Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations SDETERS on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

ZInc plating of wiremesh

Status
Not open for further replies.

Ratheesh_n

Mechanical
Dec 27, 2016
60
Dear All,

We are doing zinc plating of wiremesh ,(wire - 4.5mm dia). Anyone please tell how to check the coating thickness of wire ? is measurment with elechometer is acceptable ?

And how to maintain the shining of plating in packing and storage

 
Replies continue below

Recommended for you

Are you using electro-plating or hot dipping?
There are several ways to check thickness, but using an elcometer would not work because of the small section size. You will likely only be able to determine an average thickness of the coating over a large area. This can be done by accurately weighing the specimen before and after coating. You will have to determine the surface area of the mesh also.
 
I only use electroplating for dry interior spaces, not subject to a corrosive environment... else, HDG is the only way with zinc coating. I have photos of electroplating in a corrosive environment after a month... and looked like no coating at all.

Dik
 
Dik...I agree. Electroplating is too thin to be of any real use. Not any better than a good paint coating.
 
@dik


Please share the PICS .

We are doing both electroplating and HDG. In HDG we are facing so many problem in surface finish and post process finishing work is so high . As it is manual,we are spending so many manpower on same thats why we are suggesting our client to purchase electroplated materials.

In grinding there is big loss of coating thickness of HDG materials . Is there any other method to do the finishing with small machines ?
 
so many problem in surface finish and post process finishing

Perhaps some photos of your product before and after dipping and before and after finishing would help us understand why you are having to grind HDG at all.



Mike Halloran
Pembroke Pines, FL, USA
 
20170220_120819_tt2kmr.jpg
20170220_120825_argjgn.jpg


This is Before HDG
 
20170220_121219_hp2usd.jpg
20170220_121250_ma6zm8.jpg
20170220_121205_gvsdyi.jpg
20170220_121140_iyhwzv.jpg
20170220_121158_kgyeiq.jpg


This is after HDG .We are doing filing to remove this zinc lumps at edges and painting with zinc rich paints in the uncoated areas ...
 
OP:
I'll see if I can locate the original file, else, I'll scan the one I have on my wall.

Dik
 
When you HDG, there is generally a 'scum' that forms on the surface and this is usually removed prior to extraction from the zinc bath. It does not appear that this has been done. Your HDG does not appear to be 'clean'.

Dik
 
I thought you started asking about coating wire mesh. The pictures show something else entirely.
 
@hokie66

Ysss. but as i mentioned above we are doing electroplating because of these issues in galvanising.
 
Right. I see you have issues. But the corrosion protection afforded by galvanising is vastly superior to electroplating.
 
IR... the 'swipe coatings' look like they were caused by withdrawing the object from a 'dirty' tank.
 
Ratheesh:
Attached scan... couldn't find the photo.

They said the sag rod was electroplated... doesn't look like this happened, else, the corrosion is extreme.

The channel girts were supposed to have an epoxy zinc rich primer, with a high build epoxy intermediate coat, and a polyurethane top coat... ditto above. The pin prick corrosion centres indicate a poor application of a quality coating system, or maybe a different coating system.

The siding has a CSSBI Barrier coating and seems to be holding up (still).

I refused to sign off on the installation, and, had specifically noted on the shop drawings that the sag rods were to be HDG.

Dik
 
 http://files.engineering.com/getfile.aspx?folder=8df9c710-1ad3-4395-90e3-a2848a1f685d&file=Corrosion.pdf
Thanks Dik for Sharing the Pic


For Extreme corrosion environments like offshore , Coating system should be Zinc silicate primer + High build epoxy paint 2 coats + Polyeurethene finish paint or to be HDG .







 
I'll look into the zinc silicate primer. The zinc rich epoxy has worked well in past, but, if there's something better, I'll use it.

Dik
 
Hello Ratheesh,

I understood your situation.

So, go for chromate treatment for better corrosion resistance after electroplating.

Regards

CocoE
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor