What I’ve gained through building the RV to date (who knows if it’ll continue) is an overall impression that internal priming matters for longevity.
Exactly what is used is perhaps less important, but from my own experiments I’ve concluded it’s important that it adheres well, gets good coverage, and that the finish is non-porous. A fairly tough finish helps resist scuffs during assembly processes, but these can always be touched up afterwards so not vital. The inside of an aeroplane structure is quite a gentle environment, in that it doesn’t get pelted with dirt and weather like car bodywork does.
Of course the priming should happen before parts are riveted together, that’s the other key point. Some go further and use jointing compound everywhere in addition to priming, but I feel that’s overkill for marginal additional benefit.
I use two coats of acid etch primer followed by two coats of clear lacquer. With four coats everything is well protected and the lacquer gives a non-porous finish as well as adding a little toughness. It’s probably not as tough as 2-pack epoxy, but it’s a hell of a lot cheaper and much less hassle to apply. Before the last piece is riveted in to close up a structure I give a quick final spray of lacquer inside so that (most of) the rivet heads in there have some coverage. Assuming these structures ever become an aeroplane, I will probably give a blast of ACF50 or similar in through lightening and tooling holes before final assembly. I can’t see it corroding in any reasonable timeframe.
hazek wrote:
and can’t climb above 7500ft in summer.
Huh? That must be the most idiotic comment I’ve read here in a long time. In addition, AFAIK all the Reims Cessnas were corrosion proofed, so there’s added value in there. Price is a bit on the high side, but pro90 negotiable. In fact, this – priced in USD and of course no VAT – would probably fetch pretty close to asking over here.
172driver wrote:
hazek wrote:
and can’t climb above 7500ft in summer.Huh? That must be the most idiotic comment I’ve read here in a long time.
The Cessna in the ad was a Reims Rocket (210 hp) which can certainly climb over 7500 ft in summer. But not every mid-1970 Cessna can do that easily. I know about one with a 150 hp engine that really struggles to climb that high.
Airborne_Again wrote:
The Cessna in the ad was a Reims Rocket (210 hp) which can certainly climb over 7500 ft in summer. But not every mid-1970 Cessna can do that easily. I know about one with a 150 hp engine that really struggles to climb that high.
C172 160hp here, instructor saying “First time I’ve seen it has climbed to FL70”. Took forever.
Some go further and use jointing compound everywhere in addition to priming, but I feel that’s overkill for marginal additional benefit.
The reason for filling the joint with a PRC-type sealant is to avoid water getting trapped in there. It does make assembly hard work though because you have to be quick, and it is hard to not make a mess with the sealant. The TBs had it.
and can’t climb above 7500ft in summer.
I don’t think a C172 will go over 7.5k if full rich, and that is how most European PPL training is done – no leaning.
Chaps, we are talking about a 210hp Reims Cessna here!
That aside, I’ve flown 172s (admittedly, 180hp RG) over the Atlas and Sierra Nevada mountains well over 10k ft. Of course you need to know what the red knob does. Duh.
@172driver don’t get your panties in bunch, I admit I overlooked the 210hp engine and certainly that plane can climb much higher, even in summer. It still priced 10k to high min, that’s without the VAT.
@Peter ha ha ha. Yeah, I fly full rich all the time, what even is the red knob other than a glorified on off button, right? Please.
I know 172driver and can assure you that he would not wear female underwear…
A C150 will get to 10k, correctly managed.
For IFR in the Eurocontrol system one needs something like 15k ceiling, for a) decent routes and b) climbing on top in typical wx (you can get icing at 10k even in Spain in the summer).
I did qualify that I meant in the summer. And I’d really love to see you Peter with a fully loaded C150 go over 7000ft when it’s +15 ISA.
hazek wrote:
Yes, this one exactly ticks my boxes if you meant as an example of exactly the kind of absurd over priced ads I see. I’m sorry but the Aspen is wasted on this 172, the engine is near TBO and I don’t know how it was flown and how often so might as well consider it as requiring an urgent overhaul, it’s 1975 airframe that does 100kt and can’t climb above 7500ft in summer.I want a plane, desperately. I have the money to buy it. But I would never buy this plane for more than 75k and I’m rather without it for the listed price. I can see this plane selling to a school for 90k only because schools can make money with it. But 172 is not what I’m looking for anyway.
After taking a look at the ad, that looks like a reasonable aircraft at a reasonable price, as a starting point to evaluate further. It’s certainly likely worth significantly more than the 75k you mention. Where do you get the “can’t climb above 7500ft in summer” or “near TBO”? I would say the hours are in fact at the sweet spot for a used aircraft. A newly-overhauled engine has more risk than one at TBO, and this one is exactly half-way between. I get the feeling that you’re expecting well-equipped, fast and absolutely top condition aircraft to be readily available for a bargain price. Good luck with that.
And a C172 Reims Rocket (subject aircraft) is a very very long way from a C150.
