Jeffco problem; possible reason

[CBarber]

I may have determined why my Jeffco failed in my fuel strakes. As loyal fans may remember I had to remove all the old epoxy/Jeffco from my strakes and redo them completely a couple of months ago due to the Jeffco peeling away. Well, as I was poking around the hangar looking for something I had placed as to be able to find it easy later......yeah, right, I came across my old Jeffco bottles. Hmmmm, the Hardener is labeled 3191 and the Resin is labeled 9700. Now, I remember that when I ordered it a few years ago it was 9700. I remember specifically as when I first ordered from AS&S they sent the wrong stuff and I returned it for the 9700. THIS time I ordered new Jeffco, but choose not to use it and just use straight EZpoxy for my strakes, however, in the new order BOTH the Hardener AND the Resin were labeled 9700. My current thought is that I used the Hardener that AS&S supplied with the kit assuming (yeah, bad Chris for assuming) that it was the correct one to use with the 9700 Resin....which is what I knew to be the proper number. It was not until the new order arrived a few months ago and I saw both the hardener and resin are both 9700 and finding the original bottles from a few years ago that I would have ever discovered a problem.

 

FWIW.

 

All the best,

 

Chris

[Jerry Schneider]

Whew!

I used Jeffco as well, and was putting off fueling for fear my tanks would get "leprosy" too.

Your discovery makes sense.

Thanks for posting it. (Sigh of relief)

[Wayne Hicks]

Could yall check something for us, the curious? Perhaps the label has some verbage on it that states the acceptable resin and hardener types to be used?

[bferrell]

Chris,

 

That wasn't your problem, that's the "slow" hardener, which is easier to work than the 9700 "fast" hardener. Here's a views article about it.

Velocity Views

 

Brett

[Jerry Schneider]

That wasn't your problem, that's the "slow" hardener, which is easier to work than the 9700 "fast" hardener. Here's a views article about it.

Velocity Views

Dang!

I had hoped it would be just that simple.

[Neverquit]

Maybe, just maybe(?) it IS the solution. I had to get the gas tank sealer directly from Jeffco (Rhino Lining) . I don't think ACS carried it 2 years ago. Or possibly they didn't carry just a gallon. All you need. Anyway, I gave a lot of questions to Jeffco when ordering due to the controversy and not once did they mention a slow or fast hardner to me. Just because its suggested in the newsletter doesn't make it comfortable for me. Chris, I suggest calling one of the Rhino Lining techies or even Jeff Bassman himself for some solid advise. Keep us updated okay?

[Marc Zeitlin]

Maybe, just maybe(?) it IS the solution....

Not that I've got a dog in this hunt - my tanks are sealed, no leaks, and I use only 100LL - but it's sort of interesting from a forensic standpoint. Viewing the Product Data Sheet on the Rhino Linings Industrial website, there's no way you could convince me to use this material in an airplane wet fuel tank.

 

First of all, it says:

 

"SURFACE PREPARATION:

Substrate surfaces must be structurally sound and free from contaminants such as dust, oil or dirt. Surfaces must be shot blasted or mechanically abraded to achieve a minimum 5-mil profile. Free-standing water must be removed. Do not apply over previously applied epoxies or coatings."

 

Note the last sentence - do NOT apply over previously applied epoxies or coatings. Well, that's what the inside of a composite canard wing IS - previously applied epoxy.

 

First hint.

 

Secondly, it says:

 

CHEMICAL RESISTANCE GUIDE (3 week immersion)

Reagent % weight gain (loss)

Ethyl Alcohol 6.9

 

Holy crap - 6.9% weight gain in 3 weeks of exposure to Alcohol? What's this stuff going to do when exposed to autofuel with Ethyl in it for months or years on end? I certainly don't want to find out. Or maybe Chris just did.

 

Second hint.

 

 

It's fine with JP-4, etc. and CLAIMS to be OK with Mogas and Diesel, but that Ethyl Alcohol 6.9% would scare the crap out of me if I had an auto engine on my plane, or was planning on using auto fuel with this stuff.

 

I was never keen on this stuff as a tank sealant in the first place, but reading this PDS convinces me that it's the wrong stuff. If I wanted a tank sealant, because I had done a poor job of applying the epoxy to the tank per plans, I'd use Pro-Seal from PPG. See:

 

http://www.vansairforce.net/articles/tank_sealant.pdf

 

for a description. This is what it's MADE for. See:

 

http://buyat.ppg.com/REP_aerospace_files/Sealants/pr1440b.pdf

 

for specific material data.