Cowl Painting Done ... For Now

I completed the paint job this week. As a matter of fact I am having my car sit outside with the painted pieces inside waiting to go to the hangar to install them as I am typing this.
Why am I saying "for now" in the title then?

That is because a few things went wrong and now I know how to do it better - much better, actually - but I do not want to ground the plane for another 2 or 3 weeks to fix it right now.

The oil change is complete, I swapped the RPM line resistor and she's grounded for too long already.

So what went wrong with the paint job?

I used Floetrol at around 10-12% and some additional water of around 10-15% but the paint was still a bit thick for spraying. I went with it because I was more afraid of seeing the paint run off the many vertical areas and creating runs that would have needed sanding.
The way the paint dried with that thick coating was somewhat bubbly which created an orange peel effect even though I threw the last coat on thick and wet. The only way to remove the peel is to sand it down to an evenly dull finish and then build the paint back up with a watery consistency and thin wet coats.
I tried this on the spinner as that is the only small piece that has vertical surfaces and so it was easy for a quick test (and it would have been easy to fix had I created runs). I sanded it lightly with 400 grit wet, not enough to completely remove the peel but enough to reduce it drastically.
Then I used isopropylic alcohol (70% ) and some water to dilute the paint enough to really get down to a watery consistency. I was very aggressive with diluting it this time as I wanted to see if this worked or not.
I sprayed it on and I was able to create a very smooth and even coat in no time. The coat dried very quickly and the result is encouraging. The finish is a lot smoother than before, only disturbed by the peel effect that had not been completely removed.

So what would have to happen to get the even glossy finish that I wanted for the rest of the cowl is to sand it down to a smooth surface and then use heavily diluted paint to build it back up in 2 to 3 thin coats. I will likely do this but not right now. I left the paint surfaces as is and won't apply any wax or anything that could later be a problem when sanding down and repainting. For now I will fly this as is and at the next oil change, I will take a stab at this again. It will likely be winter at that time and the lower temperatures could help extending the drying time and create an even smoother surface than what I saw with the test on the spinner.

I got to the hangar and installed the cowl again. What was proven immediately is that the paint is too soft. I hope it will dry eventually and get a harder surface as it is very tender at this time.

Tomorrow morning we'll go flying!

Last Primer Shot

The rest of the week and even the Saturday morning where spent fixing the gazillion pin holes Van's had blessed these cowling parts with. I used the lightweight Superfil product for this job and am amazed about how good it is at this job. With the help of a squeegee (old credit card) the holes fill right up and there is not much to sand down afterwards and the Superfil sands real easy. The only downturn is that it takes 6-8 hours of at least 70 degrees to cure enough to get sanded.

After the Superfil had cured I sanded the whole surface of the parts with 320 grit dry and wiped it down with a micro fleece rag to remove the sand dust.
Then it was time for the last coat of primer to cover the light blue colored Superfil spots. I use the S-W Multi-Purpose Latex primer with ~10% Floetrol and a dash of water which looks like another 10%. After stirring it well it still has a consistency that looks thicker than what I would paint want to look like in an HVLP gun. So I use very little paint flow in the gun and 35psi and move very slowly over the surface to get good, fine coverage.

Now it should dry over night and then we will see in the morning if we need another sanding run before shooting the paint.

Priming Completed

Due to choosing the wrong filler for the numerous pin holes on the fiberglass parts I am not yet done with painting. In fact, I might not even be done with priming yet but at least I am getting there.
So what was wrong with the filler? I chose Stewart EkoFill grey (which also has UV protective properties) after my good results with their paint system. The EkoFill did turn out to be a nightmare to work with. The previous, somewhat older, can had gone bad and I received a fresh one right on Friday before the big paint weekend.
The EkoFill went on ok. The stuff is very watery and I did not feel good about spraying this as I expected it to just run off. So I used a foam brush as recommended for fabric. Well, the foam brush caused foaming of the EkoFill and it was impossible to completely remove the foam from the surfaces. Once dried I intended to sand the surface smooth but it turned out that sanding EkoFill is near to impossible to do.

It looked good when the first coats had been applied though:

The stuff has a rubbery consistency and dulls open coat sandpaper in a matter of 1-2 minutes. After 3-4 minutes the dull sandpaper does not cut anymore and just peels off little pieces of rubber similar to using an eraser. It took me 4 hours of tedious manual sanding wasting 3 sheets of 320 grit sandpaper and ending up with a not so pristine surface as I had wished for.
The episode was not over yet though. The EkoFill also did not fill the pinholes as I could not build up enough material to bridge them. This is due to being so watery and unsandable which made me not wanting to go through this more than once.

