Alodyning skins and large sheets

[Ed Wischmeyer]

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

[RS]

"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.

[Ed Wischmeyer]

> 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

[rip]

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

[larsen-tools]

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

[jls]

"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.

[rds]

"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.

[rds]

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.
>
>

[Shelly]

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

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

[Ed Wischmeyer]

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

[Orval Fairbairn]

In article >,
Ed Wischmeyer > wrote:

> 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!!

Unfortunately, IMHO, there is no alternative. As you know, Ed, I had an
alodyne tank setup in CA, which I made up, using a lye solution for etch
and a companion tank for the alodyne.

I got the lye from the supermarket and the alodyne powder from a plater.
For best reaults, the lye should be at 120 dg f. Etch for 5 minutes,
wash, alodyne for 10 min., wash.

[jls]

"Ed Wischmeyer" > wrote in message
...
> 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

Use a brush and brush it on warm. Say 80-90 degrees F. Use Iridite.
It's cheaper.

[Veeduber]

>
>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

----------------------------------------------------------

Dear Ed,

I think it will take about two gallos of each.

The process involves plastic or epoxy-coated rain guttering as a lower trough,
a series of spray nozzles & black plastic tubing along the upper edge, a
submersible pump, two or three A-frames to support the rain gutter and some
5-mil plastic sheet. The rear plastic panel is fixed in place, the front part
is suspended like a curtain, hangs into the rain gutter.

You do one side at a time.

Lift/raise the curtain, put the panel or sheet into the trough, lower the
curtain & tuck it in then turn on the pump.

Depending on temperature and the flow-rate of the pump (and output of the
nozzles... measure the 'out-fall' where the rain gutter delivers the solution
back to the sump), average time per side was about 4 minutes.

Water-rinse is done with a HOSE. Just get the plastic out of there, divert the
out-fall and walk down the length of the panel, blasting away.

----------------------------------------------------

It isn't very hi-tek and if doing 4x12's it helps if you make up some handling
frames -- things with those vacuum cups for working with glass -- that will
allow you to position & flip a panel without chopping off your foot.

The idea is to protect the metal quickly and at least cost, usually because it
will have to go into outside storage. This method is sorta gross but it works.

You can salvage the spray heads & tubing if you wish, use it in your garden.
The pump is usually trashed after pumping phosphoric for a couple of hours (but
maybe not... had a little all-plastic thingee that didn't seem to mind the
chemicals at all).

This isn't a new idea, other than the addition of the pump & sprayers. They
used to use a rack like this at NAS North Island, couple of guys, all suited up
in rubber boots & aprons, scrubbing down panels with big fuzzy brushes. The
gutter was a piece of black sewer pipe cut in half, sloped so they could
recover/reuse most of their solution. Seemed like a good idea.

-R.S.Hoover

[Cy Galley]

Might use a pump up type garden sprayer. All you want to do is keep it wet
for several minutes.

"Veeduber" > 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
>
> ----------------------------------------------------------
>
> Dear Ed,
>
> I think it will take about two gallos of each.
>
> The process involves plastic or epoxy-coated rain guttering as a lower
trough,
> a series of spray nozzles & black plastic tubing along the upper edge, a
> submersible pump, two or three A-frames to support the rain gutter and
some
> 5-mil plastic sheet. The rear plastic panel is fixed in place, the front
part
> is suspended like a curtain, hangs into the rain gutter.
>
> You do one side at a time.
>
> Lift/raise the curtain, put the panel or sheet into the trough, lower the
> curtain & tuck it in then turn on the pump.
>
> Depending on temperature and the flow-rate of the pump (and output of the
> nozzles... measure the 'out-fall' where the rain gutter delivers the
solution
> back to the sump), average time per side was about 4 minutes.
>
> Water-rinse is done with a HOSE. Just get the plastic out of there,
divert the
> out-fall and walk down the length of the panel, blasting away.
>
> ----------------------------------------------------
>
> It isn't very hi-tek and if doing 4x12's it helps if you make up some
handling
> frames -- things with those vacuum cups for working with glass -- that
will
> allow you to position & flip a panel without chopping off your foot.
>
> The idea is to protect the metal quickly and at least cost, usually
because it
> will have to go into outside storage. This method is sorta gross but it
works.
>
> You can salvage the spray heads & tubing if you wish, use it in your
garden.
> The pump is usually trashed after pumping phosphoric for a couple of hours
(but
> maybe not... had a little all-plastic thingee that didn't seem to mind the
> chemicals at all).
>
> This isn't a new idea, other than the addition of the pump & sprayers.
They
> used to use a rack like this at NAS North Island, couple of guys, all
suited up
> in rubber boots & aprons, scrubbing down panels with big fuzzy brushes.
The
> gutter was a piece of black sewer pipe cut in half, sloped so they could
> recover/reuse most of their solution. Seemed like a good idea.
>
> -R.S.Hoover

[Cy Galley]

Might use a pump up type sprayer. All you want to do is keep the surface wet
with Alodine for 5 to 10 minutes. You could even have it horizontal and do
one side at a time.

