Hey guys, what’s up?
What do you think this is here below, the brown decoloration on the fin?
So it looks like rust, but the fin is plastic and the screws are supposedly rustfree steel by fcs.
There is never any rust on the hexagonal key side, just the other side.
It only rusts on one side? Chemicals that cause this, maybe even heat from friction since it has spread out too?
What is up with that? Anybody?
Hi, the old saying is : “there is a reason it is called stainless steel and not stain free steel”
stainless steel actually needs exposure to air to keep it from rusting so the part that is not exposes rusts faster.
Hi Wouter,
The grub screws lost their “passivative layer.” Kind of like sunscreen, the metal is like regular steel but an element, Vanadium, is mixed into the steel. Once formed into parts, the outer layer corrodes (passivates) but instead of rust, you get shiny steel. To our eyes it looks like bright steel, but there is a film on it, almost like a clear coat. Right at the point where the grub screws contact the fiberglass, you will get rust. This is because the glass in the fiberglass is HARDER than steel (yes, it’s true, and diamonds are harder than glass, etc.) Since the glass is harder, it rubs the passivated layer off, and you get continuously exposed unpassivated steel to the elements. But it gets worse for us surfers, because the ocean is salt water, which is one of the most effective electrolytic solutions to have your raw steel parts in, and the result is rusting rubbed off steel particles.
BTW, if you take the screw out, lightly sand/clean the tip, your screw with passivate and stay shiny and new looking until next time…
Best regards,
George
That was good George, thanks for teaching me something new here, again.
How are your bottom contours evolving these days?
Not all stainess is created equal.
Stainless steel is steel, less than 1.5 % carbon and fer like all steel + at least 6% of one other élément mostly chrome and nickel. Atomes of chrome are on the outer of cellule and protect fer atome wich rust. Rust resistance is measure, it´s time of exposition to salt fog before rust appear. Common Stainless steel like 304l (a2 for screw) don ´t résist so much, need 316l (A4) for salt water. Plus one seems to speak about treated steel, wich are not Stainless steel but steel protect by a layer of material moleculary fixed, an other way to increase résistance of steel to rust but not often use for steel screw.
Sorry for my frenglish
Chinese manufactured stainless steel screws suck. There I said it Chinese Stainless Steel in genreal sucks. I have seen countless stanchions and hand rails on very expensive Yachts pitted and full of rust.