Science fiction television from the 1960s through the 1980s produced some of the most iconic props in popular culture — communicators, robots, weapons, consoles, and costume pieces that defined the visual language of an era. Replicating these props requires a specific set of skills that are well-documented and widely practiced in hobbyist communities.
The Fabrication Skill Stack
A prop builder working on classic sci-fi replicas needs proficiency in most of these areas:
Mold Making and Casting — The core skill. Most complex prop shapes are cast, not carved. You make a master (sculpted, machined, or assembled from found objects), take a silicone rubber mold of the master, and cast reproductions from the mold in urethane resin, foam, or other casting materials.
Fiberglass and Composites — For large structural pieces. The body of a full-size robot, the hull of a prop spaceship model, large console elements — these are practically built in fiberglass. The skill transfers directly from automotive and marine repair.
Electronics — For animated props with lighting, sound, and movement. An Arduino microcontroller, some LED drivers, a sound board, and a battery pack turn a static shell into a working prop. The B9 robot is the most electronics-intensive common project; simpler props may just need a few blinking LEDs.
Surface Finishing — Body filler, primer, painting, and weathering. A prop is only as convincing as its finish. This is often where projects stall — builders who are excellent at fabrication underinvest in finishing and end up with pieces that look handmade rather than screen-accurate.
Machining and Fabrication — For metal components. Some props have aluminum or steel structural elements. Basic lathe and mill work, or more commonly home CNC router work, handles this.
Not every project requires every skill. A simple device prop might be pure casting and finishing. A full robot requires everything on the list.
Where Classic Props Come From
Most 1960s sci-fi television props were built with exactly the same techniques available to home builders today:
Casting — Foam latex, fiberglass, and plastic casting Found objects — Commercially available hardware, plumbing parts, electronic surplus items repurposed as prop details Vacuum forming — For repeating elements like communicator shells, costume components Fabrication — Aluminum sheeting and welding for structural elements
The B9 robot from Lost in Space used aluminum structure, cast fiberglass sections, and purchased commercial hardware for surface details. The original prop builders were craftspeople working in a professional shop environment, but the methods were entirely analog and are entirely reproducible.
The B9 robot history article covers what’s known about the original prop’s construction.
Reference: The Foundation of Accuracy
A replica is only as accurate as its reference. Before building anything:
Primary source: the show itself — Stream the series and screenshot every angle of your target prop. For props that appear frequently (a main character’s weapon, the ship’s control console), you’ll accumulate dozens of usable reference shots.
Secondary source: community research — Dedicated prop communities have often done decades of research identifying exact commercial parts used in original props, measuring surviving originals, and documenting changes across seasons. The B9 Builders Club is the most developed example; Star Trek, Doctor Who, and Star Wars communities have comparable depth.
Physical reference: surviving props — Occasionally appear at auction or in museum collections. Dimensions from hands-on measurement are more reliable than photographic estimation. Not available for most builders, but community members who have accessed originals often document what they find.
A Practical First Project
For a builder starting out, the right first project has these characteristics:
- Small and portable — Easier to work on, storage not a problem, no structural engineering required
- Primarily cast resin — The most transferable skill to learn first
- Good reference available — Community-documented props where someone has already done the research
- Reasonable accuracy threshold — A prop where “close enough” reads correctly, versus one where any deviation from screen accuracy is immediately obvious
Good candidates:
- A communicator or handheld device prop
- A small robot or automaton (tabletop scale)
- The Mystic Seer fortune teller from Twilight Zone — a well-documented project that builds mold-making and casting skills
Not ideal first projects:
- Full-size B9 robot — multi-year commitment, requires all skill areas
- Large costume pieces — accurate sizing and fit add complexity
- Props with significant metal fabrication requirements
Silicone Mold Making for Props
The mold-making process for a typical prop part:
- Prepare the master — Clean, sealed, no undercuts (or plan for a multi-part mold if undercuts are required)
- Build a mold box — Sized to provide adequate rubber wall thickness around the master
- Apply release agent — Even for silicone-on-most-materials, a release prevents mechanical lock
- Pour silicone — Use a platinum-cure silicone in the Shore A 20–30 range for most prop work
- Demold and cure — Wait the manufacturer’s recommended cure time before demolding
- Cast reproductions — Urethane resin, foam, or other casting material into the finished mold
The silicone rubber mold making guide and the beginner’s resin casting guide cover this process in detail.
Communities and Resources
B9 Builders Club — b9creations.com — The most active classic sci-fi prop builder community, focused on the B9 robot but active in adjacent prop areas.
The Replica Prop Forum (RPF) — Large community covering all prop types across film and television. Research threads on specific props are often years deep with cumulative documentation.
WonderFest — Louisville, Kentucky — Annual model and prop convention with significant sci-fi prop display presence. See WonderFest coverage for reports.
The skills developed building one prop transfer directly to the next. A builder who starts with a handheld device and learns mold making, casting, and finishing has the foundation to approach a full B9 robot build — or any other fabrication challenge in the same skill family.