A month before building the frame, I wanted to kick things into gear by building my very first scratch-built piece, the Radar Eye. Being very excited, I downloaded and printed a cutting template from the tutorial section of Astromech.net and got right to work.
My first version of the radar eye was made out of scrap pieces aluminum roof flashing. I simply used heavy duty shears to cut out the pieces and then hot glued them together. Easy right? Nope. There were two major problems with craftsmanship..
First of all, the flashing was a bit too thin and flimsy causing the pieces to warp. I tried to reinforce all the inner walls by gluing another layer of aluminum flashing to them, which helped a little, but I still wasn't too thrilled with the final outcome. The added layer of aluminum improved its overall ridgidity, but still had the capability to bend out of shape.
Secondly, hand cutting it with a pair of shears did not exactly yield the straightest cuts. Even cuts that were slightly crooked left unsightly gaps between two pieces of flashing and/ or between the flashing and the dome. Patching in the gaps with Bondo or some other two-part putty system wasn't feasible because there was no solid foundation for it to adhere to, especially where the walls of the eye meet the dome. Moreover, it wasn't worth the effort to glue strips of aluminum flashing to use as a patches either.
The picture displayed below shows the back of the radar eye, the side that is hidden from view when installed on the dome, that reveals other small problems that I experienced. As you can see, the inner walls had to be reinforced by gluing in another layer of aluminum flashing. It was messy, since getting nice, clean and even seams of hot glue wasn't exactly the easiest task. Also, the aperture where the lens goes, wasn't exactly the perfect circle. -yuck!
My second attempt of the radar eye was created out of 0.040" styrene. Using my favorite heavy duty utility knife (made by Husky), a straight edge and a compass, the cuts were more controlled. The result gave way to much more cleaner pieces than the ones from the aluminum version. Because I wanted a fast setting glue, I also used hot glue to attach the pieces together. I had to be extremely gentle since hot glue could easily warp styrene. In order to prevent warping, after applying the glue using a hot glue gun, I waited until the glue cooled down a little bit before I pressed the pieces together.
Both radar eyes were painted using a modified Krider formula: one coat Rust-Oleum White primer followed by two coats Dupli-Color MetalCast Anodized Blue and then topped with two coats Rust-Oleum Crystal Clear#7701.
The radar eye lens was cut out from the convexed portion of a 2 liter soda bottle. The back of the lens was then painted black and then taped onto the radar eye.
The results looked great, but being that the eyes were hollow, they were very fragile. One wrong bump or thump may instantly destroy it. Filling the voids with foam sealer from a can might have helped but there was still no solid surface to securely mount it to the dome. Another builder suggested pouring in resin filler but I thought it just wasn't cost effective. I finally decided to to order a council approved resin version from one of the group's part suppliers at a later date and use the scratch built versions as a mock up for the mean time.
In the end, the scratch built eyes didn't look as bad as I thought. However, in the picture below, you can clearly make out the warpage on the top surface of the aluminum eye, caused by using the thin pieces roof flashing.
A year later, I obtained this fantastic solid resin version from Azman. It was also painted using modified Krider formula and aluminum tape was used for the details. The soda bottle lens was also used.
I was extremely excited about approaching closer to the first milestone of the build. So far, I had the skins, frame, legs, center ankle, dome and radar eye. This was absolutely the minimal amount of parts needed to have a standing astromech that actually resembles one!
"The Gas Pipe System"
The first step was to mount the legs to the frame which involved using a system developed by Mike Senna. This system is a tried and proven method which uses gas pipes that act as a support system much like the axle of a car, except that it is not subject to constant rotation. It's rather a clever and simple concept where gas pipes run horizontally through holes on both right and left uprights of the frame and the ends of each pipe are attached to the hubs of each leg using a pipe flange. To prevent the pipes from rotating, a U-bolt with a round bend is used to clamp it down. The U-bolt is mounted on a heavy duty steel angle bar that runs vertically with the frame. The bottom end of this bar is anchored to another angle bar used to hold the center ankle to the base plate of the frame. Pretty simple right?
From what I have figured, droids with wooden frames utilizing this clever design have three significant advantages over those droids with its legs bolted directly to the frame:
1. Reduces the stresses from locomotion. For a droids with their legs bolted to the frame, when propelled forwards or backwards, and being that the motors used for locomotion are at the bottom of the legs, the torque will produce a large amount of stress on the hub-to-body joint. While I cannot speak for those who have their legs bolted directly to the frame, whether there has been a history of weakened or damaged frames or not, I will just er on the side of caution and use the gas pipe system.
2. Acts as a frame within a frame. Rather than have the wooden frame act as the main support structure of the entire droid, the legs-gas pipe-ankle combination, acts together to forms an internal frame, independent of the wooden frame. This means that as more and more stuff is added to the droid, the added weight will bear stress on the gas pipe system (which now serves as the main support structure), and not on the wooden frame. This system also forms strong foundation to keep the legs perfectly parallel with the body and there is zero or minimal inward or outward flex in the lateral direction.
3. Can be used as a safety lift point during transport. Most fully completed droids with wooden frames and have basic functions will weigh over 100 pounds. A fully assembled droid with the dome off, can be safely lifted without the risk of damaging costly parts, especially the greeblies, when you use the gas pipe as a lifting point.
The gas pipe system utilizes two black gas pipes (one 1" and one 3/4".) and two electrical conduit flanges (one 1" and one 3.4").
The purpose for the two sizes of pipe is for the smaller one to slide into the the larger one and with careful selection, should slide together smoothly. This is a convenience for whenever you needed to detach the legs from the body, all you had to do was remove a few bolts and slide the legs apart.
Finding a pair of gas pipes where the smaller one would fit inside the bigger one was a REAL CHALLENGE. Not all pipes are made the same because the manufacturing process produces a thin internal bead, that runs across its entire length, that can vary in size. The bigger the bead size the more obtrusive it is, preventing the smaller pipe from sliding into it. I remember having gone thru the supplies of one Lowe's and two Home Depot stores until I found the perfect 1" pipe with a less obtrusive bead (at the Home Depot). I can recall a few instances where customers would give me a funny "what the hell are you doing?" look while I exhausted an entire shelf of dirty black gas pipes, trying to fit one into another.
Here's how the gas pipes look with the smaller one inserted into the larger one. You can see from the pic below how it resembles an axle for an automobile.
In order to slip the pipes thru the frame, holes big enough for the 1" pipe had to be drilled on each side of the frame, more particularly, the lateral plates. But before that was even possible, the skins had to be attached, which will allow the the hubs to be aligned correctly so that a mark can be made to cut the holes.
The skins were temporarily attached using masking tape and then marks were made which aligned with the dead center of the "leg sockets" of the skins.
The pipe was fitted and checked for squareness against the frame. So far, so good...
The center ankle angle bar mounts also make part of the gas pipe system. A heavy duty steel angle, also purchased from the Home Depot, was cut to size, and two mounting holes were drilled. The wooden center ankle was then bolted to it and as one unit, it was then aligned and finally bolted to the base plate.
The 1" flange was permanently fixed on the left leg, and the 3/4" flange fixed on right. The pipes were temporarily screwed on tightly to the flanges. I sat Artoo's body on top and between two milk crates which allowed the center ankle to clear the floor. With the skins still taped to the frame, the left leg (1" pipe) was inserted thru the hole of the left plate and out thru the hole on the right. The right leg (3/4" pipe) was then inserted 1" pipe thru the right side.
Studying reference movie stills of A New Hope, I chose to have a shoulder-to-body gap of 1/8", which of course, is my guesstimate. To help with alignment, I wedged a spacer ( a piece of scrap 0.125" styrene) between the shoulders and the body of both sides. Each pipe was then checked for the correct length, which only had to be long enough to clear both holes, but not so long that it would cause the other leg to protrude too far out.
