Select, handle & prepare tubing
Good tubing selection continues through storage, cutting, bending and assembly. Protect the surface and follow the instructions for the exact connection system you use.
Start with the service
Identify the fluid or gas, operating and design conditions, pressure peaks, temperature range and external environment. Then select the grade, dimensions, finish, cleanliness and fitting system together. A familiar tube size is not a substitute for checking the application.
Match hardness to the fitting system
A compression fitting depends on controlled interaction between the tube and its ferrules. The tube’s hardness, surface finish, diameter tolerance and wall thickness must fall within the requirements of the selected fitting manufacturer.
The supplied Uni-Lok catalogue specifies fully annealed seamless stainless steel tubing and a maximum hardness of 80 HRB for its stated tubing recommendation. Confirm current requirements for the exact product. A different fitting guide’s higher hardness limit should not be transferred to that system.
Download Uni-Lok twin ferrule fittings PDFProtect the sealing surface
- Keep tube clear of rough ground and avoid dragging lengths across rack edges.
- Inspect for scoring, dents, ovality and local damage before assembly.
- Cut squarely with appropriate sharp equipment and remove burrs without damaging the tube end.
- Keep cuttings and contamination out of the bore; apply service-specific cleaning where required.
- Use the correct size of bending tool and observe its limitations for the tube material and wall.
Assembly belongs to the connection system
Use the current instructions for the selected fitting series, size and material. Follow the specified insertion, tightening, inspection and reassembly requirements. Do not use one generic number of turns for every fitting size or brand.
Plan supports so the fitting does not carry avoidable tube weight, misalignment or vibration. Inspect and test the completed installation to the applicable project procedure.
Tools and supporting products
Fluidline can help specify tube benders, cutters, clamps and fitting systems alongside your tube schedule.
Frequently asked questions
Can surface scratches matter at a compression fitting?
Yes. Damage in the sealing and gripping area can affect connection performance. Inspect the tube and follow the fitting manufacturer’s acceptance requirements.
Can I mix ferrules and nuts from different fitting systems?
Treat them as a matched system. Confirm compatibility before mixing manufacturers or designs.