First off, thank you so much to everyone who stopped us and asked what the giant blue thing we were carrying around was! We had an overwhelming response, all positive, to our mascot and our journey to Season 3 of BattleBots as a combat robotics team! We also had several people stop us at GenCon and ask “How did you build that thing!” Since our motto is “Learn, Create, Inspire” we knew we had to write up a tutorial to teach others how we made our giant friend, so they could use that knowledge to create their own inspirational creations!
This tutorial will be done in two installments:
- the denkbot
- denkbot courier
Without further ado, let’s begin the tutorial!
Below are the materials used to build the denkbot!
- 30″ Printed Stencils (FedEx Office Print & Ship Center)
- Broken Down Cardboard Boxes (Recycling)
- Foam Fast 74 (Amazon)
- 3″ Thick, High Density Mattress Foam (Amazon)
- Armature Wire (Amazon)
- Rust-Oleum 2X Ultra Cover Spray Paint (Walmart)
- Various PVC Pipe (Lowe’s)
- Various PVC Fittings (Lowe’s)
Materials for the denkbot courier are listed below and will be repeated in Part Two!
- Various PVC Pipe (Lowe’s)
- Various PVC Fittings (Lowe’s)
- Tool Belt (Menards) with Suspenders (Menards)
- Wood Screws (Lowe’s)
- Metal Clamps (Lowe’s)
BASE LAYER STENCIL
First, we scaled a pdf of our denkbot up to print on a 30″ plotter. If you don’t have access to a 30″ plotter, you can go to any FedEx Print Center with your file and they can print it on their plotter for around $10.
Next, we cut out the denkbot so we could trace it on cardboard. If you order a lot of stuff from Amazon or Jet, just save up your bigger boxes for a month and you will have plenty of cardboard to make stencils.
If you have quilting or sewing pins, they help a lot when laying out your stencil for tracing on cardboard. We traced with a marker, wider tip markers were useful.
Once you have finished your trace, get some good scissors and get to cutting!
We designed our denkbot in two layers, so below is a picture of the bottom layer stencil cut from cardboard.
Next, we trimmed down our bottom layer stencil to create our top layer stencil.
TOP LAYER STENCIL
We cut out the eye center and denkbot outline to provide the paper stencils for our top layer.
While we were penning down the eye for tracing, as we did for the bottom layer above, our cat showed up to provide feedback.
Once both paper stencils were done, we pinned them down to begin tracing the top layer (NOTE: We cut the eye out of a separate piece above, the eye was just placed for reference) .
We then traced the outline just as we did for the bottom layer and eye above.
Next we inspected both cardboard forms to ensure all of the sizing was correct.
The cardboard forms turned out well. We reinforced the top layer stencils with some packing tape.
With all of this attention on cardboard, our dog started to get a little peanut butter and jealous. So we took a break to go catch Pokemon.
Next we unpacked the 3″ Thick High Density Mattress foam that was delivered by Amazon that day.
We had our minds blown when a 3″ thick by 24″ wide by 72″ long piece of mattress foam arrived in this average sized box.
Next we grabbed our stencils and laid them out on the mattress foam to begin tracing. Once again, our cat made sure everything was lined up correctly.
We had a be a little creative with our placing in order to fit all of the parts onto one sheet of mattress foam.
Once we started cutting the foam, we found that our steak knives cut the foam the best. Just make sure you sharpen your knives before and after.
Once we got everything cut out, we mocked up the denkbot. Our dog thought it was an elaborate food bowl we had built for him and was disappointed when there was no food in the middle.
While we still had daylight, we tested out the two brands of spray paint we had bought earlier that day: Krylon and Rust-Oleum.
We took out some cardboard and painted two layers of each paint, then let them dry.
The Rust-Oleum had a thicker fill and more vibrant color, so we went with that! We also had some white of the same brand.
Make sure you paint outside or in a well-ventilated area. If you are painting outside, lay down some cardboard in the grass. That way if you miss you just paint the grass, not the sidewalk or driveway. Also, we suggest you test your spray paint of choice on some scrap pieces of foam so that you get a feel for how the foam takes the spray paint (that is what those odd shaped pieces on the left side are in the picture below).
