Zinc chromate substitute

[Dean Fournier]

I've just entered the world of homebuilding with an all aluminum
(6061-T6)Zenith CH 701 kit. I don't live near industrial pollution or salt
air, but I do want to fly this aircraft for decades to come without giving a
thought to internal corrosion, so priming the parts now seems like cheap
peace of mind. I'm having trouble finding zinc chromate, and I'm having
reservations about the health hazards of using it as well. I've been told
by several auto body shops that any good self etching primer will provide as
much protection to aluminum as zinc chromate. Is this true?

Any help appreciated.

Dean Fournier
Ottawa, Canada

[Kevin Horton]

In article <rWtP5.81342$78.26...@news3.rdc1.on.home.com>, "Dean
Fournier" <head...@home.com> wrote:

Dean,

You may be able to find zinc chromate in spray bombs at boating stores.
I bought mine at The Chandlery at the Britannia Shopping Plaza in
Ottawa. It is hidden away on the side street on the west end of the
plaza. Phone 820-7642.

In general, self etching primers will probably provide some corrosion
protection, but not as much as a coating specifically designed for that
purpose, such as zinc chromate. There are Mil-Spec anti-corrosion
primers, but they are expensive and harder to find. They are the way to
go though if you are really worried about corrosion.

What does Chris Hientz recommend? Maybe a self-etching primer is "good
enough" for this area.

There is some info on corrosion control on the EAA chapter 1000 website,
at:

http://www.eaa1000.av.org/technicl/corrosion/corridx.htm

Take care,

--
Kevin Horton
khorto...@cyberus.ca.invalid - remove _trash and .invalid to e-mail
http://eccentrix.com/misc/rv8/rv8.html

[Mahan]

Dean Fournier wrote in message ...

>I've just entered the world of homebuilding with an all aluminum
>(6061-T6)Zenith CH 701 kit. I don't live near industrial pollution or salt
>air, but I do want to fly this aircraft for decades to come without giving
a
>thought to internal corrosion, so priming the parts now seems like cheap
>peace of mind.

>snip<

Dean, 6061-T6 has very good resistance to corrosion That's why Chris used
in the 701 and his other designs in place of the ~18% stronger 2024-T3,
which does not have good corrosion resistance. Chris says that his original
CH-200, also constructed of 6061-T6, has been parked outside in Canada for
20-25 years, and he has had no corrosion problems with it. More
sportplanes, such as the 701 and the Sonex, should be designed around
6061-T6, IMHO.

Fred in Florida

[Fletcher]

Good point Fred and one I tend to agree with. Same reason that Murphy uses
6061 T6.

I am a A&P with a major airline and see plenty of corrosion. Most all
repairs standard treatment acid etch and alodine, prime and paint if
necessary. It has been very hard for me to put the parts of my Super Rebel
together without doing the same thing. Doing this process on my plane would
add years to the building time and as you have said would probably not be
necessary. Keeping a good paint, cleaned and waxed regularly would probably
do more to fight corrosion than anything else.

[Ken Balch]

Hi Dean,

The questions of whether or not to prime Alclad aluminum & which primer to use
if you're going to prime will both elicit a storm of differing and, at times,
contradictory responses. I won't add my two cents to the bucketful of change
you're likely to get on those issues. As to where to obtain self-etching zinc
chromate, it's available from Aircraft Spruce in the Tempo spray cans (page 294
in the 2000-2001 catalog).

Regards,
Ken Balch
RV-8 builder

Dean Fournier wrote:

> I've just entered the world of homebuilding with an all aluminum
> (6061-T6)Zenith CH 701 kit. I don't live near industrial pollution or salt
> air, but I do want to fly this aircraft for decades to come without giving a
> thought to internal corrosion, so priming the parts now seems like cheap

[Rich Shankland]

"Ken Balch" <kba...@mediaone.net> wrote in message
news:3A0EE634...@mediaone.net...

