Some follow-up questions from the unexpectedly controversial 'tiny leak' guy!

Hi! As I'm about to tackle the repair that some around here insist upon calling a **** fix, I have a few details I want to clarify, mainly about the roughening of the surface of the metal so that it bonds well with the epoxy.

I bought a high-carbon-steel wire brush, and I experimented with it on an uninvolved area of the pipe to see what it would do to the surface. It appeared to make some very superficial scratches after a few strokes when I applied modest pressure. So my question is two-fold:

First, part of the epoxy will be applied to the thread of the pipe. Does pipe thread qualify as an already-non-smooth surface so that I needn't use the wire brush on that portion of the metal to roughen it? Or are the threads too 'macro', and should I nevertheless use the wire brush there to create smaller (even microscopic) imperfections in the thread surface for the proper roughening that will promote epoxy bonding?

Second, the other part of the epoxy will be applied to the fixture tightened around the pipe and just above the leak, and that definitely is smooth and needs to be roughened. But how much roughening should I do? How deep, how numerous should my scratches of the surface be for an ideal repa-- er, I mean **** fix?

My final question is: Are there any tips about this procedure that I ought to know in order to create a tight, leak-proof bond that outlives me and -- much to his frustration-- frodo by a hundred years?

EagerLearner said:

I bought a high-carbon-steel wire brush, and I experimented with it on an uninvolved area of the pipe to see what it would do to the surface. It appeared to make some very superficial scratches after a few strokes when I applied modest pressure. So my question is two-fold:

But how much roughening should I do? How deep, how numerous should my scratches of the surface be....?

Click to expand...

Well a wire brush or wheel actually appears to polish a metal surface as it cleans it. No idea how that cleaning compares to Welds Instructions. Why not ask Weld?

Don't quite get applying to the threads first, etc. Why wouldn't you apply it starting at the intersection of the pipe threads and the fitting, where the leak is? And work out a bit from there.
Of course Welds requirement for a "file or coarse sandpaper to provide for best repair", probably wouldn't do much for the threads, so the wire cleaning would help there.

Get a ginder and attach an all propose cutting blade.
Wear the proper ppe.
When you have all that done cut that pipe down the middle and replace it correctly and return the epoxy..............

Assuming you will definitely be trying this patching method in spite of warnings of doom, here are my suggestions.

The pressure should be out of the system, and the system drained enough so that no water is trying to sneak through the leak you are working on. You said this compound will set in contact with water, but will likely grab better onto dry metal.

Wire brush heavily all around the entire circumference of where the pipe and fitting join together. Especially deep into the threads, they are pbly full of mineral crust from your long slow leak. Go full circle, and go at least 3/4 inch to an inch wider than the leak, in both directions.
That starts to get the metal clean and prepped.

Then go over it all again with very coarse sandpaper, you want to create scratches that the JB Weld will grab, this is known as “tooth”.

Then vigorously wipe the sanded areas down with rubbing alcohol and a clean coarse rag, you want to remove dust and crud that will interfere with the adhesion of the patching compound.

Don’t apply anything else, just the JB Weld.
Mix it up and follow directions for thorough mixing and setting time (assuming it is a two part formula).
Whether one part or two part, apply it while it is still soft and sticky, or it will totally fail.
Follow package directions.

Use a popsicle stick, wood paint stirrer, plastic spoon, whatever, and scoop and smooth it all around the entire threads and beyond, and get some wrapped well over the edges of the fitting, in a full circle, dragging it firmly across the surface to make good contact. Don't just lay it on.

Most products like that will sag until they begin setting up, so keep sculpting the sags back into place, but don’t mess with the inner layer right near the metal surface. That layer is your leak seal (hopefully!).
The outer thickness will just be holding everything together (hopefully!).

You want to apply a full circle wide band of sealant, not just a blob where you think it leaks.

Good luck!

If it fails, get it fixed right. Get several estimates or better yet firm bids.