Merriam-Webster's Dictionary defines a Lazy Susana revolving tray used for serving food, condiments, or relishes. It's one of those gizmo's that allow easy access to that dish of Kung Pao Chicken, located on the other side of the table, that you've been impatiently waiting for. Well, the R2 Builders Club's preferred method for rotating domes is very similar to the Chinese restaurant thingamabob, except instead of a mounted platform used to transport that dish of Kung Pao Chicken, it's a Artoo's head.
Dome Rotation Basics
The club's preferred method of dome rotation has been proven to be efficient, reliable and simplistic: A specially selected lazy susan bearing, with a diameter that is slightly smaller than the diameter of Artoo's dome (< 18"), is mounted to the frame. Here is a picture of the ABS Woodcraft bearing mounted to my frame:
<click image to enlarge>
More specifically, the stationary or non-rotating portion of the lazy susan is bolted to the top plate of the frame. On the rotating portion of the lazy susan,the threaded ends of four tall #10 screws are inserted underneath and upward through custom drilled holes are secured in place with nuts. These screws that stick upwards serve as an alignment pins when dome ring and support ring are stacked on top of the bearing. Just picture a 3 layer cake, with the lazy susan bearing as the bottom, the dome ring as the middle, and the support ring as the top layer of the "cake." Washers are used as spacers between the bearing and the dome ring to adjust the dome height just enough so the dome ring does not rub against the body. Mounted on the frame is a motorized wheel that contacts the surface of the inner side of the bearing and when the wheel turns, the bearing and the dome rotate in unison. (this covered more in detail in another discussion) Easy right?
Choosing a Lazy Susan
Picking out a bearing was pretty straight forward as there were only two options at the time: Woodcraft or the gold standard, Rockler. This lazy susan was the second item purchased for the project and it is was not cheap! Trying to save some money, instead of going with the preferred aluminum Rockler bearing, I opted to go with the PVC version from Woodcraft. Not only was it was seven bucks cheaper, there were no shipping charges since there was a Woodcraft store local to me, which I was able to pick up. Here's how the two compared, based on the advertised descriptions:
A month before building the frame, I wanted to kick off Project Astromech with a little scratch built piece, which also happened to be my very first built part: the Radar Eye. Being very excited, I downloaded a cutting template PDF from the tutorial section of Astromech.net and got right to work.
The first version was made out of aluminum flashing, used for roofing, that you can get from your local home store. I simply used heavy duty scissors to cut out the pieces and then hot glued them together. I wasn't to thrilled about the craftsmanship because the flashing was a bit too thin and flimsy causing the pieces to warp. Moreover, hand cutting it with a pair of shears did not exactly yield the straightest cuts. ...sigh.
The second version was created out of 0.040" styrene. Using my Husky heavy duty utility knife, straight edge and compass, the cuts were more controlled. The result gave way to much more cleaner pieces than the ones from the aluminum version. Because I wanted a fast setting glue, I also used a hot glue gun to attach the pieces together.
The radar eyes were painted using the basic Krider formula: one coat Rust-Oleum White primer > two coats Dupli-Color MetalCast Anodized Blue > two coats Rust-Oleum Crystal Clear.
The radar eye lens was cut out from the convexed portion of a 2 liter soda bottle. The back of the lens was then spray painted black and then taped onto the radar eye.
The results looked great, but being that the eyes were hollow, they were very fragile. One wrong bump into it will instantly destroy it. Filling the void with some instant foam from a can might have helped but there was still no solid surface to mount it to the dome. Another builder suggested pouring in resin filler but I thought it just wasn't cost effective. I finally decided to to order a council approved resin version from one of the group's part suppliers at a later date and use my scratch built one as a mock up for the mean time. Note the extreme warpage of the aluminum version in the picture below.
A year later, I obtained this fantastic resin version from Azman. Since the piece was formed with the use of a vaccuum chamber, which helps reduce the appearance of air bubbles, there was no need to fill and refinish it. It was also painted using the Krider formula and aluminum tape was used for the details. The soda bottle lens was also used. Because synthetic resin was solid throughout, it provided a secure foundation for mounting on the dome.
