netneut
finishing.com -- The Home Page of the Finishing Industry
A website for Serious Education, promoting Aloha,
& the most FUN smiley you can have in metal finishing


Finishing.com has been free for 22 years,
but without net neutrality we could soon
cease to exist. Do us a solid, click on
the banner, and contact congress today!
HomeFAQsBooksHelpWantedAdvertiseForum
topic 6158

Paint adhesion is poor on Welds


(2000)

I have a situation where cold rolled steel is being welded and then painted with electrolytic dip process (e coat), however, there is no paint adhesion to the welds. I have been told that this is due to a "silicon" component of the metal rising and hardening on the surface of the weld. I wish to understand how accurate the analysis is or whether it is a generalization.

Chris Gardini
Dell - Austin, Texas US


(2001)

Chris,

There are many reasons why paint fails to adhere at welded locations, here are several I would investigate.

I would first look at the weld process and find out what electrode is being used. If the process is using an electrode high in silicon then you may want to use an electrode containing less silicon. As an example, in Gas Metal Arc welding, if the process is presently using an ER70S-6 electrode that contains considerable amounts of silicon then you may want to change to an ER70S-3 electrode containing less silicon.

Next, take a close look at the cleaning operation, and find out whether fabricating soils are being entrapped between the metals and determine whether the surface is being cleaned prior to and after welding to remove oxides, scale and those tenacious carbon residues. Carbon and silicon are adhesion killers and should be removed by power brushing.

That's all I have for now, good luck.

J. Regmont
- Warren, Michigan, USA



This public forum has 60,000 threads. If you have a question in mind which seems off topic to this thread, you might prefer to Search the Site

ADD a Q or A to THIS thread START a NEW THREADView This Week's HOT TOPICS

Disclaimer: It's not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & Devices


©1995-2017 finishing.com     -    Privacy Policy
How Google uses data when you visit this site.