MERCURY OUTBOARD PAINT ADVICE

·    Q: What would a
common procedure be to resurface a corrosion pitted marine motor outdrive
(mercury-aluminum out drive).  I
have heard that 2 part paints and epoxies have incredible adhesive properties
as well as corrosion resistance, but what would be recommended in this
application?

·    A: An epoxy primer
followed by a polyurethane topcoat is still my number one choice, but the real
issue is cleaning up the pits in the motor outdrive. Once the pits have been thoroughly
cleaned, your friend will need to immediately apply the epoxy primer. By
immediate, I mean within a few hours and not the following day. One method to
clean the pits and prepare the surface is by abrasive blasting with glass
beads. But your friend will probably need to take the drive to a ob shop to have this done. In the industrial world the
drive would probably be pretreated with a chromate conversion coating, but in
all likelihood your friend won't have access to this process, unless he/she is
willing to take the drive to a job shop that has the capabilities of pre-treating
aluminum. (Many job shops can blast clean the surface with glass beads and pre-treat
in a conversion coating).

The information
below is really about painting aluminum on small aircraft, but can be
applicable when painting anything, especially aluminum outboard motors.

Although I'm just a
60 year old hobbyist, my classic cars look quite good after I paint them. I
even win trophies occasionally. I use Sherwin Williams (SW) products
exclusively and spoke to the SW expert in Phoenix before I attacked my RV9A.
Here are his comments:

BARE ALUMINUM ON
RV9: This aluminum was coated with oil from the factory. God knows what other
stuff has landed on the surface since my QB traveled to/from Europe.

1) Use aluminum
cleaner – W4-K263 DUAL ETCH METAL CLEANER AND CONDITIONER - Mix w/water
50/50, 2-1 or 4-1 and use the 2 rag method. One rag to apply
cleaner, a separate rag to clean. I usually hose it off with clear water
and use red Scotchbright to apply.

Note that this
stuff really stinks and can cause serious respiratory problems. It contains
phosphoric acid which your nasal passages & brain will not appreciate so I
wear a forced air respirator which delivers air from the adjoining room.

When the liquid
cleaner stuff rolls off in sheets, you are done. Otherwise, repeat the process.

2) I used Scotchbright
during this process to also promote adhesion - wearing plastic gloves that
don't disintegrate from the W4-K263, I scrub the
surface with red Scotchbright.

Forget alodine.

3) After the parts
are dry, one hour before painting, wipe the parts with R7K156 cleaner. PPG
calls this stuff Prep Sol. Use one paper towel to apply and another to remove.
Move in one direction so what accumulates on the cleaner rag is not left behind
when your hand changes position.

R7K156 is used to
remove any final oils that can still be present. Don't ever touch the parts
with your bare hands. That leaves oil. Wear clean plastic gloves. This stuff
stinks too but I don't think it is as deadly as W4-K263.

4) After allowing
the R7K156 to dry (and then some) prime with E2G980 – 2 medium wets
coats, 2 min flash time between coats. There is a reducer (R7K981) that goes
with E2G980. Flows on beautifully. No runs, no sags,
(no hits).

5) Urethane paint
(I used this in the interior) – We used the Dimension line (cheaper) with
the appropriate hardener and reducer. Thus far, no matter how many things I
throw at my painted parts, I have not chipped the paint.

For the exterior of
the plane, I plan to use base coat and SW 7000 clear instead of urethane
otherwise the prep process is the same.

Buy yourself an
HVLP gun. The Sharp Finex 300 version can be
purchased for under $100. For primer, get the bigger tip and nozzle. The amount
of overspray is literally cut by more than half. U save lotsa
$$ and Mother Nature will thank you.

Make sure your
compressor has a water filter in line with the air else you'll blow water into
the paint. Ditto for an oil separator. Drain the tank
before starting.

Buy a good
regulator and position it at the gun (after the final, second, inline,
disposable air filter). Regulators can be purchased for $7 or $30. Guess which
one actually works when the compressor drops in pressure?

Don't even think about shopping at Harbor Freight.

Create a paint
booth environment that blows the fumes and overspray into a wet towel hanging
in the airstream so your neighbor's car sitting outside your window does not
come out green. Capture the overspray into the wet towel instead of asking
Mother Nature to ingest it.

Put in lots of
light cause if you're 55, you're going need it to "see the flow" your
Finex gun will apply to the surface. I'm 60 so I can
appreciate your desire to fly for 10 more years. Work with a test piece before
attacking the plane. I use a picture of my mother-in-law for test spray. Until
the fan and volume looks good, keep testing.

And convincing the
wife that you need a $600 forced air respirator is easy. Show her what chemo
costs.

I also watched the
video. His spray pattern was round instead of parallel to the item you're
painting. That's just dead nuts wrong. Your arm should be an extension of the
gun, maintaining an equal, perpendicular distance from the target at all times.