Installation was straight forward. The eye was held in the desired position and then a pencil was used to trace its outline on the dome. Using a 5/64" drill bit, two pilot holes were drilled strategically within the boundaries of the pencil outline. The radar eye was then taped to the dome in the same desired position and then the back of it was pencil marked using thru pilot holes. Using the marks, holes were drilled wide enough to accept #10 screws. The pilot holes on the dome were also widened to accept the new screws. The red arrows in the pic below indicate the marked holes.
So how does it look?, you might ask. Well, no peeking yet. Not until I've painted and mounted the dome panels. Stay tuned.
Aluminum. It's probably the first thing that comes to mind when we think of R2-D2's dome. You can have one of the correct size, shape and form, but if the color and texture were off, it would render itself useless and the entire droid would be passed off as a bad replica. ...and because the dome I was working on was not aluminum, I dreaded the day it was time to paint it because from my past experience (along time ago!), I found no metal colored paint that was able to simulate the real beauty of aluminum.
On the other hand, metallic paints have come along way since then and have drastically improved in regards to finish, yielding realistic chrome-like properties. These days, there are oodles and oodles of metallic paints to choose from without breaking the bank on some fancy chrome spray paint system or having to go to a professional paint store to have it custom mixed. For less than five bucks a can, these metal paints are available from the spray paint section of your local home store, not to mention that they've become a lot bigger compared to twenty years ago.
I must mention that there are a few paints that stand out in the open and have yielded exceptional finishes: Valspar's Silver #66010 and Rust-Oleum Chrome #7718, in my opinion, have finishes that come really close to the brilliance of metal.
Problem: There are two major drawbacks with these two paints, especially if a builder is going for the A New Hope -throne room sequence R2-D2, where he is absolutely clean, pristine and his dome is buffed to a high shine! For one, the shiny finishes will be ruined once touched by human hands. Based on what a rep from the Rust-Oleum support department had responded in an email, the secret to these paints giving off its metallic reflective finish is the very fine leafing agents that are dusted onto the surface when sprayed. At the microscopic level, this "dust" forms peaks and valleys on the surface that allow light to bounce off at different angles, which gives us the brilliance of "chrome." Unfortunately, once this dust is rubbed off or the peaks and valleys are flattened, the result is a dulled appearance. We must consider that R2-D2's dome has a large surface area and will be prone fingerprints galore during public events. What's more disturbing, once a dome with this type of paint is touched by a child's hands, the paint also ends up sticking to them, embedded within the skin. -UNACCEPTABLE.
Along the same lines, the second major drawback is that when the chrome paint is top-coated with a clear paint, it ruins the finish. As mentioned, because chrome-like reflections highly depend on a layer of microscopic peaks and valleys, adding a clear coat fills and covers these formations creating a flattened surface, giving way to a dulled appearance. The bottom line: Using a clear coat to stop these paints from rubbing off while protecting and preserving its brilliance is not possible.
It is interesting to note that water-based and oil-based clear paints have different effects when applied over the chrome paints. From a few tests that I've done, an oil-based spray, such as Rust-Oleum Crystal Clear#7701, resulted in a dull, muddy darkened appearance and using a water-based clear ( I forgot the brand name), dulled it from a shiny chrome appearance to a standard bright silver color. Explaining these huge differences in effects may refer back to the fundamental rule in high school chemistry that "like dissolves like." Since an oil-based paint (Rust-Oleum Clear) is sprayed over an oil based paint (Rust-Oleum Chrome), which both are non-polar substances, the clear paint will dissolve the chrome paint. On the other hand, a water based paint should not dissolve the oil-based, since one is polar and the other is not. Okay, so I'll stop right here before I really go off on a tangent.
