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FAQ for underwater and surf housings:
FAQ'S for Telemetry housings:
Ken Sexton, founder of Sexton Photographics, has been designing and building housings since 1968. For many years, he built housings as a sideline, while employed as a biologist, salesman, engineer, and teacher. In 1995, he committed to this work full-time.
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In 1967-9, as a young biology student at Shoreline Community College in Seattle, Ken took courses in photography and SCUBA. Wanting to share his experiences with others, underwater photography was the obvious answer. The few underwater cameras and housings that were then available were prohibitively expensive for a student pocketbook.
The college had a program whereby students could petition the school to provide any class they wanted, after meeting certain criteria. Ken and several of his fellow biology students realized that having the ability to make their own housings for cameras and other equipment could be good tools for their careers. A relative of one of the other students was a windshield designer for Boeing, who built housings in his spare time. He agreed to teach the course, the Engineering department of the school sponsored the class, and enough students committed to sign up for it. The instructor showed many techniques for working acrylic, the kinds of tools necessary, rules of thumb for depth calculations, and each student built one housing during the course.
While working at various jobs in biology and engineering, Ken built housings for his friends and their friends. It soon became apparent that he needed to start a business to track income and to be able to deduct expenses. After moving to California in 1969, he started Ken Sexton Photography in 1973. In 1983, after moving to Oregon, he decided to make the name of the company more appropriate to the kind of business, so he changed it to Sexton Photographics. In 1995, when the company he was employed by went out of business, he decided to concentrate on housings full-time, and has been doing so ever since. In 2000, he started a limited liability company, The Sexton Company LLC, and kept the business name of Sexton Photographics.
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A housing can be designed for any depth. The depth that a housing will survive is dependent upon its size, material, wall thickness, and safety factor. Deeper housing cost more. There are several classes that we use to categorize housing depths:
- Shallow or surf housings. These are designed for submersion to minimal depths, typically 25 feet. We usually use 1/4-inch acrylic for the basic rectangular box. There is usually a single o-ring sealed door, although some have been permanently sealed and a few have had more than one door.
- Deep or SCUBA housings. These are usually designed for normal save SCUBA depths of 135 feet. We usually build these of 1/2-inch acrylic for the basic rectangular box or 1/4" wall acrylic tube. We typically use a 2x safety factor for depth calculations.
- Benthic or Deep-sea housings. Usually designed for over 300 feet, these housings can be designed for any depth in the ocean. They are almost always cylindrical in form, and often made of aluminum, PVC, Delrin, brass, stainless steel, or titanium. The deeper they are intended to go the stronger the material needs to be and the thicker the walls have to be. We typically use a 4x safety factor for depth calculations.
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Depth is just one of many factors that are considered in pricing. For rectangular housings, we do calculations with the dimensions of the largest face and its thickness to determine the depth it is capable of, with a safety factor. Since acrylic is available in several thicknesses, and there is a tolerance on each of those, we use the thin end of the range of thickness for those calculations. After picking a thickness that qualifies for the desired depth, we re-adjust the CAD model to the actual thickness of the material selected, when it comes time to build the parts. That way, the parts fit as designed.
Back to your question, there is usually no difference in cost between 130 ft and 150 ft, unless the size of the largest face requires a step to the next thicker material for the deeper version. We usually use 1/2 inch [12mm] material for that depth range on housings for common SLR or dSLR cameras. That is one of the advantages of a custom design - all design parameters can be adjusted to suit the customer requirements, rather than putting the camera into the next larger size of a mass-produced box.
O-rings have been used in the pneumatic and hydraulic industries for many decades. The pistons that lift the bed of a dump truck are sealed with o-rings and develop pressures of 30,000 pounds per square inch, far more than we see in underwater housings. The key is proper design, smoothness, and maintenance of the groove or other mating surface. O-rings rarely fail; most leaks in housings are caused by failure of the user to keep the o-rings clean and free of particles that can allow water to seep past the seal.
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The use of double o-rings is usually not necessary, and causes the need for more maintenance. We rarely specify multiple o-rings, but have done so on customers' request.
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X-rings look like o-rings, except that they have a cross section that looks like an X instead of an O. They are considerably more expensive than o-rings, and can sometimes be installed with a twist that will allow the passage of water. We can provide them on request, but generally find them unnecessary.
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We test every housing in a swimming pool or hot tub. If a housing is going to leak, it will do so in only a foot or two of water. Testing to depth is unnecessary, and we design with very conservative safety margins. For the very few customers who need and are willing to pay for certification to design depth, we can contract that task to a certified testing lab with a hyperbaric chamber.
We do, however, recommend that for your peace of mind, you dive the empty housing to your desired depth before using it with your expensive camera. We also highly recommend that you use the housing locally before taking it on an expensive trip, as you would do with any new equipment.