> Hi Dean,
>
> The questions of whether or not to prime Alclad aluminum & which primer to
use
> if you're going to prime will both elicit a storm of differing and, at
times,
> contradictory responses. I won't add my two cents to the bucketful of
change
> you're likely to get on those issues. As to where to obtain self-etching
zinc
> chromate, it's available from Aircraft Spruce in the Tempo spray cans
(page 294
> in the 2000-2001 catalog).

One more thing to keep in mind.... Will your color coat lift whatever primer
you use? It might be wise to do a trial run using your selected primer and
topcoat to determine compatability. A catalyzed primer is much more
resistant to subsequent topcoats than a spraycan primer.

--
Rich Shankland
http://www.harbornet.com/folks/shankland/emeraude.html

[Bruce A. Frank]

Real Zinc Chromate is really difficult to come by these days. Most of
the stuff available actually meets the Mil Spec for the old stuff but
does not have the carcinogenic properties of it. The paint that you can
get from Randolph and Aircraft Spruce meets the spec, is the same
colors, but is much less hazardous to your health. The self etching and
epoxy "zinc chromate" primers are as-good-as or better than the old
stuff. WHen I was at New Garden the process was alodyne (sp?) and Corlar
on aluminum.

Dean Fournier wrote:
>
> I've just entered the world of homebuilding with an all aluminum
> (6061-T6)Zenith CH 701 kit. I don't live near industrial pollution or salt
> air, but I do want to fly this aircraft for decades to come without giving a
> thought to internal corrosion, so priming the parts now seems like cheap
> peace of mind. I'm having trouble finding zinc chromate, and I'm having
> reservations about the health hazards of using it as well. I've been told
> by several auto body shops that any good self etching primer will provide as
> much protection to aluminum as zinc chromate. Is this true?
>
> Any help appreciated.
>
> Dean Fournier
> Ottawa, Canada

--
Bruce A. Frank, Editor "Ford 3.8L Engine and V-6 STOL
BAF...@worldnet.att.net Homebuilt Aircraft Newsletter"
| Publishing interesting material|
| on all aspects of alternative |
| engines and homebuilt aircraft.|
*------------------------------**----*
\(-o-)/ AIRCRAFT PROJECTS CO.
\___/ Manufacturing parts & pieces
/ \ for homebuilt aircraft,
0 0 TIG welding

[Jerry]

Dean,
I work in an aircraft manufacturing plant and we got away from zinc chromate
many years ago. I can get the name of th enew primer we are using but I do
bellieve that the part must be chemical filmed ( alodined) before the primer
will adhere. If you are interested in more information let me know.

Jeremy
"Dean Fournier" <head...@home.com> wrote in message
news:rWtP5.81342$78.26...@news3.rdc1.on.home.com...

[Dean Fournier]

Jerry wrote in message ...

>Dean,
>I work in an aircraft manufacturing plant and we got away from zinc
chromate
>many years ago. I can get the name of th enew primer we are using but I do
>bellieve that the part must be chemical filmed ( alodined) before the
primer
>will adhere. If you are interested in more information let me know.
>
>Jeremy

Thanks Jerry,

But I don't want to go to the trouble of alodining everything. Thanks to
you and to all that responded to my request for info. I will definitely
check compatiblity with the topcoat, although mostly I'm concerned with
priming the parts inside the wings and tail at the moment, where there will
be no topcoat.

I was just sold a few cans of Pro - Form PF 654 Self Etching Primer, and
was told it either had zinc chromate in it, or it was as good. If anyone if
familiar with this particular primer, I'd appreciate any info about it.

Thanks again to all who responded - especially the local guy who told me
where to find zinc chromate in Ottawa!.

Dean Fournier
Ottawa
>>
>>
>
>

[T6flier]

I have found Dupont's Variprime to be a very good self-etching primer. You
will find that it has zinc chromate in it as well. It is also available in a
chromate free version I believe although I have not used it.