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Zinc rich primer Vs Zinc Rich epoxy
3

Zinc rich primer Vs Zinc Rich epoxy

Zinc rich primer Vs Zinc Rich epoxy

(OP)
I came across a client specification which reads like this
1. Zn rich primers shall be 2 pack epoxy media and must contain 80% metallic zinc by weight in dry film
2. Zn rich epoxy shall have 40% min. weight content of epoxy.


How can both be possible at the same time?

or Am i missing something.?

Thanks in advance for your inputs and feedback.

RE: Zinc rich primer Vs Zinc Rich epoxy

Is it use of the term 'dry film" that is the key difference versus the original liquid formulation?

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: Zinc rich primer Vs Zinc Rich epoxy

Yes Steve...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Zinc rich primer Vs Zinc Rich epoxy

Epoxy doesn't cure by evaporation of solvent so whatever the zinc content it will remain the same from wet to dry.

It sounds like the primer is 80% and the top coat is 40%, but that answer really needs to come from the client. At 40% there is considerable option for color, at 80%, not so much.

RE: Zinc rich primer Vs Zinc Rich epoxy

Not all epoxy coatings are 100% solids. There is shrinkage between wet film and dry film thickness.

RE: Zinc rich primer Vs Zinc Rich epoxy

(OP)
Thanks all for the feedback.

@3DDave., The midcoat given as follows.
MIO pigmented with 50% laminar MIO by weight in dry film.

So I guess, the first 2 points are talking about primer., hence it doesnt make sense to me.

I have attached the snip for reference, if that would be of any help

RE: Zinc rich primer Vs Zinc Rich epoxy

Note a is about primer.

Note b is about paint.

Is that attached image from the client?

These appear to be notes for some other drawing that confirms which combination is required.

RE: Zinc rich primer Vs Zinc Rich epoxy

2
Take a look at a manufacturer's datasheet for a zinc rich epoxy primer. Let's take Hempel Hempadur Zinc 17360 for example (no promoting here, just an illustrative example):

1. It states "In compliance with SSPC-Paint 20, type 2, level 2" - thus it claims to be an organic zinc rich coating containing a zinc dust pigment at 75% < x < 85% (BY WEIGHT)

2. It has a volume solids of 65 +/- 2% ( = Dry Film Thickness/Wet Film Thickness)

3. It also has a nominal VOC content - meaning that there will be some evaporative losses

4. It does not give an epoxy content

You just have to think how does a nominal 80% zinc content still only register a volume solids of 65% (WEIGHT v VOLUME)

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: Zinc rich primer Vs Zinc Rich epoxy

(OP)
thank u all for your valuable feedback

@Sjones. Thanks for the insight. Didnt thought that way.

@3Ddave

Yes it was a snip from client specification.

RE: Zinc rich primer Vs Zinc Rich epoxy

(OP)
@Sjones.

I came across 17360. In their safety data sheet epoxy content given as max. 10% where as % Zinc (Zinc + zn oxide) comes around 80%. so the first point is satisfied where as the 2nd point is not.

I am still at loss about how to interpret this.?

RE: Zinc rich primer Vs Zinc Rich epoxy

Where does the 2nd point come from? I don't see anything that says both points are for the same material. I do see where the two requirements are for two materials.

RE: Zinc rich primer Vs Zinc Rich epoxy

@3DDave: in point 2, what else is a Zn rich epoxy going to be used for, apart from a primer or as a repair for galvanising?

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: Zinc rich primer Vs Zinc Rich epoxy

Great question SJones - ASK THE ORIGINAL POSTER LIKE I DID.

HERE"S WHAT HE IS WORKING FROM:


RE: Zinc rich primer Vs Zinc Rich epoxy

Indeed, as the OP is finding out, the inclusion of “i.e. zinc rich epoxy” is not compatible with the associated requirement of 40% weight content of epoxy.

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: Zinc rich primer Vs Zinc Rich epoxy

That was my concern with my initial comment that I deleted.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Zinc rich primer Vs Zinc Rich epoxy

Zinc-rich epoxy primers come in a lot of flavors... What Specification(s)???

Aerospace?
Civil Engineering?
Maritime/ship/structures/etc?

Regards, Wil Taylor
o Trust - But Verify!
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation, Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", HBA forum]
o Only fools and charlatans know everything and understand everything." -Anton Chekhov

RE: Zinc rich primer Vs Zinc Rich epoxy

I wasn't aware of the coating that Steve mentioned... but looked into it, and have added it to my list of coatings.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

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