Zinc flake coating questions

A. Hi Tarun. To the best of my knowledge there are no cost estimating books for plating & metal finishing like there are in the construction industries for example; but there have been published papers on the subject like:

polynet.dk/ingpro/surface/elecomk.htm

If possible, the best approach is often to ask a shop which offers the specific coating you are looking for what factors affect their pricing. We've attached your inquiry to a thread on zinc-rich dip-spin coatings which may give you some insights, and we have threads on cost estimating for various finishes if you search the site for "cost of [specific finish]".

Luck & Regards,

A. Ford S 442 is a specification for a zinc-rich coating, applied either as a dip-spin coating or a dip-drain coating. I would interpret 'cost' as what it costs to do this process - which would include many direct costs and usually an allocation of indirect costs. Those who apply this paint from approved paint suppliers usually have a reasonably good handle on these costs. I would interpret 'price' (which hasn't been brought up, but I'm mentioning it anyway) as what approved applicators charge for this finishing process. RFQ's to approved applicators are the most viable source for this information. You can buy the standard and a list of approved suppliers online. I've mentioned 'approved' five times, just in case someone might think otherwise.

A. Hi Nick, hi John. The manufacturer of Dacromet offers a chrome-free system called Geomet. I can't say to what measure the qualities are maintained without hexavalent chrome, but trying is doubtless the goal. There are, of course, several other brands of zinc-rich dip/spin coatings available, and Tom Rochester offered a great list at

web.archive.org/web/20141217004049/http://dipspincoatings.com/

Good luck.

A. I would like to clarify here: There is difference between Dacromet and Geomet. Dacromet contains Chromium and its SST life is less than Geomet coatings.
But both the coatings are well known and accepted by many industries. And it's a trademark coating.
So my recommendation to people: choose Eco Friendly coatings- Geomet and there are a wide range of Top Coat varieties which will help you to increase Salt Spray Test And COF Range.
I am not advertising here; it's just an opinion to people.
I had worked so far in this field so I know about this.

Thanks Neeraj. Readers are reminded that there are a number of companies offering dip-spin coating processes, as well as competing technologies like sherardizing, mechanical plating, and zinc alloy platings with eco-friendly non-hexavalent conversion coatings.

Luck & Regards,

A. Dacromet 320 is one product from Metal Coatings International, the original developer of this coating. Dacromizing is a generic word to mean coating with a Dacromet product. It is not a suitable specification for a finished product. Corrosion resistance will depend on the coating thickness. In order to achieve 500 hours of salt spray resistance, the coating thickness must be at least 5 micrometers for Dacromet 320. You should contact Metal Coatings directly if you need additional information, or visit their website.

Sorry, I spelled the word completely wrong. I should have written Dacrotizing instead of Dacromizing. I think the question is answered now.

I found now that Dacrotizing is the process of applying Dacromet 320 to the surface. One web site is saying Dacrotizing = Dacromet 320 which gives min. 500 hrs in Salt Spray Test) and another site is saying Dacrotized coating gives 500 hrs in SST. So I now have some back up that with Dacrotizing we still have the same corrosion resistance.

A. Dear Sir,

Silver grey coloured coating is from Dacromet. The same type of coating is available from Delta Tone (Doerken, Germany) It is applied by dip spin technique. Process cost would be Rs. 20 per kg. These kind of coatings have Chrome free resins and are patented too. It is approved by leading automobile manufacturers. Different top coats applied on this kind of coating give dry film lubricity. The total coating thickness could be 10 or 12 micron only. It's called Microcoat corrosion protection system with dry film lubricity.

A. Hi, Pavan. You may be referring to mechanical plating with zinc? In this approach, zinc flakes and tiny glass balls are tumbled with the parts; the balls drive the flakes onto the parts under very high pressure.

adv.
If so, Plating Systems and Technologies [a finishing.com supporting advertiser] can help you.

Or you might be referring to dip-spin coating where a zinc-rich "paint" is applied. There are several manufacturers of these dip-spin coatings.

As a rule of thumb: the more zinc, the more expensive, and the more corrosion resistant. So, in general, mechanical plating and dip-spin coating will cost more than electroplating but deliver greater corrosion resistance. One reason you see so much zinc electroplating on fasteners is that in the general case there is no other way to apply zinc or other cathodic protection coatings which matches its low cost.

A. Alternative zinc coatings can indeed save money over electroplating. Mechanical galvanizing would give you the most corrosion protection but mechanical plating would be a bit cheaper. I don't think a dip spin coating would be thick enough for your application.

I would go with mechanical galv but specify zinc in flake form so that thread fit is optimal.

A. Zinc flake coating sold under the brands Zintek /Dacro / Geomet / Doerken are done by dip spin method and when done properly with a sealing lacquer give 1000 hours of salt spray test.

These coatings are very successfully done on fasteners.

Thanks Jeffrey, thanks Gurvin. I appreciate the input, and agree that the corrosion resistance of mechanical galvanizing and zinc rich coatings will exceed that of zinc electroplating, but I strongly doubt that any of these technologies will not exceed Karnatakam's cost of 4-1/2 cents a pound ($100/MT).

Regards,

A. Dear Mr. Pavan Kumar,

adv.
Our firm can do both mechanical zinc or Dacromet coating for you.

Mechanical zinc will cost four times your present cost, and zinc flake will cost 8 times your present plating cost.

A. The cost of Indian made Zinc Flake coatings is much lower, also you can get a dip-spin machine for your output at very reasonable cost, fully automatic.

A. Hi Balaji. Zinc-rich flake coatings are applied something like paint, with a dip-spin machine. Generally they are quite a bit thicker than zinc electroplating. Khozem's response to the previous question was from several years ago and for a somewhat different component. But I believe the thrust of it, that the cost of the coating is roughly proportional to its thickness. You might ask him for a quote. Good luck.

Regards,