×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

CUI vs Zinc Primer

CUI vs Zinc Primer

CUI vs Zinc Primer

(OP)
Hi,

In a supply chain mix-up, the supplier delivered a high temp CUI primer instead of a silica-zinc primer. The lead times to get the correct coating is eight weeks while the equipment is scheduled to ship out in a week. Both primers are rated for 1000F while actual application will see a maximum of 120F on the coast in tropical environment. The device is a part of a fuel feed system that does not need insulation. Would both coatings provide similar resistance to corrosion?

Thank you.

RE: CUI vs Zinc Primer

The zinc rich primer protects the metal in the event of defects and damage of the coating. I would not suggest this substitution for your application.

Does the CUI primer have good UV resistance?

Most coatings manufacturers have parallel lines of products. If your supplier can't provide the coating within your time requirements you may find a supplier with a similar coating that can.

On top of zinc-rich primer, include terms such as epoxy, surface tolerant and high build to help narrow down a suitable alternative.

Topcoating can provide UV resistance if your anti-corrosion coating can't provide it.

RE: CUI vs Zinc Primer

I can't open the data sheets for some reason. Can you tell us the mil thickness of each coating. The Zinc primer looks like it's meant to go under the 1000 primer. Anti-corrosion coatings typically require a minimum thickness of around 20 mil and the zinc rich primers in my experience only give 2-5 mil so they require additional coats of anti-corrosion primer on top.

RE: CUI vs Zinc Primer

I still can't view the zinc primer spec but can view the 1000.

My understanding is that these products are not substitutes for each other. You can use the 1000 without the zinc but will not get as good of protection. You cannot use the zinc without the 1000, if my understanding is correct.

RE: CUI vs Zinc Primer

Did anyone spot the warning on the 850 datasheet: "DO NOT USE OVER GALVANISED METAL OR ZINC RICH COATINGS." Perhaps that's why the Zinc Primer datasheet doesn't offer 850 as a suitable topcoat.

Steve Jones
Corrosion Management Consultant

www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

RE: CUI vs Zinc Primer

(OP)
Dr Jones, there was a mix-up and the wrong coating was advised/supplied.

RE: CUI vs Zinc Primer

So, you needed TemperKote 850 Primer? The 850 was NEVER going to go over TemperKote Zinc Primer.

Steve Jones
Corrosion Management Consultant

www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

RE: CUI vs Zinc Primer

Temperkote 850 is not a primer, it's a top coat.

RE: CUI vs Zinc Primer

@Tug

Check it out:

850Primer

Steve Jones
Corrosion Management Consultant

www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

RE: CUI vs Zinc Primer

They appear to have both a topcoat only and a primer in the 850. OP's link shows the topcoat.

RE: CUI vs Zinc Primer

@Tug,

Indeed, and I’m pointing out that for the 850 topcoat, the OP needed the 850 Primer

Steve Jones
Corrosion Management Consultant

www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

RE: CUI vs Zinc Primer

I'm a little confused. OP should be using the Zinc under a coat of Temperkote 600 or 1000. The 850 would be optional but could be applied to the 600 or 1000. OP will lose a lot of corrosion performance if the zinc coat is skipped.

RE: CUI vs Zinc Primer

(OP)
Gentlemen, Thank you. The end user agreed to what was available at the earliest, i.e., a 1000 primer with the 1000 topcoat.

Do books like ASM Handbook, Volume 5B: Protective Organic Coatings do a good job of listing compatibility between different coating formulations? For example, if incompatible coatings may saponify or undergo cathodic debonding?

RE: CUI vs Zinc Primer

For topcoating of zinc rich primers: SSPC-PS Guide 8.00 along with manufacturer's datasheets.

A reasonable first start for coating selection can be made from most of the major players' web sites such as Hempel

Steve Jones
Corrosion Management Consultant

www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

RE: CUI vs Zinc Primer

(OP)
Dr Jones, thank you for the recommendation. In a coating system, does the alkyd chain of a modified silicone alkyd resin react with zinc?

RE: CUI vs Zinc Primer

@Doodler

Given the warning on the 850 datasheet, one would have to say yes, for that specific 850 formulation.

Why on earth are these coating systems being selected for an aggressive CX environment at a notional 48 deg C (not allowing for temperatures generated by solar radiation)?

Steve Jones
Corrosion Management Consultant

www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

RE: CUI vs Zinc Primer

(OP)
Dr Jones, it's a one-size-fits-all approach for coatings. Unfortunately, I'm not the one in charge.

RE: CUI vs Zinc Primer

I wish you good luck

Steve Jones
Corrosion Management Consultant

www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close