This is how it looked after the sanding episode:

The coat was super thin and it needed more to really get a UV protection. However, Latex paint also has a good UV protection and so I decided to leave it as is and to apply the S-W primer. I watered the primer down to a consistency that I was used to for the paint gun. That was about 20-25% water added to the primer. The primer did not mind but when I applied a stroke with the foam brush I saw that the EkoFill coat repelled the diluted primer so there was no way I could spray this. I had to apply a first coat of undiluted primer with the brush to get it to stick.

I built up the 7'x7' greenhouse that I had found on eBay to get a clean environment for the upcoming spraying.

I put the pieces inside and started applying the first primer coat with the foam brush.

I applied a few more coats with the brush to make sure the EkoFill was well covered before I got to spray the primer tonight for two coats on all 3 pieces.

I will let this sit to dry over night and then check tomorrow if it needs more. I hope it will be sufficient and I can sand this to prepare it for the paint coats.
BTW, I used Floetrol 10% and another 10-15% of water to dilute the primer which worked fine the HF HVLP gun.

Ready to Paint

Finally I got all my parts and supplies together to get into a weekend of painting!

It took quite a few trips to (different) Sherwin-Williams paint stores before I found competent help that guided me to the right paint. It was even more challenging though to get the color mixed that I wanted. Here are the results:

The color is Laughing Orange (SW 6895) that turns out to be a very nice Mango color when applied on a bright white background.
Resilience is supposed to be better than their All-Surface Enamel which I had intended to get as it does not yellow and chip because exposure to sunlight (Tucson is really tough in the sun department).
I intend to use EkoFill as a filler and UV coating on the fiberglass, followed by the Multi-Purpose Latex primer and then by the top coats.
The idea is to roll-on the filler and primer coats and then spray the top coat. We'll see how that all works out....

Wish me luck!

Painting with Latex

I had seen an EAA Webinar by Malcolm Morrison from EAA chapter 1327 who experimented with Latex on different aircraft for quite some time and with stunning results (at least to me).
You can find the webinar here and the summary webpage with photos and description here.

The fact that the paint is water-borne, cheap and readily available and available in any possible color, made the decision easy to give this a try.

I was about to prep the fiberglass surfaces of the cowl and spinner with EkoFill from Stewart Systems (after a thorough wet sanding with 220 grit) but the EkoFill I had bought about 1.5 years ago (and never opened) had gone bad. The can showed a very watery substance on the top and clumps of tar-thick filler on the bottom. No amount of stirring helped to dissolve the filler back into solution so I threw it out and ordered a new supply.

That means that I could not make any significant progress over the weekend and it also means that I probably won't be able to make any until the next weekend.

And here the pieces sat on the workbenches all ready to get primed.

I used the timeout to order some more tools for buffing and polishing the Latex paint and a protable greenhouse as a cheap makeshift paint booth as I do not want to build another wood-frame paintbooth for this simple job.

The Blue Plague

There is not much to report from this weekend's build process. It was pretty hot and the weekend was predominantly filled with alternative activities like early morning hiking and such, so there was only limited time to work on what I consider to eventually become a plane.
I received a few more parts for completing the build. Among them was the engraved N-number plaque and the gear leg and transition fairings that I plan to add after certification. As a matter of fact, I am planning to trim and install them before certification while I still have the plane in the carport as I deem this to be easier to do at home than at the hangar. I will remove the fairings for certification and then put them back on afterwards.

N-number plaque (about 2"x1")

One problem I ran into this weekend was a self-inflicted one that many had warned me about earlier. It wasn't an issue when I had first read about the Blue Plague and I thought then that these guys were just unlucky or received a bad batch. The issue is the blue vinyl that protects the sheet aluminum from scratches.
I had read that if left on, this vinyl would become a pain in the builder's behind to remove from said sheet aluminum, to the extend that many hours would eventually go into the removal.
Back when I read this, I had checked on my vinyl coatings and found them all pretty easy to lift off the surfaces still and I remember that I repeated this check about once a year during the build process. It was no issue until this summer and I assume this is related to me changing the position of the plane in the car port. I had pushed the plane backwards quite significantly late last year when I started installing the engine to get more room in the front area while working on the engine. That move caused the aft section to get almost pushed outside the carport and it was since exposed to the searing Arizona sun a lot longer during the days than ever before.
UV light kills any softeners added to plastics and the result was that on the areas that were exposed to the sun longest, the vinyl would not peel off any longer but only break off in small chips. That makes it almost impossible to remove the coating in a reasonable amount of time and I ended up scraping it off in these parts with the help of plastic scrapers and finger nails. This is indeed a very time consuming and rather frustrating work and this is when I remembered the warnings I had read years ago about the Blue Plague.
This is even more frustrating as I had decided to leave the majority of the vinyl on the sheet metal to protect it from scratches and then ended up creating much more scratched area due to the plastic scraper used to remove the protective coating than removing it early on could have ever left me with.

