Tentacle Test Print #3 Video

I showed you the modeling aspects of this batch of prints already. Here's the finished products:

Dirty Tentacles - Print Cleaning

Nope. Not tentacle porn. Sorry.

Just to give you an idea of the process with the tentacles, it takes about 20 minutes with a toothpick to get all the support material out of the joints. This is partly my own fault due to the tentacle design.  Then it gets blasted out with compressed air.  Next it gets scrubbed with a toothbrush, then into the lye bath for 30 minutes, then rinsed and dried with compressed air.  This times eight. Curse you octopi!  The effort is worth it because a piece that still has even seemingly unnoticeable amounts of support material on it looses a ton of detail.  Also worth mentioning that this is on my end. It doesn't take into account that the print lab blasts it with a water jet, also does a lye bath and blasts it again.  This is part of the reason that 3D printing isn't quite ready for mass production. That and the cost.

Check out the slideshow:

Iris Door Test Print Video #1

As I mentioned in a previous post, I really wanted to have a working mechanical iris as an exit for the divers.  This was not as hard to design as the tentacles but it wasn't a picnic.  There are lots of irises on the web, but not too much covering the mathematics to design one from scratch.  I built everything myself but I have to send out props to emmett on Thingiverse.com for inspiration. His design helped me figure out some of the mechanics and layout.  Thingiverse is run by MakerBot industries and is a community forum for uploading and sharing 3D printing design.  You like something, just download it and print.

This was also exciting because I was actually able to prototype it on my MakerBot.  The final version will be printed on the fancy Objet printer at the NYU AMS lab.


I also need to submit a public apology to my wife Kate.  In the video I failed to mention the hours she spent helping me figure out the geometry to make this thing work.  She's much better at math than I am and I couldn't have done it with out her.  Thank you Kate!  Please let me come home now.

McMaster of the Universe! - Free CAD Models

Here's a great tip for my fellow modelers.  Go to McMaster-Carr, look up screws, bolts or some other type of hardware. Pick one at random and you will notice a 'CAD' tag pop up for the item.  Click and and download a CAD file of the item. Now open your modeling program and import it. Nice. You now have mechanically accurate parts to detail stuff with or to use as a guide for designing real-life parts.  That's what I have been doing. I downloaded the exact screws I wanted for the iris and used them to size the holes and tracks correctly.   I've been using IGS files successfully in C4D.

This is also great for my fellow MakerBots out there. You can take this file and print plastic screws. PLASTIC SCREWS! They don't have CAD files for everything, but there's still plenty.


Also, McMaster-Carr is the most awesome place in the world.  Their catalog is about 6" thick. When I order something, it's here the next day with standard shipping.  If you want to learn about rubber, plastic or static eliminating blowers, this is the place to go.  Each section has an 'About' preface that will give you a good primer on hardware.  If you email customer service, you will hear back from them in less than an hour.  It's like Christmas.

Tentacle Test Print #3 - Modeling Video

Kind of a test print, but in reality it's probably the start of final printing for the tentacles. As long as these two turn out ok I'll be printing the other six using the same model.

I had so much to cover since my last major update that I just made a video of it.  Topics of interest include: final (?) tentacle design, tentacle mount, file prep, rubber webbing and iris doors.  I'd recommend going full screen to see everything clearly.

Lye Bath! - How to Clean Prints

As discussed before, when parts come out of the printer they're covered in a rubbery, wax-like support material that has to be cleaned off.  Typically a water jet is used for cleaning but even after that I've had a lot of residue left.

This is a particular annoyance with my current tentacle design.

After some research, I found that the printer manufacturer recommends a sodium hydroxide bath which will loosen and remove the support material.  I have access to an ultrasonic cleaning tank which would work great with the solution.

The problem is sodium hydroxide, also known as lye, is kind of hard to find due to the fact that it's used in crystal meth production. Yay!  Typically, you can use drain cleaner but I couldn't find any that was pure lye.  The good news is it's also used in darkrooms and I was able to pick some up at B&H Photo. (Pick up only, no mail order).

OPUS V Design

I've been getting asked a lot about the aesthetic design of the octopod which always triggers a little anxiety.  This usually stems from the fact that I consider myself more of a builder than a designer.  I am most comfortable when presented with a mostly finished design that needs to be built and elaborated on rather than coming up with my own thing from scratch. It's just how my brain is wired. But I wanted to challenge myself and chose to try and design something from scratch.  I have been pretty comfortable with the actual modeling and mechanical design and stalling a bit with the aesthetics.

From the beginning I knew I wanted a nuts-and-bolts, mechanical design.  My first thoughts were WWII and  Cold War era design.