For builders of Murphy Aircraft Manufacturing kits - Bringing builders together
https://www.murphybuilders.net/
be the only dreaded part of building as the rest goes pretty well.Hi All
Has anyone come up with an alternative to Zinc chromate primer. This has to
prettyThanks Murray Cherkas
REBEL 505
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content="text/html; charset=iso-8859-1" http-equiv=Content-Type>
<META content="MSHTML 5.00.2919.6307" name=GENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=#ffffff>
<DIV><FONT size=2>Hi All</FONT></DIV>
<DIV> </DIV>
<DIV><FONT size=2>Has anyone come up with an alternative to Zinc chromate
primer. This has to be the only dreaded part of building as the rest goes
well.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT size=2>Thanks Murray Cherkas</FONT></DIV>
<DIV><FONT size=2>REBEL 505</FONT></DIV></BODY></HTML>
requiredMurray
Sorry I couldn't get this out sooner, my ISP seems to be having problems.
The priming part should not be a big deal except for the time/setup
theirto apply the paint. We are doing our first wing and we are much less
enthused about doing the wet wing sealant routine!
For our Elite project we have chosen a Dupont product called Corlar 810R
which is a "filling wash primer". It is a simple 1:1 ratio, 2 part
material which contains chromate and also claims to etch the base material
(before it dries). There is a non-chromate version as well. I believe a
modern product like this is a good choice especially compared to the old
zinc chromates of the past. It can be had at your local automotive body
shop supplier like UAP/NAPA, we apply it using a decent retail store
(non-bleeder) spray gun.
I contacted Dupont for their recommendation on materials and this was
windowchoice for the application. It is also used by an aircraft painting shop
not far from me so I am confident it will be acceptable. For top coating,
like on the outside of the aircraft, it should be followed by Dupont
1044R high solids primer and Imron (the polyurethane topcoat). As Bob has
reminded us always stick with a unified paint system from a single
manufacturer to avoid incompatability problems.
If you use this material and these days many paint systems, you MUST use a
fresh air system as the typical (carbon) filter mask will not remove
dangerous vapors (isocyanates etc.) from the air. I have a full face
typetype of "helmet" which is excelent for those like me who wear
glasses. I built a fresh air blower for very few $ using a central vac
techblower and the plywood from one of the shipping crates, you can see it
at our project site (www.elite583.cjb.net) under Other Details.
We have a differing opinion from MAM about the Polyfibre material shipped
with the kits, it is not a chromate and it does not etch the base
material like the Corlar and we do not subscribe to the apply wet & use it
as an adhesive for a couple of reasons. There is no guarantee that the
material will still be wet when you have painted all the mating surfaces
when you assemble something (like a wing we are working on right now)
and I have some doubt that the paint will remain stuck even after it dries
given that the parts will flex to some extent during their life. If I was
designing a structure like an airplane I would be conservative and NOT
depend on the "untrained" builder to achieve a good bond with the paint
so I would design the plane as if it was not there and any gain would be a
bonus. I would expect MAM followed this approach since for example
the riveted joints are "overdesigned" to account for "untrained" builder
errors.
I also prefer to follow the practise of Cessna who, according to their
impactrep. whom I spoke with, paint the parts prior to assembly. We dip the
rivets in Corlar prior to installing them as well.
I know I am taking an approach different from what Bob P. & the factory
recommends but since we are homebuilding for the "purpose of
learning by experimentation" (EAA) we will not always make the same
decisions and your decision must be made by weighing all of the
information you have available and deciding what is right for you. Our
location close to the ocean and possibility of going on floats had an
primer.in our choices.
Hope this hasn't added to the confusion!
Cheers
Dave R.
Francine D.
Elite583.cjb.net
Murray & Carol wrote:
Hi All Has anyone come up with an alternative to Zinc chromate
This has to be the only dreaded part of building as the rest goes pretty
well.Thanks
Murray CherkasREBEL 505
--
David A. Ricker P. Eng.
DARTEC Engineering Inc.
Fall River, Nova Scotia
Canada
_________________________________________________________________
Get a speedy connection with MSN Broadband. Join now!
http://resourcecenter.msn.com/access/pl ... vation.asp
Hello BOB
No problem with the primer. My concern is that it is so toxic. Thanks for
the info on using the right primer for the paint being used. And yes I did
use Endura over the zinc chromate primer on the inside of the fuselodge. On
the outside I am using RM brand with their primer .
