1:7 Scale Star Wars Astromech Series WIP

This is a build log for a series of 1:7 scale astromech droids from Star Wars. As I’m sure you know, R2-D2 was not the only astromech in the film series, nor was the R2 model the only R series of astromech droid in the films. My intent is to build several different astromech serial numbers of several different astromech models: R2 (the guy we know and love), R3 (clear dome), R4 (conical head) and R5 (cylindrical head).

I'm doing this (so I tell myself) to become familiar with the different astromech models so that I can move on to building a 1:1 scale model later this year. Yeah, hmmm…

The MPC kit of R2-D2 was first released in the late 1970s (the box indicates ©1977). Since little merchandise was actually available with the original Star Wars release in May of 1977, this kit may have been issued later (1981?) with the re-release of the movie. The kit was re-boxed in 1983 for Return of the Jedi, but it is one of the few original Star Wars MPC kits that have not been re-released since the Prequel Trilogy was launched in 1999.



As with many modelers my age, I built one of the original issue R2-D2 kits, complete with sloppy tube glue fingerprints all over it. There would have been terrible brush strokes in the paint as well, but this kit came molded in appropriate colors of plastic including chrome plated sliver on the dome, so no paint was required. Much maligned as being inaccurate, I have never returned to this kit to re-build it as an experienced adult modeler. And that’s a shame, because it turns out that the MPC R2-D2 kit is a real jewel that just needs a bit of TLC to build into a beautiful and accurate astromech droid.

I pulled the R2 Builder’s Club astromech blueprints and, on a whim one evening I pulled out the MPC kit from deep within my kit stash and started taking measurements with my digital calipers. A short while later I came to the stark realization that the MPC kit is shockingly accurate in both dimensions and details. I suddenly had my next modeling project!

As a sidenote: if you’re looking for one of these kits to make your own astromech you’ll find several on eBay at any one time. But beware of what I consider as unreasonable prices for these kits; I’ve seen some eBay auctions starting at $100 or more! I would not suggest that you be prepared to spend that kind of money on these kits. Instead, be patient and you should be able to snag one for $20 or less plus shipping. I managed to acquire three of the kits over a period of a year or so at similar prices. Simply watch the auctions and you’ll eventually see some come up at the lower prices and not be bid up to astronomical levels.

ACCURACY AND SCALE

No scale is stated on the box or instructions for the MPC kit. Measuring at approximately 6 inches in height, most folks attribute the scale to be 1:6. Per the R2 Builder’s Club blueprints, this is incorrect. My extensive measurements of overall body shapes as well as details, compared to the blueprints, reveals that the MPC kit is nearly spot-on 1:7 scale.

The tables below are screen shots of my spreadsheet calculations comparing the model to the blueprints. You’ll see that the model is nearly 1:7 scale in every dimension. Note also the areas that are most in need of modification are all three feet and the battery boxes. The center ankle and leg in the kit is also a poor representation of the screen-used article, so those will need to be redesigned as well.

The first column in the table is the measurement from the Club blueprints. The second column is my measurement from the MPC kit. The next column is what the MPC kit scales to relative to the blueprints. The next-to-last column indicates what the MPC kit would need to measure to be exactly 1/7th of the Club blueprints. The final column indicates the percent error between the MPC kit and the club blueprints.



The base of the dome (the “neck ring”) is strangely bulged on the kit. I have no idea where MPC got the idea that this was accurate for R2-D2. However, the height of the neck ring is accurate, so the bulge can simply be sanded down.

There are small details that will need to be redesigned throughout the kit: the radar eye is centered in its housing on the kit but should instead be off-center, the front vents on the body need sharper detail as do the power coupling and octagonal detail at the base of the body, plus there are some side vents on the body not represented by the MPC kit. All minor stuff and you’ll see how I approached it in this build.

Awesome!

Sweet... Can you tell me if the kit is identical in both boxes. I need an r2 foot for my narcissus build and I could save a few bucks getting the Jedi one. Looking good.

Great project. I'm doing a 1/48th Red 4 X-Wing right now and it has an R4 for the droid. The head I have is conical, I wasn't aware of that circle to hex transition. I may just take the easy way out and leave it circular on the top, due to the small scale.

Looking forward to more!

jedimaster said:

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Sweet... Can you tell me if the kit is identical in both boxes. I need an r2 foot for my narcissus build and I could save a few bucks getting the Jedi one. Looking good.

Yes, the kits are identical; only the box art changed.

I've always liked MPC's R2-D2 kit, so it's nice to see someone else has an appreciation for it. Yes, it has it's inaccuracies, but even an out-of-the-box build will give you a very decent representation of the world's most famous astromech droid; with a little extra work you'll get a near-perfect miniature replica.

Troy, great research and nice work so far on your R4 unit. I'm really looking forward to seeing your continued progress on this project!

Cool thanks. Just saved me a packet.

Jedimaster: yep, identical plastic in both boxes. Thx Zombie_61 for chiming in on that as well.

