Hello Hello!

[Aretaic]

Howdy - Just put together a 4ch FT Simple Cub and spent a rainy evening adjusting gimbals and programming my new QX7 tx. I've watched all the FT videos I can find, so here I am on the forums!

I've always wanted to get into RC flight since I was a kid, but was only ever able to peruse the magazines and read whatever era aircraft encyclopedias my library had available. Fast forward to now and not only have electric components improved incredibly and prices have come down to accessible levels, but Flite Test is around now too!

I've got loads of foam and enough parts to comprise another B pack, so if the rain persists I might be building another model before even taking the first one out for a maiden flight. Perhaps another Simple Cub with some STOL mods like flaps and leading-edge slats?

It's awesome to have this community. I've lurked around a bit just to do research and catch up on what's what, hopefully I can put some handy info or fun experiences back into it!

BTW,
I work as an automotive painter, so if I get some paint on a nicer model I'll post some pics!

 

[Gazoo]

Awesome to have you here. Welcome. I'm on my second simple cub as well. It flies really nice.

Looking forward to seeing some paint! I have yet to master packing tape color. I'd like to see what you do and maybe get some paint tips.

 

[PsyBorg]

Welcome to the forums mate.

FT builds are for sure a great way to fill a rainy afternoon with something productive. Be sure to test what ever paints you use on the foam first as some will eat it quicker then a goat in a field. I know you will probably be air brushing but I have got by on the "Sanding" primer spray bombs. I go and coat all exposed foam and over lap the paper with white Gorilla wood glue. Then I prime using a very dry method until the entire thing is covered. A light sanding and a second more normal coat still being as dry as possible. Sand once more then spray bomb with what ever colors you want with the same brand to be sure no bad interactions.

Here is what my first painted project came out to be like doing it that way.

 

[Aretaic]

Looks good PsyBorg. I've been planning to crash my first Cub and paint the second one. I'll probably use Minwax followed by a thin automotive sealer, which should do well as a barrier against any other coating. We use waterborne Standox basecoats and Axalta clearcoats in the shop - it's nice stuff, but I may pick up some cheaper solvent base and something like Transtar Max clear from the local Motorparts supply store.
I'll bring some scrap foam to set in the booth and spray excess paint on it to test!

 

[Aretaic]

I'll create a new thread for this, but I've already painted a few samples (my unused bomb drop cutouts are perfect for this!). I've been able to take advantage of today's workflow and try going straight to base color, no prep, and also straight to sealer, then base, both samples cleared and baked. In a few moments I'll prime two more samples, sand one perfectly flat, and then follow the same procedure. Lots of pictures! I'll organize my results in another thread tonight.

 

[TexMechsRobot]

How much weight does the automotive paint add to the foam?

 

[Aretaic]

Good idea! That's something I'll check as well, once I have a full set of samples - I'll weigh each method I use against an unpainted sample.

 

[Spitfire1945]

Hey, welcome to the forums maybe you should try covering film sometime. Here is an example of one of my planes covered in film:

Sorry but the little plane has taken some battering so the film is a little peely at the edge

 

[PsyBorg]

If you are "baking" I will assume you are using epoxy type paints or lacquer base paints. They will tend to spider web and chip a lot on the foam. I would highly suggest latex or soft flexible paints unless you are building static hangar queens for show.

 

[Aretaic]

When I say 'baking' I mean that I increase the booth temp to 120 degrees Fahrenheit for about 45 minutes. This is the time and temperature necessary to fully cure the topcoat, which hardens and seals all previous coats of basecoat or wet-on-wet sealers.

Additionally, I'm thinking these paint systems might hold up on the foam without cracking. We spray even higher film build paints on plastic bumpers, some of which are quite flexible, without much issue. If I did notice cracking or spider-webbing on the foam samples, I might add flex additive to the paint, which makes it extremely flexible and also chip resistant.