I hope that the poyfibre epoxy primer you suggested is more people friendly.
As I am thinking of building another airplane, if there isn't a viable
alternative to the zinc ch. I will have second thoughts as to whether or
not to start a new project.
Thanks for all your help to myself and all the rest of us.
requiredMurray
Sorry I couldn't get this out sooner, my ISP seems to be having problems.
The priming part should not be a big deal except for the time/setup
theirto apply the paint. We are doing our first wing and we are much less
enthused about doing the wet wing sealant routine!
For our Elite project we have chosen a Dupont product called Corlar 810R
which is a "filling wash primer". It is a simple 1:1 ratio, 2 part
material which contains chromate and also claims to etch the base material
(before it dries). There is a non-chromate version as well. I believe a
modern product like this is a good choice especially compared to the old
zinc chromates of the past. It can be had at your local automotive body
shop supplier like UAP/NAPA, we apply it using a decent retail store
(non-bleeder) spray gun.
I contacted Dupont for their recommendation on materials and this was
windowchoice for the application. It is also used by an aircraft painting shop
not far from me so I am confident it will be acceptable. For top coating,
like on the outside of the aircraft, it should be followed by Dupont
1044R high solids primer and Imron (the polyurethane topcoat). As Bob has
reminded us always stick with a unified paint system from a single
manufacturer to avoid incompatability problems.
If you use this material and these days many paint systems, you MUST use a
fresh air system as the typical (carbon) filter mask will not remove
dangerous vapors (isocyanates etc.) from the air. I have a full face
typetype of "helmet" which is excelent for those like me who wear
glasses. I built a fresh air blower for very few $ using a central vac
techblower and the plywood from one of the shipping crates, you can see it
at our project site (www.elite583.cjb.net) under Other Details.
We have a differing opinion from MAM about the Polyfibre material shipped
with the kits, it is not a chromate and it does not etch the base
material like the Corlar and we do not subscribe to the apply wet & use it
as an adhesive for a couple of reasons. There is no guarantee that the
material will still be wet when you have painted all the mating surfaces
when you assemble something (like a wing we are working on right now)
and I have some doubt that the paint will remain stuck even after it dries
given that the parts will flex to some extent during their life. If I was
designing a structure like an airplane I would be conservative and NOT
depend on the "untrained" builder to achieve a good bond with the paint
so I would design the plane as if it was not there and any gain would be a
bonus. I would expect MAM followed this approach since for example
the riveted joints are "overdesigned" to account for "untrained" builder
errors.
I also prefer to follow the practise of Cessna who, according to their
impactrep. whom I spoke with, paint the parts prior to assembly. We dip the
rivets in Corlar prior to installing them as well.
I know I am taking an approach different from what Bob P. & the factory
recommends but since we are homebuilding for the "purpose of
learning by experimentation" (EAA) we will not always make the same
decisions and your decision must be made by weighing all of the
information you have available and deciding what is right for you. Our
location close to the ocean and possibility of going on floats had an
primer.in our choices.
Hope this hasn't added to the confusion!
Cheers
Dave R.
Francine D.
Elite583.cjb.net
Murray & Carol wrote:
Hi All Has anyone come up with an alternative to Zinc chromate
This has to be the only dreaded part of building as the rest goes pretty
well.Thanks
Murray CherkasREBEL 505
--
David A. Ricker P. Eng.
DARTEC Engineering Inc.
Fall River, Nova Scotia
Canada
Hello BOB
No problem with the primer. My concern is that it is so toxic. Thanks for
the info on using the right primer for the paint being used. And yes I did
use Endura over the zinc chromate primer on the inside of the fuselodge. On
the outside I am using RM brand with their primer .
I hope that the poyfibre epoxy primer you suggested is more people friendly.
As I am thinking of building another airplane, if there isn't a viable
alternative to the zinc ch. I will have second thoughts as to whether or
not to start a new project.
Thanks for all your help to myself and all the rest of us.
Murray Cherkas
REBEL 505
*-------------------------------------------------------------------------*
To unsubscribe go to http://www.dcsol.com:81/public/listserv.htm
Archives located at http://rebel:builder@www.dcsol.com:81/default.htm
To contact the list admin, e-mail mike.davis@dcsol.com
*-------------------------------------------------------------------------*