Tank leak question

jazzbazzfazz · #1 10-31-2009, 07:36 PM

I've discovered a leak in my right tank after assembly. It's at the seam between skin and outside rib, at the top side of the leading edge. In a nutshell, I can't reachit through the filler capwithout blindly tryingto dab or smear proseal where I'm guessing the leak is.

Anyway, as I see it I have (at least) 4 options:
1. Guess and dab through fuel filler opening and check. Repeat. Repeat. Etc.
2. Hole-saw a 3" access hole in the rear baffle, try to thoroughly clean out aluminum shavings, and go from there.
3. Remove the entire rear baffle, clean, re-proseal where needed and reattach
4. Slosh with PR-1005-L(maybe only at the leading edge/ouboard rib seam.

I'm sure each *can* work, but am interested which combination of ease-of-application/likelihood of success other builders prefer. I'm not sure that (1) will ever succeed (no guarantees). (3) is guaranteed to work, but involves drilling out hundreds of rivets. I've heard that sloshing (4) is better now...can I apply it only to the leaky area? And I'm not sure that a 3" hole inn the baffle will be easier to work through than the filler hole.

Randy Hooper · #2 11-01-2009, 06:31 AM

It sounds like the area will only have fuel when the tank is near full. If that is the case, there will be little pressure on the seam.
I think I would try putting a slight vacuum on the tank, then appling proseal thinned with MEK to the area. After the proseal is sucked in, release the vacuum and dab a little more sealer on the seam. Let it cure and check for leak.

Mel · #3 11-01-2009, 06:56 AM

Personally I would cut the 3" hole in the rear baffle and seal from there. It's easy to do and easy to make sure you have everything sealed. We had to do this on a lot of tanks that used the old unacceptable white slosh compound.
On the other hand, I don't see any problem using the PR-1005 slosh. I wouldn't do the whole tank. Just pour it into the area you are trying to seal. The PR-1005 remains flexible and seals quite well, but is also quite expensive.

D-Dubya · #4 11-01-2009, 07:25 AM

First off, I'm assuming you can't just put a fillet seal of Proseal on the outside where the rib meets the skin. This would be the easiest approach, even if you had to glob up a few inches to make sure you've got the affected area covered. But I'm assuming you evaluated and didn't opt for that approach.

I tried something else that worked for me when I had leaks on the rear baffle. Mine were on the 2nd and 3rd bays in, so they were a little harder to reach. Yours should be much easier to do, if you want to do it this way.

I got one of those bargain grease guns, just like you'd use on a car; get one where you can squeeze the handle with one hand. On the outlet, I attached a piece of copper tubing using a 1/4 tubing to 1/4" NPT fitting screwed into the end of the gun. The size doesn't matter, just make sure you get a new (clean) gun where the nozzle can unscrew, and get a fitting that fits it. Cut the tubing length so that you can operate the gun comfortably and the tubing will reach the leaking area.

I also got one of those little round mirrors from Sears that's on a telescoping rod. I also picked up one of those "bendy lights" (has a bulb on a flexible arm) while I was there, but you should be able to get any kind of small light inside the tank since your leak is on the end. One of those pocket LED lights dropped into the tank (on a string!) may make it easier. Walmart or Academy has them for a couple bucks.

The goal is to stabilize the tank on your workbench in a position where you can access the interior through the fill cap, then insert the light and mirror where you can see the leaking area. Make a test run with the grease gun to make sure you have the copper tubing bent into the proper shape so that it will reach the leaking area. Yes, all three things will be sticking into that hole, but it can be done. I think I ended up taping the bendy light down, leaving my hands free to work the gun and the mirror.

Once you have all of that ready, mix up some Proseal and load it up in the grease gun. You should then be able to glob enough on the seam by guiding the tip of the copper tubing and watching it in the mirror; it doesn't have to be pretty, just get it on there. If this sounds a little awkward, it is--to some extent. But it really wasn't that bad considering the alternatives I was faced with at the time. As I recall, I spent about $25 in tools (the grease gun gets tossed afterwards), and it took a few hours to do.

But the benefit is that you don't have to cut a new hole in the rear baffle (Van's recommendation), or remove the rear baffle altogether. Either of those could create more leaks than you already had. Van's also recommended against the sloshing compound, as they said some builders had reported this stuff sloughing off later on. There may be newer & better compounds out there now, but that's what they told me a few years back.

You may try the easiest approaches first, then give this a shot if those don't work.

rv9aviator · #5 11-01-2009, 07:25 AM

Need a little education here. Is the PR-1005 slosh different from the old slosh that would peel and come loose causing all sorts of problems? How do you prep for using this product after you have already had fuel in the tank. Thanks

Mel · #6 11-01-2009, 08:23 AM

Quote:

Originally Posted by rv9aviator

Need a little education here. Is the PR-1005 slosh different from the old slosh that would peel and come loose causing all sorts of problems? How do you prep for using this product after you have already had fuel in the tank. Thanks

PR-1005 is a red compound that drys to a "rubbery" state that remains flexible. The old slosh we used originally was white and dried to a somewhat "non-flexible" state.
I used the PR-1005 as a final seal in my bi-plane tanks. It works great but is quite expensive. A quart is almost $100.

Kyle Boatright · #7 11-01-2009, 08:28 AM

Quote:

Originally Posted by Mel

PR-1005 is a red compound that drys to a "rubbery" state that remains flexible. The old slosh we used originally was white and dried to a somewhat "non-flexible" state.
I used the PR-1005 as a final seal in my bi-plane tanks. It works great but is quite expensive. A quart is almost $100.

Thread drift alert!!!

What biplane?

Mel · #8 11-01-2009, 12:55 PM

Quote:

Originally Posted by Kyle Boatright

Thread drift alert!!!
What biplane?

No thread drift here. The original question asked about using PR-1005 slosh. I simply stated that I trust it enough to use it in my bi-plane tanks. I've been scratch building a bi-plane in the back ground for several years now.

DanH · #9 11-01-2009, 01:04 PM

Quote:

Originally Posted by Mel

No thread drift here. The original question asked about using PR-1005 slosh. I simply stated that I trust it enough to use it in my bi-plane tanks. I've been scratch building a bi-plane in the back ground for several years now.

Scratch a serious builder and you'll always find a biplane guy in there somewhere

Kyle Boatright · #10 11-01-2009, 01:44 PM

Quote:

Originally Posted by Mel

No thread drift here. The original question asked about using PR-1005 slosh. I simply stated that I trust it enough to use it in my bi-plane tanks. I've been scratch building a bi-plane in the back ground for several years now.

I was the one drifting the thread in order to find out what biplane you're building...