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Finally, a simple, easy to load system for processing 4x5 sheet film. Handles up to 4 sheets in only 16 oz (475ml) of solution!
Finally, a simple, easy to load system for processing 4x5 sheet film. Processes up to 4 sheets in only 16 oz (475ml) of solution!  Now available on our website: shop.stearmanpress.com
Finally, a simple, easy to load system for processing 4x5 sheet film. Processes up to 4 sheets in only 16 oz (475ml) of solution!  Now available on our website: shop.stearmanpress.com
972 backers pledged $69,552 to help bring this project to life.

Someday I'll laugh about all this...

25 likes

It's been a long two weeks.

After untold emails and phone calls, (including midnight skype-ing to China), we've reached some conclusions:

1. Turns out that there was some confusion about silicone molds for Polypropylene (PP); ABS vs PP and other technical details that I doubt anyone really cares to hear about. Summary: the manufacturing engineers have convinced us that we do not need another prototype.

2.  While these conversations were taking place, we were rechecking everything before giving the order to cut the steel molds. One of the final tests we ran was a "light leak" test, just to double check the light baffles in the latest prototypes. We loaded up 4 sheets of ISO 400 film, set the tank under an 80 watt light, waited an hour and then processed the film.  Of course, since we've never seen even a hint of a light leak, we knew the film would be blank.  Here's what it looked like:

The '4' is written with a marker after processing, just to keep track of what slot it was in.
The '4' is written with a marker after processing, just to keep track of what slot it was in.

Wow. Bummer. It was only the two outside sheets that were affected and at first glance, the pattern roughly matches the holes in the outside edges of the inner baffle. But it was at the far end from the fill/drain, so maybe it was the vent port? After all, light can bounce around in strange ways.

Now I won't waste everyone's time describing the fiasco that followed but after numerous mods to the baffles, followed by testing/processing; we concluded that everything was light tight.

So, as Sherlock Holmes would say, "once you've eliminated the impossible, whatever remains..."  That meant that light was leaking through the solid plastic tank.

Here's the embarrassing part, (that we'll laugh about, someday, maybe); the prototype tank isn't solid. (Remember, the tank is made out of five pieces of plastic?)

While everything looks solid in the daylight, here's the tank, in a dark room with an flashlight illuminating the inside.

the ultimate leak test
the ultimate leak test

Turns out that the prototype shop used a clear epoxy to assemble the tanks. Not enough light gets though to matter in normal processing; only by setting the tank under bright lights for an hour did it show up. Darn.

The good news is that the light baffles are now over-optimized. The bad news is that we lost a week (and wasted a lot of film.) Like I said, someday we'll laugh about this.

The mold engineers are reviewing the final design files and should submit their comments tomorrow. Hopefully, we'll be cutting metal by the middle of the week. At that point, they will give us the updated production schedule.

Thanks for your patience, we'll keep you posted.

Comments

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    1. Wong Koon Wing
      Superbacker
      on

      Looking forward to your 8x10 version. cheers.

    2. Missing avatar

      Aaron
      Superbacker
      on

      Thanks for explaining it all! It's great to hear all of the mistakes being made, as well as the successes :) And yes, someday you'll laugh over that. Maybe _after_ you get this all done and shipped out.

    3. Missing avatar

      Brian Swanson on

      Your updates are really interesting and honest. I love following the process of going from prototype to manufacture. Two thumbs up.

    4. Jan Vangheel on

      Hang in there ! It'll make you stronger ;-)

    5. Vince Donovan on

      A terrific story! Worth the price of backing this project.

    6. Pierre Gaudet on

      You are the best! one week is not much in the whole process, so no worries about a bit of delays... of course I can't wait to get those tanks - as I just bought my first 4x5 (Technika!) - and spring is on the way... keep up you excellent work!

    7. Colin Shaw on

      Thanks for the update. Amazing stuff this engineering business!

    8. Missing avatar

      Michael Josefsson on

      Thanks for the detailed update. It is amazing how much you learn from reading kickstarter updates. It feels like being in the directly in the process - sans the labour of course:=D
      And, yes, I am looking forward to the result!

    9. Nathan Herholdt
      Superbacker
      on

      Awesome update, glad you checked :) out of interest can we see what the new overlap designs look like?

    10. Tim Meisburger on

      Sorry, I'm laughing already...

      Thanks for the great update. Good luck!