Salt Corrosion

[manta22]

Has anyone ever tried this stuff? http://www.youtube.com/watch_popup?feature=player_embedded&v=IPM8OR6W6WE

It sprays on as a two- part coating-- expensive but so is salt corrosion. It supposedly lasts 8 months before needing to be re-coated.

Regards, Neil  Tucson, AZ

[Crackerman]

A major necessity prior to coating the first time would be proper surface prep and salt removal. Check out high performance industrial coatings. An epoxy of sorts would be great.
By salt removal i dont mean just chlorides, you need to clean off nitrates and sulfates too. A good wash would be chlor-rid for starters. A proper blast cleaning and primer as specified by coating you choose.
If you have no salts under coating to absorb moisture in atmosphere through coating, you will effectively negate corrosion under your coating. Keep in mind ALL coatings allow moisture through, the rate they make it through is different.

[manta22]

Thanks, Crackerman. This would be for a new build so existing salt would not be a problem.

[Crackerman]

There will be some salts on new metal, albeit not as much. Tuscon also helps with low humidity. Blasting will drive salts present on the mill scale into the metal (keeping in mind, not just bonneville salts) mill scale is blue metal surface as a result of red hot metal interfering with atmosphere. It is cathodic in relation to parent metal. Blasting it off will also leave a great anchor profile for new primer/ coating to stick to.

I only know all of this this week because of a coatings inspector course i am at.

I belive you spending more time to do the prep right, you can make that coating last years instead of months. Redoing the coating is the hardest part and way more expensive that doing it right the first time.

[Crackerman]

Also, all coatings shrink when drying, drawing back from sharp edges. If you radius the edges to a 2mm radius, you will be 98% covered on any coating you use.

[Vinsky]

Cosmoline 'Weathershed' is available in aerosol cans. It creates a moisture barrier that really protects against rusting, and probably salt. It's not as difficult to remove as the old mil spec version. Naptha or gasoline works well.