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How To Repair A Damaged Air Compressor Hose Using A Reusable Brass Sleeve Fitting

If you accidentally cut your compressed air hose while using it, then conventional wisdom says nothing can be done except to throw it in the garbage. However, a cut or damaged air hose can often be repaired and put back to work, resulting in savings for you or your employer. The repair process is simple and only requires a few basic tools plus inexpensive fittings. Below is how you can perform a repair on a damaged air hose:

Tools and materials needed

  • Adjustable wrench

  • Bench vise or clamping pliers

  • Sharp utility knife

  • Ruler or tape measure

  • Reusable brass fitting sets (2)

  • Shop rag

  • Isopropyl alcohol

Step-by-step procedure

1. While a repaired air hose can be used safely, be sure to remember the limitations on its use. Brass fittings will have a limited PSI rating, and a repaired hose should never be used for applications that exceed this rating. In addition, if you need to repair a hose that is damaged, be sure to inspect the remainder of the hose for other signs of damage; an accident that cuts the hose in one place may also cut it in another location. Finally, never attempt to repair a hose that possesses more than localized damage. Cracking, fraying or bulging are all signs that an air hose is unsafe to use, even if repaired. All hoses have a limited useful lifespan, and discarding a thoroughly-worn hose is the safest course of action.

2. When you determine that a damaged air hose is repairable, the first course of action is to remove the damaged area plus a small amount of undamaged hose. This helps to ensure that no hidden damage is accidentally overlooked during repair.

As such, make 2 perpendicular cuts across the hose so the damaged area is surrounded on each side by at least 1 inch of undamaged hose. For example, if you have an air hose with a 2-inch long cut, then make an allowance for 1 inch at each end of the cut, thus removing a total of 4 inches of air hose. Install a new blade in your utility knife and make the cut as cleanly as possible. A ragged or uneven end will not properly seal inside the fitting.

3. Once you cut away the damaged section of hose, measure the diameter between the inside walls of the hose. Then, measure the diameter of the outer walls of the hose. Record these measurements for use when purchasing your fitting.

4. After obtaining diameter measurements, purchase 2 reusable brass fitting sets that contain an outer hose sleeve and an inside NPT (National Pipe Thread) fitting. Be sure the inside diameter and outside diameter measurements match the fittings exactly; never attempt to use a missized fitting or the connection may fail during compression.

5. Once you purchase the fittings, wipe away any grease or other contaminants from the end of the hose with a shop rag dampened in isopropyl alcohol or another rubber-safe solvent. Push the end of the hose into the sleeve fitting and begin twisting the fitting in a counter-clockwise motion; most fittings are threaded opposite from the conventional clockwise direction. The fitting will gradually bite into the exterior of the hose and thread itself downward. Continue twisting the fitting until the inside shoulder of the sleeve touches the end of the hose. If you experience difficulty installing the sleeve fitting, you can use an adjustable wrench to provide extra torque. Do not use oil or any other lubricant on the threads as these may cause the hose materials to soften or break down.

6. After the sleeve fitting is threaded on to the end of the hose, place the end of the hose into a bench vise or secure it with clamping pliers. Insert the long end of the NPT fitting into the end of the sleeve and begin turning the fitting clockwise. You will need to use an adjustable wrench to provide torque as the fitting threads itself deeper into the sleeve; this action results in the threads of the NPT fitting compressing themselves against the sleeve fitting. Continue to tighten the fitting until it can longer be turned with a wrench.

7. Once you install the fitting set in one end of the air hose, repeat the process at the other end that was cut away in step 2. This will provide you with two sections of air hose with NPT male-threaded fittings, and they can be used separately or joined together with the appropriate NPT male-to-male adapter.

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