Devin: on your quarter scale droid you might use a drawing template to sketch the hex pattern on the top of your R4 unit. Then use that as a guide to gently swipe the edges with sandpaper to get the shape. The transition from hex to circle occurs approximately 1/3 to 1/2 of the way down the head from the top. Make sure that a point on the hex faces forward.

Troy, that's a great idea. I'm going to make a copy of the head I have anyway, as it's the only copy in an out of production set, so I'll make two and experiment with your suggestion. I should also double-check and make sure the studio model actually had the R4 with the trapezoid head.

Devin, which call sign are you building? E.g. Red 4

Is this the FineMolds kit?

Or, I guess what I'm really asking is whose R4 kit?

Yes, the Fine Molds kit. The R4 is from Starship Modeler's Blue Moon line from back when they did the resin 1/48th scale Star Wars kits. I bought the set years ago, it's long out of production.

But enough of my hijacking of your thread! Question: Are you going to light these droids?

Shweet! I was thinking about doing something very similar since I made my 1/48 Droids. I do have 3D drawings of each Part of the Astrodroids that I drew up for my project that I can scale to 1:7 if you would be interested in 3D printed replacement parts...?

Lookin' forward to seeing more scaled droids!

Devin, I sure wouldn't mind having that R5 head from the Blue Moon set, but yeah that R4 head just isn't quite right. Casting a copy to play with is probably worth your while. It could turn out great!

I have plans to light one of the R2 units and the "brain" of the R3 unit under the clear dome. Although R5-D4 actually had lights in his eyes in A New Hope, it's really tough to see them (see attached screen capture from a dark scene inside the jawa sandcrawler). There's probably a bigger bang for the buck with lighting the R2 and R3 units than there is with the R4 and R5 units.

Seven: I appreciate the offer. Not sure what I might need at this point. The front vents on the main body are still left, but SLA probably wouldn't reproduce those delicate fins inside the vents very well. I'll keep it in mind, though. Thanks!!

R5 ASTROMECH HEAD



The R5 head consumed a great deal of time; I knew that it would be the most difficult head to scratch build. I’ve been using modified versions of the Dave Everett / R2 Builders Club styrene plans to build this head. First to come was the internal structure with three boxes built into the profile frames. I’ll cut these out later after I glue the skin into place.



After cutting and wrapping the neck skins, I approached the main head wrap skin. I knew that the joint between the upper neck skin and the lower head wrap would be delicate, so here’s a trick: I placed rolls of Milliput on the upper neck skin at the joint where the head wrap skin would intersect the neck…



…then I pushed the head wrap skin down on the internal structure, resulting in the Milliput “oozing” out at the joint just a bit.



Milliput has a workable time of about 1 hour (you might need to occasionally moisten it with water) after which it begins to cure. The box says full cure in 4 hours, but I tend to leave it overnight. At full cure, you’ll have a rock-hard compound which has also adhered to the surfaces it was applied to (hence the name “epoxy” putty). For the R5 head it helped create a solid joint between the neck and head wrap skins that I can sand and count on not warping or deforming while I’m creating molds for casting copies.

As for the head boxes, I could see through the top of the head the location of the three boxes. A 1/8 inch drill bit was used to drill a line of holes to outline the box interior…



… then I played “connect the dots” with an Xacto blade to enlarge the hole. A small file was used to clean up the sides and square the corners. In the photo you can see that I’ve smeared blue 3M glazing putty into areas where a bit of tidying up is required.



In this photo I’m detailing the R5 neck band. This pretty much finished up the R5 head master, so it’s ready to get covered in silicone!



Here I am “rolling” the silicone mold away from the first resin R5 head copy:



A few things to explain on this one: First, the pink-colored mold is one-piece, made from high-tear strength silicone rubber (this is from Micro-Mark, but Alumilite makes a similar product). This stuff can be stretched and deformed to a great extent without harming the mold. It’s great for projects such as this where there are undercuts in the master that require a great deal of flexibility in the mold to extract the resin copies. As you can see here, I can basically peel back the silicone mold to reveal the resin R5 copy. In this photo the mold has been rolled back about half-way to reveal the neck band. I can roll it back a bit further and then pop the resin copy out of the mold once those three side grooves on the R5 model have been partly exposed.

Second, you’ll note the bottle sticking out of the middle of the resin copy. This is my low-tech way to make the cast hollow inside. The bottle, which I salvaged from the recycle bin, is permanently cast in the part. I’ll cut it down when I trim the head to fit the astromech body. Making the heads hollow saves expensive resin (it would probably take more than twice the amount of resin to cast the heads if they were not hollow) and it also makes the heads lighter. I was concerned that solid resin heads would make the final astromech models too top-heavy and subject to easily falling over. This hollow space will also more easily permit me to light the models (if I decide to run fiber optics and LEDs in the models) and might permit me to somehow construct a way for the heads to rotate and be positionable on the final model. Maybe. We’ll see…

A quick note regarding how I finally managed to achieve the panel detail on the top of the R4 and R5 heads: I tried a number of different approaches, including scribing the detail and gluing thin sheet styrene, but nothing looked right or subtle enough. What finally worked (extremely well, I feel) was to cut out the panels in blue painters masking tape and attach them to the masters…



… I then sprayed the masters with 4-5 light coats of gray primer. It was just enough to build up a 0.01” (or slightly less) thick layer on the head. When I removed the tape – viola! Nice, subtle recessed areas representing the panels. These have been duplicated perfectly in the cast resin copies and should work well to help with painting the panels. Note that I got this tip from Steve Neill here on the RPF forums - a true master modeler!!



