Stainless fittings into aluminium

[team karst]

That’s a great, but damage filled story. Thanks for the link. I need to inspect mine next time the fuel is low.

[skipmac]

Originally Posted by team karst

That’s a great, but damage filled story. Thanks for the link. I need to inspect mine next time the fuel is low.

Hopefully you have a decent inspection plate you can remove to look inside. If, like me, you have only a small hole where the gauge mounts my trick is the same thing I did to inspect my SCUBA tanks. Took a small 12V bulb, soldered it onto a couple of 3-4' wires. Connect that to a battery then lower it into the tank. Gives a good light without blocking your inspection hole with a flashlight.

[RaymondR]

Originally Posted by team karst

What is the other metal in the tank bottom example? I suspect it may be the alloy itself; possibly Cu in the mix.

It does not need much difference in the metallurgical make up of the metals to create a corrosion cell.

[Wideocean7]

It seems my original post has been subject to a bit of "topic creep" away from my original post about fittings. But this is great and certainly not a criticism as it is fascinating and educational to hear what others are doing. For what it's worth, I'll be using ss fittings into alu and will do my extreme best to isolate the two. I'm also going with two fuel supply ports. The primary is at the bottom of the tank which will also have a drain valve. This way all fuel (and crud) will go to the twin Racors before the engine. The second supply will from the top of the tank via a pick-up tube in case of a suspected blockage of the primary port. There will be a changeover switch between the two. Perfect - undoubtedly not. Other options - most certainly. But that seems the best option in my case having listened to the great comments on this forum.

[mitiempo]

Originally Posted by Wideocean7

The primary is at the bottom of the tank which will also have a drain valve. This way all fuel (and crud) will go to the twin Racors before the engine. The second supply will from the top of the tank via a pick-up tube in case of a suspected blockage of the primary port. There will be a changeover switch between the two. Perfect - undoubtedly not. Other options - most certainly. But that seems the best option in my case having listened to the great comments on this forum.

I would keep the primary pickup from the tank top. I would keep the drain as well.

[sailingharry]

Originally Posted by thinwater

You are NOT going to succeed in electrically isolating them if they are at all tight. I hope this is obvious on the face of it, and you can check with a multimeter. What you are trying to do is exclude oxygen. A thread sealant such as Locktite will do that, as will a hard-to-wash-out grease like Tefgel. However....



Teflon pipe dope is a better sealant for this application, particularly with straight/taper mismatch (which does does not always work out).

Thin,


Slightly off topic, and on a thread a few months old. But not too astray, I hope.


I'm preparing to set stainless threads into aluminum, the nightmare of sailors the world over. Recommended materials include blue locktite, tefgel, and lanocote. Tefgel is simply teflon paste -- and googleing got me to your comment above.


Is Teflon pipe dope an effective alternative to Tefgel? Sure, a tub of TefGel is only $35 (or double that at West), but it's more money spent and more stuff to store if the Teflon pipe dope on my shelf is comparable.


Your thoughts?


Harry

[Cheechako]

Originally Posted by sailingharry

Thin,


Slightly off topic, and on a thread a few months old. But not too astray, I hope.


I'm preparing to set stainless threads into aluminum, the nightmare of sailors the world over. Recommended materials include blue locktite, tefgel, and lanocote. Tefgel is simply teflon paste -- and googleing got me to your comment above.

Is Teflon pipe dope an effective alternative to Tefgel? Sure, a tub of TefGel is only $35 (or double that at West), but it's more money spent and more stuff to store if the Teflon pipe dope on my shelf is comparable.

Your thoughts?
Harry

One thing I like about Lanolin is you cant wash it off with water.
I suspect none of them are perfect though.

[Stewie12]

I used to lived on an aluminium boat and we put SS screws into a plastic rawlplug and made a plastic or rubber gasket for whatever were were going to fix to the boat. The alternative is that the paint will bubble.