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Permalink Reply by Chris Aysen on July 3, 2013 at 7:09am

For paint to stick to aluminum the surface must be etched. Even though it is a stol aircraft and you're not a picky guy; done wrong the paint will peel in just a few months. I used the Poly Fiber Aircraft Coatings system (Aero Thane) with a their EP-420 epoxy primer. I'm not saying this is the best product but mine has no signs of peeling and it spent its first year of its 4 year life outside. Most paint suppliers recommend their own primers but if you know what you're doing you can use other primers. With all that said as you know surface prep and etching is very very important. I believe you can get it done for about $1500 may be less. NO LATEX PAINT and make double sure the surface, including between mating parts, is COMPLETELY dry before shooting any coating. My two cents. Best of Luck.

Chris

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Permalink Reply by Alan Uhr on July 3, 2013 at 1:53pm

Christopher,

I am now due for a 3rd paint job in 3 years. Do it right the 1st time. I didn't. I used alumiprep to wash the plane down with. At Harbor Frieght they sell a scotch bright ball that goes into a high speed drill. I used the medium but you can probably use the fine. The idea is to lightly scuff up the aluminum. These 2 steps took me a few hours without killing myself. Ise primer for aluminum or you will be painting again within the 1st year. Spray can primer is OK but is expensive. After the primer, use the best paint you can afford. I did not and am paying the price. Also, make sure that your pressure is correct for the paint you are using. What I used called for 50lbs. I set 50lbs at the air compresser but by the time it reaches the gun it will probably something like 30-40lbs. That will lead to instant orange peal.

 

Alan

 

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Permalink Reply by Jim B Belcher on July 3, 2013 at 4:39pm

I used ACME FP301 primter/etcher, 4th Dimension color coats, and ACME FC720 clear coat. I used about a gallon of primer, 2 gallons of color coat, and a gallon of clear coat, all on my 601XLB. Different hardeners were used with each product.

Total cost was in the $500-600 range. I have no idea where this stuff is carried around the country, but I got mine from an auto paint supply in Odessa, Texas.

I cleaned the aircraft surface thoroughly before I painted, and I've had no problems due to the paint. Now, if I could just learn to keep from dinging things myself, this paint job would last a long time!

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Permalink Reply by John Austin on July 3, 2013 at 6:06pm

My painter used Presta "Scuff Stuff" to scuff the surfaces. It goes on like a rubbing compound and the paste-like consistency made it easy to work it right around the rivets, then it rinsed off easily with water. He said it really made the scuff much easier and thorough.

John

N750A

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Permalink Reply by Jon Crew on July 3, 2013 at 9:09pm

With all the research I did before I painted my previous plane, I found that metal prep was #1, a quality primer was 1, and the finish coat was #2.  That said, use a maroon scotch brite pad with dawn detergent, an alkaline based detergent, and scrub it down good.  Use warm water to rinse if available.  Prep with what the military uses, PREKOTE,  it makes the paint job last 2/3rds longer  than acid/alodine when using prekote.  About a half gallon will do the whole plane.  Again, follow the directions, don't let it dry and rinse with warm, non hard water, then let it air dry. Prime within 12 hours.

 

Primer used can be a host of things,  in the past epoxy primers were king but with the new chemistry, the pure urethane primers matched with you topcoat should be used.  Not automotive paint!  that is acrylic-urethane which will show cracks at seems after years of expansion and contraction.  So I have been told by airplane painters with many years of experience.  That is why all the airlines do not use automotive paint!  They use industrial finishes, which airplane paints are classified under, that are pure urethane.

 

Top coats:  Your color will determine the number of coats and weight.  A one stage will give you a nice finish with the least weight.  You will always have some orange peel with the paints just like you see on the most expensive showroom cars.  Subtle but there.

 

Now for the cost of paints.  You can buy cheap, and you can buy what you think is expensive.  How much solids is partly what determines the cost.  The less the solids, the more coats you need and the cheaper the paint.  I have seen where you can get a gallon of paint with catalyst and thinner for 125.00.  I have also seen the same stuff in top of the line go for 1000.00.  depending on color.  For instance, Dupont, sherwin williams, basf, ppg, and a few others, make two to three lines of paint from bargan basement to top of the line, and that is for automotive paint.  Industrial paint for which airplane paint is classified under has fewer options and product lines.  I honestly think that for most of us, after the first scratch, the auto paint would work reasonbly well, but for my first plane I went with quality urethane and the results look like a highly polished onyx rock.  Super smooth and the depth is better than the best pearl coat you have seen.  But it cost.  On my 750 which I am almost ready to paint, I will probably go with a one step paint to reduce weight and work.  Its only a stol plane for heavens sake.  The skins of the plane would probably look worse with a super paint job. 

 

Matrix makes a one step urethane that finishes well and is reasonble in cost. 

I saw a red sonex painted with this and it won best kit plane at several flyins. 

If you have one of the better Harbor Freight HVLP guns, then you need to run about 50 psi at the beginning of the hose and about 25-32 psi at the regulator at the gun, that will give you the proper cap pressure.  Do a test panel first.  There is a sequence to adjusting the gun properly, but once done, you can do the same job as most of the 200 dollar guns that sell elsewhere and not much worse than a sata. 

 

You can find as many opinions on paint and primers as you can on Obama Care, ha ha, but the bottom line is that prep is the most important, and after all that work, do yo want to skimp on a 100-200 dollar cheaper primer and top coat?  I can bet you that you would gladly give someone 500 bucks to strip it down so you can start over if you could find someone!

Jon

 

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Permalink Reply by Jon Crew on July 3, 2013 at 9:57pm

OH, and if you want to do it supppper cheap.  Go to Napa auto parts on the second saturday of the month, that is there super sidewalk sale day. save up to 3/4 depending on item.  buy two cases of dupla acid etch primer, and three cases of their seymore auto paint in a spray can.  About 2/5th of retail.  Wash the plane as described, spray, spray spray.  A good finger can do a good job with a rattle can, and you can paint the plane for a few hundred bucks.  And it will hold up somewhat, and when it starts to fail, just sand and repaint in the failing spots.  I did that hatch back of my grand cherokee limited with this technique, custom paint which was put in spray cans, and I used a clear for final,  Looks like the rest of the car after 6 years.  still sticking and even with a licking, for all you timex users out there.

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Permalink Reply by Christopher Braun on July 4, 2013 at 6:03pm

Is it safe to say that once you clean and scotchbrite, that almost any alum etching primer from any source is fine. I want to go ahead and prime, and then decide on topcoat later

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Permalink Reply by Bob Pustell on July 8, 2013 at 6:56pm

You are, generally speaking, better off using a primer made by the maker of your topcoat. At the very least, make sure it is a primer that is compatible with your topcoat. If you decide on the topcoat after having put on "almost any" primer, you may have compatibility problems.

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