Latex Paint for Your Homebuilt

[Aaron Novak]

Plastic, stainless, coated aluminum and brass. Unfortunately many of the older spray guns have bare aluminum areas in them, and aluminum cups. I personally had a cup ruined by thinned latex of a certain brand in 20 minutes. I had used it previously with another brand latex for over a year without issue. It literally ate the cup, turned the paint grey, and made a pretty severe mess. The 3M disposable head gun does a pretty decent job shooting latex. You will also find better luck using an acrylic extender to thin the latex as it tends to not destroy the weathering performance as badly.

[Sam Buchanan]

Ehhhh its a risky business. Depending of the chemistry of the latex emulsion, thinning it can cause severe performance reductions. For something like an R/C model sure, and thats what I do frequently. However if you are at all concerned about the weathering performance it is something that should be tested very carefully. You also have to be careful from an equipment standpoint as latex emulsions are corrosive to aluminum and can damage paint guns quickly. Equipment designed to handle waterbourne finishes would be the best choice.

Yes, latex paints can be thinned with water and the finish works beautifully. Twenty years of field history bears this out.

Weather resistance is a moot point for our airplanes. How many aircraft that are lovingly crafted in our shops spend their days tied down outdoors? For all practical purposes....none. When you calculate the hours typically flown by the low-n-slow custom-built aircraft the exposure to UV during the course of a year is measured in tens of hours. A finish that was designed for thirty years exposure 24/7 to the elements is overkill for our application whether it is thinned, not thinned, rolled, brushed, or sprayed.

If you want to spray latex, Lowes's sells a latex spray gun under the Kobalt brand for less than $50. According to the presenter of the webinar that started this thread, it works like a charm.

http://www.lowes.com/pd_220964-47120...ductId=3401350

[Aaron Novak]

Yes, latex paints can be thinned with water and the finish works beautifully. Twenty years of field history bears this out.

Weather resistance is a moot point for our airplanes. How many aircraft that are lovingly crafted in our shops spend their days tied down outdoors? For all practical purposes....none. When you calculate the hours typically flown by the low-n-slow custom-built aircraft the exposure to UV during the course of a year is measured in tens of hours. A finish that was designed for thirty years exposure 24/7 to the elements is overkill for our application whether it is thinned, not thinned, rolled, brushed, or sprayed.

If you want to spray latex, Lowes's sells a latex spray gun under the Kobalt brand for less than $50. According to the presenter of the webinar that started this thread, it works like a charm.

http://www.lowes.com/pd_220964-47120...ductId=3401350

Sam,
You are arguing a different point. Whether or not thinning the latex material can cause a change in its performance ( in many ways ) is not a question. It can. Determining if that change is acceptable, is up to the builder. That along with the extreme brand to brand variation would seem to easily justify the homebuilder doing some test work before paintng their whole airplane. I am not trying to discourage anyone from using a process, just trying to impress the notion that you have to ( or should ) do a little more "leg work" when you are using unknown materials.

[mmorrison123]

I have set up a website, www.wienerdogaero.com, to serve as a central repository for information on painting with latex paint. The most recent additions are three videos that show the sanding and polishing process on a Mirco Mong biplane project. The videos are on youtube but can be reached via a link on http://www.wienerdogaero.com/MicroMong.php . They show some of the potential for latex paint on your airplane.

Malcolm Morrison

[Frank Giger]

Malcolm, can I borrow a couple of pictures from your website for a presentation I'm giving on painting with latex to our EAA chapter later this month?

[mmorrison123]

Frank

Help yourself. Good luck with the presentation.

Malcolm

[Frank Giger]

Presentation went well!

I had covered a large picture frame with fabric, priming and painting with sections left showing every stage, from raw fabric to final layer of color. I didn't sand it, as I wasn't going for aesthetics. Hell, I didn't sand the paint on my airplane!

The big deal was when I cut a square of the fabric from the finished area and passed it around to show the flexibility and grip of primer and paint on the fabric. We all took turns stretching and rubbing the five inch square trying to get it to delaminate. I was pleased to see it held up to our abuse.

Many thanks for letting me use some of the slides from your website; I referenced it, of course and gave you credit for your work.

[Fastcapy]

So, what is the consensus on painting an aluminum plane, like my Sonex with latex? I seem to only find info about fabric aircraft and latex paint.

I know that aluminum siding, soffit and fascia are painted with latex all the time. But what about using it on aircraft. I assume thinning it with washer fluid would be a no-no but are people using other methods to use latex on metal skinned aircraft?

[1600vw]

Latex paint and your home built.

http://www.eaavideo.org/video.aspx?v=2735032127001

[Aaron Novak]

So, what is the consensus on painting an aluminum plane, like my Sonex with latex? I seem to only find info about fabric aircraft and latex paint.

I know that aluminum siding, soffit and fascia are painted with latex all the time. But what about using it on aircraft. I assume thinning it with washer fluid would be a no-no but are people using other methods to use latex on metal skinned aircraft?

I would think that standard finishing methods should be followed up to the topcoat, meaning the use of an epoxy primer after proper surface preparation. There are DTM (direct to metal) acrylic paints available. Big question I have is, why would you? I cannot think of one advantage of acrylics in this application that outweigh the risks. If its health concerns remember that emulsion paints have nasty things too in them. If its cost, then use synthetic enamel (same price as "latex").