Charles
We ran into the same sourcing issues on the Polyfibre product and looked at alternatives,
I have attached he text of a reply I made to the list back in April discussing our
decision. For what it is worth a friend of mine building an RV independently came up
with the same answer and was reassured to think he was not alone in his conclusion. I
used the RV list archive as a ref. also.
On whether the Polyfibre contains zinc chromate the answer is no! See my correspondence
below for the particulars.
If you want to look at more of the thread I'll refer you to the archive (dcsol.com ref'd
in the mailing list .sig file) to track down the thread since it is too long to repeat
here. Good luck & let us know how you make out.
Dave R.
Elite 583
--------------------------
Subject:
Re: corrosion protection - Dupont Products
Date:
Thu, 20 Apr 2000 12:10:57 -0300
From:
"David A. Ricker" <
ricker@dbis.ns.ca>
Organization:
.
To:
" (Murphy Rebel Builders List)" <
murphy-rebel@dcsol.com>
References:
1
Terry
On Elite #583 we are using Dupont Corlar filling wash primer. This is available in
chromate bearing (820R) and non-chromate
formulation (810R), we are using the chromate version. When you use the chromate version
they say you do NOT need to apply a
chromic conversion treatment (Alodyne/Iridite). This is a big plus for us since we do
not want the problems associated with disposing
with the hazardous waste from the process. When I looked into it, being above board (and
convincing raw material suppliers to sell you
the material in bulk at a reasonable price) would have required being certified to handle
the material and using approved disposal services
(unless it went down the drain but having a septic system and a well rules that out even
if your concience doesn't). Local service
providers were not capable of providing the irridite service to our satisfaction either.
BTW, Alodyne = Iridite, these are trade names for
chromic conversion treatment chemicals, Alodyne is the name you hear around aircraft &
Iridite is what you hear around elelctronic
chassis/sheet metal fab shops.
Back to Corlar, this material is used in local aircraft refinishing and float
manufacturing facilities. I suppose they have a good handle on
corrosion issues in this area due to the proximity of the salty Atlantic Ocean....... I
first got a lead on using this material by reading the RV
archives. I guess I should also mention that we are building with the possibility of
putting this plane on floats at some point so we wanted
to apply some corrosion protection to all of the internal surfaces and procuring the Poly
F product in that quantity was going to be a royal
pain so we went looking for locally sourced alternatives
As for application, the Murphy instructions say you should assemble the parts wet
implying to "glue" the parts together (with the Poly F
product), in our case that was not consistent with our basement assembly area (fumes) so
we assemble after the parts dry with the
exception of dipping the rivets. I call on two reasons for believing this is adequate,
first I cannot believe Murphy would design the
structure so close to the edge that the "adhesive" properties of the paint would make a
pass/fail difference on the strength of the structure
and the fact that I spoke to a tech person at Cessna who told me that they assemble their
aircraft "dry" after all the piece parts are
alodyne/iridite treated and painted.
We contacted the Dupont Tech center (Ontario?) to get advice on this. It is recommended
to follow the Corlar with a high solids
urethane primer 1020R (Ochre) or 1044R (Gray), and a Dupont topcoat like Imron. They
also said we should be able to get good
advice from their re-sellers like UAP but we felt speaking to "the horses mouth" would
provide the best information. We got the requisite
data sheets (including application instructions and MSDSs from the local UAP.
These Dupont products are available at your local UAP auto body supply jobber - off the
shelf, no HAZMAT shipping issues.
Dupont is clear on their direction to use a paint "system" from ONE manufacturer to avoid
incompatibility.
Application of all these products must done with a fresh air supply to the painter since
these days just about every paint you will
encounter will have very nasty chemicals like isocyanates (or chromate in typical zinc
chromate) in them. Normal charcoal etc. masks are
NOT adequate for these paints. Your fresh air system does not need to be expensive, ours
is just a shop vac located in a room
outside the painting area to supply air to the painter and an old furnace blower which
exhausts the paint fumes and maintains the shop at a
pressure lower than ambient. This ensures that fumes won't enter the house attached to
the workshop (that is a description of
priorities isn't it!). You will need a hood/visor to pump the air into, we made one from
a Canadian Tire clear visor and some fabric or you
can spend more $ for an official version.