"Veeduber" > 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
>
> ----------------------------------------------------------
>
> Dear Ed,
>
> I think it will take about two gallos of each.
>
> The process involves plastic or epoxy-coated rain guttering as a lower
trough,
> a series of spray nozzles & black plastic tubing along the upper edge, a
> submersible pump, two or three A-frames to support the rain gutter and
some
> 5-mil plastic sheet. The rear plastic panel is fixed in place, the front
part
> is suspended like a curtain, hangs into the rain gutter.
>
> You do one side at a time.
>
> Lift/raise the curtain, put the panel or sheet into the trough, lower the
> curtain & tuck it in then turn on the pump.
>
> Depending on temperature and the flow-rate of the pump (and output of the
> nozzles... measure the 'out-fall' where the rain gutter delivers the
solution
> back to the sump), average time per side was about 4 minutes.
>
> Water-rinse is done with a HOSE. Just get the plastic out of there,
divert the
> out-fall and walk down the length of the panel, blasting away.
>
> ----------------------------------------------------
>
> It isn't very hi-tek and if doing 4x12's it helps if you make up some
handling
> frames -- things with those vacuum cups for working with glass -- that
will
> allow you to position & flip a panel without chopping off your foot.
>
> The idea is to protect the metal quickly and at least cost, usually
because it
> will have to go into outside storage. This method is sorta gross but it
works.
>
> You can salvage the spray heads & tubing if you wish, use it in your
garden.
> The pump is usually trashed after pumping phosphoric for a couple of hours
(but
> maybe not... had a little all-plastic thingee that didn't seem to mind the
> chemicals at all).
>
> This isn't a new idea, other than the addition of the pump & sprayers.
They
> used to use a rack like this at NAS North Island, couple of guys, all
suited up
> in rubber boots & aprons, scrubbing down panels with big fuzzy brushes.
The
> gutter was a piece of black sewer pipe cut in half, sloped so they could
> recover/reuse most of their solution. Seemed like a good idea.
>
> -R.S.Hoover

[Ed Wischmeyer]

> Might use a pump up type sprayer. All you want to do is keep the surface wet
> with Alodine for 5 to 10 minutes. You could even have it horizontal and do
> one side at a time.
>
> > The process involves plastic or epoxy-coated rain guttering as a lower
> trough,
> > a series of spray nozzles & black plastic tubing along the upper edge, a
> > submersible pump, two or three A-frames to support the rain gutter and

thank to both!

Ed

[O-ring Seals]

On Wed, 28 Jan 2004 01:32:55 GMT, Orval Fairbairn
> wrote:

>In article >,
> Ed Wischmeyer > wrote:
>
>> 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!!
>
>Unfortunately, IMHO, there is no alternative. As you know, Ed, I had an
>alodyne tank setup in CA, which I made up, using a lye solution for etch
>and a companion tank for the alodyne.
>
>I got the lye from the supermarket and the alodyne powder from a plater.
>For best reaults, the lye should be at 120 dg f. Etch for 5 minutes,
>wash, alodyne for 10 min., wash.

Using lye ( sodium hydroxide ) for an etch is a disasterous choice.
The treatment you describe will more than remove all of the alclad
from the sheet and leave you worse off than when you started.

O-ring

[John Ammeter]

On Sun, 01 Feb 2004 20:17:56 GMT,
(O-ring Seals) wrote:

>On Wed, 28 Jan 2004 01:32:55 GMT, Orval Fairbairn
> wrote:
>
>>In article >,
>> Ed Wischmeyer > wrote:
>>
>>> 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!!
>>
>>Unfortunately, IMHO, there is no alternative. As you know, Ed, I had an
>>alodyne tank setup in CA, which I made up, using a lye solution for etch
>>and a companion tank for the alodyne.
>>
>>I got the lye from the supermarket and the alodyne powder from a plater.
>>For best reaults, the lye should be at 120 dg f. Etch for 5 minutes,
>>wash, alodyne for 10 min., wash.
>
>Using lye ( sodium hydroxide ) for an etch is a disasterous choice.
>The treatment you describe will more than remove all of the alclad
>from the sheet and leave you worse off than when you started.
>
>O-ring

I'm reminded of the time a student in an automotive class
put his engine block in the caustic solution over the
weekend. It works great on a cast iron block. Removes all
the crud, paint, etc.