We let the pieces dry for a few hours, applied a second layer of paint, then let them dry for another hour, then brought them inside and put them on some trash bags we had slit the sides of so they laid flat. We let everything sit overnight so both layers could fully dry.
Once everything had dried, we were ready to glue it all together with some Foam Fast 74! (NOTE: We only sprayed the foam fast adhesive outdoors, similar to the spray paint setup, because it is an industrial strength adhesive)
FOAM FAST 74
Before we started gluing our final pieces together, we tested the Foam Fast 74 on some pieces of foam we had tested the spray paint on earlier. It worked fantastic, even on foam surfaces that had been painted!
To make the antennas, we made a slit in our painted pieces of foam and laid 1/4″ armature wire in the slit.
Then we sprayed Foam Fast 74 into the slit and onto the armature wire to hold it in place, then foam-fasted the two antenna parts together (slit side facing in).
To attach the antennas, we just stabbed them into the bottom layer. There is probably a more eloquent way to do this, but stabbing worked just fine for us – just make sure you leave a long enough piece of armature wire extending out of the piece to be mounted.
Next we cut a piece of 3/4″ diameter PVC pipe to layer inside of the bottom layer and attached two 5-foot pipes using two right-angle fittings. We left the full 5-foot pipes intact so we could cut them to length later.
Similar to how we traced the cardboard stencils, we used quilting/sewing pins to mark the location the PVC pipe needed to lay inside of the foam.
Like we did above, we used a steak knife to cut along the corridor we marked in the previous step. Since we will be hollowing out a channel in the foam for the PVC pipe to lay, the exact location of the cut is not pivotal (it just needs to be down the middle of the pins).
Next we cut out a small channel at the base (bottom of the denkbot) that was wide enough for the PVC pipe to fit in. This gave us a reference width to begin hollowing out a channel up the denkbot underneath the cut.
We found the easiest way to do this was to pull apart the foam where we had originally cut it, then make a ~1″ slit halfway down on the walls of the foam you have pulled apart from your original cut. Once you have made this slit, get a hold on the foam on the bottom half of the slit you just made and firmly but slowly start pulling out foam while inching your grip up the channel. It will come out in long strings if you are doing it right. Just go slow and experiment, you will figure it out – we believe in you!
Once the areas under the cuts are hollowed out, lay the PVC structure down then spread the foam apart and gently press the pipe down into the hollowed channel while pulling up the foam to enclose the PVC pipe in foam.
After the PVC was firmly placed in the foam, we used Foam Fast 74 to seal up the seam. We sprayed the adhesive in foot long runs, pressed the foam together, let it dry, then moved up and did another section.
Once the bottom layer was done, we used the foam fast adhesive to attach the top layer to the bottom layer. Again, only sprayed the foam fast adhesive outdoors, because it is an industrial strength adhesive.
As mentioned above, we simply stabbed the armature wire of the antennas into the bottom layer. Simple, yet effective. This also allowed us to remove the antennas whenever we needed to work on other things.
Once all of the adhesive had been sprayed and the parts assembled, we let it sit outside for an hour to dry.
In order to more conveniently store the denkbot, we built a simple standing mount with threaded fittings to screw into the bottom of the denkbot poles.
We cut a few pieces of PVC to length, tossed them into a T-fitting (slip to threaded) and tossed some end caps on it. We used wood screws to hold everything together.
By putting slip to threaded adapters on the bottom of the denkbot poles, we were able to screw on the standing mounts or the courier mounts as needed.
We let denkbot stand outside for a few well deserved moments in the sun (with human supervision of course)!
We will continue our tutorial in Part Two, where we will detail how we built our denkbot courier! We will also go over some Lessons Learned from our build, outlining cost and design improvements!
If you have any questions on how we did things, if you find any sections could use more detail or clarification, if we made any errors, or if you just want to let us know what you think – please let us know in the comments below!
Thank you for your interest in our endeavors and for taking the time to read this article! We will see you next Friday with Part Two!
— denkbots (@denkbots) August 7, 2016
Before we go, we wanted to leave you with the video that learned several of the techniques used in this build from; Adam Savage’s creation of Patton Oswalt’s Doc Ock costume inspired us to create such a large scale denkbot.
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