All of the R4 and R5 heads are now cast for this project (three of each plus a few bad pulls that I might let the jawas have later). I’ve had a setback with the R2 and R3 domes. More on that later.

Up Next: Holo Projectors and Radar Eyes

Pretty clever and looking great.

Looks great. I wish I'd see these kids when I was younger. I found the casting materials from Micromark to be easier to use than some others I tried.

Very clean, very nice. Loving this thread!

I've just found this thread and I love it already. I never thought about making a new head for the body before. I might have to get this kit myself now and give this a try. I love the R5 head and would love to see Red Leader's droid R5-K6.

If you want some good astromech references you can't beat this website
Star Wars Astromech Droids

Junk Pilot said:

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If you want some good astromech references you can't beat this website
Star Wars Astromech Droids

Agreed! That is absolutely the best one-stop source for figuring out which astromech went with which Red Squad member at the Battle of Yavin.

HOLO PROJECTORS AND RADAR EYES



The MPC kit holo projectors (HP) are vague forms and sorely in need of replacement. I searched for days to find a sphere or hemisphere that could serve as the base of the HP but came up cold until I found this… thing… stashed away in my tools. It’s some sort of wood dowel with spheres at each end. One is labeled “8” (it is 8 mm in diameter) and the other end is “10”. I have no idea what they’re used for, but I judged that the 8 mm end would work well as a master for “smash forming” a shell.



I anchored the dowel in my vise with the 8 mm end pointing up. Holding a small square of 0.02 inch sheet between two clamps, I heated the sheet with a hot air gun and then smashed the sheet over the 8 mm sphere (hence the term “smash form”). I smashed two sheets, one of top of the other to make two layers for base. You’ll see why in just a minute.





I made a lot of rejects…



But finally I ended up with a handful of inner and outer shell pairs that I could use.



The shells were trimmed from the sheet, and it turned out that they were 11/32 inch in diameter. That’s a bit small per the Club blueprints, but it looks okay in this scale.



The reason for having an inner and outer shell is because I wanted to model the mount in which the ball rotates. The holo cowl opening defined by two offset circular cuts. At 1:1 scale it’s two 1.9" circles offset by 0.2" from the middle.

In the photo below, the outer shell with the square cutout will slide over the inner shell which remains uncut. Note that this square shell is incorrect; I returned later and corrected the shape to represent the double-circles as noted above.



In the photo above you can also see the tapered projector lens cover. This was made from 1/4 inch styrene tube which was gently “sharpened” in a pencil sharpener to get the taper. The end of the tube was cut off, then a slightly smaller diameter tube was placed inside the tapered lens cover to make a short stalk. Note that I first closed off the end of the smaller tube so that the “lens” is really just a styrene disk. Once I have cast resin copies of the HPs I’ll have the option to drill out the lens and light it with an LED or similar.



I mounted the lens covers on the swivel balls slightly off center to add interest. You’ll note that I left off the raised ridges on the swivel head. That would be difficult to get right in this scale, plus they would be miniscule and difficult to see on a scale HP. If needed, they would be better represented by a decal (hmmm… I might need to make some decals).

Overall, I’m pretty happy with the HPs that I ended up with. I’ll start casting resin copies once I get the radar eye built.



Next, the radar eye frame needed some attention. After I filled the eye hole in the MPC kit part, I started comparing the kit frame part to the Club blueprints and realized that the eye location is just about right (doh!). Instead, the MPC frame needs the sides to be re-contoured as shown by the black lines in the photo, plus it needs a small styrene strip attached to the bottom to make the part taller.



I also crafted new “greeblies” for the side of the eye frame and scribed a fine line at the bottom for the slot (I would love for this to be a CD / DVD slot on my 1:1 scale model !). In the photo below you can see the clear eye lens that I have used on this master. It's made from clear plastic packaging from kids' "Squinkies". This packaging consists of excellent clear plastic hemispheres 1 inch in diameter. I've already found several uses for them in models and I have quite a stock of them hidden away in my stash - my little girls love the toys so for the moment I have no shortage of supply!



Okay, now I’m ready to cast up a whole mess of HPs and radar eyes for this project! Here I’m brushing the HP and radar eye mold with talcum powder to improve the resin’s ability to “wick” down into the details and reduce bubbles in the final cast:



Dumping out the excess talc:



Measuring the two-part resin by weight for mixing (in this case, some leftover Alumilite White that I had sitting around):



Pouring the resin into the mold:



Watching the bubbles come out of the resin in the vacuum chamber:



And pulling all of those glorious parts out of the mold:



I have a dozen radar eyes and a couple dozen HPs cast at this point. That should be sufficient for this project.



Up next: Feet and Legs

Dude. That's awesome. I'm loving this project!

Very cool work so far!

Very cool stuff