Aluminium Heat sink — K2Forums.com

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Aluminium Heat sink

chuubabachuubaba Posts: 110Member ✭✭
I dipped a heat sink but the print ripped within seconds after the dip. Did not pre-treat the surface with any chemical but sanded and scuffed thoroughly. Used acrylic paint and home brew activator. Took me by surprise as the paint was used many times for many successful dips. Thought the aluminium surface reacted with the activator or the paint did not grip properly so switched to 2k paint but same situation. The film is from Taiwan. 2k paint is NEXA. I suspect over activation but the film will not glass with less activator. One thing new here is that the lid of my activator gallon was discovered ripped as if gas pressure from inside ripped it open. Its winter season here and average tempratures are 25C. Last time i checked the activator container was a week ago and it was intact then. First pic is with 2k paint and the second is with acrylic.

Comments

  • MidOhioHydrographicsMidOhioHydrographics Posts: 9,084Member, Moderator, Business Ninja El Moderator
    Too definitely looks over activated. Bottom looks under.

    Try spraying and leaving a bit of texture on the film, then let it sit a bit (15sec or so) then dip.
  • MidOhioHydrographicsMidOhioHydrographics Posts: 9,084Member, Moderator, Business Ninja El Moderator
    And ALWAYS dip speed shapes to practice with new film. Every time. Paint your parts and paint 4-5 test pieces at the same time. Much less work to redo a speed shape than the actual part.
  • MidOhioHydrographicsMidOhioHydrographics Posts: 9,084Member, Moderator, Business Ninja El Moderator
    Also why the green base? That should have a light tan under it, unless that’s the look you’re going for to match something?
  • chuubabachuubaba Posts: 110Member ✭✭

    Also why the green base? That should have a light tan under it, unless that’s the look you’re going for to match something?

    Used the green base because that's what i had available in 2k to test with. Do you suspect my activator has changed composition owing to open lid because before dipping in 2k i tried to spray minimum activator but the film did not glass then i waited after spray but the activator evaporated. Had to discard few pieces of film in tests. Another unusual thing i noticed that i have to keep 3 or 4 inch gun distance to activate else it would not glass after up to 4 passes. See how it looks now after sitting for 2+ hrs
  • studebakerstudebaker Posts: 2,893Member, Business Ninja ✭✭✭✭✭
    Your basecoat paint is the problem... It's become hydrophobic. You will have to use a different type of basecoat. I suspect the 2k paint has dried past its dipping window. It's not necessary to us a 2K paint as your basecoat. 2K for the clearcoat is great!
  • MidOhioHydrographicsMidOhioHydrographics Posts: 9,084Member, Moderator, Business Ninja El Moderator
    How long between painting and dipping?
  • DeviousDipsDeviousDips Posts: 1,513Member ✭✭✭✭
    If your using the 2k paint don't let it cure before dipping. I would say that's the problem. Dipped outside the window of the paint. 
  • chuubabachuubaba Posts: 110Member ✭✭

    How long between painting and dipping?

    For acrylic 1hr and for 2k <20mints.
  • chuubabachuubaba Posts: 110Member ✭✭
    @studebaker Maybe the 2k cured too fast but with acrylic it was within time window. I am going to dip this again with acrylic in one of my tested films to clear the doubts about film and activator health.
  • chuubabachuubaba Posts: 110Member ✭✭
    @MidOhioHydrographics plz read the gun distance as 4-5 inches
  • chuubabachuubaba Posts: 110Member ✭✭
    edited November 2017
    quick dip using home brew, acrylic, old bit of film, same gun, same temperature and no tearing of print so is my film the culprit?? .
  • chuubabachuubaba Posts: 110Member ✭✭
    Now its fixed. Reduced the activator flow setting to minimum (only a half turn from full close). The film did not glass but expanded considerably (to signal activation??). Maybe more experiments and advice to fine tune. Many thanks to all.
  • chuubabachuubaba Posts: 110Member ✭✭
    After rinse and clear.
  • MidOhioHydrographicsMidOhioHydrographics Posts: 9,084Member, Moderator, Business Ninja El Moderator
    chuubaba said:

    @MidOhioHydrographics plz read the gun distance as 4-5 inches

    Yeah, Whatever works to get a good pattern with your gun is fine. Most people are higher than that, and that probably didn’t help with your over activation. But ultimately That was your problem, too much activator.
  • WileECoyoteWileECoyote Posts: 6,025Member, Moderator, Business Ninja El Moderator
    Yeah... you say you had to cut the distance for your activator gun and make more passes... that is a huge red flag. You compensated for a problem that you didn't have. You expected a new film to act like your old film and glass out
  • chuubabachuubaba Posts: 110Member ✭✭
    edited November 2017
    @WileECoyote @MidOhioHydrographics It was my first time to use home brew on a film with tainted activator side and glassing it caused over activation but activating to only expand it worked very well. The part also did not cut through the film. So am i right in thinking of extending the soak time to >90secs or is this how it will always be with my home brew on this kind of film? The parts always cut through my other films.
    I did not make more passes but on seeing the film not responding as usual i cut the distance immediately. just like a reflex. I think i was back on 6" mark later on. This film takes very little activator to expand only.
  • WileECoyoteWileECoyote Posts: 6,025Member, Moderator, Business Ninja El Moderator
    Sorry man. Home brew activator will be as consistent as YOU are when you make it. NO ONE in their right mind would attempt to guess at how something like that would work. To many variables outside of our control.
  • K2ConceptsK2Concepts Posts: 12,950Administrator El Jefe

    Sorry man. Home brew activator will be as consistent as YOU are when you make it. NO ONE in their right mind would attempt to guess at how something like that would work. To many variables outside of our control.

    And yet you make the assumption the members of this forum are in their right mind?... :dizzy:
  • chuubabachuubaba Posts: 110Member ✭✭
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