Will rust spots spread?

[Query]

Due to a leak, my boots and blades got wet, when I left them unused for over a week. The water was clean rainwater, so I'm not worried about infections.

The damage to the boots is mostly on the heels and outsoles - and should sand right off.

But there are also rust spots on the bottom of the blade, mostly inside the hollow. I started to remove them by sharpening. (I also tried vinegar, but it wasn't taking anything off real fast.)

But I don't want to remove more metal than I have to, as these blades (MK Dance) are ridiculously over-priced. If I leave a rust spot that doesn't reach the sides of the blade much (and therefore doesn't affect the edges), will those rust spots spread fast enough that it would be worth it to keep grinding until no rust is left? Assume that in future I will keep them as dry as possible when not in use.

I'm only skating several days a week now, maybe 6 hours/week total. I sharpen my blades carefully, and straighten instead of sharpen when I can, so I only grind off maybe 003" of metal every 60 hours on the ice (slower than most people). If the rust spots are .006-.009" deep, and they don't spread, it would take 2 - 3 more sharpenings to remove the rest of the rust - 20 - 30 weeks from now.

Incidentally, the rust is almost black, unlike the brown on rusted cars. Why? I assume it has something to do with the alloy.

[Query]

P.S. Can rust spots spread even if I coat them with oil between skate sessions?

[SynchKat]

Shoot Query that isn't very good luck.  I have no advice other than I know most people when they leave their skates for a few weeks and then skate and inevitably have rust on their blades they just skate and it comes off after rubbing them on the ice a bit.

I will see my skate sharpener tomorrow at the rink, I can ask him opinion for you.   Doesn't rust bloom because it is exposed to air?  So I would assume as long as they aren't in water anymore and you have oiled them they should be ok.  (my husband had some rust fixed on his car recently and was giving me a lesson about the science behind rust--gotta love engineers). 

[sampaguita]

In my experience, small rust spots can come off after a good skate. However, if you really want to remove the rust without sharpening, I suggest applying a generous layer of petroleum jelly, then rub it off with a scouring pad like that of 3M:

http://www.amazon.com/Heavy-Duty-Scour-Pad-86/dp/B000KKIMU0

Worked wonders for my old skates, when I left my skates unused for a month and found a really THICK layer of black rust on the blade. Careful with rubbing though -- I cut a really small portion of the scour pad to make sure I don't dull the blade.

[Query]

most people when they leave their skates for a few weeks and then skate and inevitably have rust on their blades they just skate and it comes off after rubbing them on the ice a bit.

When I first got on the ice yesterday, the blades didn't glide. Surprise! At first I thought some part of the fabric from the soakers I stored them in had been left behind. I forced them to glide under reduced weight, and they started to glide a bit better. My brief sharpening afterwards should have removed anything left on the very tip of the edge. But there is still rust on some of the rest of the hollow, which never touches the ice. (Mike Cunningham, an expert sharpener, says that even the non-skateable area next to the toe pick touches during high level jump landings, based on ice tracings. But my microscopic jumps can't possibly force much ice penetration.)

I suggest applying a generous layer of petroleum jelly, then rub it off with a scouring pad like that of 3M

I mostly get your idea - if I only remove the center part, between the edges, that won't affect skating much.
 
But what is the function of applying petroleum jelly before rubbing it? I.e., why apply a lubricant before using an abrasive?

Would a less chemically active grease do? Petroleum jelly contains plasticizers (according to an industrial chemist on another forum) that might alter the chemical structure of any leather it touched. (The chemist was actually saying why Vaseline isn't ideal for waterproof gaskets - divers use Silicone grease instead - but the same principle likely applies.)

[AgnesNitt]

http://icedoesntcare.blogspot.com/2012/08/rusty-blades-and-gummi-stones.html

[sampaguita]

But what is the function of applying petroleum jelly before rubbing it? I.e., why apply a lubricant before using an abrasive?

Would a less chemically active grease do? Petroleum jelly contains plasticizers (according to an industrial chemist on another forum) that might alter the chemical structure of any leather it touched. (The chemist was actually saying why Vaseline isn't ideal for waterproof gaskets - divers use Silicone grease instead - but the same principle likely applies.)

I'm not a chemist and I don't know any petroleum-based material can actually soften rust, but I think any type of oil will work. I used petroleum jelly and it had no adverse effect on the metal. I didn't apply it on the leather sole, just on the hollow.

Why apply a lubricant before scrubbing it? Basically the same reason why you'd apply dishwashing soap before scrubbing a plate clean. Petroleum jelly just makes the rust "softer", but unless you have something that will physically remove it, it'll stay there.

Hope that helps!

[Query]

I tried the scouring pad thing. Sigh, this rust doesn't want to come off certain spots. I think it goes deeper in those spots too.

Basically I should replace the blades. (And the boots too, which are broken down.) But I don't have the cash right now.

[FigureSpins]

Active, red rust eats away at the edges/hollow and makes the blades difficult to skate on, but don't worry about the dark spots that are left behind after the red rust is gone.  I don't know of any way to get those spots off; they last through many sharpenings.  Some people have suggested metal polish, but it didn't work on my old blades.

It's just cosmetic - have someone qualified sharpen them and then go skate instead of obsessively trying to restore them for hours.  Your handheld sharpener wasn't intended to deal with rust; it's just supposed to straighten/bring up the edge.  Spend the money and have an expert do the right thing to salvage the blades.