I've primarily sprayed modern automotive paints like R-M, Dupont/Axalta, PPG, Metalux 2, Diamonte, Chromax, Standox, and Nason. All except for Standox are solvent based and can be reduced with lacquer thinner (but each have a specific reducer per mfg TDS). Standox (their Standoblue line) is a waterborne basecoat, pretty different - it requires a lot of airflow and a dryer system because instead of flashing off solvent reducers, you are flashing off water. Without a booth set up for this, it takes all day to dry.

I couldn't really find a good place to start a new thread so I may as well just post the pics since I'm done with work for the day and the conversation is already rolling here. I had 4 bombdrops and limited time so I tried a few things in the interest of productivity (i.e. "would I want to do this myself?"). I sealed one with a wet-on-wet sealer (this requires no prep before basecoat, only ~20 minutes dry time) and for the other one simply went straight to spraying waterborne basecoat. The sealer worked well but attracts dust and other trash from the floor and other places due to the time spent drying in between stages. Spraying basecoat directly on the foam board, as you might expect, caused the bombdrop to curve as it sank into the paper. For the remaining two I primed both, and sanded one of those with 500 grit on a DA (I was pretty rough with it, but sanding by hand would yield a nice result, I feel) and the other I simply scuffed with 3M red scotch-brite. These turned out the best, with the scuffed bombdrop still showing some wrinkling of the paper, and the sanded bombdrop having the smoothest finish of the 4. On a proper plane with even the slightest amount of prep work (I literally just stuck these in the booth and sprayed without any prep), it would surely look excellent.

 

[Aretaic]

I just took the samples and bent them 90 degrees, and the paint flexes with the foam and paper without much trouble, and even flexes back to being straight without cracking. I'd wager the film build is still quite thin, maybe 6 to 8 mils, so it flexes right along with the paper!

 

[Aretaic]

I started a new thread (possibly in the wrong place) with some photos of another FT Simple Cub with pontoons painted using these materials.
http://forum.flitetest.com/showthread.php?36722-Automotive-Paint-(!-)

How much weight does the automotive paint add to the foam?

It added about 120 grams for the entire plane including the floats. Weight may vary depending on different brands film build, but probably not too much.

 

[Iglooman]

Shiny bombs! I have to admit, I'm a little worried about painting now that it's harder to find oil based paint in Canada... Everything is going water based latex. Even some of the oil based stuff isn't the quality it used to be. We paint railing on our boats with flat black Tremclad - used to be the best - never flaked. Now when we paint them in the fall they flake by spring...

 

[Aretaic]

The materials industries are changing, and they need to change to keep up with increased regulation of VOC's. My region isn't VOC regulated but the shop I'm at is one of the few to opt-in to lower VOC materials (like waterborne basecoats). It's newer technology, which has pros and cons of course. It doesn't have as much time into development as solvent based paints, but the things waterborne accomplishes are very relevant to today's industry. Waterborne paints are now some of the best matches for factory color spec available, and the metallic flake consistency is incredible. The dry time is really punishing on high humidity days though - even with a heater/dryer system in the booth. In a high production environment it needs to be force dried with blower systems to keep up the pace - of course that increases the likelihood of getting dust and other trash in your paint!

That being said, we still use a lot of solvent-based materials where appropriate. It is much faster flashing. It's the only thing to use in a small/medium size shop or at a home garage where large, complicated, heated, downdraft booths aren't available. Clearcoats are still all solvent based. POR15 is the toughest thing I've used for metals in areas where rust might be a concern. You can brush it on or spray it with a larger tip spraygun, and it does extremely well. It doesn't have any UV protection so if it's ever going to be in sunlight it absolutely must be topcoated with anything else. Great for suspension components, linkages, frame rails, etc. Not sure if it's available to you in your area but it might work well - that or an epoxy primer.

 

[JimCR120]

Wow! I have a lot I can learn from you about paint. I also notice you are in eastern NC. I'm hoping to relocate from ME to northeast NC.

Welcome to the forum.
—Jim