What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Another tank repair question

navy06

Active Member
I need to address some long standing small fuel leaks on my RV3. I have read many threads and gained some good info. I will be ordering some of the round cover plates from vans but have a few questions.
1. My tanks are older and I think they may have used the formerly recommended slosh compound in addition to proseal (they are white inside) how will this complicate any repair if true.
2. When riveting on the repair plates with proseal can they be easily removed if necessary for a second repair?
3. When i installed my tank end sender I used the supplied rubber gasket with both sides of gasket covered with permatex type 2 non hardening sealant and ten years later no leaks. Would a homemade gasket using the same stuff work on the new inspection plates? Would be advantage to make plates easier to remove. Has
anyone had to drill out the blind rivets for a second repair? Is it hard to do?
 

Attachments

  • 33BF6BFC-808B-44AC-BA1F-EA951B30BD1D.jpg
    33BF6BFC-808B-44AC-BA1F-EA951B30BD1D.jpg
    344 KB · Views: 113
The slosh compound is a problem. Best I know, you can't use proseal over it. I have removed slosh from older composite Kitfox tanks with MEK and a stiff brush, but it ain't fun.

Offhand I don't know of anyone who has removed rear baffle repair plates for a second repair, but drilling the closed end rivets would not be a problem.

I would not use gaskets on repair plates. The joint is more or less structural.

BTW, here's something for the group. Polysulfide sealant has a standard for elongation, minimum 200%. Problem is, if two metallic surfaces are placed in extremely close contact, the thin sealant film can fail cohesively if the joint is stressed so relative movement between the surfaces exceeds the available elongation. For example, if the sealant film thickness is only 0.001", and the joint is stressed to 0.003" in shear, it may fail the sealant.

So, best practice is a joggle outside the rivet line so the sealant is thick there, while maintaining the tight structural shear joint at the rivet line. Cohesive failure is impossible in the thickened section without shearing the rivets.

Look close at the plates in the photo.

Not cheap, but here's the easy way to deal with slosh:
https://www.weepnomorellc.com/services.html
.
 

Attachments

  • Closed End Rivets.JPG
    Closed End Rivets.JPG
    47.8 KB · Views: 204
  • Joggle Seal.jpg
    Joggle Seal.jpg
    31.7 KB · Views: 109
  • P1220002.JPG
    P1220002.JPG
    250 KB · Views: 197
I had the dubious honor of removing one of the plates after a fix fail. The rivets are easy to remove. Getting the cover off took some patience. Gently working a sharp plastic tank scraper along the edge of the seam with a little Toluene solvent and it eventually came off and I was able to reuse it.
Mike
 
I need to address some long standing small fuel leaks on my RV3. I have read many threads and gained some good info. I will be ordering some of the round cover plates from vans but have a few questions.
1. My tanks are older and I think they may have used the formerly recommended slosh compound in addition to proseal (they are white inside) how will this complicate any repair if true.
2. When riveting on the repair plates with proseal can they be easily removed if necessary for a second repair?
3. When i installed my tank end sender I used the supplied rubber gasket with both sides of gasket covered with permatex type 2 non hardening sealant and ten years later no leaks. Would a homemade gasket using the same stuff work on the new inspection plates? Would be advantage to make plates easier to remove. Has
anyone had to drill out the blind rivets for a second repair? Is it hard to do?

Here is an option if you don't feel like tackling the project yourself.

https://www.weepnomorellc.com/rvgallery.html
 
I am checking with weep no more and would consider building new tanks. Does anyone know if vans even supplies new tank kits for the original RV3A? I plan to contact them Monday. Thanks all for the replies. I would also like to communicate with the owner who had a soda blaster clean the tank internally.
 
Repair tip for removing prosealed access plates ---

Not sure where I read this, but if you are trying to remove a repair plate or the standard access plate that is on the wing root, once you have removed all the pop rivets or screws and you have started to scrape away the pro-seal, once you have a little bit of plate lip exposed, use 12"-18" of .020 safety wire and use it as a garotte and slice the proseal by working it back\forth.

I have re-opened patch plates on two seperate aircraft, not difficult, just drill out the rivets and work away at getting the pro-seal removed.

Good luck
 
Has van’s switched from original proseal to another product call Flame (something). Small portions comes in a prepackaged mixing tube. Are current builders using something different than proseal from van’s?
 
1. My tanks are older and I think they may have used the formerly recommended slosh compound in addition to proseal (they are white inside) how will this complicate any repair if true.
2. When riveting on the repair plates with proseal can they be easily removed if necessary for a second repair?
3. When i installed my tank end sender I used the supplied rubber gasket with both sides of gasket covered with permatex type 2 non hardening sealant and ten years later no leaks. Would a homemade gasket using the same stuff work on the new inspection plates? Would be advantage to make plates easier to remove. Has
anyone had to drill out the blind rivets for a second repair? Is it hard to do?

1. It will complicate matters greatly! If you take off the slosh around the repair how will you ensure the edge is sealed so the remaining slosh doesn't just peel off? You may have to remove the slosh completely...
2. Yes but my experience is removing the plates is difficult after the rivets are drilled out. I have had to use a long blade knife to get in between the plate and the structure.
3. The repair plates are just circles of 2024 with holes at about 1" centres around the circumference. Any type of fuel proof sealer would work, most people use Proseal or another kind of polysulphide sealer, in Europe it is called PR1440. Van's now don't recommend using a rubber gasket - cork may be OK. Along the lines of Dan's post it is best to try to get a fillet on the inside edge and a gob around the rivet tail.
 