However, on Monday, when he opened the tank to remove his
block, all he found was a few bits and pieces plus the
cylinder liners.

Caustic solutions and aluminum are NOT a good mix. Even an
aluminum engine block can be "eaten away". Think what it
will do to a thin aluminum skin...

John

[Veeduber]

>
>Using lye ( sodium hydroxide ) for an etch is a disasterous choice.

---------------------------------------------

Not necessarily.

Not all aluminum is Alclad and sodium hydroxide has long been a standard for
surface preparation for aluminum. But as with heat treatment or re-forming, it
isn't an amateur sport :-)

-R.S.Hoover

[O-ring Seals]

On 02 Feb 2004 01:12:03 GMT, (Veeduber) wrote:

>>
>>Using lye ( sodium hydroxide ) for an etch is a disasterous choice.
>
>---------------------------------------------
>
>Not necessarily.
>
>Not all aluminum is Alclad and sodium hydroxide has long been a standard for
>surface preparation for aluminum. But as with heat treatment or re-forming, it
>isn't an amateur sport :-)
>
>-R.S.Hoover

Veedubber,

As a high school student, I filled baloons with hydrogen gas by
cutting up TV Dinner trays and dumping them into lye water and piping
the gas into the baloons. The aluminum metal definitely goes away. I
stand by my statement, and Alclad was not the point.

Bob Seals
M.S. Chemistry

[Veeduber]

> The aluminum metal definitely goes away. I
>stand by my statement, and Alclad was not the point.
>
>Bob Seals
>M.S. Chemistry

-----------------------------------------------------

Dear Bob,

Of COURSE the aluminum goes away... if you use a strong enough solution or
leave it in the tank too long. But since you DID mention Alclad I think it's
fair for me to have assumed that WAS your point especially since lye has been
used as a surface treatment since Jeeter was pup. (Indeed, it is a REQUIRED
step for some finishes.)

-Bob Hoover (no, I'm the other one)
-Greasy Fingernails (and fifty years experience)

PS - you would have had better luck with your ballons if you'd used iron
filings and sulphuric acid... and yes, acid was -- and still is -- a standard
method of surface treatment for some metals. Visit a plating shop. Or an
aircraft factory :-)

[Daniel]

wrote...
> ...
> The process involves ... a submersible pump, ...
> The pump is usually trashed after pumping phosphoric
> for a couple of hours (but maybe not... had a little
> all-plastic thingee that didn't seem to mind the
> chemicals at all).
>

"Little Giant" brand pumps. They make hundreds of models. The
hardware stores carry the ones for water pumping (pool covers,
fountains, etc). Low cost, high quality. They also make a bunch for
chemical pumping at similar pricing. Used to order them on occasion
for customers back when I sold hardware.

Daniel

[Badwater Bill]

On 03 Feb 2004 02:37:17 GMT, (Veeduber) wrote:

>> The aluminum metal definitely goes away. I
>>stand by my statement, and Alclad was not the point.
>>
>>Bob Seals
>>M.S. Chemistry
>
>-----------------------------------------------------
>
>Dear Bob,
>
>Of COURSE the aluminum goes away... if you use a strong enough solution or
>leave it in the tank too long. But since you DID mention Alclad I think it's
>fair for me to have assumed that WAS your point especially since lye has been
>used as a surface treatment since Jeeter was pup. (Indeed, it is a REQUIRED
>step for some finishes.)
>
>-Bob Hoover (no, I'm the other one)
>-Greasy Fingernails (and fifty years experience)
>
>PS - you would have had better luck with your ballons if you'd used iron
>filings and sulphuric acid... and yes, acid was -- and still is -- a standard
>method of surface treatment for some metals. Visit a plating shop. Or an
>aircraft factory :-)


You are going to get Twyla ****ed off if you don't spell her name
correctly. It's pronounced Jeeter as in Jeep, but it's spelled
Geeter. Damn, I hope she isn't reading this group right now. Next
thing you know, she'll be after Tommy Cooper again for pulling Sally
Faukwash's undies down in the third grade.

BWB

[Badwater Bill]

>I'm reminded of the time a student in an automotive class
>put his engine block in the caustic solution over the
>weekend. It works great on a cast iron block. Removes all
>the crud, paint, etc.
>
>However, on Monday, when he opened the tank to remove his
>block, all he found was a few bits and pieces plus the
>cylinder liners.
>
>Caustic solutions and aluminum are NOT a good mix. Even an
>aluminum engine block can be "eaten away". Think what it
>will do to a thin aluminum skin...
>
>John

I think the worst thing many of us has seen is someone buffing away
the alodyne on an older airplane to shine it up. Once the alodyne is
gone, the shine doesn't last and the skin re-oxidizes deeper. It
corrodes the airplane away in short order.

BWB