THERE'S STILL...HOPE. Realistically, aluminum isn't always shiny, as it can also appear with a dull gray finish, indicating being aged and oxidized. Many builders, including myself, with non-metal domes have gone to replicate this look with the ability to use a protective clear coat. As discussed, since using a clear coat over a chrome paint can "ruin" the finish in different ways, depending on which type of clear paint is used. This can serve as a great idea after all, giving the appearance of a dirty, oxidized look, given you use an oil based clear. This is a great alternative, provided you "weather" the rest of the droid to match and from what I have seen, going this route yields more convincing results, as opposed to replicating polished aluminum. ...so say goodbye to the Throne Room scene and say hello to the murky swamps of Dagobah! ...well not for me, as I wanted an oxidized look, but not so grimy. For my dome, I plan to simply use a basic silver paint, topped with Rust-Oleum Crystal Clear.
Which metallic paint to use?
As I've mentioned, the dreaded part of this project was choosing which paint to use for the dome! All silver metallic paints have their pros and cons, so I created a few guidelines to help narrow my selections down:
Project Astromech Dome Paint Criteria
1. Finish is 0% affected by the addition of a clear coat.
2. Will not rub off on your fingers.
3. Not too sparkly/ glittery (no large metallic particles or flakes)
4. Durable hard finish (wont easily dent).
5. Can be wet sanded and polished.
6. High performance spray: Not easily prone to runs or drips.
7. Mirror/Reflective finish.
8. Yields a uniform bright silver color.
9. Does not take months to cure.
10. Inexpensive and available locally.
The Paint Test
Purpose: To find the best dome paint, according to the above criteria, appropriate for a slightly weathered R2D2.
Researching through numerous articles, blogs, and forums on the net, and following the above criteria, it allowed me to narrow down a humongous selection of different paints to four:
Procedure: Outdoors, and in the sun, each of the soda cans were quickly sprayed with one heavy coat of paint with a distance of six inches between it and and the spray nozzle. The temperature was about 88 degrees and the humidy was about 60%. No clear coat was used.
Results: I have included Valspar's Silver #66010 and Rust-Oleum Chrome #7718 despite its drawbacks (discussed above) because I wanted to use them for the purposes of comparison. Rust-Oleum and Valspar (exclusive at Lowe's) gave the best looking finishes, but the Rust-Oleum was hard to work with as you can see it had more drips and runs. The Valspar paint looked the most beautiful of the four and performed the best as it produced no runs or drips. As discussed earlier, both these products cannot be clear-coated without ruining the finish and this was not the look I was going for. The Krylon Bright Silver #1401 (a special order from ACE Hardware) can accept a clear coat but was too glittery to my taste.The Duplicolor Radiant Silver #BCC0338 (from Pep Boys) is actually a touch-up automotive paint that is designed to accept a clear coat and wasn't as sparkly as the Krylon, and according to my criteria for an ideal paint, this was a good thing. If the Duplicolor is durable for an automobile then I think it's okay to say its plenty durable for R2-D2.
...and the winner is:
Duplicolor Radiant Silver #BCC0338
The inner and outer styrene dome was painted with Rust-Oleum White Primer #249058, followed by two coats of the Duplicolor Radiant Silver and topped with two coats of Rustoleum Crystal Clear#7701.
...and the same went for the dome ring.
After the paint was allowed to cure for a few days, it was not as glossy as I've wanted it and the surface felt a bit gritty. I improved the finish with a little buffing and polishing which was accomplished by rubbing folded pieces of standard copy paper on the dome in light circular motions. The paper acts as an extremely fine sandpaper, resurfacing the clear coat without introducing unsightly scratches. The dome was then cleaned and buffed using a microfiber towel. In the end, I was happy with the results which gave way to a more glossy, smooth, and reflective finish.
The first and foremost item of the entire build was R2-D2's dome, which puts all things into perspective as far as its size in proportion to his cylindrical body. In other words, I never realized how big Artoo was until I actually held the dome in my own hands! But then, I realized that it had to be big enough encase actor, Kenny Baker. In addition, having the dome early in the build also provided an "inspirational fuel" to finish this project.
