Always Get a Prebuy

killbilly

Vocals, Lyrics, Triangle, Washboard, Kittens
ACF-50 or CorrosionX. Dielectric goop that gets fogged into the airframe. They come out, remove some inspection panels, stick the wand in and hit the trigger.

Stops corrosion cold by chemically interfering with the process. It’s basically halon for corrosion. It has weird surface properties that makes it wick into every nook and cranny, even between riveted panels, but is gooey enough to stick around for a long time. Seriously, your airplane will ooze that s4!t out for months.

Been around 25 years or so. Surprised someone has never heard of it.
I'm familiar with ACF 50 in cans. I didn't know you could have it fogged into an airframe. Sounds like it might be a good idea.
 

TWP

Well-Known Member
He couldn’t feel the dead cylinder?!

Some people REALLY earn their aviation related deaths.
 

trafficinsight

Well-Known Member
He couldn’t feel the dead cylinder?!

Some people REALLY earn their aviation related deaths.
Believe it or not, the weird way continental has you do compression tests (so that they wouldn't have to warranty as many cylinders), 15/80 may not actually be too far off from an acceptable reading.

A compression test is done static at the worst spot in the cylinder for wear. A cylinder with any compression at all probably ran fine but oil consumption might be high. Leaking past the exhaust valve is common in Continentals and isn't necessarily going to cause a problem right away but as the valve and seat deteriorate the valve can't cool properly and runs hotter and hotter until eventually it will either burn and then you have a dead cylinder, or in extreme cases it fails and the end of the valve drops into the cylinder and that makes an awful racket.
 

inigo88

Composite-lover
It will not, however, stop a major corrosion problem already in progress.
Then there’s Kenmore Air. I took an intro floatplane lesson in one of their supercubs on Lake Washington. Totally geeked out at the history of the seaplane base itself while I was there, and got to check out a couple of their hangars that was in the middle of a Beaver restoration. I’ve heard the only reason their Beavers don’t turn to dust is because every 5 years they take everything apart, strip them down to nothing (like, I saw an empty fuselage skeleton on sawhorses kind of nothing) and then sandblast out all the corrosion, prime, paint and put it all back together.

That blew my mind. That’s a hell of a corrosion control plan! Salt water floatplane flying in an aluminum airplane is serious business I guess! :)

@Roger Roger did you guys have to do similar in SE AK?
 

Roger Roger

Paid to sleep, fly for fun
Then there’s Kenmore Air. I took an intro floatplane lesson in one of their supercubs on Lake Washington. Totally geeked out at the history of the seaplane base itself while I was there, and got to check out a couple of their hangars that was in the middle of a Beaver restoration. I’ve heard the only reason their Beavers don’t turn to dust is because every 5 years they take everything apart, strip them down to nothing (like, I saw an empty fuselage skeleton on sawhorses kind of nothing) and then sandblast out all the corrosion, prime, paint and put it all back together.

That blew my mind. That’s a hell of a corrosion control plan! Salt water floatplane flying in an aluminum airplane is serious business I guess! :)

@Roger Roger did you guys have to do similar in SE AK?
5 years no, but corrosion control up to and including major rebuilds was a continuous battle. I’ll write more tales after the kids are in bed.
 

trafficinsight

Well-Known Member
Then there’s Kenmore Air. I took an intro floatplane lesson in one of their supercubs on Lake Washington. Totally geeked out at the history of the seaplane base itself while I was there, and got to check out a couple of their hangars that was in the middle of a Beaver restoration. I’ve heard the only reason their Beavers don’t turn to dust is because every 5 years they take everything apart, strip them down to nothing (like, I saw an empty fuselage skeleton on sawhorses kind of nothing) and then sandblast out all the corrosion, prime, paint and put it all back together.

That blew my mind. That’s a hell of a corrosion control plan! Salt water floatplane flying in an aluminum airplane is serious business I guess! :)

@Roger Roger did you guys have to do similar in SE AK?

That stuff is really impressive. I wish I could do more major airframe stuff like that.

I work at a flight school. Bandaids on bandaids on bandaids.

I can do a 500 hour mag inspection in like 35 minutes though.
 

Roger Roger

Paid to sleep, fly for fun
I'm told this is a reasonably straightforward skill to acquire. I'd like to learn.
Well, sort of. To do the full Monty you need to run it on a test stand which most places don’t have access to. That’s why we stopped doing them in-house.
 

texas_pilot

Well-Known Member
Paid a person ( not named here ) $300 to drive 3 hours away for a prebuy on a 50 year old Piper who's owner died 15 years earlier.
Thumbs up, paid the cash, My new IA was only 50 miles away, $15,000 later it was signed off!
He ain't on my Christmas card list.
 

Space Monkey

Well-Known Member
Paid a person ( not named here ) $300 to drive 3 hours away for a prebuy on a 50 year old Piper who's owner died 15 years earlier.
Thumbs up, paid the cash, My new IA was only 50 miles away, $15,000 later it was signed off!
He ain't on my Christmas card list.
The very best thing about having a 3rd party WRENCH do the pre-buy inspection? It takes the onus with the seller off of YOU and eliminates one's own particular, er, particularities from the negotiation. Very much like why one hires an attorney even if one knows the law.
 
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CFI A&P

Exploring the world one toilet at a time.
Is it smart/practical/acceptable to be present when the mech is doing the pre-buy?
The purpose of a pre-buy is to gain information, so do whatever you think is beneficial for you to get the most information about the aircraft.

Here’s something to consider about prebuys: there is not any guidance or industry standard on prebuys, unless the two parties agree to complete it and record it as an annual inspection. I’ve done prebuys that were more like preflights because they’ve already bought it and I’m flying it home, but I’ve also done prebuys where the buyer didn’t want an in depth inspection for one reason or another. “Don’t look too hard, it’s a good [price, paint, avionics, nostaliga] yada yada yada and I really don’t want to pass on it.”
 
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