Inflatable Movie Screens
From 10’ to 100’ wide, inflatable screens are workhorses of the outdoor movie industry.
By size, the greatest number of units in use are 12′ to 40′ wide. Screens with projection surfaces up to 24’ wide can be quickly set up and taken down by one person and, if properly installed, a well-made model remains stable in wind up to 24 mph.
Inflation methods
Continuous Air screens have an inlet tube attached to a blower operating full time. Top of the line frames will stand rigid, not flex in the wind, and blower back pressure allows for small leaks in seams or seals without diminishing firmness. Tolerance for leaks is inescapably related to materials, construction and (therefore) price.
Sealed Air movie screens are inflated right before they are needed, then disconnected from the blower. If the air pumped inside cools relative to air temperature outside the unit, additional inflation will be required. Sealed air screens operate silently, although lower-quality units sag and distort as small leaks develop in seams and seals.
Frame Geometry
Pictured above are two styles of inflatable movie screens. The first is a rectangle shape, and the second has a-frame outriggers added.
Similar to a sailboat, an outdoor movie screen’s wide surface area forcefully transmits the slightest breeze to the surrounding frame. This amplified torque will distort, stress and shorten the life of any screen without four or more tethers anchored high on the frame. When the laws of physics prevail, a poorly anchored screen could sail away or into an audience.
A-frame screen manufacturers promise hands-free set up with images of upright movie screens resting on their outrigger ‘legs’. In reality, if all other measures of longevity and quality are equal: a-frame screens weigh more, cost more, and take an equal amount of time to set up SAFELY.
Folding Frame Movie Screens
Designed for indoor use, folding frames should only be used outdoors on windless nights.
Even if held down by sandbags or heavier ballast, a tiny gust can bend or break a standard (t-foot) or heavy-duty (a-braced) aluminum folding frame.
Portable truss-frame movie screens reinforced by anti-sway braces far exceed the cost of a same-sized inflatable movie screen, not to mention the additional time needed to set up and dismantle one.
Economics sometimes support a truss-style frame for multi-day events if the budget includes a gigantic (80′ to 100′ wide) acoustically-transparent screen surface with speakers placed behind for true theater-caliber projection and sound.
Good, Better or Best?
Exploring the parts of an inflatable outdoor movie screen explains why it is either good, better or best.
The critical components of an inflatable screen include the projection surface, screen frame, anchor points, blower and inflation inlet, tethers, anchor stakes and deflation port.
Examining the design, materials and construction of individual components reveals the relative quality of an entire movie screen.
Movie Screen Frames
Visualize two assemblies: the inflatable screen frame and the projection surface.
Almost every commercial-grade inflatable movie screen frames is made from coated poly vinyl chloride (PVC), an extremely flexible fabric with high tensile strength and remarkable stability even after prolonged exposure to the sun’s punishing ultra-violet (UV) light spectrum, and it resists punctures, abrasion, moisture and fire.
With so many redeeming qualities, the performance of coated PVC is at the mercy of design and construction methods. Fabric thickness, counterintuitively, has less influence on screen stability and endurance than seams, anchors and panel design.
Seams
Inflatable frames are constructed from four or more fabric panels. Where these panels intersect are seams connected by one of three methods:
RF Welding
If someone says welding, you might think of a torch welderFaero joining metal parts. Welding PVC fabric with radio waves is actually how the very best inflatable outdoor movie screens are built.
- Essentially, a focused beam of amplified high-frequency radio waves fuses overlapping layers of movie screen fabric from inside to outside
- RF welded bonds are super strong, reliable and long lasting. The work takes longer and much more skill than sewing
Hot Air Welding
Bonding seams with hot air melts the PVC material outside to inside
- It is faster to melt PVC with heated air than with high frequency radio waves, therefore it costs less
- The major downside is that hot air melts outside surfaces first, in contrast to RF welds being visually confirmed by the outer layer melting last. Consistency suffers, and real-world experience proves hot air welded seams are more prone to fail.
Stitching
Seams can also be sewn air tight without the time and expense of welding. However, as you can imagine, the performance and endurance of a stitched-only inflatable movie screen can be well above average or downright awful.
- Sewing integrity is determined by stitch pitch, thread characteristics (strength and elasticity), knot type and redundancy
- Suspiciously low-priced inflatable movie screens sold on Amazon.com constantly disappoint owners after less than a year of use
- Conversely, top-tier inflatable screens reinforce every welded seam, anchor, air inlet and deflation port with double-sewn nylon stitching
Anchor Points
An inflatable movie screen frame is no stronger than its weakest link, and experienced outdoor movie operators will tell you anchor point damage is the most common point of failure.