Since the accuracy of its shape will either make or break what is considered a replica and what is just a "wannabe" R2-D2, I turned to two notable builders/ part suppliers of the of the R2-D2 Builders Group, Daren Murrer and Cole Horton. They are most noted for supplying the latest and greatest aluminum screen-accurate replica called the "300 Dome." But because the 300 Dome was not offered at the time when I first joined in March of 2009, I had to opt for another great dome that they also offered, called the "C&D Dome." The C&D Dome was a styrene version of their 300 Dome.
The C&D dome is a 3 piece set which includes an inner dome, outer dome, and a dome ring (not pictured below). The purpose of the inner dome basically serves to hold the outer panels in place and at the same time, gives structural support to the outer dome.
As you can see, these are plain blank white domes which will require alot of cutting and painting. Also notice that the shape of the dome is not a perfect hemisphere but more of an ovoid shape, much like the real prop. I have seen many astromechs utilizing a hemispherical dome, perhaps made from a lamp shade, BBQ grill or even a squirrel guard, which was probably the only options available in the past. Unfortunately, to many, it gave its overall appearance an odd look. The the upside is that the general public may not take notice to the hemispherical dome, unless they are true Star Wars movie buffs, or until it is placed side by side with another astromech with a more accurately shaped dome.
The only major drawback is that this dome is not aluminum. According to special visual effects person for Empire, Brian Johnson, he mentioned in an interview that in one instance, R2-D2's dome was "built in a compositic epoxy resin fiberglass moldage structure, rather than aluminum..." As we have seen in the movie, because of the right amount of lighting, you can never tell the difference between what is metal and what is not on-film, but I'm certain that a scrutinizing Star Wars buff would easily point out its non-metallic properties if it was to be seen in person. From a builder's standpoint, the dome can be painted an "aluminum" color, but as far as I have seen, there is no paint in the world that will ever simulate the elegance of real aluminum. I eventually will have my hands on an aluminum dome, but for the mean time, this will have to do. Don't get me wrong, I believe that a non-metallic dome painted in efforts to simulate aluminum is perfectly acceptable, but if your budget allows it, I feel an aluminum one is a better option if you really want to be screen-accurate.
Fortunately, Daren and Cole were nice enough to post printable cutting templates in PDF format, which allowed me to roughly mark the locations, spacing and height of each panel and orifice.
After each panel was lightly marked using the templates, I attached a flexible straightedge to the top dead center of the dome using a drywall screw. This allowed served me two purposes:
1. To redraw all the vertical lines each panel, using the straight edge of the ruler.
2. To redraw all the horizontal lines of each panel, by using the top dead center as a pivot point and allowing the pencil lead to ride along a fixed point on the straight edge.
Here's a short video to make things more clear.
Here's how it looked after all the panels were drawn on. The "dome ring," mentioned earlier is indicated by the green arrow. Throughout the entire time, the dome was taped to the dome ring to keep it in place while I was cutting. Without it taped to the ring, the dome would be extremely flimsy. An internal support ring will be used in the future to help maintain its shape, and to secure it to the body. This will be discussed later on.
Since there were no cutting templates nor official club specs for the top panels, with the help of a little high school geometry and studying a few reference movie pictures, I was able to estimate the size and spacing.
Using the traditional score and snap method for cutting styrene sheets on this dome isn't easy as it seems. Because of its convexity and it's 0.125" thickness, most of the cutting was done using a miniature saw. Made by X-ACTO, I bought this little saw for a few dollars, and it worked out great. Notice that I taped the outer dome to the ring to maintain its original shape because the more panels that were cut out, the more it started to lose its rigidity.
As for the holes of the dome, I utilized an adjustable circle cutter, that I bought from Harbor Freight, that can be attached to a drill:
Loose panels that needed holes were taped down to make drilling easier.
Cleaning up the top dome panel was a cinch. A screw was inserted through the center and then the panel was rotated against a disc sander.
