Powder adhesion on red oxide surface and primer

A. Hi, Brian. Powder coat is not actually a material, it is an application method: finely powdered plastic is sprayed onto the parts, and sticks to it by electrostatic charge; the article is heated to melt/fuse the plastic into a coating on the article.

The point of making that distinction is that there are many different powders available, including epoxy, polyesters, nylons, vinyls, and teflons, and I'd be quite confident that -- with a supplier's help -- one can be chosen that will be completely resistant to the oils. Good luck.

Regards,

A. "Red-oxide" primer will not be able to withstand temperatures of 180 to 220 °C encountered in any powder coating. With the primer failing at such temperatures, the top coat viz., powder coating, will also fail. Please consult your powder supplier and select a compatible primer which would enhance protection of the substrate even in the case of scratches and minor damage to the top coat. Also beware of some suppliers giving you "Gheru Mitthi" or saffron clay in the name of red oxide!

A. Please contact your supplier. There are pre coat powders available just as primer to wet painting. You need to coat the precoat powder at 180 degrees for a specific time depending on the thickness, and go for the required finish coat.

A. In Australia ,
Door frames of steel are usually hot dipped galvanized and they last for many many years , usually they require painting only when the colour of the house is changed , but the process is expensive .
A cheaper alternative would be Zinc Electroplate with a yellow chromate finish

A. The downside to the galvanizing or the electroplating is that you wouldn't be able to (at least, not economically) do it on-site. And certainly not with untrained manpower.

Try looking into rust converter [on eBay or Amazon] - these are paint-like products that convert the rust already present on the door into a very corrosion resistant and not horribly unattractive finish. If you search through the archives (or enter the following google search - "https://www.google.com/search?hl=en&q=site:www.finishing.com+rust+converter"), you should be able to find more information.

Good luck!

A. Hello Aradhana;

The pretreatment of Mild Steel is rarely done well in India; most people use a powdered red oxide which is a powder that falls off the steel. When this red oxide powder is mistaken for a primer and directly painted upon; is where we go wrong.

You can't get down the line and stop this, so your best bet is to use Hot dip galvanised or zinc plated sections and use a zinc chromate before you paint.

A. Dear Aradhana,

We also face these problems. What I suggest is the newer Al and Zinc powder paint to be painted on the door frames. Being involved in this development work we have more solutions with different kind of products.

Take care

Prad

? Hi Farhan. I have heard of the word "distemper" to mean "anneal" (sort of the opposite of 'temper') but I don't think that is what you are referring to.

I think 'distemper' is also a coating used on artistic paintings, but I am not familiar with what it actually is. We'll have to wait for a reader with a better understanding of the subject than me :-)

Regards,

A. When I was young - a very long time ago - distemper was the common name for water based domestic paint.
But we still have no idea what you are trying to achieve.