Squeeze the trigger
before the paint gun arrives at the piece. Release the trigger after you pass
over the entire piece. Never squeeze the trigger while over the target. He did
that a few times too. No matter how good the regulator, there
is a drop off when the trigger is squeezed.

Hope this helped.

Paint cost

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Painting's a huge
job. I'm curious: does it really save that much over a pro paint job? The materials
and equipment are so expensive, I think. I don't know. Maybe you can give an
estimate how much you save painting yourself?

Using Sherwin
Williams products, good stuff, I figure primer will be $500. My design scheme
calls for two colors and separator colors. Using base coat / clear coat I
expect to use two gallons of base (white and yellow which are less expensive
than red) & appropriate reducer ($800), plus two gallons of clear and
appropriate reducer/hardener $800.

Total = $2k
(approx) for materials and many hours taping because I plan a complex scheme.
If I color sand the clear, add another 200 hours. I'm old and slow.

One day should be
required to paint the fuse on a rotisserie, one day per wing (also on a
rotisserie), and one day for tail feathers. The shop is only 20x24 and I'd
rather spread the workload over 4 days than bump into wet parts.

This presupposes
you have the appropriate guns (a decent Sharpe hvlp
is $100, primer guns are cheap or get a large cap for your Sharp), 5 hp
compressor (or more), water separators ($70), regulator and good breathing
apparatus. A LOT of light, and a room that's properly
ventilated.

Don't scrimp on the
breathing equip. There are so many carcinogens in this stuff it's scary. Home
Depot masks just don't cut it. If you can smell, you're breathing it.

This also
presupposes you know how to paint. Of the many tasks involved in building a
plane (thus far we're half done), none requires the steady hand of a paint gun
and the feel of when paint is just wet enough to give you a good flow but not
too wet to run down the side of the panel.

Practice and read.

What would a pro
charge for base coat / clear coat? Yes, if you use single stage urethane you
can save approx $1000 but single stage is actually harder than base coat /
clear coat.

Self Etch Primers

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Don't go over an alodine piece with self etch primer. Think of it like
this...

Take a part and
acid etch it, then alodine it for Corrosion protection,
it does a surface conversion to the metal then prime it with a two part epoxy
primer.

Simple when doing a
small part, however think of a rudder skin, how are you going to dip it in alodine? True you can brush it on but what a hassle. This
is where you use a self etching primer to prevent the acid etch and alodine process. The self Etching primer has an acid in it
that will flash off when it drys but allows the
primer to bond to the metal but DOESN'T seal the metal from moisture,
you must go over it with a two part epoxy to seal the self etching primer. So
use self etching primer to avoid acid etching and alodine
but then prime with epoxy primer to seal.

There is a
comprehensive explanation on www.txrv10.com under knowledgebase, then select down
arrow and primers - or follow this link
http://www.txrv10.com/pages/primerpages/primermain.html

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

Don't go over an alodine piece with self etch primer. Think of it like
this...

Take a part and
acid etch it, then alodine it for Corrosion
protection, it does a surface conversion to the metal then prime it with a two
part epoxy primer.

Simple when doing a
small part, however think of a rudder skin, how are you going to dip it in alodine? True you can brush it on but what a hassle. This
is where you use a self etching primer to prevent the acid etch and alodine process. The self Etching primer has an acid in it
that will flash off when it dries but allows the primer to bond to the metal
but DOESN'T seal the metal from moisture, you must go
over it with a two part epoxy to seal the self etching primer. So use self
etching primer to avoid acid etching and alodine but
then prime over the self etching primer with epoxy primer to seal.

There is a
comprehensive explanation on www.txrv10.com under knowledgebase, then select
down arrow and primers. or follow this link
http://www.txrv10.com/pages/primerpages/primermain.html

WOW!
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I can't believe
this thread has been circling the drain for two years now. I am almost through
priming everything that needs priming and have learned a couple of things.
Sherwin Williams self etch (P-60) is plenty good enough for the insides of my
plane and for Van's quick builds for that matter. I used dish soap and hot
water with a red Scotchbright pad to clean all the surfaces that were primed.
Right before I sprayed the primer I wiped everything off with a cloth with a
little lacquer thinner on it then lightly went over the parts again with a tack
rag. The P-60 is fairly hard and doesn't soak up oils and grease like Vari-Prime does. I won't use that again.

I primed all the
interior pieces of the cabin area, like the floors and seat backs, and then top
coated them before installing them which looking back wasn't such a great idea.
There is no way to keep all those parts looking nice until the plane is ready
to fly. I should have used an Epoxy primer on the interior parts and let it go
at that until the plane was all but finished. They tell me you can lightly sand
the epoxy primer even six months later and seal then top coat it. It supposedly
doesn't draw moisture like normal primer dies. If I'm giving bad information
please correct me, but I've heard this from several sources.