When I repainted my airplane I considered this essential. Otherwise you have no idea what is going on under that paint. Corrosion is a killer and anyone who thinks it's cheaper not to strip off all the old paint is fooling himself in the long run.
We found them off, and had to add weight. Cessna didn't use any more balance weight that they needed to, and they were using light lacquers or enamels, with no primer beneath. Strip those off and put on epoxy primers, then urethanes, both of which weigh a lot more than the old stuff, and the balance WILL change. And why are they balanced? To prevent flutter at high speeds within the Vne.
It's going to depend on what is used and how many coats are sprayed. A gallon of two part is going to weigh around 10 pounds when sprayed out, depending on spray conditions and how much additives are required. A C-172 will require about 3 gallons of top coat and 2 gallons of primer.
Is that truly the weight of just the solids, or are you including all the volatiles that are going to evaporate?
From a Cessna 172 service manual, some examples and notes:
It's been stated that if you add a 5 pound radio that a Weight & Balance revision is necessary so, why wouldn't adding 18 pounds of paint?
The reason I wanted a new W&B is because of the many, many mods I've made to it over the past 5 years. So any change will be a combination of paint job, but probably mainly drift from doing all those mods and updating the W&B by calculation, not measurement.
I’d still suggest double-checking their math.
Neither of the errors I've found moved the CG by more than a couple of tenths of an inch.
Understood. Mine's the same way; many pieces of equipment installed and removed over the years, some logged as "negligible" for W&B, sometimes with new calculations. Some stuff was logged in but never out when it was removed. Besides, I've found and corrected two calculation errors, so there are probably more.
Someday I'll have the thing weighed and get a clean, fresh number, but in the meantime I stay away from the load limits. I doubt the weight is wrong by more than my passengers' fibs about their personal weights, anyway.
With a good cleaning before painting you'll probably remove weight in excess of the the paint alone.
Open up the floorboards and get a look in the tailcone. Dust gets blown into the tail, and moisture can flush it down under the floorboards. Dirt from shoes finds its way under the floor. Oil from the engine runs down the belly and gets through lap seams in the skins and mixes with the dirt and makes considerable sticky sludge, sludge that often blocks drain holes in the belly so that even more moisture accumulates. I have seen watermarks in bellies indicating that there was serious accumulation.
Here's a fun party game: ask all the anp's you know how many have found tools in wings, fuselages, engine bays.
I, on the other hand, have flown an inch outside the envelope due to an error in the empty calculations.
Hey - need some pictures of the new paint!
You missed the thread?
Corroding faster...The plane is probably unairworthy now.....