As we did, you should look at the alternatives and satisfy yourself that the decisions
you make are best for your situation. Our choices
were made based on our needs and imposed restrictions and hopefully we have made good
ones!
Hope all this is useful,
Dave R.
McClary, Terry (GEAE) wrote:
Dave R.,
Care to share where you got your recommendations on which DuPont products to
use? Did you use a web site, local dealer, or user recommendations to determine
which is the best product for the application and how to apply.
I've bought a quart of the Poly Fiber primer and the associated pre-prime
chemicals. I also talked to the distributors at Sun N Fun about pre-prime
cleaning and primer application. The Poly Fiber factory was very helpful and
fast about providing MSDS sheets and answering questions by telephone, but, I
didn't ask for any of the details you did.
I know a couple of the fellows in my EAA chapter have talked about using DuPont
products on their projects. I decided to stay with the Murphy recommendation
but I haven't started priming. If DuPont supports their products better, maybe
I'll switch before I get started.
Terry
-----Original Message-----
From: David A. Ricker [mailto:
ricker@dbis.ns.ca]
Sent: Thursday, April 20, 2000 9:44 AM
To: (Murphy Rebel Builders List)
Subject: Re: corrosion protection
Ken, Bob
It looks like something changed (before we got our kit, about March '97). Our
package
says nothing about chromate and a quick call to Poly F confirms that there is no
chromate
in the product. The guy I talked to said they had put in some "miracle"
additive called
"hibosil" or" hiboseal". When pressed on how this worked (as in, does it form a
sacrificial anode like zinc chromate or does it simply improve adhesion) the guy
wouldn't
discuss it. Trade secret. For me that just confirms our decision to deal with
Dupont
who are willing to discuss their products and not give you the PR face.
FWIW, we are using a Dupont etching wash primer recommended for aluminum
(Corlar) which
has the option of chromate or not and is availible at your local auto parts
jobber (no
HAZMAT shipping issues). For the chromate version they specifically say
alodine/irridite
chromic conversion treatments are NOT required.
Hope this helps put more info in the hands of those that can use it.
Dave R.
klehman@albedo.net wrote:
Dave
FWIW my old can says "EP-420 Epoxy Chromate Primer". My brand new can says
simply "EP-420 Epoxy Primer". Sounds like something changed.
Ken
*-------------------------------------------------------------------------------
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*-------------------------------------------------------------------------------
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--
David A. Ricker P. Eng.
DARTEC Engineering Inc.
Fall River, Nova Scotia
Canada, B2T 1E8
ricker@dbis.ns.ca
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The Murphy Rebel Builders List is for the discussion
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David A. Ricker P. Eng.
DARTEC Engineering Inc.
Fall River, Nova Scotia
Canada, B2T 1E8
ricker@dbis.ns.ca
------------------------------------------
C/M Beck wrote:
Hello to all...Since MAM has discontinued shipping ProSeal and Polyfiber
Epoxy Zinc Chromate, I'm looking for an epoxy to use. Polyfiber makes no
mention of zinc chromate in their current description of "Epoxy Primer
EP-420. Has the product changed, or am I lookinmg at the wrong product?
Keeping this in mind...I've used Martin Senour Epoxy Primer-Sealer
#5120...it was available from lodal NAPA auto parts store for about
$42/gal. It is gray in color, needs activator #5123, and can be thinned
with lacquer thinner to give a smooth finish as a sealer/fogger, cleaning
the surfaces with #6879 prior to paint. Can be top-coated with urethane,
acryl. enamel...whatever. It is readily available to me locally, so no
Haz-Mat charges...and reasonably priced. I believe Dupont has similar
material available here also.
Would it be a mistake to substitue an automotive/marine epoxy like this for
the Polyfiber Epoxy?
Thanks..Charles Beck
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