SonexBuilders.net

There have been several discussions about how much extra a painted Sonex weighs compared with one that is polished. I have heard claims of 30 pounds, but unfortunately nobody has weighed their Sonex before and after painting, so the guesses are nothing more than that, however an aircraft at my home airfield was painted recently and the owner did weigh it before and after painting. The aircraft was a Victa Airtourer, somewhat larger than a Sonex with a wing area of 120 sq ft compared with the the Sonex wing area of 98 sq ft. The fuselage and empennage are also larger so on that basis I would guess the paint area is at least 20% more than the Sonex.
The aircraft was finished with a grey primer when it was first weighed. It then had:
1 coat of some type of primer that is intended to promote adhesion - I would guess a very thin coat
3 coats of metallic red paint
2 coats of hard clear protective paint. Let''s call that a total of 5 coats.

Weight gain after painting was 8.5 kg or 18.7 pounds. A Sonex with similar paint should gain about 7.1 kg or 15.6 pounds; about 1.4 kg or 3 pounds per coat.

Peter

From past posts on the forum:
- Based on the weight of the paint I started with and what I was left over with I was somewhere around 25lbs for my paint job.
- I think the factory said about 14 pounds to make theirs yellow as opposed to polish.

Years ago there was an article about building a Waiex. There was a lot of attention paid to a very custom paint job, and they did weight the aircraft. The weight of the paint came to 20 lbs.

One of the reasons I left mine polished; to save weight.

I'll happily pay the weight penalty for the benefit of paint.. I can always go on a diet to compensate.. in fact I probably should anyway.

My very rough estimate on the paint on my own aircraft:
I used 3/4 of a gallon for 2 top coats. Not all of that ended up on the aircraft and I did a certain amount of rubbing back, but assuming a density of 1, that's about 3 kg. Guessing another 1.5 kg for primer, that gets me only 4.5 kg or about 10 pounds. That fits pretty well with the estimate from the Airtourer I mentioned so probably about right.

Peter

Brett wrote:I'll happily pay the weight penalty for the benefit of paint.. I can always go on a diet to compensate.. in fact I probably should anyway.

Or do both! I am still running between injuries, am in the gym weekday mornings, and have really cut down on what I eat. Still, my middle age metabolism is not very cooperative. I know I can save weight with my polish job. Not sure I can reach my 20 lb weight loss goal.