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Zinc Chromate

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ihab.awad(at)gmail.com
Guest

Posted: Thu Apr 03, 2008 12:39 pm Post subject: Zinc Chromate

On Thu, Apr 3, 2008 at 2:16 PM, James E. Lanier <jim.lanier(at)charter.net> wrote:

 	  Quote: 	
		    Zn-Cr


	


http://www.google.com/search?hl=en&q=%22primer+wars%22



-- 

Ihab A.B. Awad, Palo Alto, CA

larry(at)macsmachine.com
Guest

Posted: Thu Apr 03, 2008 12:53 pm Post subject: Zinc Chromate

Hi James,

With Zinc Chromate inside the wing, you'll notice with some paints that 

the yellow will bleed thru your primer.  Not too much to cover with color

but problematic with semi-solid paints.  During the wash, etch, prime, I 

had a lot of difficulty with the yellow stain penetrating the white primer.

Perhaps that wouldn't be a problem if the Zinc Chromate was white too.  

If not, I'd suggest you do a test coat under what you intend to prime with

outside the skins or find an epoxy prime that would coat and protect 

your aluminum to avoid the hassle.



For most of 6061 alloys, you only need to prime the surfaces that make 

contact with each other and light spray areas that could collect moisture.

Don't forget to drill the small drain holes in boxed surfaces, or your 

wash-etch will never dry well, i.e., stabilizer etc.



Larry McFarland 601HDS at www.macsmachine.com

James E. Lanier wrote:

 	  Quote: 	
		   

 <jim.lanier(at)charter.net>



 Zn-Cr



 First, does everyone do this on their kits? Do you only apply it only 

 to the contact surfaces, or the entire inner surfaces? I am looking 

 for pros and cons.



 Jim

notsew_evets(at)frontiern
Guest

Posted: Thu Apr 03, 2008 1:02 pm Post subject: Zinc Chromate

Being the now expert painter that I am....  I strongly suggest that if you 

use zinc chromate primer that you seal it with a paint compatible product. 

I didnt!  I had bleed through and it took four coats to finally get it 

stopped from bleeding.  On the metal to metal joints the chromate works fine 

but if you plan on painting for looks use an epoxy primmer..  AND be 

absolutely sure its compatible with your finish coats....

SW



Steves Aircraft Painting Service.............NOT !

---

jim.lanier(at)charter.net
Guest

Posted: Thu Apr 03, 2008 1:33 pm Post subject: Zinc Chromate

Thanks. Just to make sure we are on the same page..I intend to use this 

inside the wings, rudder, horizontal stab and not on the exterior 

surface. What I am asking is whether or not to cover the entire interior 

surfaces or just at the contact points.(.ie rib to skin)



Jim

steve wrote:

[quote] 



 Being the now expert painter that I am....  I strongly suggest that if 

 you use zinc chromate primer that you seal it with a paint compatible 

 product. I didnt!  I had bleed through and it took four coats to 

 finally get it stopped from bleeding.  On the metal to metal joints 

 the chromate works fine but if you plan on painting for looks use an 

 epoxy primmer..  AND be absolutely sure its compatible with your 

 finish coats....

 SW



 Steves Aircraft Painting Service.............NOT !

 ---

tigerrick(at)mindspring.c
Guest

Posted: Thu Apr 03, 2008 2:30 pm Post subject: Zinc Chromate

Hi, Jim.



The way the quick build kits come is as you describe, with chromate ONLY between the metal mating surfaces.



Of course, you can chromate the whole interior, but the weight of the layers will add up.  Some kit manufacturers do chromate other than contact areas, but this is generally limited to inaccessable areas on airplanes that carry a load.



My strategy was to just fog the unpainted areas of the interior of the fuselage, and the wings and stabilizers, with ACF-50 for corrosion protection (and repeated every year at inspection).



Since empty weight is so precious on LSA aircraft, I went for a partial exterior paint job as well.



Just my $0.02.



Rick Lindstrom

601 XL  N42KP



--

agibeaut

Joined: 21 Mar 2007
Posts: 64

Posted: Thu Apr 03, 2008 3:04 pm Post subject: Zinc Chromate

I started the kit with Zn-Cr which was applied to only one surface. I did not like the potential health related issues and after reading dozens of opinions on this and other sites decided to switch to Self Etching Primer in a rattle can that I buy from NAPA Auto. I tested the stuff for resilience, and it is pretty good, and have used it throughout. I'm done with the tail, wings, and rear fuselage on my 701 and I have not regretted it. Just my opinion. 

