Chassis rail discussion

[Geese]

I would recommend that you paint these cause they WILL rust.

[mx5ash]

Thought stainless doesn't rust?

[Steve]

Which bit do you mean Geese?

The sills have undercoating, the holes I drilled were anti-rust primered, greased bolts etc.. + stainless rails.

When washing the car I stick the hose down em too, no fear of water retention really as they are right in the air flow under the car so dry in mins.

[Geese]

Stain+Less steel not Stain+Free Steel!

First it depends on what grade of stainless, some will rust more than others. Rust on the normal steel can migrate and rust stainless very fast. Basically if you join a piece of mild steel and stainless the rust from the mild steel will spread to the stainless.

Second, heat from the exhaust, dirt, oil, petrol rubber and all sorts are gonna batter anything under the car. This will rub away the chromimum in the Stainless.

Some of us who don't drive much or garage our cars might get away but just in case I'd give them a single coat of paint.

[Steve]

meh, I don't plan on having any of my mild steel rust in the first place (hence the anti-rust primer in the holes drilled), so no worries there.

If the stainless steel rails eventually rust (doubt it tho, they look like 304).. you could just unbolt them and bolt new ones on

My rails have already saved my stock rails from being flattened twice (reversed off a high kerb.. ouch.. and @ the entrance to Hilly's house!).

[galwaytt]

ola, Steve - how'd that last batch work out ?

[Steve]

don't know if anyone has fitted them yet... (?) you thinking about a set?

[galwaytt]

no, just wondering.

But Hark - am considering...............Paint!

....time for a 'paint' thread ? Am looking for pics of cars with.......stripes !

[sidewaysreilly]

304 good, 316 grade better. Stainless Steel will not rust if left in contact with Oxygen. It relies on its oxidation layer to remain bright and shiny. Paint it and you will exclude Oxygen and it will rust which is actually black in colour and it will pit also. The rust streaks you often see on stainless are caused by drilled holes using ordinary HSS Drillbits, use cobalt drills and this wont happen.Remember, exclude oxygen and it will deteriorate as quickly as mild steel. If placed beside a dissimilar metal and subjected to a salty wet envoirenment and it will rot the other metal which is lower down the galvanic scale.

[fabfiveferg]

304 good, 316 grade better. Stainless Steel will not rust if left in contact with Oxygen. It relies on its oxidation layer to remain bright and shiny. Paint it and you will exclude Oxygen and it will rust which is actually black in colour and it will pit also. The rust streaks you often see on stainless are caused by drilled holes using ordinary HSS Drillbits, use cobalt drills and this wont happen.Remember, exclude oxygen and it will deteriorate as quickly as mild steel. If placed beside a dissimilar metal and subjected to a salty wet envoirenment and it will rot the other metal which is lower down the galvanic scale.

Nice Sideways. I'm gonna try and memorise that one. I love that you finished with 'galvanic scale'. Beautiful it was

[sidewaysreilly]

I work on Boats 24/7 and 2 of the biggest problems we have are electrolysis and galavanic corrosion. Rotten wiring, internal engine corrosion and many more problems. I know its a different envoirenment but the same conditions can exist underneath a car with salt on the roads plus we use negative earth returns which are a definate no no on boats .

Sean.