Tried a new sealant on a Cessna fuel tank, got a nasty surprise

I decided to try PR-1440 instead of the usual PR-1422 on a Cessna 172 wing fuel tank last month. I figured it would cure faster and get me out of the hangar quicker. Well, it cured in about 4 hours like they said, but when I did the pressure test the next day, I had three pinhole leaks I hadn't seen before. Turns out the PR-1440 doesn't flow as well into tight seams when it's warm out, and I was working in a 90 degree hangar in Phoenix. I had to scrape all that new sealant out and redo it with the old stuff, which cost me an extra 6 hours of labor. Has anyone else had problems with fast-cure sealants in hot weather like that?

2 comments

2 Comments

charles67811d ago

Used to be one of those guys who thought all sealants were basically the same chemical goo, just different labels. That changed real quick after I tried to shortcut a wing root on a 172 with PR-1440 during an Arizona summer. Had the exact same pinhole problem you mentioned, three in a row along a lap joint that looked perfect when I laid it down. Had to grind it all out with a carbide burr, and that stink of cured sealant dust got in my sinuses for a week. Now I just pay the extra hour of cure time with the 1422 and keep a cooler in the hangar for the sealant itself.

karen41010d ago

Exactly what I needed to hear, like a kick in the pants from someone who already made the mistake. I’m about three months into trying to seal my own project, a beat up old Cessna 150 that’s been sitting in a barn for a decade. I thought I was being smart with the 1440 because it was cheaper, but after my third pinhole in a row I started wondering if I was just bad at this or if the goo itself was out to get me. Now I’m pretty sure it’s both, and I’m buying a cooler for the 1422 this weekend.