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  1. sampsond's Avatar Active Member
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    Doug
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    I've been modifying my model by filling various openings and everything looked great until after the painting and assembly was finished. All the areas I had filled developed a small crack around every place I had worked on. The pictures show the glue and putty Problems! Glue, Putty, Resin, what else can go wrong? I used. Should I be using something different? The paint is lacquer Problems! Glue, Putty, Resin, what else can go wrong? .

    Problems! Glue, Putty, Resin, what else can go wrong?-20200614_132758-jpgProblems! Glue, Putty, Resin, what else can go wrong?-20200614_132845-jpg

    Another problem I'm having is my resin Problems! Glue, Putty, Resin, what else can go wrong? casting Problems! Glue, Putty, Resin, what else can go wrong? seems to stay a little too much on the flexible side so it makes it very difficult to sand Problems! Glue, Putty, Resin, what else can go wrong? a flat surface when everything bends. What brands does everybody here use?
    QUOTE QUOTE #1

  2. MODEL A MODEL's Avatar Yearly Subscriber
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    don
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    Hello, what resin Problems! Glue, Putty, Resin, what else can go wrong? are you using? -and how old is it? -and are you always stirring or better shaking the resin Problems! Glue, Putty, Resin, what else can go wrong? overly thoroughly? Many resins will have some of the soilds settle on the bottom of the container, and that needs to be reincorporated into the solution. If it is not, it does affect the quality of your castings. Becoming worse as you progress.

    And / or, resins are thermosets. The heat generated in the catalyzing is a chemical reaction, and it needs to happen to cure Problems! Glue, Putty, Resin, what else can go wrong? the resin Problems! Glue, Putty, Resin, what else can go wrong? . Do not over catalyze, and of course do not under catalyze.

    Do not dilute the resins, with anything. Not thinner Problems! Glue, Putty, Resin, what else can go wrong? , Acetone, Alcohol Problems! Glue, Putty, Resin, what else can go wrong? , water, . . . .

    Once a container is open, the "Shelf Life" clock starts to tick. Most resins have a year. (Some less)

    Toss the model putty Problems! Glue, Putty, Resin, what else can go wrong? . Its usefulness is limited to tiny pin-holes and it does shrink quite a bit.

    Use instead a catalyzed Problems! Glue, Putty, Resin, what else can go wrong? body filler. Evercoat makes several, of varying hardness, depending on its use, and the fillers Problems! Glue, Putty, Resin, what else can go wrong? that are present. Talc, Micro-balloons, Fiber Glass fibers or pulverized cured solids.

    Where ever possible try to apply in a shallow trough. A "V" groove. Apply in excess but just onto where its needed, -this will lessen the "Witness Marks" and ultimatley make a better blend of surfaces.

    Priming is important too!

    When you judge a painted model, he first thing you notice, other than the color, -is the surfacing. No amount of paint will improve a poorly prepared surface.
    Priming is a time to check high-lights, gaps, clean contours and clean lines!

    Welcome to modeling!

    -Don

    I use a catalyzed Problems! Glue, Putty, Resin, what else can go wrong? primer Problems! Glue, Putty, Resin, what else can go wrong? by Evercoat, 4:1, -and several different body fillers Problems! Glue, Putty, Resin, what else can go wrong? , (not BONDO, though too many people use that word as a generic.) The spot puttys offered by Testors, and others, that are not catalyzed Problems! Glue, Putty, Resin, what else can go wrong? are not worth the time. I use BJB resins, and sometimes the Alumalite brand.

    These are my opinions and may not be shared by others. There are after-all many ways to do almost anything, and I do make more mistakes than anybody I know!!
    Last edited by MODEL A MODEL; 06-14-20 at 07:48 PM.
    -craftsmanship is a lifelong project of
    self-construction and self determination
    QUOTE QUOTE #2

  3. sampsond's Avatar Active Member
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    Doug
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    My resin Problems! Glue, Putty, Resin, what else can go wrong? is way over a year old, maybe ancient. I'll buy new and try again. I've seen Alumilite in my local store, I will give it a try. Does adding color affect the resin Problems! Glue, Putty, Resin, what else can go wrong? ? I have resin Problems! Glue, Putty, Resin, what else can go wrong? dye and heard tempra powder will work.
    QUOTE QUOTE #3

  4. MODEL A MODEL's Avatar Yearly Subscriber
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    don
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    Hello, when ever you add dye, colorants, pigments, it is usually best to not add more than 3% by weight. (That's a rule of thumb). -and add it to the resin Problems! Glue, Putty, Resin, what else can go wrong? side of the solution, not the catalyst. (I have added pigments to both sides, again not more than 3% but it does affect the shelf life of the catalyst, or did for me)

    Dry tempera? should work, it is just pigment Problems! Glue, Putty, Resin, what else can go wrong? and binder. Never tried that. No water!!

    Casting Problems! Glue, Putty, Resin, what else can go wrong? clears and tinting those, is something that at first seems straight forward, but isn't. A thin section of 3mm will have X amount of pigment Problems! Glue, Putty, Resin, what else can go wrong? . 6mm will of course have twice as much, and appear twice as dark or saturated. To cast a clear part, a lens for instance, it is best to cast it clear and then paint it with a transparent paint. You'll attain a more uniform color that way, and if you don't like it? -you can sand Problems! Glue, Putty, Resin, what else can go wrong? or polish it off and repaint.

    Humidity also affects resins, as do temperature extremes.

    Experiment and let us know!

    Last year I learned of using Mineral Spirits Problems! Glue, Putty, Resin, what else can go wrong? to dilute RTV Problems! Glue, Putty, Resin, what else can go wrong? after mixing, and then demolding after the rubber had set. Setting it aside a few weeks allows the solvent to evaporate, de-bulking the RTV Problems! Glue, Putty, Resin, what else can go wrong? , and the result is a shrunken mold! Cast a part, mold that again, the same process, and you can achieve a mold with all the fidelity but at a reduced size. I have two experiments going with radiator mascots. A quail and a RR Flying Lady. Eventually I hope to have two 1/4th scale replicas of the actual parts? Initial trials are promising!

    Have fun! Learn something new! Share.

    -Don
    -craftsmanship is a lifelong project of
    self-construction and self determination
    QUOTE QUOTE #4

  5. sampsond's Avatar Active Member
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    Doug
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    Thanks for all the tips!
    That sounds fascinating, shrinking a mold. Any idea of the percentage of shrinkage or is just a hit-or-miss process?
    QUOTE QUOTE #5

  6. MODEL A MODEL's Avatar Yearly Subscriber
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    don
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    30% solvent has given about 15% shrinkage. You have to remove the pattern of course to allow the mold to shrink. (Not a science)

    I've been using OMS, odorless mineral spirits Problems! Glue, Putty, Resin, what else can go wrong? , I read that Naptha and a few other solvents have been tried successfully, but I haven't tried anything else. Too many variables, best to stay with one and learn what I can.

    The pattern has to be unaffected by whatever solvent is used. (again, not a science)
    Last edited by MODEL A MODEL; 06-15-20 at 02:56 AM.
    -craftsmanship is a lifelong project of
    self-construction and self determination
    QUOTE QUOTE #6

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