All the cut panels were hand sanded and carefully gapped to 1/8" with the outer dome. In the pic below, here's a tricky combination of three panels which will house the rear logic display later on. Sanding the panels to make the 1/8" gaps parallel with the outer dome edges was a challenge. I'm happy with the results.
After a few weeks working on and off, despite being a long and tedious part of the build, it turned out to be a very rewarding experience.
...and here's the cut outer dome with masking tape labels over the panels, placed over the inner dome. I also placed a mock holoprojector on top just for kicks.
Understanding the general concept of leg construction required consulting several astromech blogs of other notable builders, who have also scratch built their parts, such as Victor Franco,Dan Baker, and Alex Kung, just to name a few.
Much like most scratch-built items in R2 building, Artoo's outer legs and center ankle are built up of layers of varying thickness using one material or the combination of different materials, whether it be plastic, wood or metal. These layers are specifically arranged so they match the dimensions of the club blue prints. Consulting Victor Franco's leg tutorial , I gained an understanding of how all the layers of plywood were put together.
Materials & Tools:
Outer Legs / Center Ankle Layers: 1 -3/4" x 4' x 8' Birch Plywood 1 -1/2" x 4' x 8' Birch Plywood 1 -1/4" x 4' x 4' MDF Board 1 -1/4" x 4' x 4' Hard Board _______________________
Router/ Router Table 1/2" Router Template Bit (w/ bearing) Table saw Power Hand Held Drill Drill Press General Hand Tools: Hammer, Screwdriver, pliers, etc... Power Hand Held Jig Saw Power Circular Saw Power Miter Saw Disc/Belt Sander Assortment of Sand Paper Pencil Metal Ruler/Straight Edge Digital Caliper Compass (to draw circles) Assortment of Clamps Dremel w/ Router Attachment Pneumatic Brad Nailer + Air Compressor 1 -1000 pack 1 1/4" Pneumatic Brad Nails 1 -Bottle of Wood Glue 1 - 1/2-Pint Elmer's E848D12 Carpenter's Wood Filler Several cans of Rustoleum White Spray Primer Several cans of Rustoleum Satin White Spray Paint 1- Can Valspar - Bright Silver Spray Paint Most importantly: Eye, Ear and Respiratory Protection * I actually used every tool I owned for this part of the project!
Making the Templates
Two uniquely shaped templates were needed to create the different layers of the legs. There was one for the outer layers and one for the inner layers. The templates had to be as perfect as possible or else the defects would have been replicated in all the layers I made.
Using the dimensions in the club prints, labeled "Assembly Outline Drawing" , I redrew the general outline by hand on a 1/4" MDF board. This one was made particularly for the outer layers.
A power hand held jigsaw using a fine-cut blade was used to carefully cut the straight portions of the template. When I got to the circular portion (shoulder) I cut a 1/8" margin around the outline because I wanted to use a more accurate method of cutting a perfect half-circle. To achieve this, I created a jig that allowed me to pivot the template against a disc sander. I did the same for inner leg layer template as well (not shown).
The results for both templates turned out pretty good. The inner layer template is the one on the left.
Cutting the Layers
Using a template router bit, I was able to route several copies of all the needed layers for the legs.
Shown below are all the cut layers used to create one leg. Because Birch plywood is not so common in 1/8" and 1/4" thicknesses, alternatively, I used hardwood board and MDF board, respectively.
In order to get the "armpits" to spec, the outer layers needed some special attention using a router, Dremel, and wood chisel.
The center ankle was made up from a total of four layers: two inner layers of 1/2" Birch plywood sandwiched between two layers of 3/4" Birch plywood. Since the center ankle was only one unit, no templates were needed. The outlines from the blue prints were just hand-drawn directly on the wood.
Just to get an idea how they look at this point, here they are roughly put together with clamps:
With respect to the blue prints, the curved section of the ankles were made from cutting several segments of 6.0" diameter circles made from 3/4" Birch plywood and then gluing them together.