These pictures are taken AFTER the scraping. See the close-up on the left side and compare that to the right side which is still shiny as this side was less exposed to the sun.

The lesson that was learned from this is to not worry about scratches on the sheet metal and just remove it all at the time of riveting. It will look better in the end that way and with less buffing. Most of us paint the aluminum anyway and the sheet metal will get scratched up as a preparation for the paint, so there is no reason to be too protective.

With the help of my wife, we were able to remove the broken up patches of resilient vinyl from the tail cone in long scraping session and I will remove the rest on the frontal areas when I get home from the paying job tonight.
Also, the sealants all arrived and I patch up those rivets and holes on the firewall to seal them off in one of the next sessions.

Paint Booth Removed

It took me two half days to get the paint booth removed from the car port. Building it was actually faster :-)




Now on to building some more....

Tank Painted

I'm late with updating this entry but the work has been done as anticipated. Yesterday I painted the last parts for the interior, the map box, the fuel neck and the tank.
Despite my troubles in getting a good job done when priming (remember, I produced some small runs), the paint job turned out way better than my previous average work. Actually I think the map box and the tank are my masterpieces with the spray gun.

Take a look at the pieces and note the shiny reflections which prove that the surface is really smooth. Here are the parts right after applying the last coat.




And here after a night of polymerizing in the heated paint booth.


I believe, I am done with painting large interior parts at this point but before tearing down the paint booth I will do an inventory and see if there's nothing hiding in a corner of the shop ...

Side Skins Painted

So I rushed home after work to spray paint at a good temperature of around 75F. I mixed a little bit too much paint but this better than running short like last time.
Here are the first shots about 45 minutes after painting. The skins and some additional stuff are still sitting in the paint booth. Temperature is now falling quickly with the cold front moving in and when we got down to 68F I had to do something. Well, I put the space heater in the booth which is safe as the Stewart paint is not flammable.



Later tonight when the paint is dry to the touch I'll probably move the parts into the shop and heat the area there. Might keep the temperature better than 4mil plastic ...

Update:
I did remove the parts from the paint booth and put them all in the shop for overnight heated curing. Looks pretty nice, I think I am getting better with the paint gun.

Little Touch-Ups

Today was touch-up day. I found a few spots that needed touch-ups and I also had to respray the side supports of one seat back and the opposite side of a piece I had sprayed before. I also decided to spray the inner part of the vent doors without additional priming. The paint is adhering well, even to surfaces it is not at all intended to adhere to. Like stainless steel for example. I missed to tape a spot on the firewall and ended up with some paint on it. I had a real hard time getting it off and had to use MEK to get it off. I guess I was lucky it hadn't polymerized completely yet when I started rubbing. After 5 minutes it was finally off. I guess I could have easily painted the firewall if I had decided to do so.

No new photos today as the stuff practically looks like yesterday. Currently the parts are all in the shop and enjoying the space heater again. Tomorrow I'll be moving the fuselage back on the outside workbench and see if I can get some assembly done as well. I might have to postpone that though as I need to finish my tax work. Argh!

Big One Done!

I feel much better now! All the anxiety about how to best spray that basic fuselage are now a moot point. I finished it and there's only one spot I have to touch up with tomorrow's batch of parts that get painted.
But let's start in the correct order. I finished the masking tape job in the morning.




I cleared out the paint booth and vacuumed out the dead bugs and some dust that had collected on the floor. I also put a 6' long folding table in there and covered it with a tarp. Underneath the tarp is mover's blanket to provide some cushion for the fuselage.


Then I had to move the fuselage into the paint booth. I thought I had measured it to require around 7' of space but I obviously hadn't taken into account that the fuselage might sit a bit tilted and therefore require more room than just the 7'. The paint booth was built using 8' long 2x4s which I think now to be too short to be comfortable. If you follow my lead consider using 10' long 2x4s to get a bit more room to move around the fuse!
I got it in however, but then needed to rely on the pressure from the fan to make the door plastic foil bulge to get around the thing. Not very comforting!


Spraying itself was simple and much easier than I thought. Although I didn't mix enough paint (I used 180 grams for part A) I was able to finish 3 good coats. On the last, third, coat I focused on the visible high stress areas, the foot area and the baggage area. It turned out to be enough paint everywhere and the finish is great. Only in one spot I had put some masking tape on where I shouldn't have but it's in the gap where the wing spars will sit and so a brush touch-up will be sufficient.


This is two hours after spraying and the masking tape is still on.


Same time but different angle.

Another two hours later I returned and removed the masking tape as the paint was "dry" to the touch. Then I moved it out of the booth and into the shop where it is easier to maintain the necessary temperature for the curing process.




I just hope the color turns out not to be too bright. On the paint chips I selected it from it looked two steps darker than it looks now....