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The Case of the Yellowing White Bricks



  • Pitfall69Pitfall69 0 miles to Legoboy's houseMember Posts: 11,401
    I've used UV light and that didn't do anything near what just placing the parts outside in sunlight. It may be the combination of electromagnetic radiation, infrared and UV that does the trick than just using UV alone. 

    as @CCC said; when HP heats up, it degrades the solution and releases oxygen. I know when it's time to take my parts out from the sun based on all the oxygen bubbles that have formed all over my parts.
  • GomjabaGomjaba UKMember Posts: 20
    Problem is - we barely know how to spell sun in the UK ... we still got 12 degrees here and had like 5 minutes sunshine .. might just park the project until that kicks up or just be more ... patient :) 
  • dmcc0dmcc0 Nae far fae AberdeenMember Posts: 774
    We've got plenty of sun at the moment, it's just not very warm :(  Given that I had to defrost my car yesterday morning, probably not optimal conditions for putting HP out in the sun, more likely to freeze over rather than warm up.
  • 560Heliport560Heliport Twin Cities, MN, USAMember Posts: 1,191
    edited December 2019
    I experimented with a blacklight bulb- a compact fluorescent, 7-watt ("60-watt replacement"). I put several yellowed parts in 3% hydrogen peroxide with the bulb about 3 inches/75mm away for 24 hours. On the white plate, you can see where I put a 1x1 plate to show the change. On the Medium Stone Grey wing, the 3x6 rectangular section was normal to start, while the angled section was quite discolored. It's now actually lighter than the "undamaged" section! (My apartment faces north; I can't get any direct sun most of the year. The railing of my balcony gets sun in the summer.)
  • Switchfoot55Switchfoot55 The Northwest, USAMember Posts: 1,756
    Interesting that the black light bulb would do this. I know nothing of light wave length and UV hydrogen-science, so maybe it's obvious to others. 

    I have an aquarium hood light that I guess I could try this with as well. The only weather I currently get is rain... 
  • AstrobricksAstrobricks Minnesota, USMember Posts: 2,763
    Black light bulbs emit UV-A rays that cause fluorescent things to light up.
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