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Having sent in a few photos recently of my first attempt at spray painting the tail sections of my 701, I have been invited to commence a blog on the subject. I’ve never done a blog before – nor built a plane for that matter, so here goes:
I've never designed or installed an electrical system before either, but after reading widely, watching Jon Croke’s DVD and having my circuit diagram drawn up and checked over by an electrical engineer (my son in Canada) I did it and everything worked first time without sparks or smoke!
So why not paint it? – all the people I know who are building planes in my district (and there are a lot) have had theirs professionally and beautifully done by Craig of Riverside Refinishers in his paint shop in Blenheim (New Zealand).
OK so painting is the final finish that every one sees and which can add to or detract so much from the value of the finished product – what if it the paint runs, insects or dust stick to it ….will a poor paint job suggest poor construction within…(?)
But I've done everything so far myself so why not paint it too? Is it that impossible?
Now lets be realistic, my CH701 is no show pony. Its going to cost me around NZ$50,000 (that’s what I told my wife!) and it will be in and out of farm airstrips etc with mud, sheep and cow sh…., a far cry from most of the other planes being built here, especially Rex’s three perfectly built RV’s for instance in which he has invested over $200,000 in each. They will never set down on anything other than a well prepared surface, and they deservedly feature on the front cover of magazines after winning the Air NZ Award for the best home-builds of various years. Their professional finish (applied by Craig) in usually two toned metallic paint sourced from top European car manufacturers is outstanding, (and expensive!). So it’s a bit intimidating to admit to these guys that I am going to paint my plane myself.
Firstly, I searched the internet for information. Ron Alexander’s excellent article at http://exp-aircraft.com/library/alexande/painting.html was enough to convince me to give it a go – besides I had already sprayed an etching primer on all interior surfaces at the insistence of a local aero engineer who’d completed his apprenticeship removing corrosion from aircraft!
That experience taught me that a good spray gun was going to be required, the cheap one I used for the inside primer (the one that came “free” with the compressor) just blasted paint in great quantities all over the place, but using it, I did get the feel for the way to use the gun and do the overlaps etc without too much mess.
I took time to talk with knowledgeable people at the local machinery supply shop and learned that a good gun with fine tuning control of the spray jet’s size, shape and volume was essential and that a gravity fed gun (with the paint bottle on top) was the way to go. $300 seemed to be the outlay required for a good mid-range gun that would be suitable for the purpose and it would seem a good idea to set up a panel to practice on. I also needed to get a new moisture filtering regulator for the compressor to get better control of air-pressure and to reduce moisture in the compressed air to avoid blemishes in the paint finish from this cause.
I invited one of my son’s friends up who happened to have just completed his apprenticeship with Craig. He enthusiastically confirmed it would be easy to do the job myself, I just had to laboriously scrub every square centimetre down in preparation for an etch primer and then apply the colour coat – simple! If I got a “run”, then just be prepared to sand it down and patch it up!
He spoke with his boss, Craig who said he’d be pleased to offer me advice and provide all I needed, so down to the paint shop I went, no longer guilty at the thought of asking him for advice that may be viewed as doing him out of a job.
Craig was keen to help and gave me further confidence that I could do it. He offered to put together a full kit of everything I needed from spray gun, a box of rubber gloves, respirator, paper overalls, paint strainers etc and of course all the paint.
$1,500 later I was home with everything I needed and set to work on the rudder, stabiliser and elevator.
Using Septone Wax and Grease Remover and Scotch Brite, I set to work cleaning the surfaces, wearing gloves and working outside as the degreaser gave off an unpleasant smell. It was no simple task. Its four years since I built the rudder, it had oxidised and was sticky and dusty, so required a bit of elbow grease as I scrubbed it for well over an hour – maybe two, but it came up shining. I went through a few rubber gloves (and a finger nail) as they catch on the rivets which are a bit of a pain to work around. I later took it down to Craig for inspection to see if I had done a good enough job. He took one look and said it was more than enough, but better over than under, so that set the upper standard for the ongoing cleanup.
Once I had brought the elevator and stabiliser up to almost the same standard (my elbow was feeling it by then) it was time for the real stuff.
I cleaned out my spare garage, hung tarpaulins around the wall, hosed out the floor (and kept it wet through out – professional tip) and prepared to paint.
I had read up on the various paint systems available but in the end chose to rely completely on Craig’s recommendation – the same system he uses on our aeroclub planes using polyurethane paint.
The first job was to apply the etch primer. Craig supplied me with DuPont 820R Primer and DuPont 821R Activator/Thinner which is mixed 1:1. Technical information for these products is easily found on the Internet. It was simple enough to mix the two products and then strain it through one of the throw away paint strainers supplied. I donned my paper overalls, respirator (these paints have very toxic fumes), turned off / removed any motorised appliance from the garage which may cause a spark (a concentration of fumes can be explosive) and I was ready to go.
I should add that I did not fancy enclosing myself inside the garage with everything closed up which would require ventilation, extra lighting etc, so I choose a calm warm day and hosed down my gravel drive and a wide area surrounding the garage to keep down dust (including wetting the floor again before I started).
After checking the paint gun set up on a sheet of customwood outside, I set to work on the real thing in light overlapping strokes using the techniques demonstrated to me by Craig and as described in Ron Alexander’s article and the instructions that came with the spray gun. The secret to avoid runs is to apply light coats, working around the whole part which I had strung from the ceiling with hooks to enable it to be held in various positions as I went, to ensure I could see and reach the leading and trailing edges. Getting paint into the cavities and inside edges had the potential to cause runs, so this was accomplished by short quick blasts from different angles at different times.
Before long the paint was exhausted and I had to fiddle around to mix and strain an extra 100mls to complete the job. Estimating the amount required was going to take practice and I didn’t want to mix too much and waste any of that expensive paint at this stage of the exercise!
It was a warm afternoon (25 degrees) and the paint was touch dry within minutes which made it easy to build up the paint coverage and avoid runs. Before long it was time for the top coat.
The paint supplied was DuPont Imron 700, with Activator Imron AU270 and Thinner AU 370, mixed 4:1:1. (Again, full technical details are available from the internet).
Following the same procedure I applied three light top coats with about ten minutes in between as recommended by Craig and was delighted with the result – no runs, a shiny finish – EASY!! (Beginner’s luck?) Perfect? – Probably not, but so far I am happy.
Of course, I am far from finished, I still have lots to do including masking etc on the fuselage around the door cavities, windows etc. applying the stripes, painting underneath etc so I might want to rewrite all this before I am done!.
I have had to stop to undertake an assignment in East Timor, such are the joys of my lifestyle and business, and the reason why I have taken so long to get to this stage – but then this was a project to keep me busy “between jobs.”
The hardest part so far? – Choosing the colour scheme – but that’s another story.