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10K CLUB INTERVIEW: The Three Investigators - The Heqdquarters by Claus-Marc Hahn

In today's 10K Club Interview, we meet Claus-Marc Hahn, aka Valkon, and his fantastic recreation of The Three Investigator's Headquarters. Fans of the show and LEGO-Mastery alike, gather round! What do you think of this cool creation?



  1. Who are you?
    Claus-Marc Hahn.

  2. Where are you from?
  3. How old are you?
  4. What do you study or do for a living?
    I am a teacher at a vocational school.
  5. What hobbies do you have?
    Building with LEGO Bricks. 
  6. Do you have a personal LEGO portfolio website that you can share with us?
  7. How and when did your interest in LEGO come about?
    My dark age ended in 2013 and I got ‘infected’ again with LEGO while doing Christmas shopping for the kids. My wife asked me about a Christmas gift for me and my answer was: I would like a LEGO set, too.
  8. What is LEGO for you? What does it mean for you? How does it fit in your life? E.g. build, display, meetups, play the games or 'just' watch the cartoons.
    LEGO bricks are a medium for me, with which I can bring dreams to life. Building is also something that is good for my health and calms me down. It is a great pleasure for me to get my family and friends excited about my hobby. 
  9. What is your favourite LEGO theme (current or past)? Why? And has any theme inspired your building style or preference in any particular way?
    My favourites are fantasy themes like The Lord of the Rings and Harry Potter. The minifigures are designed so well. Every LEGO set tells a story, and every LEGO set inspires me to create more MOCs.
  10. What is your favourite official LEGO set ever? Why?
    That is my first set that I got as a Christmas present from my wife: An Unexpected Gathering 79003 from The Lord of the Rings.
  11. What is your favourite LEGO element? Why?
    The 3001, because it is the brick that has accompanied me from childhood.
  12. Is there a LEGO designer (official LEGO designer or fan designer) who you are inspired by and look up to? Who and why?
    Justin Ramsden - Hogwarts Castle and The Upside Down are two of my favourite LEGO sets of all-time. I met Justin in Cologne during the casting of the first LEGO Masters Season in Germany, and at the end of the casting I talked to him for some minutes, and it was very funny. Since I also won the LEGO Masters Show (German Television RTL) in 2018, I fondly remember the casting. Without his ‘go’ I would probably not have ended up on the TV show. 
  13. Is there one or more particular LEGO-related websites (not official LEGO websites) that you visit often and/or are inspired by?
    I know that all sites are in competition. Since everyone knows each other by now, I would like to say politely, I love you all!


  1. Where did your interest in this particular model come from?
    At the beginning of 2019 I got sick and had to go without painkillers. During this time I listened to a lot of audio books of ‘The Three Investigators’ and built with LEGO bricks. Then the idea came to me to build the Headquarters.`

  2. How long was the process of making the project did, and what did you have to research as well. What kind of prep, research and design phases did you go through to produce your creation?
    The building time was episode 1 to 177. That is around 200 hours of construction time. The hardest thing about the project was to find something that could serve as a template. There were movies of The Three Investigators’, but the headquarters could only be seen from the inside for a short time. I researched them in some fan forums and looked for information from the first years after release of the books in 1968 and found a trailer that was very popular in the USA that year: the Airstream. And then I started building. 
  3. What special challenges did you face creating the model? What was the most difficult part to recreate?
    It was quite difficult to get the round corners attached. 
  4. If you could talk to yourself before you started on this project, what would you tell him? What do you know now that you wish you knew then? 
    Nothing real. I think from today’s perspective, I would tell him, start now with episode 178 and work his way onto episode 213! 
  5. How long did it take to complete the model? Did you finish it fairly quickly, or did it take a long time? And how did the build time compare to the time you spent promoting your Product Idea to reach 10,000 supporters?
    Effective construction time was very short compared to the time I spent sharing in various forums, fan sites and social media. 

  6. How did it feel when you reached the magic 10,000 votes and how long did it take?
    The project hit 10,000 at the end of Christmas. It was really great event! It took over 660 days to reach the milestone. I got most of the votes after shared my project on the official channel’s Facebook and Instagram. 
  7. Approximately how many LEGO bricks did you use to create your model?
    I have used around 2500 parts, but my focus was also on being able to transport the model. By changing the construction of the subsurface, you can certainly save 1000 parts.
  8. What is your favourite building technique or part/section that you’ve incorporated into your Product Idea?
    The trailer itself: it is stable and playable. It can be opened to the rear so that the set can be used better for playing. 
  9. If you built your model digitally, what software did you use to build and render your model?
    It is a physical build. 

  10. If you used custom stickers or prints for your design, how did you create them or where did you get them?
    I use stickers or printed tiles from original LEGO parts. (I am 99% sure, because I do not know all stickers or printed parts from the LEGO Group.) 


  1. Do you have any useful advice about creating a successful LEGO Ideas project?
    Not really. I loved my first models, but they completely flopped on LEGO Ideas. At first, I built this model just for myself, and then I thought that it would be a good submission for LEGO Ideas. Maybe this is a good piece of advice that I can give: Have fun! Build something for you! If it fits the requirements for the submission, then submit it. 
  2. What (if any) methods did you use to advertise and attract support to your Product Idea? 

    Promotion in various LEGO Fan Forums. Share in groups on Facebook. Share on Instagram and TikTok. Get support from news sites like, who will share a project. Get help from communities like Schwabenstein 2x4 or

  3. What is your favourite LEGO Ideas Product Idea (besides your own of course)? Are there any Product Ideas you think have been overlooked?
    I am a fan of LEGO Ideas sets. I think it is fantastic to hold in your hands an Ideas set of a model which comes from the idea of a LEGO fan designer. That is why there is no such thing as the best, or the most unique set. I found every set to be something special and a unique thing that you may experience once in a lifetime. 
  4. What is it about the platform that attracts you? What tips would you give to anyone who is thinking about uploading an idea?
    Do it. You learn from mistakes, and you get a feeling of what people like and what they don’t. 
  5. Do you have plans to submit any other Product Ideas in the future? If yes, can you give us a hint of what that might be?
    Yes and no. I would like to, but I have no idea what it should be. 

  • 10k club
  • 10k club interview
  • product idea
  • the three investigators - the headquarters
  • claus-marc hahn
  • valkon

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