Painting on an Existing Paint Which is as Per Spec is OK?
08/08/2012 5:53 AM
We have recently imported an exchanger for one of our projects. But, there is a problem, paint color of exchager and structural support are swapped (just colors, specs are followed, however) as compared to color coding used at site.
I want to know, either we should repaint both (exchanger and structure) as per color coding and remove old paint through power brush ? Or we can simply apply two more coats of paint as per required color code on existing paint (In this case, will above coats make a proper bonding with existing paint). In second option, if we remove all existing paint using power brush, then will we have to do hydrotesting again?
Re: Painting on an existing paint which is as per spec is OK?
08/08/2012 7:04 AM
I like the old joke about the guy who comes home to find his Ferrari neatly painted with Magnolia emulsion.
The decorator man pops up and says "Ah to be sure, you asked me to paint the living room and porch, but ya know that's not a Porche it's a Ferrari"
health warning: These posts may contain traces of nut.
Re: Painting on an Existing Paint Which is as Per Spec is OK?
08/10/2012 12:39 PM
"(We) recently imported an exchanger for one of our projects" ...
There is no indication in your original post as to *where you are*, let-alone from which country the exchanger was imported.
What difference might that make...? There are "paints" (for cosmetic applications), and there are "protective coatings" (to prevent corrosion of the substrate).
In both arenas , there are MULTITUDES of different formulations, designed to be applied either as single-coat products, primer-topcoat systems, primer-intermediate coat-and topcoat systems, and some products are disallowed in certain countries.
Some 'lesser' coatings will "wrinkle" if topcoated with an epoxy type coating, due to the 'tenacity'-&-'shrinkage' while curing (of the epoxy).
I am certain that EVERY other post will be "assuming" that you are going to re-coat using the identical same product that was used originally ... and thus, their replies will be (more-or-less) accurate.
All this to say: DO apply some common sense in your solution to the problem ... but (better yet) apply some knowledge.
Both NACE (National Association of Corrosion Engineers, International) and SSPC (formerly 'Steel Structure Painting Council', now known as "The Society for Protective Coatings") offer tremendous volumes of information on the subject of coatings for steel structures.
A little bit can go a LONG way ... ... best wishes!