What Gasket Material for Diesel Tank Inspection Port ?

[rebel heart]

I picked up a tube of this for $8 and so far it's working:

Amazon.com: Permatex 81724 #77 Sensor Safe Ultra Blue RTV Silicone, 3.35 oz. Tube: Automotive

The "right" way to do it is to have custom nitrile(nitrite?) gaskets made. If my $8 solution keeps working I'll be happy.

[never monday]

Originally Posted by ShipShape

ABYC Standard 33.18.1 for diesel fuel tanks:

"All materials used shall be resistant to deterioration as a result of contact with diesel fuel and other liquids or compounds with which the material may normally come in contact under normal operating conditions, e.g., grease, lubrication oil, common bilge solvents, and salt or fresh water."

Buna-N meets this standard.

In the "Findings and Recommendations" section of a survey report, fuel system deficiencies are usually reported under "Safety Deficiencies and Federal Violations". If you are using a gasket material that does not conform to the ABYC standard, in the event of a fuel mishap it is likely that your insurance company will find you negligent and will not cover you.

could you point to that in the CFR


5200 and the Permatex I mentioned are excelent for sealing aluminum parts. Neither are a "permanent" seal.

Gord,
Please post the half life of 5200 in splash exposure to diesel. With a material thickness of 5 mils.

[GordMay]

Originally Posted by never monday

... Gord,
Please post the half life of 5200 in splash exposure to diesel. With a material thickness of 5 mils.

64 Hours

[never monday]

Originally Posted by GordMay

64 Hours

gonna have to call bunk on that one

[GordMay]

Originally Posted by never monday

gonna have to call bunk on that one

Ok - show us otherwise.

[um saudade]

Don’t know if you can still buy this but Kapro made a paper gasket material called Karopac(Sp?) It will not deteriorate under any petroleum product that I know of. It is not very thick so surfaces have to be pretty close fit and it does not crush very well so won’t fill gaps.
　
Three layers of brown paper bag (to make up the thickness needed for proper crush) will goes for years and years with either gasoline or diesel fuel.

Cork, if you can get a big enough pieces will last forever.

I would never use anything out of a tube to seal up a tank of fuel. Good luck with that!

Um saudade

[MPB]

Hello Everyone,

I am in the process of installing a tank access into our aluminum fuel tank in our sailboat.

Although I had initially designed a top plate and bottom plate for my cover, similar to the Seabuilt product (except rectangular).
But after reading so many posts from a variety of areas including automotive, I am thinking that I could discard the bottom plate idea and still get good results.

I would still just use a an 1/8" aluminum top plate, a1/8" Nitrile Buna- N gasket, and use sheet metal screws to secure both pieces to the tank.

Is there a draw back to using this short-cut method ?

Thanks

[GordMay]

I don’t recommend sheet metal screws for permanent installations, as they always work themselves loose, eventually.
Most aluminum tanks aren’t thick enough to accept threaded fasteners.
Accordingly, I’d recommend installing the threaded backing ring.

[David M]

Use nuts and bolts with the bolt head on the inside. Tighten it down by double nutting the end of the bolt threads while you turn the nut that does the actual tightening. Punch holes in the gasket material that are slightly smaller than the bolt diameter.

Use Permatex Aviation Grade #3 Sealant as you sealer along with Nitrile Buna-N rubber as your gasket material. Diesel does not chemically affect either.

I have an aluminum boat with integral aluminum tanks and aluminum access plates that are held together with stainless steel bolts in this manner.

Do not use sheet metal screws.

[MPB]

Gord May and David
Thanks. From reading your previous posts, I guessed you would recommend the nuts and Bolts.

Nuts !!

The project is a fuel polishing system and the plate will have 2 fuel hose connectors (threads /barb) screwed into it - one outlet line and one return line.

Nothing is ever easy.

Thanks

[GordMay]

Originally Posted by MPB

... Nothing is ever easy.
Thanks

"If you didn't have time/$ to do it right in the first place, when will you get the time/$ to fix it?"

[AllezCat]

I have a similar issue with ss diesel tanks. The deck hatch has no gasket, so has been leaking seawater onto the tanks.
There are several low points on top of the tanks, one has pitting in a 3 inch section.
Surveyor mentioned cutting and welding (how empty do the tanks need to be?).
But, would cutting inspection hatches in this location be better? And matching location on other tank. I like the ideas mentioned here.
Or is it too much chance of more problems(since sea water has obviously been flowing through for 10 years) underneath at the mounting points? And just replace?(ok no "just" about this). Seller mentioned "just patch with 'something'...
Cheers

[brankin]

I repaired my fuel tanks with this stuff and it is working great. I also used it to seal my port lights after every marine product on the market failed. It is expensive but well worth the cost....because it works!
http://www.flamemaster.com/TechnicalsPDF/cs3204.pdf

[ShipShape]

cutting and welding (how empty do the tanks need to be?).

more problems(since sea water has obviously been flowing through for 10 years)

Completely empty - diesel fuel has more energy than gasoline, and debris from the process will fall into the tank. After cutting a port, clean the tank very well and have it professionally inspected - ten years of water in the bottom of the tank is a serious concern.

Oh dear, I misread your "onto" as an "into" - never mind my comment about water IN the bottom of the tank. Still a good idea to have the tanks inspected though, and this would be a convenient time to do it.

[AllezCat]

Originally Posted by ShipShape

Completely empty - diesel fuel has more energy than gasoline, and debris from the process will fall into the tank. After cutting a port, clean the tank very well and have it professionally inspected - ten years of water in the bottom of the tank is a serious concern.

Oh dear, I misread your "onto" as an "into" - never mind my comment about water IN the bottom of the tank. Still a good idea to have the tanks inspected though, and this would be a convenient time to do it.

ok thanks.
I think it would be safer to cut inspection ports and add bolted covers. No welding involved. And will "look like a bought one".
Unless there is more serious stuff down below.
600 liter tanks so would imagine expensive to replace, difficult to remove...