Matt’s Props

I stopped by Hobby Lobby this weekend, on the hunt for three things. A) Something to use for the main radar eye lens. B) Something to use for the holo-projector lenses. 3) The main orb for one of the holo-projectors, since I don’t want to pay another $25 dollars for the correct doorknob set. It turns out Hobby Lobby now has their Christmas ornaments out, and I found one for each of my needs.

Radar eye with lens (not glued in)

Radar eye lens and bolts being glued in

Ornament sanded and cut with small ornament for lens

Scope cap in place

Fence-post cap in place

The original, from A New Hope

A later version, from a museum tour

These will all need to be repainted

So yeah, I’m going to have to re-paint these panels. Either my clear coat is too old, my new can of anodized blue isn’t playing well with the other coats, or it was too humid or something. Also, I screwed up some of the parts that I had masked-off when I removed the tape – I ran an exacto blade along the edge of the tape before I peeled it off, but it actually looked better when I didn’t do that. There’s also a “dent” in the paint on the radar eye, where I watched a piece of fluff/lint/hair land on the primer, and I tried to gently remove it. Finally, I forgot to paint the blue ring around the collar, so I’d have had to break out the rattle cans again anyway.

But damn – it looks nice all put together, doesn’t it?

I spent the better part of two days getting back to work on R2, prepping and painting the dome panels mostly, but also figuring out and cutting the holoprojector surrounds. I was unhappy with the way I had cut the first set of fence-post caps to use for surrounds, and since they cost about $2.00-a-piece I bought some more. This time, I spent a while planning out the shape I would cut, then carefully cutting out exactly the shape I wanted (i only cut one so far, so I’ll document the process with the next one and add photos).

After filling in some dremel mistakes with Bondo, I painted all the dome panels and the radar eye. This involved double-checking reference photos to make sure I was painting the correct panels, and masking-off certain panels that needed only a frame of blue or the opposite. I used what I thought was the same formula I used when I painted the pie-panels years ago, but it didn’t turn out as well as it did last time. The pie-panels have much more depth to the finish. Maybe I need to add a few more layers of clear coat. Either way it’s a subtle difference, and not too terrible, so I’m not freaking out.

Cutting the data slot in the eye

Cutting the slot was made simple by using the dremel cutting guide. On the right, the side boxes were constructed from my old trash can.

Much time passed since the last time I cut the dome, during which I primed and painted the pie panels using a variation of the “Krider blue” rattle can formula, which can be found on astromech.net. My blue may not be exactly like the real R2, but it uses colors I know I can find consistently.

First holoprojector test fit

Now that I had gotten two dremel accessory kits for Christmas, it was time to start cutting again. I used the same dome blueprints I used for the pie panels. This time I printed one of them out at full scale so it took up several sheets of 8.5×11 paper, then tacked them all down on a piece of plywood and set the dome on top. I used the measurements from the other dome drawing to get a figure for the heights of the panels (this particular drawing measured in fractions of the circumference of your dome). Once everything was drawn in, I compared it to images of R2 to make sure I wasn’t making any stupid mistakes.

I started by cutting out the circles for the holoprojectors. I started by using a circle-cutter drill bit, but I found it to be unreliable and prone to sticking. I’m sure it works great if you’re using a drill press and/or cutting a flat surface. I ended up rough-cutting the circles with the dremel+cutoff wheels, and cleaning it up with the dremel+sanding attachment and files.

Panels cut. Also, I'm a dork.

I finished off a Guinness to steady my hands, and cut out the rest of the panels with the dremel. I know some of the panels should have cutouts within them, and I missed one small additional panel, but I feel like I’m done cutting. I may end up just painting those in.

I should also mention I’m using the “fence-post cap” method for creating my holoprojectors (developed originally by Craig Smith, the god of scratch-builders). This involves cutting a hole into the top of a cap for a chain-link fence, putting a door-knob into it, and capping it off with the top from a bottle of Scope mouthwash. Funny story, these were actually the first things I built for R2 since they’re so cheap to make, and I promptly lost them. Someday years from now I’ll find that first set somewhere safe where they wouldn’t be damaged.

Panels cut, pie panels and inner dome fit

All panels cleaned up, back in place

First cut

After making sure I had a successful fiberglass inner dome, it was time to begin cutting the top “pie panels.” I used several techniques to figure out the template for these. First I had to find the exact center of the dome, where I would drill a hole and mount a bolt to use as a pivot for tracing my circles. The lines/grooves from the production of the dome were not completely sanded out, so I had a good idea of the ballpark it had to be in, then I put the end of a string or tape measure at the point I picked and measured to the bottom of the dome at several different points.

To get the measurements, I used a combination of two different dome layout “blueprints” I got from the R2 builders’ yahoo group. I remember them being difficult to track down, since there are so many different dome profiles and a pattern that works for one won’t work for another. As shown in the “first cut” image above, I drew the lines several times before I was satisfied. In the end, I just had to suck it up and go with what looked right to me. That’s one of the things I love about the R2 builders’ community: no two droids are exactly alike, and the only ones who notice that your panels are off are other builders (and they understand).

Pie panels cut

I used a dremel with cut-off wheels to get the cuts started, then I used a jig saw to cut all the “latitude” lines. If I had it all to do over, I would have mounted some felt or something to the baseplate of the jig saw since it left scratches that I later had to sand out. I used the dremel only for the “longitude” lines – I don’t remember my reasoning. One important thing I did was to number all the panels clockwise, and write the number on the back of each of them (I also marked the dome in pencil above the first panel). Since I didn’t make perfect cuts, each panel was unique and fit best in its orginal spot. I screwed up later and had to switch two panels around, and it sucked having to make it fit.

Once all the panels were cut, I cleaned up all the lines with diamond files from American Science and Surplus and sandpaper. I cannot overstate how satisfied getting the dome to this point made me. It was finally starting to look recognizeably like R2D2.

Blank Dome

In 2003 I was single, living in an apartment in Chicago, and I got the bug (from reading Alex Kung’s website) to build myself an R2-D2 replica. I spent a lot of time reading and researching via the R2Builders club, which at that time was a yahoo email group (but by now has a great forum and wiki at astromech.net). Having just recently gotten my first full-time job, I had a very small budget for robot parts. When a parts run opened up for budget, blank aluminum domes, I signed up. I think I spent $70 on it. Cut to 3 years later, and all I’ve done so far is sand out all the spin lines. Then, over the course of 1 week (I think I had taken the whole week off of work for some reason) I finally started doing some serious work on it

Fiberglass Tools

To provide a support structure for the panels I would be cutting out of the dome, I decided to create a fiberglass inner dome. This will be my first time working with fiberglass, and I didn’t really know what I was doing. I did the whole thing with fiberglass “cloth”, whereas I’ve seen other people recommend using “mat” for strength.  The dome has been prepped with car wax as a release agent, which ended up working really well.

Fiberglass laid into the dome

Inner dome unmolded

As the above image shows, the end product has a lot of pits, resulting from (I think) me rushing to lay the fiberglass in. I think I mixed too much hardener into the resin, making it set up really fast. Also, I ended up going back and laying in a few more layers for strength. I then filled in the really bad spots with bondo, but I had to be really careful so the domes would still fit together.