Galvanized steel for high pressure fittings?

[rjack321]

Not more than residual dampness.

I'm asking this for different purposes, but one of them being additional Filter for my compressor.

I suppose it will get wet with condensate.

And what about other kinds of threads? JIC, BSP (G)?

Stainless steel fasteners in aluminum will create dissimilar metal corrosion no matter what kind of threads/connection there is. For compressor filters its not relevant, the filter housings (and aluminum manifold blocks etc) last a couple of decades and wear out for other reasons first.

 

[broncobowsher]

There is also the insulation of the Teflon (and there is O2 safe Teflon as well) tape. That is only used on tapered threads (NPT). Not straight threads (gasket or O-ring seal). That Teflon tape does a pretty good job keeping the threads dry and electrolysis in check.

The biggest issue of AL + SS is galling. Those two metals like to gall. Not that you would, but never use power tools when mating AL and SS. Hand assemble only.

 

[happy-diver]

Even by hand I lube them or something SS to SS even parallel threads

Previous people, usually have a spanner in contributing to my galling.

Weicon I toothbrush onto changing filter head threads and the o rings
makes screwing easy and when screwing becomes harder brush more
having cleaned out a bit the threads, with a different stiffer toothbrush

and use it also for other things I will never run out with my one big tub

Even my stainless tank bands, I gall by hand without some sort of lube

 

[ThePimp]

Stainless steel fasteners in aluminum will create dissimilar metal corrosion no matter what kind of threads/connection there is. For compressor filters its not relevant, the filter housings (and aluminum manifold blocks etc) last a couple of decades and wear out for other reasons first.

I would be VERY happy if it would last a decade

So that sounds very good!

 

[ThePimp]

There is also the insulation of the Teflon (and there is O2 safe Teflon as well) tape. That is only used on tapered threads (NPT). Not straight threads (gasket or O-ring seal). That Teflon tape does a pretty good job keeping the threads dry and electrolysis in check.

The biggest issue of AL + SS is galling. Those two metals like to gall. Not that you would, but never use power tools when mating AL and SS. Hand assemble only.

I thought galling is the same thing as galvanic corrosion? What is the difference?

 

[rjack321]

I would be VERY happy if it would last a decade

So that sounds very good!

The Bauer filter housings are rated to a specific number of pressure cycles. Corrosion is not usually what kills them unless stored outdoors or in a salty environment (like on the deck of a yacht). Most other manufacturers of filter housings are vague on lifespan but a decade is easily achieved. Many in use shop compressors are 30 years old.