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Teflon coating of stainless steel


Q. I work in a watch company and we are having a problem with one of our straps. The strap is made of 316L stainless steel and is sandblasted with a special blend of coloured sand to achieve a matte and grayish finish. The sandblasted pieces were coated with a very thin layer of PU (polyurethane) coating.

The problem with this finish is scratches show up very easily, which our customers don't like. One solution from our vendor is to coating the pieces with a thicker PU coating but the straps are shinier than before. I'm not sure whether the coating really helps to reduce scratches, or the scratches are just less obvious on such finish. What are the advantages and disadvantages in such an application?

WY Wong
- Hong Kong


A. You can put a water based Teflon coating instead of a thick PU coating for your application. Water based Teflon coating is very easy to use. It produces a very thin layer of coating that has good wear resistance, non-scratchable, good chemical resistance and heat resistance.

S. Y. Yuen
- Hong Kong, China


Q. I work in a portable measuring instruments company, and we need to put PU coating on stainless steel, is there some special requirements for the part surface, and how about the process of PU coating and equipment? Thanks in advance!

Fei Peng
- Shenzhen, Guangdong, China


Q. I'd like to manufacture a product in SS306 and I want to coat it with Teflon coating.

My condition is: The SS tube with OD 4.6 mm and length 310 mm. I'd like to coat Teflon coating thickness of 20 microns on OD throughout length.

Purpose: Anti corrosion, non conductivity of heat and non conductivity of electric current.

Area of application: Pharmaceutical / Surgical.

1. Please let me know the best method of Teflon coating considering my area of application.?
2. Is there any specification for Teflon coating, surface finish, hardness, etc.? If so, what purpose it will be used?

With regards,

M. Mahendran
- Coimbatore, Tamil Nadu, INDIA


A. Coating the OD is absolutely no problem. Typical two coat Teflon coating is 35 microns +/- 10 microns. Lower thickness can be archived with good coating practices.

It will serve the purpose of anti-corrosion, heat transfer and electrical insulation (to some extent only).

However, if the application is surgical, then Dupont specifically restricts use of Teflon®. Prior clearance will be necessary from Dupont on selection of grades and the application process.

Hope this helps you.

Gurvin Singh
Coatec India -

Mohali, Punjab, India

June 18, 2008

Q. Hello,

I need to coat a SS-316 rod (currently coated with epoxy powder coating) of 60 cm length & 6 mm dia with Teflon, over the powder coating.

I need to use it for a prototype design.

It should meet the following demands
- Environment of application is oil & salt water
- Need to get electrical insulation

- Need to know how long it will last, if it is used in a water flow region?

- What should be the coating thickness to withstand such a rough condition?

Isaac Jacob
student - India

sidebar November 10, 2009

A. Try PEEK Coating instead.

William Maghen
- Bayan Lepas, Penang, Malaysia

June 27, 2010

Thanks William, but please take the time to tell us whether you are suggesting that PEEK (Polyether ether ketone) coatings would be better than Teflon for Wong's watches, or better than PU for Fey's portable measuring instruments, or for Mahendran's pharmaceutical/surgical application, or better than Teflon over the epoxy on Isaac's rods? And in what ways would they be better and for which specific application? If you are just making the general suggestion to consider PEEK, well, there are literally thousands of other coating technologies that can be considered for the general case devoid of specific application. Thanks.



pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey

June 1, 2012

Q. I am interested in a thin coating of a low coefficient of friction material for stainless steel sheet metal, to prevent metal to metal contact and act as a smooth surface when components are slid against each other. Minimal load bearing on the surface.

Brian LeNlanc
- West Berlin, New Jersey

June 25, 2012

A. Depending if it has to be permanent and very long lasting or is only for occasional contact and short periods the possibilities are so vast and range from the cheapest special greases to mid-cost treatments like Teflon spray, to more expensive platings to the most expensive and exotic composites deposited by PVD, CVD, Thermospray, Plasma, etc.
G. Marrufo - Mexico

Guillermo Marrufo
Monterrey, NL, Mexico

June 30, 2012

A. Teflon adhesion to stainless steel is a problem. However, it was sorted out when Gillette introduced their Teflon coated razor blades and put down an interlayer of Pt-Cr onto their stainless steel blades. This is well patented and documented, but in essence, the process involved vacuum deposition of the Pt-Cr followed by spray coating and sinter polymerisation of PTFE. The adhesion mechanism is believed to go through a Cr-F complex structure, although I am not sure of its details.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK

January 31, 2013

Q. Can we coat Teflon coating of 70 microns on SS304 material? If so what is temperature that needs to be maintained for curing.


Thin Opaque Dip-able coating for stainless steel

March 3, 2014

Q. A handful of years ago I was shown a thin, dip-able coating applied to a stainless steel bicycle spoke which was opaque, had very good color, and was so thin that cleanly coated the fine threads of the spoke allowing the nipple to thread on without issue. Even white was very bright with no stainless showing through, on a coating that seemed to be microns thick. We chose to go another direction and I've not thought about it again until recently as I need a thin disable coating for a part with threads.

Supposedly the finish was 'sol-gel' and was being performed in Taiwan and was commonly used in manufacturing electronics, that is really all I remember about it.

Now, I've been involved in composites manufacture for a long time and am familiar with sol-gel processing for aluminum (Boegel, AC-130), but this is clearly something completely different.

Essentially, I need a very thin, dip-able cosmetic coating and can't for the life of me seem to figure out what what I'm actually looking for!

Many thanks in advance for your help

Josh Poertner
Product Engineer - Indianapolis, Indiana
  ^- Privately contact this inquirer -^

March 2014

A. Hi Josh. My understanding is that sol-gel coatings were most used for thin films on electronics in the beginning, but that they are now applied to glass, plastics, and metal as functional coatings. Although I have no real experience with them, it would not surprise me if you had seen TiO2 sol-gel coatings, as I'd expect them to be both white, and useful as a metal protector.

Although they are dip-able, I don't think I'd categorize them as low technology . . . by which I suggest that competitive thin coatings that are not "simple dip coatings", like electrophoretic lacquering, PVD coatings, or anodizing may sound more complex but may actually be just as "simple" and inexpensive, or more so :-)


pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
Pine Beach, New Jersey
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