a dusty layer that doesn't have much for a finish coat to bite into. Before all my gloss finish coats I give the model a going-over with some 320 or 400-grit sandpaper. It knocks off that dustlike top layer that you can get, and it makes the surface smooth (very important for gloss paints to have) while etching just a tiny amount of tooth into the primer coat. Then I wipe the model down with a tack cloth before moving onward.

      For whatever it's worth I've used Tamiya spray primers for close to two decades and they have never given me any unexpected surprises with any kind of paint. As a bonus, they don't seem to etch seam lines and other modified areas the way other primers do. They can be expensive but they have saved me a ton of grief over the years.

      Jodie Peeler

      In 1924 Wien was Alaska's first airline. In 1980 it still is.

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      Tango-Bravo


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      Post #70239, posted on 06-21-2018 GMT-5 hours    
      Until my supply finally ran out, I used Floquil gray primer (enamel) exclusively as a base coat; it was flat and... well-thinned with MM thinner for airbrushing it gave a smooth (enough) surface that well-thinned gloss paints applied over it became virtually smooth as glass, and... the primer coat adhered securely to plastic lightly 'roughed up' with fine grit wet/dry sandpaper and sprayed clean with a strong mist of plain water, which also also served to remove any lingering surface oils, and... Model Master gloss enamels applied adhere securely to said primer coat -- never a problem with 'lifting' when masking is removed. Have more recently used MM Gray Primer with same results, the only difference being that MM primer gives a satin finish. An added benefit of using a dark neutral shade of primer (ie gray) is that when covered with a top coat of satisfactory opacity, there is no chance of 'see through' effect and a top coat of gloss white or a similar light shade (like Airbus/Boeing gray or SAS gray) will look its vibrant best.

      So, at the end of the proverbial day, it seems the keys to obtaining great results with flat (enamel) primers are 1) thinning primer to somewhere around 1:1 primer:thinner and 'fogging' it on over well-prepared surfaces and 2) 'fogging' on (almost) equally well-thinned gloss enamels over primer, also at low pressure (~15#).

      Todd
      BJI

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      Challenger350Pilot


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      Post #70240, posted on 06-22-2018 GMT-5 hours    
      I have to agree with ALL of Christian's post. His descriptions are exactly how I paint all of my models, though I haven't graduated to airbrushing to the detail he does, though I am progressing in that direction. I still believe in and rely on decals for some of the super detailing. Jennings asked about temperature and humidity...these are very influential factors where I live, in the deep southern USA. Temperatures can crawl into the low 90s regularly in the summer time, and humidity reach as much as 80% and higher. I spray/airbrush in my garage, where it can be even hotter. I try to carefully plan to paint when the temps are a bit lower, and humidity is too, and this helps tremendously. Preparation of surfaces is the gold standard to get the final finish as you want it. Be patient, sand properly, and allow ALL paints to thoroughly dry and cure, including primers. As for taping, I like the Tamiya products for details, and I use standard Frog Green tape (found at any hardware store) for large masking. Never, ever leave any tape on for long periods of time...this will insure that you have chipping and peeling, and leaving behind a gluey mess from the tape. Happy modeling!

      Cheers....

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      Alex Veltze


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      Post #70258, posted on 06-25-2018 GMT-5 hours    
      I always let the primer cure for a few days before doing anything with it. I have used Humbrol no 1 with water based on top and the water based peeled slightly, reason for that was that the primer hadn't properly cured, I could smell the oil after a couple days.

      Oil on oil would have been ok, however I left the Humbrol until all the solvent smells went - no problem. If you can smell it it's not ready.

      Also over polishing with Micromesh can cause adhesion snags unless you are using something like Alclad with is very fine and can 'bite' in on the first application due to the strong solvents used.

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      nielsamd


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      Post #70259, posted on 06-25-2018 GMT-5 hours    
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      Challenger350Pilot : allow ALL paints to thoroughly dry and cure, including primers.................
      Never, ever leave any tape on for long periods of time...



      Yeah I used to leave the tape on as long as the paint was curing. Now I take the tape off when the paint `seems' dry but, in fact, needs some more curing still.