What defines a good/better/best anchor point begins with the welding and stitching methods used to bond frame panels. Bearing the full force of holding a screen straight and secure, anchor points located near each corner of the movie screen frame ideally combine:
- One or more layers of PVC-coated frame fabric, welded or sewn to the screen frame
- Seat-belt quality polyester webbing looped around and extending from a wide gauge rustproof metal d-ring
- Waterproof UV-resistant polyester/nylon thread triple stitched through all anchor components
Tethers
Connecting four or more anchor points on the frame to ground stakes (or other appropriate ballast) should be 8 to 10 tethers made of polyester/polyamide rope or, preferably, flat webbing with carabiner ends.
A worthwhile upgrade: Tethers straps with inline ratchets allow operators to quickly set and fine tune frame and screen to a vertical, square and tight position.
Ground Stakes or Ballast
Steel rods driven into the ground are the most popular way to tie off anchor tethers. Stakes with double hips or welded loops keep upper and lower tethers untangled.
To secure a screen placed on loose soil or sand, use auger-style stakes.
Where driving stakes is not permitted, suitable ballast can be substituted. Always ask the manufacturer for a screen-specific weight when using ballast on a turf field, parking lot, pool deck or other hard service. Portable water tanks and concrete-filled buckets are widely in use. Relying on small trees, fences, car bumpers or other wing-it alternatives invites trouble and, potentially, legal liability.
Air Inlet and Deflation Port(s)
Air pressure inside an inflated movie screen determines the difference between a sturdy upright frame and a slumping mess.
Fabric specs, seam strength and blower output are factors. These, combined with the design and integrity of the air inlet, inlet flange and deflation closure(s) will either maintain or defy intended pressurization.
A top-tier screen tolerates small leaks without diminishing performance. Midrange models respond to pressure loss with proportionate sag. The cheap ones barely stand straight out of the box so, once again, save your money and the embarrassment.
Minor leaks can be repaired in the field with a patch or anchor replacement kit. Serious tears or seam failures require shipping the frame to the manufacturer or a repair facility.
Warning: Imagine the downtime and expense involved with shipping a screen to China or another country. Always ask a screen manufacturer where they perform repairs!!
Leaks are inevitable. So, how many years of ‘quiet enjoyment’ will a screen frame provide? The answer is a tug of war between frame quality and accumulated wear. Defying instinct, purchase price does not always predict screen durability! \
In an average year, subjected to 36 cycles of moving, unfolding, inflation/deflation (3x), cleaning, folding and storage:
- Top-tier AIRSCREEN frames last 10 years or longer
- Value-priced AEROPRO frames are built to be in service 5 years
- Owners of mid-range models report 3 to 6 years of use before the frame had to be repaired or replaced
Warranties offer peace of mind, although the length of coverage is often more sizzle than steak. Defects in materials and workmanship are obvious in the first or second year of normal use. Beyond that, buyers are at the mercy of a manufacturer’s interpretation of damage as a covered repair versus claiming the cause was abuse or misuse. In this regard, reputation matters!
Blower or Inflator
Full time blowers and sealed-air inflators are universally a third-party component specified by the movie screen manufacturer. Given the critical role this component plays, it is wise to own an identical spare. Always match the screen OEM’s static pressure specification.
In noise-sensitive environments, a sound dampening case can lower blower noise by 20 decibels. Good ones double as a rolling road case.
FAQs
What is the difference between continuous air and sealed air inflation?
Continuous Air screens have an inlet tube attached to a blower operating full time. Top of the line frames will stand rigid and not flex in the wind, and blower back pressure allows for small leaks in seams or seals without diminishing firmness. Tolerance for leaks is inescapably related to materials, construction and (therefore) price.
Sealed Air movie screens are inflated just before they are needed, then disconnected from the blower. Additional inflation is required if the air pumped inside cools relative to air temperature outside the unit. Sealed air screens operate silently, but lower-quality units sag and distort when small leaks develop in seams and seals.
What is a RF-welded outdoor movie screen?
If someone says welding, you probably think of torch welders joining metal and imagine someone working on a large building or vehicle frame. Welding PVC fabric with radio waves is actually how the very best inflatable outdoor movie screens are built.
Essentially, a focused beam of amplified high-frequency radio waves fuses overlapping layers of movie screen fabric from inside to outside.
RF welded bonds are super strong, reliable and long lasting. The work takes longer and much more skill than sewing.
How is an a-frame different from a rectangle-shaped inflatable movie screen?
Similar to a sailboat, an outdoor movie screen’s wide surface area forcefully transmits the slightest breeze into the surrounding frame. Without four or more tethers anchored high on the frame, this amplified torque will distort, stress and shorten the life of any frame. Worse yet, when the laws of physics prevail, a poorly anchored screen could sail into an audience.
A-frame screen manufacturers promise hands-free set up, and present images and illustrations of upright movie screens resting on the their outrigger ‘legs’. In reality, when all other measures of longevity and quality are equal: a-frame screens weigh more, cost more, and take an equal amount of time to set up SAFELY.