I have pulled left tank and it appears only one rivet leaking. It’s a blind rivet on the distal tank end plate. Any advice on technique to drill out, proseal and reinstall? Part of rivet will remain in tank I presume?
 
Since I am considering having WNM fix my tanks would an attempt for time being using epoxy be possible? Clean around the pulled rivet with Mek and scotch brite area and place a good quality epoxy in a dome around and over rivet.
 
Since I am considering having WNM fix my tanks would an attempt for time being using epoxy be possible? Clean around the pulled rivet with Mek and scotch brite area and place a good quality epoxy in a dome around and over rivet.

If on the top of wing, green locktite has been used with a good degree of success.

BTDT
 
If on the top of wing, green locktite has been used with a good degree of success.

BTDT

Thanks. I took another look and will just order some proseal and rivets from Vans. Here is a photo of leak. If this fixes this tank maybe I can live with the other side leaking a little as I in the past left it nearly dry and just filled up for a long trip burning it near empty first.
 

Attachments

  • 0A9805A1-ECBD-4584-B926-6660347643B2.jpg
    0A9805A1-ECBD-4584-B926-6660347643B2.jpg
    315.5 KB · Views: 123
I Have discovered that careful use of a heat gun like used for skrink tubing will soften the proseal and make for easier removal of inspection plate. One question is I ordered the 3.5 oz tubes of the proseal replacement product from aircraft spruce. What is the difference between CS 3204 B1/2 and CS3204 B2 ?
 
I Have discovered that careful use of a heat gun like used for skrink tubing will soften the proseal and make for easier removal of inspection plate. One question is I ordered the 3.5 oz tubes of the proseal replacement product from aircraft spruce. What is the difference between CS 3204 B1/2 and CS3204 B2 ?

B1/2 has a 1/2 hour working time. B2 has a 2 hour working time.
 
Remove slosh easily

I have personally removed slosh in both my tanks when I had my 6A. I used Professional strength Goof Off. It would wrinkle in less than 20 seconds and almost wipe right off. Removing the Proseal was the hard part. Goof Off softened it but was difficult and removed the Proseal using a plastic putty knife. It took me a total of 30 hrs for each tank from removing the tank to installing the tank. If I had to remove Proseal again I would spend the money to buy Polygone, it probably would have saved me 10-15 hrs for each tank.

Instead of using the circular replacement baffles I had rectangular replacement baffles made to give me more room to work. For the wing root circular baffle for the fuel sender I made a cork gasket and used Sealube or EZ Turn lube on both sides of the gasket and worked perfectly. Use the Chemseal (less than Proseal and is the same stuff). Chemseal B2 2oz. Get the $15 mixer tool used for a drill to mix it, well worth the cost). From memory you’ll need four 2oz tubes per tank including installing the rear baffles. The B2 gives you 2 hrs of working time. Scott rite the joints/seams and use a tight fitting rubber glove. You will not be able to apply the Chemseal/Proseal using a caulk gun or pushing the handle. Attempt it if you like but you will quickly abandon it. Apply with finger is best, quickest, and easiest. You will need a mechanics mirror to make sure you didn’t miss any spots.

I cut the rear baffle holes using a dremel. REMEMBER TO FLUSH YOUR TANK WITH WATER AND BLOW PLENTY OF AIR THROUGH YOUR TANK BEFORE CUTTING WITH THE DREMEL UNLESS YOU WANT TO RISK AN EXPLOSION. REMOVE THE BAFFLE WITH THE FUEL SENDER IN ORDER TO BLOW AIR THROUGH THE TANK BEFORE CUTTING REAR BAFFLE HOLES.
 
Last edited:
Kyle and FireMedic
Thanks for the info-very helpful. Right now I have both tanks off and planning to do minor fixes to get me back in the air and soon have weep no more redo the tanks. They are hard to contact but I do know the cost which is substantial. I got my RV3 less engine in 2012 for a very good price and feel part of the cost of tank repair can be recouped when I sell it in 3 or 4 years. I think that much if the leak in one tank is due to the large inboard inspection cover on right tank which will be easy fix. It’s a blank plate as the fuel sender is on back due to having flop tube. I am going to try a nitrile rubber gasket using sealer and test before reinstalling.
 
I have had to go into some fuel tanks multiple times to reseal them. Some tanks are cursed! The tank repair kit covers are easy to get off if needed. I have a special pop rivet removal tool that centers the bit on the rivet and prevents you from going into the rivet hole too far. Once the head of the rivet is drilled, just punch it out. I have a small putty knife that is well smoothed out that I can get under the proseal and then work it around to pry off the repair kit cover. I use the Poly-Gone product to remove the old sealant before resealing.
 
I've owned 4 Mooney's,3 out of the 4 had integral wet wing fuel tanks. 3 out of the 4 eventually developed tank leaks.

I never had one with runny pro-seal, which is quite common to see in RV tanks.
I think this is because Mooney uses a brushed on overcoat (PR-1005-L) applied over the bare Pro-Seal. It is definitely not tank slosh, it is brushed on (not applied anywhere except over the proseal).

I've never seen it come loose or flake off. It is my understanding it's purpose is to protect the underlying sealer from volatiles in the avgas. My experience (4400 hours flight time in Mooneys and performing annual inspections on many others) it seems to work for that purpose.
 
Back
Top