[s24789]

I am about to install the fuel sending units in my 7A wings. Looking for thoughts about scrapping rubber seal and sealing with ProSeal. Also wondering if there is any need to replace the cork seal in the main cover before wings go on or just replacing with ProSeal?
Please any constructive ideas are welcome.

 

[instructor_bill]

sender/cover sealant

I also did a bit of reading on the topic before sealing them up.


I decided to go with titeseal along with the gaskets supplied with the wing kit and sending units. If memory serves... it's what the Orndorff vids advocate.

I've found titeseal easy to work with as it never dries, held up fine to my pressure tests, and is easy to clean up. I also will never have to worry about being able to get back into the tanks should I need to remove the cover or sending unit. You will however need to use gaskets of some sort with this product.

I'm pretty sure I bought it from aircraft spruce.

 

[Mel]

Do not use the cork gasket. Regardless of other sealants you use, the cork gasket will become saturated and begin to seep within about 3-5 years.
I use pro-seal only with no gaskets. I've done many tanks and never experience leaks. Removal, if necessary, is relatively easy with a sharpened putty knife.

 

[L.Adamson]

Do not use the cork gasket. Regardless of other sealants you use, the cork gasket will become saturated and begin to seep within about 3-5 years.
I use pro-seal only with no gaskets. I've done many tanks and never experience leaks. Removal, if necessary, is relatively easy with a sharpened putty knife.

And there are a whole lot of other RV builders who found this to be true.... too!

Besides, if you really have to get into the tank later, the proseal can be removed with a few simple tricks. But in the meantime, you'll have the best possible seal by leaving all the gaskets hanging on the garage wall pegboard.

L.Adamson --- RV6A

 

[jsharkey]

I'll third that...

And there are a whole lot of other RV builders who found this to be true.... too!

Besides, if you really have to get into the tank later, the proseal can be removed with a few simple tricks. But in the meantime, you'll have the best possible seal by leaving all the gaskets hanging on the garage wall pegboard.

L.Adamson --- RV6A

Proseal only - no leaks so far. A leak (slow drip) from a fuel drain with a minute piece of building debris caught on the O ring - even after what I thought was a thorough pre clean. Pain to drain the tank but easy to fix.


Jim Sharkey
RV-6 Phase 1

 

[Rick6a]

Do not use the cork gasket. Regardless of other sealants you use, the cork gasket will become saturated and begin to seep within about 3-5 years.....

........you'll have the best possible seal by leaving all the gaskets hanging on the garage wall pegboard....

Using medium weight Tite Seal, I installed the cork gaskets on the fuel tanks of my -6A. As a newbie at the time, I simply followed a George Orndorf construction video suggestion. That was over 8 years ago....well past an arbitrary 3-5 year prediction of failure. Still, in all this time no seepage or leaks have been observed.

That said, since that time 8 years ago, I contacted Van's regarding this perennial issue. Turns out, they use cork and proseal. So the second time around, I followed their highly seasoned and experienced lead and chose to go with cork and proseal. With thousands of RV's flying and especially given all the feedback they get from builders past and present, if Van's discovered a fundamental problem using cork gaskets as supplied with their kits, don't you think they'd let us in on it?

When those Tite Sealed cork gasket and cover plates finally start to seep or leak....I'll let others know. At this point 8 years later, time and leak free operational experience have suggested to me there is no right way or wrong way, just differences in personal OPINION. Opinions are shaped by our own experience and to a lesser extent...what we "hear" from others. My opinion? Just do what you want.....but do it with care.

 

[Kyle Boatright]

My airplane had no leaks with the proseal and cork for 5-6 years until I had to pull the tank access plates to comply with the service bulletin on the anti-rotation fitting for the fuel strainer. Like the pictures in a previous post, I had applied a filet of proseal over the edges of the cork and had buttered the cork on both sides with proseal.

When I replaced the access plates, I skipped the cork gasket and just used proseal.

Either way works.

 

[Sam Buchanan]

Proseal only - no leaks so far. A leak (slow drip) from a fuel drain with a minute piece of building debris caught on the O ring - even after what I thought was a thorough pre clean. Pain to drain the tank but easy to fix.


