Hi djewell
Not sure I understand what you are getting at here
(07-29-2011, 01:43 PM)djewell Wrote: The GFE will probably be electrically insulative, so it will prevent the cathodic protection of the aluminum in this configuration. In order for the aluminum to provide corrosion protection, it must be in contact with the base metal.
Surely cathodic protection is provided for the steel alone. There is nothing in this system that could possibly provide cathodic protection of the aluminium.
From my point of view the TSA is there to protect the steel substrate, partly by cathodic protection. The aluminium coating will be in contact with the steel except for a small overlap around the interface where the two coatings meet.
Wait a moment, re-read everything
If what you meant is a situation where the aluminium coating only covers the GFE with no contact with steel substrate, then yes that would be pointless and I assume you meant it will prevent the cathodic protection of
the steel by the aluminium in this configuration. Sorry, probably being a bit pedantic.
May be misinterpretation of OGMT's original question. I assumed 2m of pipe end would be bare or have GFE coating removed before TSA and that the question was what to do at the interface of two coatings.
Hi OGMT
Maybe butt the two coatings as best as you can and coat interface region with GFE.
Is the reason for TSA because of high temperatures at the end of the pipe i.e. too high for the epoxy?