--- On Thu, 4/3/08, James E. Lanier <jim.lanier(at)charter.net> wrote:

 	  Quote: 	
		   From: James E. Lanier <jim.lanier(at)charter.net>

 Subject: Zinc Chromate

 To: "Zenith-List Digest List" <zenith-list-digest(at)matronics.com>

 Date: Thursday, April 3, 2008, 4:16 PM

 Lanier" <jim.lanier(at)charter.net>

 Zn-Cr

 First, does everyone do this on their kits? Do you only

 apply it only to 

 the contact surfaces, or the entire inner surfaces? I am

 looking for 

 pros and cons.

 Jim

You rock. That's why Blockbuster's offering you one month of Blockbuster Total Access, No Cost.  

http://tc.deals.yahoo.com/tc/blockbuster/text5.com

zenith-list(at)steensland
Guest

Posted: Thu Apr 03, 2008 3:37 pm Post subject: Zinc Chromate

Wicks is pushing Zinc Oxide now, so I got a few rattle cans of that to 

try. I too worry about the longevity of my lungs breathing Zn-Cr so I'll 

try this.

I have also heard good things about self-etching primer as well (albeit 

a little more expensive than Zn oxide).

Art Gibeaut wrote:

 	  Quote: 	

 I started the kit with Zn-Cr which was applied to only one surface. I did not like the potential health related issues and after reading dozens of opinions on this and other sites decided to switch to Self Etching Primer in a rattle can that I buy from NAPA Auto. I tested the stuff for resilience, and it is pretty good, and have used it throughout. I'm done with the tail, wings, and rear fuselage on my 701 and I have not regretted it. Just my opinion. 

 --- On Thu, 4/3/08, James E. Lanier <jim.lanier(at)charter.net> wrote:

> From: James E. Lanier <jim.lanier(at)charter.net>

> Subject: Zinc Chromate

> To: "Zenith-List Digest List" <zenith-list-digest(at)matronics.com>

> Date: Thursday, April 3, 2008, 4:16 PM

> 

> Lanier" <jim.lanier(at)charter.net>

>

> Zn-Cr

>

> First, does everyone do this on their kits? Do you only

> apply it only to 

> the contact surfaces, or the entire inner surfaces? I am

> looking for 

> pros and cons.

>

> Jim

>

>     

 You rock. That's why Blockbuster's offering you one month of Blockbuster Total Access, No Cost.  

 http://tc.deals.yahoo.com/tc/blockbuster/text5.com

-- 

Lee Steensland

601XL/Corvair (7637L reserved) Kit/Scratch builder 0.0% complete!

messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Fri Apr 04, 2008 7:19 am Post subject: Re: Zinc Chromate

The bleeding issue is with zn chromate on the exterior, right? I've used it on all interior surfaces so far (wings, tail feathers). The spray cans sure leave dust all over the shop, too.

_________________
Dan

larry(at)macsmachine.com
Guest

Posted: Fri Apr 04, 2008 10:21 am Post subject: Zinc Chromate

No Dan,

The zinc chromate inside a wing will wick out between edges and discolor 

your primer and final color if the finish coat isn't solid cover.  Even the

wash-etch prior to prime will have a yellow stain flowing from the wing 

during a rinse.  I the case of an etch that needs to be primed within 8 

hours,

it's unlikely that the inside of the wing will be dry enough to keep the 

zinc chromate from seeping out into your primer.  Best advice, try a sample

of your paint over zinc chromate before actually doing it.



Larry McFarland 601HDS at www.macsmachine.com



messydeer wrote:

 	  Quote: 	
		   



 The bleeding issue is with zn chromate on the exterior, right? I've used it on all interior surfaces so far (wings, tail feathers). The spray cans sure leave dust all over the shop, too.



 --------

 Dan

messydeer

Joined: 13 Feb 2006
Posts: 214
Location: Bellingham, WA

Posted: Fri Apr 04, 2008 11:20 am Post subject: Re: Zinc Chromate

Thanks, Larry 



I've used the green zn chromate both from Tempo and Orr-Lac. I suppose that would do the same? I'm planning on trying a polishing job first and if that doesn't look good enough (which may be caused by dings yet undung), I'd paint. 



There are a few areas where I ran out of the zn chromate and used a couple spray cans of  SEM Promax 61103 Gray Primer. It only says 'general purpose enamel for metal,...' and was what the autobody store recommended.



So it looks like I should read through this topic a bit more in detail. I chose zn chromate for it's corrosion resistance, price, and ease of application (rattle cans).



Cheers!

_________________
Dan

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