Jim Sharkey
RV-6 Phase 1

Why did you drain the tank? Next time this happens, take the 1/8" NPT plug that you carry in your flight bag (hint, hint) and quickly swap it out with the drain valve. You shouldn't lose more than a few dribbles of fuel. After cleaning the o-ring, you can reinstall the valve at your convenience without draining the tank.

Even better than carrying the plug, a spare drain valve will have you flying again in a few minutes if the o-ring lets go while on a ramp away from home (usually where it happens......).

 

[Kyle Boatright]

Why did you drain the tank? Next time this happens, take the 1/8" NPT plug that you carry in your flight bag (hint, hint) and quickly swap it out with the drain valve. You shouldn't lose more than a few dribbles of fuel. After cleaning the o-ring, you can reinstall the valve at your convenience without draining the tank.

Even better than carrying the plug, a spare drain valve will have you flying again in a few minutes if the o-ring lets go while on a ramp away from home (usually where it happens......).

I carry a spare quick drain for that purpose. And a 7/16" wrench (IIRC). Pull the old drain, thumb over the hole, position the new drain and screw it right in. Clean the junk out of the drain you removed, and put it back in the spares kit. Literally a 1 minute job if you have the stuff on-hand.

 

[rvbuilder2002]

.

That said, since that time 8 years ago, I contacted Van's regarding this perennial issue. Turns out, they use cork and proseal.

You received incorrect information.
All of Vans Aircrafts protypes and demonstrators have covers and level senders installed with tank sealant only.

 

[az_gila]

...and an hour or two...

I carry a spare quick drain for that purpose. And a 7/16" wrench (IIRC). Pull the old drain, thumb over the hole, position the new drain and screw it right in. Clean the junk out of the drain you removed, and put it back in the spares kit. Literally a 1 minute job if you have the stuff on-hand.

...for the smell of 100LL (or auto gas) to disappear off your arm....

 

[nomocom]

Save the cork for wine bottles and nice flooring

Why have the cork in there when proseal works just fine? Cork should probably be avoided if there is any mogas in the airplanes future (google cork and ethanol compatibility for more). Maybe you have no intention of putting 10% ethanol in your airplane, either running 100LL or testing all the mogas for ethanol, but seems like a good idea to set it up now for a future of maximum flexibility and minimal hassle. Hard to know what you might want to do 5 years from now or what the next owner will use for fuel?

Here's a source for more if a person is so inclined. 28 bucks or an existing subscription to get the whole paper

Suitability of Corkrubber Gaskets in Gasoline-Ethanol Blends
Journal Materials Science Forum (Volumes 636 - 637)
Volume Advanced Materials Forum V
Edited by Lu?s Guerra ROSA and Fernanda MARGARIDO
Pages 266-272
DOI 10.4028/www.scientific.net/MSF.636-637.266
Online since January, 2010
Authors P. Gil, J. Fernandes, M.M. Neves, Lu?s Reis
Keywords Corkrubber, Flat Gasket, Fuel Resistance, Gasoline-Ethanol Blend, Sealing
Abstract The increasing use of biofuels, namely blends of gasoline with ethanol, requires the identification of its impact on the fuel admission components of internal combustion engines that have not been specially design to work with high levels of ethanol. This paper provides a discussion on performance testing of corkrubber gaskets from a commercial company (ACC ? Amorim Cork Composites) to seal these engines using gasoline and gasoline-ethanol blends. In order to evaluate the chemical compatibility of four corkrubber composites, several samples were immersed in different blends of gasoline with ethanol to determine the changes of hardness, volume, thickness and weight. The results of these tests differed between materials, but all of them showed less damage tolerance to blends with low and medium percentages of ethanol (e.g., E5, E10, E25, E50) when compared to gasoline or blends with higher percentages of ethanol (E85).An aggressiveness factor is proposed to compile results from the immersion tests. Validation tests were carried out in conditions as close as possible to the service and accordingly to similar test standards. This study allows concluding on which of these corkrubber composites have adequate sealing properties for gasoline as well as blends of gasoline with ethanol.

 

[Bavafa]

Toss the cork or the rubber gasket and proseal or equivalent is the way to go. I did my main access with proseal and left the rubber gasket for the sending unit. Well both sides leaked from the sending unit but the main access that I used proseal has never leaked.