SGS 1-23

"sanded" ???!!!!

As in sanded with a power sander? OR sanded by hand with sand paper?

Not good! You don't "sand" aluminum airplanes! (not the bare metal)

Metal airplanes are "stripped" using chemical strippers, or (sometimes) blasted with plastic bead media, or sometimes "soda blasted")

There are pros and cons to each method...and each needs to be done professionally.

"Sanding" ...puts scratches on the metal surface...scratches in aluminum can easily lead to cracks..structural damage.

Chemical stripping can leave chemicals in the seams, rivets, and other places it should not be....corrosion later.

Blasting media can be easily "over done" causing overheating of the surfaces, and warping...


Beyond that..preparation of aluminum for painting is a detailed, involved process. Done incorrectly, the paint will soon fail. Getting paint to adhere to aluminum is tricky

Usually you need to treat with "Alumaprep" which is a cleaner and "etcher" to get every last trace of dirt and oil off the aluminum. Next step is to apply Alodine solution. This is a "conversion coating"...which chemically changes the surface of the aluminum to a new compound, one which will allow the adherence of primer.

In the old days the primer of choice was zinc chromate... Durable, corrosion resistant, and good adhesion. Now hard to get...dangerous to use.

Many now use an AIRCRAFT type epoxy primer...also good adhesion. It is possible to find a "high build" primer, which can be LIGHTLY sanded between costs to smooth out problem areas. Do not sand into the metal though!

Top coat should be a polyurethane AIRCRAFT topcoat paint. Avoid automotive paints, although they may seem to be the same stuff...autos are typically made of steel, and are very stable. Airplanes are aluminum, are very bendy, flexible, and have many seams and rivets etc.

BTW..."typical automotive "base color coat /clear coat" jobs on airplanes look great for a while but the clear coat almost always fails and peels..

Polyurethane paint is highly toxic to the amateur painter...you need a full Tyvec suit, gloves, hood, tight fitting full face mask, and remote air supply.

For a brand name...Superflight...

But you can look at Aircraft spruce catalog and see other brands and SYSTEMS of painting aluminum airplanes.

Then...you may have to pre-weigh, and later mass balance the control surfaces...Whole airplane will need new W&B...Log book sign off by A&P...


Yes, you CAN do a quality DIY airplane paint job...homebuilder so it all the time....but it is not so easy to do it right...

A "professional" job is very expensive (you get what you pay for)...but done properly it has to be expensive...well worth the money IMHO.


Cookie

PS....the above is based on my personal experience...having built and painted two airplanes, and having painted and restored a bunch more.

Be ready for some arguments...for every different painter, you will get a different set of advice!







On Friday, November 23, 2018 at 12:23:22 AM UTC-5, wrote:
We have our ship sanded and exposed metal primed
Have sprayer
Our painting skills are in “dangerous amateur�
category
We are committed to DIY
Suggestions on paint type and brand?