Fuel Tank Filler

[Mudlux]

Hi,

Just looking for some advise on installing an above deck filler. I have an aluminium tank with a screw in cap. The only fitting I am able to find in the correct size is made of brass. Is it a bad idea to use a brass fitting in an aluminium tank?

The other option is to have a new filler neck welded in the tank. So does anyone know of someone who will weld an aluminim tank, preferably on the southside of Brisbane.

Thanks.

[finga64]

yep, bad idea but you should be able to get some stainless fittiing somewhere though.
What fitting are you looking for?? Somebody may know where o look

[toymod]

I went to a place off moss street to get some prices on a few jobs I wanted done (still havent done them yet ) ......but I got recomended by a few people, not too sure of the name but it is stright oposite Auto barn at moss street....he is on the fergerson street (I think I have spelt it wrong)

He was nice and gave me a good price........hope this helps

[vermin]

I got one of those stainless fillers from BIAS and screwed it to the tank. Had to work 3 threads on the tank of course. Gasket in beween the two different metals. You can put some of the yellow stuff on the screws if you don't want any corrosion. I didn't and haven't seen any for about 3 months.

May need to cut the neck a bit shorter though.

Cheers,
GG.

[impulse492f]

You shouldn't have to much of a problem using Brass (Marine) with Aluminium based on the below info.

Galvanic Corrosion

Galvanic corrosion results from the electrochemical reaction that occurs in the presence of an electrolyte when two dissimilar metals are in contact. The strength of the reaction—and the extent of the corrosion—depend on a number of factors, including the conductivity of the electrolyte and potential difference of the metals.

The metal with less resistance becomes anodic and more subject to corrosion, while the more resistant becomes cathodic.

The Galvanic Series Table, developed through laboratory tests on industrial metal alloys in sea water (a powerful electrolyte), list metals according to their relative resistance to galvanic corrosion. Those less resistant to galvanic corrosion (anodic) are at the top, and those more resistant (cathodic) are at the bottom.

The metals grouped together are subject to only slight galvanic effect when in contact, and metals at the top will suffer galvanic corrosion when in contact with metals at the bottom (in the presence of an electrolyte).
The farther apart two metals are on the table, the greater the potential corrosion.

[finga64]

I suppose it depends on which brass, aluminium and stainless your talking about.
I know from personal experiences (overhead line worker on the coast) that if you put brass and aluminium together you got troubles very quickly.
Seems to me that the aluminiums and stainlesses are closer together then the aluminium to say manganese bronse, cartridge brass or red brass. Fromt these metals you have to go through stainless steel to get to aluminium.
On the table shown the right hand column should be below the left hand column, not next to it.

[impulse492f]

On the table shown the right hand column should be below the left hand column, not next to it.

Thanks and yes that is correct. The clip i posted was from a full pdf file on corrosion and i simply did a screen grab, I didn't feel like re-typing it.

[Mudlux]

Thanks Toymod, will try to find the place you have mentioned. From memory the only place I can think of oppisite Autobahn is the exhaust shop.

The hole is approx 2 1/4" in diameter, the same size as a 44 gallon drum cap. If anyone knows where to get a fitting this size in stainless it would save me some trouble.

As I am unsure as the type of brass and alloy I will probably try to avoid the brass fitting.

[toymod]

its on the same street as tip top I think its next to the work wear shop (im pretty sure that what is is by memery) and its down a short drive way........same side as tip top fergasen street but it is directly opposite auto barn......... sorry imm crap with directions

Sorry change of plans its the corner of moss and algas street My bad

[Grand_Marlin]

Hi Robgr,
Depending on exact size and thread, I can get the fittings in alloy for you from our wholesalers.
If you could give me the exact thread diameter of the screw in bung, hopefully I can help you.

Welding will cost you a mint because the tanks have to be emptied, steamed and gas detected so you dont go up in smoke.....

Do you know what type of thread it is? Most things used these days are BSP.

If we cant match that thread, we can install a new filler neck. These can either be bought, or I usually get one made (Noble Engineering) and install it on gasket material and screw or rivet it it to the tank.
I have all the gasket materieal etc if required.
With respect to the reactivity series table, 316 stainless is a very stable material and does not readily react with aluminium, given normal boating conditions

Definitely dont use brass, or bronze....only alloy or stainless
If you have an alloy boat, it always pays to have annodes on it.
Impulse, dont get me wrong, I am only stating what happens in practice.

It has a lot to do with the form of the material too.... for instance:
Aluminium powder in acid explodes.
Aluminium plate (like boat) reacts slowly, but oxidises to form a protective coating,
Aluminium foil wont react at all with acid.

If you want, call me 0419 263 264

Cheers
Pete
(Valet Boat Services)