Paint on sheet metal

[Bruce Caldwell]

I'm getting ready to paint and would like to know what you guys do on the aluminum. I'm gonna use Poly Tone and see that the results on metal are not always 100%. I've been told to use automotive paint but would like to know what you guys would recommend. I'm painting a 1946 BC-12D. Thanks in advance!

[3Dreaming]

It has been a while, but IIRC I prepped and sprayed with the white epoxy primer. When the last coat of primer was still tacky I sprayed on a coat of white Polytone. Give this a week to cure, then paint with Polytone.
This is from memory 15+ years ago. On that airplane there has since been a few scratches and chips, but overall it still looks good.

[Robert Lees]

In my opinion, don't spray Polytone on metal, even with the "half-cured" primer and two spray guns; the manual even suggests (rightly) it's a poor product for that.

It could be better to use full-gloss Aerothane over an epoxy primer (as per the manual) like I have on my Taylorcraft...

Or if you are serious about not going full-gloss on the metal, then add the flattening agent which reduces the gloss on the Aerothane.

Just my opinion

Here's my Taylorcraft with Polytone on all fabric, and Aerothane on all the doors, cowls, boot cowl etc.





It looks better that way, in my opinion, and you won't have the worry of the paint falling off the aluminium in the future.

Rob

[astjp2]

Don’t do the polytone, spend the money for a 2 part eurothane, I learned that lesson twice! Also skip the enamel, it fades real fast and doesn’t spray worth a shit!

[Ragwing nut]

apply epoxy, let it set an hour, put a couple coats of white poly-tone down and let it dry. You can topcoat after that with poly tone.

[Mark Bowden]

Rob, still the most creative Taylorcraft T paint scheme ever. Hope I can see her in person some day.

[Scott]

Just in case...
You probably know that nothing will properly adhere to aluminium unless it is properly prepared. This means some kind of etching process.

An etching primer is an option, or if you want to be sure, first used alumiprep 33 followed by alodine. Don't touch the surface without clean gloves on and apply epoxy primer within a couple of hours.
S

[otrcman]

I am just now in the finishing up stages of an antique restoration and am using Poly Tone on the fabric and Aerothane on the metal. Do I think you should do it the same as me ? I don't know. It's a judgement call depending on what you want out of your finished airplane and how you intend to use it. There are so many pros and cons to each method, and considerations for how you expect to use the machine that I can't make a one size fits all recommendation.

Buy and read the Poly Fiber manual. That's a good starting point in your education. After a diligent study of the manual, you are bound to have questions. Norm Douthit is your man. Norm went to work for Ray Stits at the very beginning of development of the Poly Fiber product line. He's now an independent supplier of PF products. Norm is knowledgeable, honest, and can give you realistic answers to your questions. I don't like to post phone numbers on the internet, but you can find him easily. Try typing in "Norm Doughit Aero". Or do a search in Barnstormers using the same term.

Here a a few considerations:

1. Your painting equipment and facilities.

2. Your protective equipment.

3. Appearance expectations.

4. Durability.

5. Repairability.

6. Expected service life.

7. Time required to complete job.

8. Cost of materials.

[astjp2]

I agree, follow the manual

[otrcman]

Couple of other comments:


1. I bought the flattended Aerothane for my metal parts and it came through very, very, flat. Didn't match the gloss of the Poly Tone at all. Norm sent me a quart of full gloss Aerothane clear to mix in with the flat to match my Poly Tone gloss. A lot of experimentation to get it right with each color I had to use.

2. Gloss is dependant on whether you use the fast reducer or the slow reducer. There is also a retarder that can be used to increase gloss. And your spraying temperature can alter the gloss as well. So it would be quite possible to spray your two wing panels on different days, all out of the same can, and yet come out with different gloss on the two panels.

3. If things like this sounds like there are lots of sources of frustration, you are right. A shop that specializes in fabric work does this all the time and they know the pitfalls. You can do a very nice job yourself, but a full time fabric shop already knows the pitfalls and can probably do it faster and cheaper than you. I did mine because I love to work on airplanes, but if I had a utility airplane (like a flight school) I would take it to a well recommended shop in a heartbeat.

[astjp2]

A shops labor is never cheaper than an owners. Most owners consider their labor free.