COOL WEATHER PAINTING

[IBob]

I painted my Savannah (2 pot) late winter, with daytime temperatures not usually above 15'C. More by accident than design, I came up with the following setup, which may work well for others:

1. I erected a spray tent inside my workshop (Supercheap Autos car parking tent). I taped up all the gaps in this.

2. I put double fluoro tubes all down one wall, screwed to ply, with foil behind to reflect the light. Ideally I would have had them down both walls, as it was I tended to spray from the light side, then run round the other side and get my head down to check on the finish. YOU CAN'T HAVE TOO MUCH LIGHT!

3. Another pilot/builder lent me two 150mm domestic extractor fans. I fitted these at the back end of the tent, venting through the workshop wall. (The alternative is to run temporary ducting to the outside but this greatly reduces the airflow). These fans do not shift a lot of air, but they shift enough to remove the spray mist without stirring up the dust, so I found them ideal.

4. I made a very simple ply frame to fit over a standard domestic 2.3kW radiator, cut a hole in the tent to take this at the front end.

5. I had a $2 thermometer hanging in the tent.

 

On spray days, with the job set up, I would turn on the radiator, wait 5 mins or so then turn on the extractor fans.

The air coming into the tent would be drawn between the fins of the radiator, and the temperature in the tent would rise slowly but steadily.

After 30 or 40 mins, with the temp at approx 24'C and still rising, I would suit up, mix paint, and spray. Sometimes I would have to turn the radiator down to prevent the temperature rising too sharply.

[old man emu]

Sounds like for a few shekels you made a spray booth as good as any professional one. Was it a case of thinking outside the tent?

[IBob]

OME everyone uses the car tents for painting.

The fans were offered early in the piece, that was plain good fortune.

The lighting I knew a bit about, though I didn't realise just how much you need until I started painting the big bits. If you look at spraybooths for quality jobs, the entire walls and ceiling are all lights. My one row of double fluoros was only just adequate (provided I cleaned the overspray off them).

And the heater thing occurred to me when I was waiting for warmer weather...and it just happened to fit in neatly with the amount of air the fans were extracting.

I've detailed it here as, starting from scratch, I'd have had no idea how much fan and how much heat might be required. I was fortunate it all just lined up as it did...............)

[facthunter]

You will blow yourself up, if you use bar radiators or electric motors with brushes and evaporative flammable solvents. Have it all on the incoming side of the airflow.. Floodlight bulbs probably get hot enough to reach flash point as well.. I found out the hard way, so I pass it on. On coolish days the paint may bloom especially in the afternoon. A "retarder" thinner can help prevent it. Nev

[IBob]

Thanks for that, Facthunter, you raise a very important point.

 

The radiator was oil filled, and upstream.

The fans are brushless induction.

And the strip lights are cool and sparkless.

The switches for all the above were outside the tent.

 

But you can't be too careful.

 

And yes, I did use winter thinner and hardener; in fact used both winter and summer, as the painting went on for a while, last parts being the cowls.....)

[skippydiesel]

I made my "spray booth using cheap forming timber & plywood "stiffeners" (which I recycled at the end) made up into a long rectangular X section tube.

Builders plastic sheet over the entire frame, including the floor to facilitate wetting down (to prevent dust), double doors at one end (to get the big bits in/out. Bubble wrap over top/sides (as insulation).

For air movement/control, I had a cheap workshop pedestal fan as my extractor, at the door end (suitably cowled) venting to the outside of the shed and a half wall of air conditioning filter material at the other end - which I could curtain off in whole or part with bubble wrap. Filter material prevented dust & insect ingress and was large enough to minimise any air turbulence, while facilitating good general air movement in one direction.

Sheeting, wrap & filter material stapled to frame.

Lighting - a combination of ambient and multiple pre loved fluoro's, some of which could be moved for best effect.

I used the Stewart paint system, which has a much lower risk of ignition, due to being water born and sprayed using very low pressure (minimising aerosol )

The top coat required maintaining a temp above 21C + for 24 hrs or more, so I purchased a pre loved "window rattler" air conditioner for $40. Mounted it about mid way down the spray booth, near the floor. Monitored with several digital thermometers, hung at intervals down the booth, that recorded min/max, at painted part hight. With a little experimentation was able maintain desired temperature range over 24 hrs, no matter weather conditions.

Result - amateur paint job that I am insanely proud of.

[kgwilson]

You blokes certainly went to some trouble. I just used my hangar as a spray booth & my problem wasn't the cold it was the heat. I prepared the aluminium with Prekote & primed it in November 2014. I used Hichem grey etch primer. I started the white on small bits in December which was not successful. I used Dulux Luxathane 2 pack white with Dulux Quantum FX gloss blue metalic. The spec sheet said application temps up to 45 degrees & 85% humidity but the aluminium got far too hot even at 30 deg so the paint would dry instantly & not form a glossy film. I gave up & began again in late March 2015. I built a rotisserie for the fuselage but that wasn't successful either. I bolted the prop flange to one end and made a bracket for the elevator spar. It put too much stress on the engine mounts. In the end I laid the fuselage on it's side to paint the bottom & then did the rest with it on a bench. I hung the wings from the ceiling & painted everything else on the bench

 

Ventillation was the entire front of the hangar open with lighting from the sun. I didn't even get any bugs or dust as I always painted on a calm day & I think the smell of the 2 pack put the bugs off. I'd never painted anything before & bought a HVLP spray set off Ebay for $30.00 & an in line air dehumidifyer which attaches to the spray gun & a ventillator with replaceable filters. I got one run on one of the wings that no-one other than me has ever noticed. Masking for the stripes was a mission but it looked good when done. I finished in July 2015.

 

Wing & rudder hanging from ceiling, Quantum FX blue bits , Finished pre rego

 

[IBob]

Really nice job, kgw.

We get lots of wind, also bugs, so it had to be an enclosed area.

I'm a novice also, so I went to some trouble to position the parts so I wasn't trying to spray at odd angles. I originally planned to rotisserie the fuse, but the Savannah is very belly heavy when held by the engine mount and the rear fuse. In the end I put a rope round the engine mount, crossed over and up to 2 points in the roof, and this allowed me to roll the fuse sufficently to get at all surfaces easily.

With the wings I made simple tilt arrangement so they were titled towards me for spraying, but i would then lift them up flat.

I started on smaller parts, and reworked a number of those: initially my results were very poor until I got the proportion of thinners and the gun setting into the zone. After that it went a whole lot easier, and the colour, which was the last bit, was a doddle (I could actually see what I was doing!)

I got no runs, and while the wings are certainly not 'perfect' I am very happy with the overall result.

[kgwilson]

Ibob, very nice. That car tent is the beez kneez.

 

Five years on & I have plenty of stone chips on the spats some on the cowl & leading edges & a bit of hangar rash here & there. It is a bit like when you get a new car. Everything is perfect & you wash & polish it every week. Then you get the first scratch, and another & soon afterwards you just give up and it begins showing its age. One day I'll deal with it but now I just prefer to go flying.

Edited July 30, 2020 by kgwilson

[IBob]

Got you there, KGW....I built her to fly too, though I'm still mopping off most of the bugs quite regularly..........)

[IBob]

It seems to me like Skippydiesel wins the prize for sheer innovation.

Show us yer paint job, Skippy!!!

[skippydiesel]

Will have to "reduce" some photos for you.

[skippydiesel]

In the mean time here are some photos of the spray booth (next time it will be a little wider):

[skippydiesel]

About to commence work - a bench went in and lighting was improved. The bubble wrap & air conditioner came later.

[skippydiesel]

[IBob]

Yep...........looks terrific, Skippy..........:)