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View Full Version : Fuel Tank Cork Gasket Sealant


ten4teg
12-26-2007, 07:20 PM
Looking for recommendations on a sealant for the fuel tank access cover cork gasket. I would like to use something that will allow easy removal if needed down the road, unlike proseal. Thanks, Tom

rv6ejguy
12-26-2007, 07:48 PM
Permatex makes some brown aviation goop which I used on my 6A 4 years ago- no leaks and non- hardening. Can't remember the name of it and it's out at my hangar unfortunately.

I'll try to look it up.

I think this is the stuff: http://www.jamestowndistributors.com/userportal/show_product.do?pid=9403&familyName=FORM+A+GASKET

NYTOM
12-26-2007, 08:11 PM
Funny you should ask at this time Tom since I just did a little research into sealing my own fuel tank cork gaskets. It seems the best stuff out there is what Ross mentioned. It's Permatex Aviation Form-A-Gasket No.3. It works great according to the experts on this site and is non-hardening. You can find it here in the USA at www.aircraftspruce.com and in their catalog on page 291.
A 4oz. can goes for $6.35 and a 1pt. can for $9.70. Just do a search of their site using the term form-a-gasket and it will pop right up.
The other popular option is using the tank sealer "Pro-seal" which works really good but is a one time affair and you have to sacrifice the gasket if you ever want to disassemble the cover.

n5lp
12-26-2007, 08:51 PM
...The other popular option is using the tank sealer "Pro-seal" which works really good but is a one time affair and you have to sacrifice the gasket if you ever want to disassemble the cover.Many, like me, have ditched the cork gasket after problems. Proseal isn't all bad!

JAT
12-26-2007, 11:31 PM
I just helped two guys do their fuel tank SB and ProSeal is very hard to get off! I used Permatex Form-A-Gasket (Aviation) on one side only to hold the cork gasket on the plate. The important difference is that I use Allen head 8-32X1/2" screws to fasten it on instead of the Phillips head screws called for in the plans. The Allen heads will allow you to torque the screws evenly; just don't overdo it. You will need a longer screw, 3/4", for the sending unit due to the thickness of the rubber gasket. Put a dab of the Permatex on the threads of all screws before installing and then give the whole works several days to dry before refilling the tanks. The above Permatex is available at NAPA Auto Parts and has Aviation on the label. The screws are available at your local hardware store in plain steel and they work fine.

sprucemoose
12-27-2007, 03:12 AM
Another vote for Aviation form-a-gasket. Available locally at auto parts stores. Ditto the recommendation for socket head, torx, or anything other than phillips screws.

One little trick- dip the screws into Fuel Lube or similar prior to inserting. Keeps fuel from seeping around the screws threads.

Rick6a
12-27-2007, 05:28 AM
Per an Orndorff construction video suggestion, I used medium weight TiteSeal on the cork gaskets and fuel tank access covers. After 2-1/2 years of operational service, it seems to be holding up just fine.

http://img20.imageshack.us/img20/9605/titeseal00615jt3.jpg (http://imageshack.us)

L.Adamson
12-27-2007, 07:39 AM
I just helped two guys do their fuel tank SB and ProSeal is very hard to get off!

That's because it seals so good! :D

When doing the SB, I initially got a bit excited (in a negative way) about the removal too; until I figured it out. I then put them back on with pro-seal only. I highly trust the pro-seal only method.

L.Adamson -- RV6A

erich weaver
12-27-2007, 11:25 AM
One little trick- dip the screws into Fuel Lube or similar prior to inserting. Keeps fuel from seeping around the screws threads.


I dont disagree with this, but be aware that at least one screw must make a good electrical contact with the plate that it is holding or you wont have an electical ground path and your fuel level floats wont work. Ask me how I know...

Go ahead and dip those screws - but check the ground path to the adjacent root rib with a multimeter

erich

sprucemoose
12-27-2007, 01:49 PM
Go ahead and dip those screws - but check the ground path to the adjacent root rib with a multimeter
Excellent point. I'll go you one better- run a ground wire from the sender to a nearby screw and don't rely on the screw/platenut/proseal/gasket to form a good ground. That's what I did (maybe overkill) and my gauges work great.

Flyrod
12-27-2007, 03:42 PM
I think I would go Pro-Seal and be done with it. The tanks on GG were constructed 8 years ago and the sender for the flop tube tank has started leaking. You gotta pull the tank to get to that sender..... oh joy.:(

When I do the deed, I will let you know what didnt work more than 8 years.

rvbuilder2002
12-27-2007, 04:45 PM
I just helped two guys do their fuel tank SB and ProSeal is very hard to get off!

This is too general of a statement...It all depends on how the covers are installed in the first place.
I have never used the gasket for either the cover or the level sender (more than a dozen RV's to date) and have removed a number of senders or covers with no problem at all.

The key is to actually mold a gasket of proseal by spreading a liberal amount on one of the mating surfaces. Install the cover or level sender (it helps to have one or two screws in the screw holes to help properly position it) and push in place just enough to squeeze a little sealant out of each screw hole.
Install the rest of the screws but only tighten them enough to slightly squeeze out sealant around the perimeter of the part.

You must leave a 1/32 to 1/16 inch thickness of proseal between the parts to act as a gasket. If you do this, it is not difficult to tap a small putty knife between the parts and easily separate them.
If you use proseal and fully tighten the screws, all you have a a thin (.005 - .010 inch) layer of sealant between the parts...very difficult to remove.

Many builders use the gaskets and go quite a few years with out any problems. The down side is that It is pretty much guarantied that they will leak eventually.
If you properly use proseal, it pretty much guaranties that the cover or sender will never leak.

NYTOM
12-27-2007, 08:32 PM
To you who have used the ProSeal method. Did you use the cork gasket and smother it in ProSeal or not use a gasket at all? I'm thinking a gasket isn't really required unless you have to get back in there for any reason.:eek: I was definitely leaning towards the Permatex camp but now you got me thinking the Pro-Seal way might last a lot longer. :)
rvbuilder2002 spells it out pretty good in the last post but does anybody else have any input?

L.Adamson
12-27-2007, 08:46 PM
To you who have used the ProSeal method. Did you use the cork gasket and smother it in ProSeal or not use a gasket at all?


No gasket

L.Adamson

CFI1513840
03-16-2008, 05:42 PM
Per an Orndorff construction video suggestion, I used medium weight TiteSeal on the cork gaskets and fuel tank access covers. After 2-1/2 years of operational service, it seems to be holding up just fine.

http://img20.imageshack.us/img20/9605/titeseal00615jt3.jpg (http://imageshack.us)

I used TiteSeal to seal my access covers and fuel sensors, but wondered about the tendency of it to "run". On the outside of the tank, the excess TiteSeal that was squeezed out slowly ran down the rib and "pooled" at the flange. I wondered what it looked like on the inside and if it could possibly contaminate the fuel?

I tried a test using a blob of TiteSeal in a glass jar with mogas. After a couple of hours, there was a lot of sediment in the jar and the mogas turned grey. Shaking it really stirred up a lot of sediment. For the test, I didn't allow the TiteSeal to "dry". My assumption was that as it never hardens and always remains in the gooey state, drying or aging should not really change the way it reacts to fuel.

Now I'm thinking about removing the covers and resealing them, possibly with Proseal (the wings are still in the cradle).