I have been asked to help discover the source of a Tnemec failure on an existing interior steel tube railing. The railing in question had some areas of rust, other areas patched with bondo, and some still with original iron oxide primer. The rail was painted with 135T over a weekend and looked fabulous on Monday but then started to deteriorate as the week went on. The coating became soft and easy to move around by hand on the surface. Questions:
Applicator problem?
Substrate preparation problems?
Improper thinner added to coating before applied?
Any other possible sources of the problem?
Any and all thoughts would be greatly appreciated.
Maybe applicator did not let Part A coat fully dry before applying Part B coat over? Or maybe applicator mixed “old” (beyond pot life) with new? To many questions for anyone to even begin to guess. Need to find out who/why someone recommended hi-perf mat’l over lesser primer (total coating system is only as good as that first “layer”). What/how exactly did applicator mix/apply (i.e., each step, enviro conditions, time, etc.). If coating is soft, sounds like it didn’t catalyze (maybe incorrect mixing?) Did applicator strictly follow Tnemec’s complete instructions?
JFYI I have commented to Tnemec that their web site does not list specific reps and I have called their main number for technical services not getting the sharpest rep. My guess if Tony cannot help you he will know the actual name and number of the person you need to contact.
The Tnemec rep in my area has told me before that it doesn’t matter how good the paint system is, if the surface is not prepared properly and the correct application process is not followed, then the paint system will fail.
We have a specific statement in our special coatings section that failure due to improper application or improper surface preparation is the responsibility of the applicator and that the applicator will be responsible for doing new prep work and providing new primer or surfacer coats and finish coats at no additional cost to the owner.
Update! I appreciate everyone’s response to my question. I have been in touch with Tnemec here in California about the project in question and have received an answer. Tnemec took samples and put them under the microscope. It appears the applicator put Part A on first, then Part B, then possibly an alkyd on top of that. That doesn’t quite fit the favorite typos thread running elsewhere on this site, but it comes close in my book.