Slime Flux: Installing Relief Pipe?

[PinkFloydEffect]

I have been working with some elms for a while now that are experiencing heavy fluxing at breast height, Camperdown elms to be exact. The fluxing has become very damaging to the trunk bark so I have no choice but to come up with a solution; install a pressure relief pipe. Now there is not much information online regarding this procedure besides to make sure the pipe is plastic (PVC?) and to make the hole 1ft below the exit wound. I have unanswered questions such as the diameter of the pipe, the angle the hole should be drilled, the depth, and if 1ft below wound is just an estimate or can I improve the effectiveness by adding or subtracting a few inches? I would have thought to insert a pipe right where it's coming out...

 

[Raintree]

Interesting, installing pipes is real old school, haven't drilled an Elm in over 25 years.

Why is bark staining from Slime Flux "very damaging to the trunk"? I would tend to believe it's merely cosmetic.

The old canker wound is weeping nicely, I would leave it alone & maintain tree health.

 

[PinkFloydEffect]

Well this is 2 years ago; it's getting worse, I think if my skin was being eaten I wouldn't be too happy:

That is a canker? I think the heartwood is infected, what time of the year do you insert a pipe? What has this procedure been replace by I realize it's old school but if it was working then...?