Tanks in progress

blueflyer · #1 12-18-2013, 03:11 PM

I am now working on prosealing my tanks. I am using Rick Galati's suggested method outlined here http://www.vansairforce.com/communit...ead.php?t=7602 Now that I have the hang of it, and I have a feel for mixing better portion sizes, this tank work aint the worst thing in the world. It is slow work when it comes to covering each rivet head with proseal though. Here's a couple of photos of my progress. I hope to get them finished up this weekend.

N941WR · #2 12-18-2013, 03:16 PM

Just don't clean any of the tank, rivets, etc. with MEK. Let it harden and then you can sand it off the outside but don't wipe it clean with MEK.

I made that mistake on the top of only one tank and guess where I had leaks that I had to fix?

blueflyer · #3 12-18-2013, 03:25 PM

Quote:

Originally Posted by N941WR

Just don't clean any of the tank, rivets, etc. with MEK. Let it harden and then you can sand it off the outside but don't wipe it clean with MEK.

I made that mistake on the top of only one tank and guess where I had leaks that I had to fix?

Dang it! I did that! Oh well.....that's the joy of building, live and learn. I'll address that issue when it raises its ugly head. How did you fix the leaks?

N941WR · #4 12-18-2013, 03:32 PM

Quote:

Originally Posted by blueflyer

Dang it! I did that! Oh well.....that's the joy of building, live and learn. I'll address that issue when it raises its ugly head. How did you fix the leaks?

I sanded off the paint, put a negative pressure on the tank using a hand vacuum pump with gauge and then applied green, wicking Loctite to each rivet head. After that dried, I pressed some proseal into each rivet head. (I still need to repaint the top of my left tank but that may wait until spring.)

One of the rivet leaks was right next to the fuel cap. This allowed me to feel in there to see if I didn't put enough proseal on the rivet. As it turned out, that rivet was covered with proseal. All I can figure is the MEK penetrated the proseal and allowed the vapors to leak.

At about the time I found this out, a friend who used to work for Boeing told me that they never touch any proseal with MEK unless it was to clean tools. (I don't think Boeing uses MEK for anything any more, but I'm not sure about that.)

Some will say that MEK can't cause these leaks but I don't buy that. Again, the only place I had leaks where ware I cleaned the surface with MEK. Go figure! In short, I wouldn't risk it.

Good luck with your tanks!

blueflyer · #5 12-18-2013, 03:37 PM

Quote:

Originally Posted by N941WR

I sanded off the paint, put a negative pressure on the tank using a hand vacuum pump with gauge and then applied green, wicking Loctite to each rivet head. After that dried, I pressed some proseal into each rivet head. ........

Thank you.

JimWoo50 · #6 12-18-2013, 04:24 PM

When you install the rear baffle to the skins the tendency for me anyway was for the sealant to be squeezed out of the skin/baffle seam. Good Luck.

JimWoo50 · #7 12-18-2013, 04:29 PM

I can't tell from your pics if you opened up the lightening whole on the fuel filler rib to full diameter but if you do this and the next inboard one it will make fueling the plane easier.

Andrew M · #8 12-18-2013, 04:33 PM

After assembling wet, most of the excess sealant can be scraped off with a tongue depressor that's dyked off square. Then I wipe off the sealant with a very lightly damp small piece of paper towel. If I can wring out any fluid, it's to much. One or two passes out of each piece. Then sealant is applied with these "spoons"

(edit, link don't work. see signature for build photos)

The tool is kept clean,scooping a small amount out of a cup and laying/pushing the sealant on. The syringe is used for the seams, and again, the spoon is used push it in.
When I went to the hardware store to buy these nails, I asked the guy how much he wanted for da few nails. He just laughed at me and sent me on my way. Free tools!

akarmy · #9 12-18-2013, 05:07 PM

Quote:

Originally Posted by blueflyer

I am now working on prosealing my tanks. Now that I have the hang of it, and I have a feel for mixing better portion sizes, this tank work aint the worst thing in the world. It is slow work when it comes to covering each rivet head with proseal though.

Looking good. Keep at it and you'll be on to the next challenge soon!

YellowJacket RV9 · #10 12-18-2013, 06:29 PM

I wouldn't worry too much about the MEK. I did at first, and then started looking into it. There are many other builders that use MEK to actually thin the pro-seal for some applications, and plenty others that have used it to clean the outside of tanks with no ill-effects. I am not saying that the problems somebody else experienced are not real, but would not worry too much about the MEK causing leaks IF you make sure to fully cover every rivet shop head and form nice complete filets around every seam. I cleaned my tank skins with MEK and they tested leak free right off the bat. Maybe fuel vapors will be different, but they'd have to go through a LOT of MEK to get out. Proseal is (relatively) cheap, I used plenty.

I agree that the tanks were actually not nearly as bad as I had thought. Just messy. And seeing that balloon stay inflated overnight was one of the best feelings of the build so far!

Chris