Alodyning skins and large sheets

Anybody have any favorite techniques for doing big pieces? I've not been
able to find any alodyne tanks locally, and I've only got a gallon each
of aluminum cleaner (phosphoric acid) and alodyne. The option is to use
a self-etching primer on the inside.

Ed Wischmeyer
RV-10

"Ed Wischmeyer" wrote in message
...
Anybody have any favorite techniques for doing big pieces? I've not been
able to find any alodyne tanks locally, and I've only got a gallon each
of aluminum cleaner (phosphoric acid) and alodyne. The option is to use
a self-etching primer on the inside.

I went with PPG DX-1791/1792 self etching primer. It is chromated (i.e. good
stuff) and can kill you if you try hard enough. I love that stuff.

I went with PPG DX-1791/1792 self etching primer. It is chromated (i.e. good
stuff) and can kill you if you try hard enough. I love that stuff.

I've got some self-etching primer (two kinds, actually), but I'm trying
to figure out a tidy way to alodyne.

thanks, though

Ed Wischmeyer

Kiddies wading pool, rubber gloves, and a scotchbrite pad.

Rip

Ed Wischmeyer wrote:
Anybody have any favorite techniques for doing big pieces? I've not been
able to find any alodyne tanks locally, and I've only got a gallon each
of aluminum cleaner (phosphoric acid) and alodyne. The option is to use
a self-etching primer on the inside.

Ed Wischmeyer
RV-10

I'm trying to figure out the "priming problem."

I took the SportAir course on RV assembly and it is well worth the time &
money. It's intended to get us beginners ready to build an empenage.
Priming was briefly outlined, as follows......
1- pull the plastic & clean the metal w/ MEK
2- use Alumiprep #32
3- use Alodine #1201
4- use AKZO fast drying interior epoxy primer (that's what it's called in
Aircraft Spruce catalog at $111 for the 2 gal kit and $50 for the thinner)
Oh, and don't breath any of this stuff or get it on your skin..... or you
will die a horrible death.

Does "interior epoxy primer" mean you shouldn't use it on the exterior?.....
seems like a fine distinction when dunking a part in a tub.

Then reading "Aircraft Painting & Finishing" (Jeppesen) one learns that 2
part "epoxy primer is the most popular for use under polyurethane finishes
and where max. corrosion protection is required."
Also,
"Zinc chromate is still a good primer as far as corrosion resistance is
concerned, but it is inferior to the others with regard to adhesion.........
it can be effectively sprayed over a surface which as been properly treated
with a conversion coating such as Alodine..... the Alodine provides for the
adhesion."

Both sources say.... "well, there's rattle cans and then there's the best
way."

I emailed Van's and asked if the QB kit comes primed and if so, with what
.......... so far, no response.

Then I called SportAir inquiring about their course in painting. It's only
offered in Griffin, GA, and not this year.

So, it seems the choice is A) the inconvenient 2 part epoxy system or B)
second rate rattle cans.

I figure that whatever they do for the QB program should be good enough for
the empenage...... right?????

Also, does one have to drill, cleco, de-burr, etc, etc. and then prime, and
then re-fit all the parts before finally driving rivets?????

See the problem??? .... the priming part of the equation sound like a real
fun-killer.






"Ed Wischmeyer" wrote in message
...
Anybody have any favorite techniques for doing big pieces? I've not been
able to find any alodyne tanks locally, and I've only got a gallon each
of aluminum cleaner (phosphoric acid) and alodyne. The option is to use
a self-etching primer on the inside.

Ed Wischmeyer
RV-10

"larsen-tools" wrote in message
news:xbgRb.4176$F15.1350@fed1read06...
I'm trying to figure out the "priming problem."

I took the SportAir course on RV assembly and it is well worth the time &
money. It's intended to get us beginners ready to build an empenage.
Priming was briefly outlined, as follows......
1- pull the plastic & clean the metal w/ MEK
2- use Alumiprep #32
3- use Alodine #1201
4- use AKZO fast drying interior epoxy primer (that's what it's called in
Aircraft Spruce catalog at $111 for the 2 gal kit and $50 for the thinner)
Oh, and don't breath any of this stuff or get it on your skin..... or you
will die a horrible death.


Alodine for an RV skin is probably overkill because the skins are already
coated with a thin layer of pure aluminum, which is in itself a hedge
against corrosion. Schumacher and Annick built their RV-8 on the teevy
without Alodine, which being hexavalent chromium is nasty toxic stuff. (See
Erin Brockovich for details.) I use Alodine, but not on Alclad.

"larsen-tools" wrote in message
news:xbgRb.4176$F15.1350@fed1read06...

I'm trying to figure out the "priming problem."

2- use Alumiprep #32
3- use Alodine #1201


In my neck of the woods, alumiprep and alodine are problems - not easy to
dispose of and I live near a stream and I do not want this stuff anywhere
near the town water supply. So, cleanup is the problem. This is what I use
as an alternative:

1. Wipe clean with rag and a spray bottle with PPG DX-330
2. Scuff with 3M pads
3. Clean again with rag and PPG DX-330
4. Spray a light coat of PPG DX-1791/1792
5. For steel parts I'll also lay out some PPG DL-LF epoxy primer on top of
the DX-1791/1792.

That way, cleanup is limited to whatver is left in the pot and is easily
contained.

Forget about getting a clear answer from anyone regarding primer. You're on
your own unfortunately - there is no right or wrong way to do it, although
there are better or worse ways. With benefits and disadvantages. You'll get
the picture the more you dig into this subject... just do whatever suits
your concience and circumstances.

I think the only sure thing about this topic is that steel MUST have some
sort of corrosion protection. All else is a choice.

Forgot to mention that the fist step is to wash with soap and water.

"rds" wrote in message
news:wOhRb.157783$xy6.755890@attbi_s02...
"larsen-tools" wrote in message
news:xbgRb.4176$F15.1350@fed1read06...

I'm trying to figure out the "priming problem."

2- use Alumiprep #32
3- use Alodine #1201


In my neck of the woods, alumiprep and alodine are problems - not easy to
dispose of and I live near a stream and I do not want this stuff anywhere
near the town water supply. So, cleanup is the problem. This is what I use
as an alternative:

1. Wipe clean with rag and a spray bottle with PPG DX-330
2. Scuff with 3M pads
3. Clean again with rag and PPG DX-330
4. Spray a light coat of PPG DX-1791/1792
5. For steel parts I'll also lay out some PPG DL-LF epoxy primer on top of
the DX-1791/1792.

That way, cleanup is limited to whatver is left in the pot and is easily
contained.

Forget about getting a clear answer from anyone regarding primer. You're
on
your own unfortunately - there is no right or wrong way to do it, although
there are better or worse ways. With benefits and disadvantages. You'll
get
the picture the more you dig into this subject... just do whatever suits
your concience and circumstances.

I think the only sure thing about this topic is that steel MUST have some
sort of corrosion protection. All else is a choice.

Check out his site - very good, easy to use, and tough as nails!

http://www.aircraftfinishing.com/metal-aircraft.htm

Folks, the question is not about alternatives to alodyne, or about
primers -- it is how to alodyne large sheets without having huge
quantities of chemical!!

Ed Wischmeyer