A few months back an outside copper pipe developed a leak longitudinal split on a 90° bend. This pipe is probably 40 years old, installed when house was originally built.
Since plumbers charge more than doctors (probably not in the league of lawyers however who charge like wounded bulls), I had a go at fixing this myself. I don't have a brazing torch, pipe cutter or grease-monkey wrenches, so I tried the band-aid approach.
The bottom line is - Self fusing rubber tape worked well, but several layers and it appears that allowing a thin layer of water between successive layers improves the seal. - Cloth reinforced epoxy worked OK as an interim fix
The small residual leak I can live with (OK - this would not be satisfactory for an inside leak, so I empty my catch bucket into the eagerly watching plants once a week).
The complete gen follows :
Stikka Tape Self Fusing Rubber Tape (Ampol Pty Ltd) - Creates an effective Moisture and water proof seal, and is UV resistant - Moisture barrier seal that does not arc with electricity and water.
Recommended stretch of 100-150% (breaking strain is 400%) Overlap at least 50% Overlap 2-3 times at the end Rubber fusing is effective within minutes Max temperature (continuous) 85°C
Cold water, mains pressure, outside coper pipe, crack on 90° bend Leak after epox coat reinforced with cloth tape - approx 30L /4hr (defn. LR0) (sprayed in fine jet)
After several weeks carefully removed epoxy, first crack lengthened and widened and second crack opened on a second 90° bend within 3 cm (don't think the removal caused this). Leak rate looked far higher, hard to estimate but 1L/2min would not surprise me (equiv. 120L /4hr = 4 x LR0).
Double wrap of Stikka Tape, from one side, across both joints then back. Still leaked, steady dripping. The same day put another layer on after thoroughly drying rubber outside. Leak rate was down to 20L /24hr (3L/4hr to compare = 0.1 x LR0).
A week later wrapped a fourth layer, did not dry surface water, trapping a thin layer of water seemed to create a hydrostatic (capillary) seal as the leak rate is greatly reduced by just one layer (one drip every 15s or so). My 20L bucket only half fills in about a week, thats ~ 10L/160h (0.25L/4hr = 1/120 LR0).