What do we know about topcoats?

captain_john · Post by **captain_john** » Sun Dec 12, 2004 5:22 pm

I gotta admit, I haven't done ANY research on top coats. I have at LEAST a few years before it becomes a concern. May as well see what the knowledge base has in store.

I understand we have Polyurethane, one step processes and two step (paint and clear coat) processes.

Feature / benefit matrix, please? Brands, methods and materials.

Anyone?

CJ

Snap · Post by **Snap** » Tue Dec 14, 2004 1:23 am

It seems to me that people that use the PPG type (is that the same as polyurethane?) seem to get great results. I dont know how difficult it is to do but good is good.

Reheat · Post by **Reheat** » Thu Dec 16, 2004 10:14 am

I find this subject confusing too. There are lots of aluminum airplanes out there with zero paint on them (American Airlines comes to mind as well as a few RV's I have seen). So... what if ya just wanted to leave it in primer? Seems a few folks have done that for a while during testing phase and even up to a year or so while figuring out what paint scheme to use. I want a WWII scheme (olive drab with a light grey bottom) and have primers that closely match what I want. In the interest of weight and simplicity... wonder if I could just use the primers???

Post by **Spike** » Thu Dec 16, 2004 2:11 pm

Hmm, my opinion on this might not be of much help to you but frankly Im going to pay someone who does know about top coats. The paint job can make or break and airplane and I'm happy to announce that I know I cant handle that task. That was one area where I wasnt blessed with a cocky streak thank the Lord.

You guys who paint your own are better than I.

-- John

captain_john · Post by **captain_john** » Thu Dec 16, 2004 9:52 pm

I don't see any reason why you can't leave the plane primer. It isn't my choice, but that is why they make chocolate and vanilla.

I do plan on painting it myself... along with the auto body instructor at school!

What a great place to work! Talk about resources!

CJ

mustang · Post by **mustang** » Sun Jan 02, 2005 4:16 am

You don't really want to leave your plane in primer. Nor do you want to fly it before you paint it. Both of these practices are bad for finish coating your aircraft. When you fly, a fine mist of oil will coat your airplane's belly and further back on to the tail feathers. The oil will creep into the rivet dimples and your finish coat paint will lift, over, and around the rivets that got oil soaked. Likewise, when you fly in primer, the oil will soak into the primer which has a "grippy" porous surface that loves to be coated. Once the primer is coated with oil however, the finish coat will not stick the way it is intended, no matter how much you clean off the oil. Best to clean, prime, and then paint within 24 hours for the best job. Then fly it. The weight and balance should be re-done after painting if you did it earlier to fly, another reason to paint first, fly later.
Cheers, Pete

captain_john · Post by **captain_john** » Sun Jan 02, 2005 7:42 am

I am leaning towards painting first, piece by piece. Reason being, I can bring each part to school individually over the summer and do it in the paint booth. For me, this is at least a couple of summers away.

They say Imron is not really used much anymore, but is a good choice for airplanes. Anyone have an opinion?

CJ

Dan A · Post by **Dan A** » Sun Jan 02, 2005 12:33 pm

Any idea of the shelf life of Imron? I have a couple gallons of Imron clear coat I might be using but it's been on the shelf about 7 years.
Dan

captain_john · Post by **captain_john** » Sun Jan 02, 2005 7:16 pm

Good, question!

I am guesing that if t has been stored in a stable environment and looks "appliable" it is pobably good! By that I mean, not skinned and even in texture and consistency.

Just a guess. I am not a bodyman... at least not yet, anyhowwww!

CJ

captain_john · Post by **captain_john** » Tue Jan 04, 2005 5:47 pm

I just learned that we have "Single Stage" and "Two Stage" top coats.

The single stage lacks the "mile deep" appearance, but is easier to apply. It costs less as well.

The two stage is a tined base coat and a clear top coat for protection and gloss. It also "activates" with the top coat to make a very LUSTROUS finish.

I am thinking single stage is for me.

They say DuPont Imron used to be the preferred coat, but there is a new PPG product on the market that costs less and is supposed to be somehow better.

I will let you in on anything else I learn.

CJ

mustang · Post by **mustang** » Wed Jan 05, 2005 2:24 am

Yes,
The clearcoat over basecoat looks really good and that is the way most cars are painted today. However, when it comes to repair or touchup, the single coat is way easier. Also, the basecoat/clearcoat is heavier than the single stage paint. I intend to use acrylic enamel which is relatively cheap, easy to apply, very durable and will last a long time. We will paint our own aircraft.

I got to practice on our Citabria last Spring and it turned out great. I used a Dupont line of acrylic called NASON and it was very easy to spray. I painted it outside for the most part and it turned out pretty good. I painted it section by section. Just a few bugs came to visit afterward. The Nason kicked off in about 20 minutes outside in the sunshine even though the temp was only 65. The NASON went over old, sanded, unknown enamel on fabric, over repaired fiberglass cowlings lightly primed, over alodined and primed aluminum, (spinner) and over silver dope on new fabric on a repaired stab. It seemed to work over all of the substrates and I used a flex additive over the new, silvered fabric. The RV will be painted inside!

There is nothing wrong with Imron or Polyurethane paints but our airplanes will be hangared so the best of the best is not mandatory. Consider that our airplanes will spend most of their lives inside.

It's up to you
Cheers, Pete

captain_john · Post by **captain_john** » Wed Jan 05, 2005 6:52 am

YES, I am familiar with the DuPont NASON product. In fact, when I run out of VariPrime, I am considering the NASON Self Etch primer alternative there as well! I am glad to hear that you liked the application process of the acrylic enamel. Please let me know how the acrylic animal holds up!

I talked to the Auto Body instructor at school yesterday. As it stands right now, I am planning on painting the assembled pieces in the spray booth and then trucking them to KPYM for assembly. The acrylic enamel is probably the best choice for that system as the parts will likely need touch up after final positioning at the airport.

Looking forward to it!

CJ