This goal of this article is to give a very basic idea of the elements involved in manufacturing mandrel wrapped silicone hose. The quality assurance elements will be addressed under Quality Assurance.

• Quality Silicone: everything starts with quality silicone from reputable suppliers. The silicone is normally purchased by pallet of 30 lb bricks and the silicone is translucent in appearance.

• Mixing: the silicone is placed in a large mixer with several additives to assist in processing the material. The material may be colorized at this point.

• Milling: after the mixing the material is milled or to the appropriate width and thickness in roll form.

• Calendering: the material is then taken to a calendar where the fabric is pressed on the silicone material and the final thickness is established, the output from this process is a 30" roll of silicone sheet that is fabric reinforced, colorized, and made to the appropriate thickness.

• Cutting Material to Size: the material is the cut to the appropriate dimensions for the part being made. A 16" ID Hump Hose will require more material of greater dimensions than a 1" ID Elbow for example.

• Mandrel Wrap: the silicone sheet is actually wrapped by hand over the mandrel which has the inside diameter shape of the hose product that is being made. For highly complex geometry, a hand made silicone hose may take as long as 3 to 4 hours to manufacture.

• PVA: is a strong plastic tape, (if you will) that is applied to the cover of the hose in order to obtain the final shape. It will leave a glossy finish as a result of the contact.

• Nylon Tape: may be used as a substitute to wrap the hose to achieve the final shape and when done so the resulting finish is referred to as "Matte".

• Cure/ Vulcanize: there are a number of different methods to cure silicone material such as autoclave which provides heat & steam under pressure. The key is to achieve the proper temperature for the proper duration. The typical curing time is 30 min. or less and an approx. 300°F temperature.

• Trimming: after the part is cured there is still a fair amount of work to do since the hose must be trimmed properly and as specified. Some parts require complex trimming with special notches, angles, and lengths.

• Marking and Packaging: a number of parts specification require the hose to be marked and packaged in a particular way, these requirements require additional labor and materials.

• Cleaning & Final Inspection: the hoses are cleaned by hand with a cloth and the final inspection is completed in accordance with written criteria.