Castair 1/4" Copper Tubing (Sold by the Foot) CT25
Castair's 1/4" copper tubing sold by the linear foot is the correct material for small-bore connections on commercial air compressor systems — pilot lines, gauge connections, unloader lines, and control tubing. At $7.70 per foot, order the exact footage you need for your installation. Copper is specified over nylon for any connection near compressor heads or discharge points where temperatures exceed what plastic tubing can handle.
Where 1/4" Copper Tubing Is Used on Compressor Systems
- Pilot valve lines: The small-bore connections between pressure switches, pilot valves, and unloader systems typically run 1/4" copper or nylon tubing
- Gauge lines: Connecting pressure gauges to the tank or discharge line
- Unloader connections: Running the unloader signal line from the check valve unloader port to the pressure switch
- Control tubing: Any control or signal line in the 1/4" size range where copper is specified over nylon for heat resistance
- Low-volume instrument air: Small service drops for instrumentation or specialty tools
Why Copper vs. Nylon for These Connections
- Temperature resistance: Copper handles the heat near compressor heads and discharge points. Nylon softens at elevated temperatures and is not suitable for hot-side connections
- Pressure handling: Properly connected copper tubing handles compressor system pressures at 250 PSI and above
- Oil compatibility: Fully compatible with compressor oil and oil mist in the air stream
- Vibration routing: Copper can be bent to form isolation loops at vibrating components, preventing fatigue failures at fittings
- Castair also carries NT25 — 1/4" nylon tubing for applications where flexibility is the priority and heat is not a concern
Ordering Information
- Sold by the foot — specify footage when ordering. Add 10-15% extra for bends and cuts
- Part Number: CT25
- Price: $7.70 per foot
Castair Copper Tubing Lineup
- CT25 — 1/4" copper tubing, $7.70/ft (this listing) — control and pilot lines
- CT50 — 1/2" copper tubing, $10.01/ft — standard discharge tube size
- CT58 — 5/8" copper tubing, $13.09/ft — larger discharge and inter-stage connections
- CT75 — 3/4" copper tubing, $15.40/ft — large-bore discharge and supply mains
Installation Notes
- At connections to vibrating components, form a short coil or offset bend in the tubing to act as a vibration isolator
- Use compression fittings or flare fittings rated for the pressure in your system — don't use low-pressure plumbing fittings on compressor lines
- Castair's systems operate to 250 PSI and above; ensure your fittings carry appropriate pressure ratings
Technical Specifications
- Part Number: CT25
- Manufacturer: Castair (Spicer, Minnesota)
- Material: Copper tubing
- Size: 1/4"
- Sold: By the linear foot
- Price: $7.70 per foot
- Application: Control lines, pilot lines, gauge connections, instrument connections on air compressor systems
Why Buy From Air Compressor Factory Direct?
We stock the full Castair copper tubing line. Order the exact footage you need. We can advise on whether copper or nylon tubing is right for your specific connection and which fittings work with each tubing size.
- Free shipping on qualifying orders to the lower 48
- Free tech support — call with tubing selection or fitting compatibility questions
- Full manufacturer warranty on all Castair products
Call 866-217-0063 for quick answers and help!