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No. A properly designed housing will not flood unless it has been damaged or the seals have not been properly maintained. We test every housing before it is shipped, so that we know that there are no defects in design or workmanship. After that, it is the responsibility of the user to be very careful to avoid damaging the housing, and to pay meticulous attention to maintaining the o-rings and their sealing surfaces. Included with every housing is a
user's manual that describes the care and maintenance of the housing is great detail.
We do recommend that you purchase flood insurance for your camera and housing. Please see the
Flood Insurance topic at the end of the Design Considerations section.
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Housings must be kept out of direct sunlight and protected from shock and abuse. Any kind of padded, rigid, opaque container will do that. We have used rigid cool chests in the past. For ease of use, we prefer to use transport cases made by such companies as Storm and Pelican. That kind of case typically has foam inserts that can be custom-cut to fit the housing and other associated equipment, such as chargers, film, and spare parts. It will have many reinforcements to allow it to stand up to the abuses of travel, secure latches to keep it from opening unexpectedly, and one or more locking points for security. Some models even have wheels and handles. We like these cases so much that we have become a dealer for them, and usually include an appropriately sized case and custom foam cutting in the quotation. We have never had shipping damage to a housing shipped in these cases.
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The first of these housings was ordered in 1979, by a customer who was familiar with underwater housings for cameras made by Sexton Photographics. He thought that an adaptation of that technology might work well for his field work. He was using the Telonics TR-2 Receiver and TS-1 Scanner in a rubber boat in a salt water lagoon.
The early model had more space inside the top area for cables to wrap around between the connectors mounted inside the door and the connectors on the receiver. It had fewer controls, and required modifications to the receiver to fit the controls. Later, with feedback from the customer and from Telonics, the Model 9121 was born.
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The telemetry receivers made by Telonics are complex electronic instruments, but they are not waterproof. As with any fine electronics, moisture is a major hazard. Dunking the unit in freshwater will probably render it unusable for the balance of the trip, but it may be recoverable by the factory later. Immersion in saltwater will almost certainly ruin the unit. Snow, mist, rain, and high humidity are all forms of moisture that can affect your electronics. Even if the unit can be refurbished later, the resources expended on the trip can be jeopardized by the loss of a key piece of equipment for the duration of the trip.
If you are working in a desert environment, moisture may not be a problem, but dust, sand, and other debris can jam controls, invade connectors and switches, and cause the receiver to malfunction.
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Of course, you can do whatever you want, but 63% of our customers report having had damage to units prior to ordering our housings, and 94% of those report having tried plastic bags.
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The bump case is a protective outer covering for the environmental housing. Made from 1/4 inch [6.4 mm] closed-cell Neoprene ®, id dies not absorb water. It is coated with Nylon ® on both inside and outside. You will recognize this as the same material that wetsuits are made from. The bump case protects the housing, a waterproof plastic box, plastic box from shattering, protects the instruments inside from greenhouse effect heating, and it provides a place to attach a strap to the unit. The strap can be used to carry the unit, or to tie it to a secure point, such as in a rubber boat. The bump case was first sold as an option, but since almost every customer ordered one, it soon became a standard part of the package.
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Universal joints in the context of these housings are devices to mate the control shafts in the door of the housing with rotating controls on the Telonics unit. Each U-joint consists of two chrome-plated brass collars and a white nylon piece which joins the two brass parts together. The brass parts are attached to the control shafts by setscrews, and the nylon part is a snap fit between a pair of brass pieces. The U-joints allow a tool-less (after one-time initial installation) removal of the Telonics unit from the housing.
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The foam provides shock protection of the Telonics unit inside the housing, as well as to keep the unit mated against the controls and connectors.
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Yes. For example, several customers have requested a receiver channel select control be added to the Model 9121, like in the Model 9111. This can be added during manufacture for $35, or added to an existing unit for $125. Obviously, it is more cost effective to plan ahead. If you have ideas or suggestions, contact us.
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We welcome such suggestions, especially feedback from the field. The warranty return cards (soon, on-line warranty registration) solicit such suggestions. Customer suggestions have resulted in refinements to the product, such as application of threadlocker to the connectors to keep them from loosening during rugged use.
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We are displaying a gallery of photos of our housings in use in the field. We welcome you to send us photos (prints, slides, or digital images) for inclusion in our album.
