Hoses or flexible lines are made from a variety of materials. Natural rubber, silicone and Teflon are the most commonly used to construct hoses on homebuilt aircraft. Natural rubber is black in appearance and best represented by the radiator hoses in your personal automobile. Silicone hoses can come in a variety of colors and is not as affected by a majority of chemicals like natural rubber is. Silicone does not deteriorate as quickly as natural rubber, so is a bit more durable and a bit ( you got it) more expensive. Silicone applications are primarily used as heat insulators on fuel and oil lines. Teflon hoses are all those pretty stainless steel braided lines you see on high performance cars, and definately around turbine engines. Teflon can handle a high operational pressure and is impervious to all known chemicals used on aircraft. The braiding on Teflon hoses is provided for extra protection to the hose and provides no additional strength for the hose. The cost of each hose increases as presented, natural rubber being the cheapest and Teflon the most expensive.
If you have hose assemblies made for you understand that prices will vary depending on the material used, length, diameter, and style of end fittings used.
Tidbit of Info: I thought you might find this interesting otherwise- forget it. When an engineer is selecting a hose material to make lines for a system the intial factor is the fluid type being transfered. A natural oil (petroleum) used in a natural rubber line will tend to revert the hose back to it's normal state of...petroleum. The same type of thing will happen in a synthetic hose with a sythetic lubricant. So the systems engineers tend (keyword there-tend) to use a synthetic hose with a natural petroleum product. This is why it's improtant to periodically replace hoses after a given amount of time, even if they look fine on the outside the inside has been taking a beating. As you can now understand it is important to stay with the same type of hoses as what was initially installed in your aircraft. Trust the engineers and the work they have done to make your project as safe as possible.
Hoses in aviation may be of fine or course thread and the flare angles used are specific to aviation. Do not try and use a car hose assembly where aviation hose is located- it won't work. It will leak very efficiently though.
You will most likely be using natural rubber hoses for a majority of the construction. These hoses are cut to length and then slid into postion to fit over a bulb type fitting and secured with hose clamps. After installing and tightening the clamp or torquing the fitting mark the clamp or fitting with torque seal. The torque seal will give a visual reference for signs of loosening or slipping of the connection joint.
Take a look at AC43.13-1 for some good info on fabrication, installation and inspection techniques. Now move on over to Rigid Lines.
Precision Hose Technology Inc.
Specialty Hose Aerospace Corp.