Rather than cutting each individual segment one by one, to expedite the process, I screwed together two circles and cut them as one piece. This way, one chop from the miter saw got me two segments. As you can see, in the pic below, I used a piece of scrap plywood (green arrow) to clamp the circular pieces in place. There was no way I was putting my hand near the blade! Safety comes first!
The red line you see, in my dimly lit garage, is a laser, which is a an unreliable feature that comes with many of today's power tools. I say this because you can't even see the laser if you use this outside or with a bright light.
To make one piece, it took about six segments that were glued and clamped together...
...which equated to a total of 24 segments for both legs and center ankle.
The next day I had to cut a 55 degree angle on each of the curved ankle pieces. This was very tricky, since my cheap miter saw maxed out at 45 degrees. To make the correct cut, I had to create another jig that angled the piece an additional 10 degrees from the horizon. I mounted the jig with a combination of clamps and viola!, 55 degrees.
Here's how two newly cut pieces looked like.
After the pieces have been filled, sanded and followed up with a few coats of Rustoleum white primer, they were aligned, glued, and secured using a pneumatic brad nailer.
Here's how they look before the lengthy process of filling and sanding. According to spec, the holes, located in the outer side of the shoulder, were drilled. On the inner side, 1" and 3/4" gas pipe flanges, which will be later used to connect the legs to the frame, were installed. We will visit this process again at another time.
At this point, the filling-sanding-priming-filling-sanding-priming process began. Then it was repeated over and over and over again until the wood grain and the surface imperfections were all gone. As they say, patience is a virtue.
The 3/8" hole near the apex, which supposed to use a 3/8" bolt to connect to the foot motor mounts, was drilled 1/8" lower than the blue prints called for. This was recommended to eliminate the foot shell-to-ankle clearance problem that builders have experienced when Artoo was in his three-legged stance. ...and what great timing that the newly drilled holes could now double as an ankle joint and a paint drying apparatus!.
The legs were primed again and finally painted using Rustoleum satin white. They were hung and left to dry in the garage for a week. Also notice the flanges (used for electrical conduit) installed on the outer legs. This flanges will be used later as a way to connect the legs to the body.
Other Details
According to the blue prints, there is a channeled section located at the angled face of the ankle (green arrow). I simply dug this out with a chisel, then lined the inside with left over styrene from the skins. This great idea came from Victor Franco's leg tutorial.
I purposely made the styrene lining stick out a little past the surface so I could sand it flush. The gaps were later filled and sanded smooth.
For the "armpits," I used some left over styrene to help patch up a few imperfections that wood filler alone couldn't fix. At the same rate, it was also used recreate edges that needed to be straightened. I used a wood chisel to remove just enough wood for the styrene patch to sit flush with the surface.
Using a two-part filler (Bondo) made things go alot quicker as it only took a few minutes before I could begin sanding it.
After filling, sanding, filling, and sanding more areas of the leg (it never ends!), primer was applied once again and left to dry for 30 minutes. The entire leg was then immediately painted with Rustoleum satin white (again).
The following day, the "armpits," were painted with Valspar bright silver. As you can see, the styrene patch really cleaned things up nicely.
A beautiful detail that I really admire is the thin channel that goes around the periphery of the lower middle section of the leg which is also continuous on another separate piece called the "booster covers" (I will cover this later). In the final product, this channel was painted to simulate "bare metal," which supposed to indicate a metal foundation beneath the white exterior. To accomplish this, the 0.1" wide channel was created by clamping a metal straight edge and using a Dremel with a router attachment adapter with an appropriately sized routing bit. I had to make a few practice runs on a few pieces of scrap wood before I used it on the leg that took so long to make. God forbid I screw that up! After finding the optimal RPM and the optimal speed in which to move the Dremel along the straight edge, I followed through, on each side of the leg, with a steady, continuous pass. It was a scary endeavor, but a successful one.
Here's how the leg looked with the channel painted with Valspar bright silver.
