Tanks tested

cjensen · Post by **cjensen** » Thu Aug 17, 2006 11:12 pm

Well, I finally got around to testing my tanks. One is leak free, one has two small leaks in the rear baffle and sender unit. No big deal to fix that, and I'll have two leak free tanks!!

Here's the pics of the leaks-

Just a dab of sealant after they dry overnight and tomorrow, and I should be good to go to install 'em!

JohnR · Post by **JohnR** » Thu Aug 17, 2006 11:20 pm

I was wondering how they came out for you. Since getting home from Osh I have been to busy with work to get much done. However night before last we did a couple of ribs in the last tank and last night a couple more. Only three left! I plan on finishing this last one this weekend. I have to have it done before next Wed when Luke heads to Texas.

How did you test your tanks? Did you use a balloon or another method?

cjensen · Post by **cjensen** » Thu Aug 17, 2006 11:25 pm

Yup, balloon and soapy water-

Worked great, and I think it's much quicker than the manometer method. I knew the instant the spray hit the air hole, that I had a leak.

captain_john · Post by **captain_john** » Fri Aug 18, 2006 7:35 pm

Chad, most guys fix 'em from the inside. Sounds like you aren't gonna do it that way?

Just goop stuff on top?

CJ

cjensen · Post by **cjensen** » Fri Aug 18, 2006 10:02 pm

Yep. I talked to the guys at the chapter meeting last night, and they concurred that smearing it spanwise would work just fine.

We'll see...

bmurrish · Post by **bmurrish** » Sat Aug 19, 2006 9:00 am

Chad,

I am amazed at how clean the rear baffle joints are with the skin. It doesn't look like even have sealant there. Hopefully this won't bite you down the road. I was told to go heavy (but not too much that it interferes with the spar) on the rear baffle, especially in the corners.

How long did you leave the balloon on? When I tested my tanks I used the balloon method as well. I pumped it up with a bike pump and let it sit. The balloon went down a little after 3 days but still had nice size. I figured this was fine since a balloon normally loses size. Just to be safe I plan on doing the manometer method before I mount the wings to the fuse permenently.

cjensen · Post by **cjensen** » Sat Aug 19, 2006 9:11 am

There's a pretty good amount of sealant "bead" inside the tank at the rear baffle/skin. I've never seen or heard of anyone putting sealant on the outside of the baffle/skin joint (unless to fix a leak...

). The other tank was leak free...

I didn't leave the balloon on very long, but spraying with the soapy water would've shown every leak. The tank was swimming in soapy water. I'm confident in this method as it's what we use at work to check for tank and exhaust leaks.

prestwich · Post by **prestwich** » Sat Aug 19, 2006 9:26 am

Of course, no matter what you do, an RV tank can't be considered fully airworthy until CJ has gone swimming with it.

cjensen · Post by **cjensen** » Sat Aug 19, 2006 9:35 am

I gotta figure a way to get mine out to him for the "official" test!

bmurrish · Post by **bmurrish** » Sat Aug 19, 2006 11:08 am

cjensen wrote:I've never seen or heard of anyone putting sealant on the outside of the baffle/skin joint

Check out this site. I consider Dan one of the experts in the RV building arena. http://www.rvproject.com/20020804.html

You might be right in that you never get a leak, but a little insurance never hurts.

captain_john · Post by **captain_john** » Sat Aug 19, 2006 3:07 pm

CJ

cjensen · Post by **cjensen** » Sat Aug 19, 2006 6:11 pm

bmurrish wrote:
Check out this site. I consider Dan one of the experts in the RV building arena. http://www.rvproject.com/20020804.html

You might be right in that you never get a leak, but a little insurance never hurts.

Man, I've been on Dan's site a million times looking over tank stuff, and I never saw that picture.

I blew up the right tank this morning with the balloon, and it hasn't budged AT ALL. I'm gonna go for it as is for now. If I need sealant along the rivet line on the baffle, it's an easy fix later. Since that tank is leak free, I'm movin' on. I see that Dan did that for extra protection, though it's not called in the plans to do so. Seems like overkill...

I did put some along that line to fix the leak I had on the left tank, and it worked great.

Dan A · Post by **Dan A** » Sun Aug 20, 2006 6:03 pm

Bill,
I wouldn't worry too much about the ballon shrinking a little. An increase in barometric pressure will cause the ballon to shrink a little. So if a high pressure area is coming in you will think the tanks leak a little. If there are no soap bubbles, you have no leaks!

Dan

cjensen · Post by **cjensen** » Sun Aug 20, 2006 9:29 pm

That's exactly what happened here yesterday. I let the tanks sit all day with the balloon inflated, and by the evening, high pressure had moved in, and coupled with dropping temps, my balloon had shrunk. No bubbles, no leaks is right!

N200PF · Post by **N200PF** » Mon Aug 21, 2006 6:58 am

VERY COOL CHAD!!! That's a nice section of the project to be past...that I'm still dreading!

- Peter

RV7Factory · Post by **RV7Factory** » Mon Aug 21, 2006 2:05 pm

I riveted my first baffle this weekend and I did exactly as the instructions say and Chad did. I only applied sealant on the skin rivet holes forward, and when I laid the baffle in place, very little sealant squeezed backward. I haven't leak tested yet, and I am keeping my fingers crossed.

Im with you Chad, these rivets are dry under normal condition, meaning the shop head isn't in the fuel. No sealant should be needed here IF a good bead formed ahead of the baffle/skin joint. No harm in testing it first, then applying sealant if needed. At least that is what I am telling myself.

captain_john · Post by **captain_john** » Mon Aug 21, 2006 3:25 pm

I did the same thing. The directions say to leave a bead just ahead of the rivet line. Mine ended up pretty dry too.

On my second one I favored the rivet holes a tad. Some stuff oozed out and it made me more comfortable. I felt that the bond was better, and... after all, isn't that what this is all about? How it makes you feel?

CJ