The authoritative public forum
  for Metal Finishing since 1989
  

  -----

Lodging of steel balls in Copper U-bend tubes

SIR, I AM CARRYING OUT BURNISHING PROCESS ON COPPER U-BENDS OF 3*8 (9.5MM) DIAMETER. THESE U-BENDS ARE REQUIRED FOR AIR CONDITIONING AND REFRIGERATION PURPOSE. THE PROBLEM THAT I HAVE ENCOUNTERED IS ABOUT LODGING OF STEEL BALLS IN THE U-BENDS AFTER UNLOADING. IT REQUIRES MANUAL WORK TO REMOVE THE STEEL BALLS FROM THE U-BENDS, WHICH IS TIME & MONEY CONSUMING. SO KNIDLY SUGGEST A PROCESS WHEREIN I CAN REMOVE THESE STEEL BALLS DECREASING OR ELIMINATING MANUAL WORK. THANKING YOU.

NIRANJAN S. KULKARNI
sales engineer - THANE, MAHARASHTRA, INDIA
2003

---

2003

Niranjan !

There are perhaps 4 ways to 'bend' a pipe. Sometimes heat is used or has to be used.

l. Do nothing at all except to form it over a mandrel in which case you'd get a flattening of the bend
2. To use a spring inside it
3. To use sand
4. To use a so-called rosin (which sets hard and prevents kinking) but this is an expensive method and suitable for, say, high quality, tight radius bends

But you infer, I assume, that the tubing is filled with balls which sometimes, often (?) get stuck as the bend is made.

a. Perhaps use some heat to bend?
b. Perhaps use a larger radius?

There is no easy fix. Have you tried the spring approach?

And just HOW does the competition get over this problem?

Freeman Newton [deceased]
(It is our sad duty to advise that Freeman passed away
April 21, 2012. R.I.P. old friend).