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Yes, but with some difficulty. The inner extender part of the connector comes off with a 1/4 turn, like any other BNC. The panel-mount BNC connector for the antenna connection is pretty straightforward, but the hex nut is down inside a 1 inch [25.4 mm] diameter recess on the bottom of the door. It can be turned with a pair of needle nose pliers, but it is difficult to overcome the thread locking compound applied at the factory without a socket wrench. On early and non-9151 housings, a very thin-walled 3/4 inch [20 mm] socket with a maximum outside diameter of 0.975 inch [24.7 mm] is needed. On later housings, a standard deep 5/8 inch [16 mm] socket can be used. Alignment of this connector is not a problem. All other connectors are aligned to this one.
Be sure to apply thread locking compound to the new connector, between the hex nut and the threads of the connector body. Loctite® 290 works well. Avoid getting any threadlock on the plastic of the housing or connector body. A good way to do this is to place a small drop of threadlock on the tip of a sharp knife blade, like a scalpel or
X-Acto. The knife tip can be used to place the threadlocker at the point of contact between the hex nut and body threads.
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Yes, but with some difficulty. The factory-installed connector has threadlocker on its threads, which will make removal of the hex nut difficult. Use a 3/8 inch [9.5 mm] socket. After removal of the old connector, clean old RTV silicone adhesive from the countersunk hole in the door. Be sure to place a 6003 1/4 inch [6.4 mm] ID O-ring over the mounting threads of the connector, seated at the shoulder of the connector. This O-ring will compress into the countersunk mounting hole in the housing door. To install the new connector, place a small bead of RTV silicone adhesive around the O-ring, then place the connector into the hole on the door. Place the hex nut on the threads and tighten it gently. Place the Telonics unit in the housing, and test fit the door over the housing. The alignment key is the antenna connector. If the battery charger connector does not align with its mate on the Telonics unit, rotate it by turning its hex nut clockwise (tighten). The still uncured silicone adhesive should act as a lubricant and allow the body of the connector inside the housing to turn. When proper alignment is achieved, stop turning the nut.
Be sure to apply thread locking compound to the new connector, between the hex nut and the threads of the connector body. Loctite® 290 works well. Avoid getting any threadlock on the plastic of the housing or connector body. A good way to do this is to place a small drop of threadlock on the tip of a sharp knife blade, like a scalpel or
X-Acto. The knife tip can be used to place the threadlocker at the point of contact between the hex nut and body threads.
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All models except 9151: Yes, but with some difficulty. The factory-installed 1/4 inch [6.4 mm] connector has threadlocker on its threads, which will make removal of the hex nut difficult. Use a 1/2 inch [12.7 mm] socket. After removal of the old connector, clean old RTV silicone adhesive from the countersunk hole in the door. Be sure to place a 6003 5/16 inch [7.9 mm] ID O-ring over the mounting threads of the connector, seated at the shoulder of the connector. This O-ring will compress into the countersunk mounting hole in the housing door. To install the new connector, place a small bead of RTV silicone adhesive around the O-ring, then place the connector into the hole on the door. Place the hex nut on the threads and tighten it gently. Place the Telonics unit in the housing, and test fit the door over the housing. The alignment key is the antenna connector. If the phone connector does not align with its mate on the Telonics unit, rotate it by turning its hex nut clockwise (tighten). The still uncured silicone adhesive should act as a lubricant and allow the body of the connector inside the housing to turn. When proper alignment is achieved, stop turning the nut.
Be sure to apply thread locking compound to the new connector, between the hex nut and the threads of the connector body. Loctite® 290 works well. Avoid getting any threadlock on the plastic of the housing or connector body. A good way to do this is to place a small drop of threadlock on the tip of a sharp knife blade, like a scalpel or X-Acto. The knife tip can be used to place the threadlocker at the point of contact between the hex nut and body threads.
Model 9151: Yes, but with some difficulty. The factory-installed mini phone connector has threadlocker on its threads, which will make removal of the nut difficult. Use a small spanner wrench or tips of needlenose pliers. After removal of the old connector, clean old RTV silicone adhesive from the hole in the door. Note that there is no O-ring used with this connector. To install the new connector, place a small bead of RTV silicone adhesive around the top of the connector body, but not on the threads, then place the connector into the hole on the door. Place the nut on the threads and tighten it gently. Place the Telonics unit in the housing, and test fit the door over the housing. The alignment key is the antenna connector. If the phone connector does not align with its mate on the Telonics unit, rotate it by turning its nut clockwise (tighten). The still uncured silicone adhesive should act as a lubricant and allow the body of the connector inside the housing to turn. When proper alignment is achieved, stop turning the nut.
Be sure to apply thread locking compound to the new connector, between the hex nut and the threads of the connector body. Loctite® 290 works well. Avoid getting any threadlock on the plastic of the housing or connector body. A good way to do this is to place a small drop of threadlock on the tip of a sharp knife blade, like a scalpel or X-Acto. The knife tip can be used to place the threadlocker at the point of contact between the hex nut and body threads.
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Further questions or comments? Contact
us!
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