Are twisted lugs scratch magnets or was I just careless?

fleetwoodmac · Nov 3, 2023

Hi, all,

After I recently cleaned my previous generation speedy racing with a soft toothbrush and dish soap (contains baking soda), I noticed some "swirlies" on the surface of the twisted lugs. I examined them under a magnifying glass and the amount of swirl marks was astounding. They were all hairlines and nothing deep, but still, I couldn't believe how much swirlies those lugs had picked up, as I thought I had been pretty careful with the watch.

The brushed surfaces, however, were pretty much pristine except for a random hairline here and there.

Is this normal? Or did I manage to scratch those lugs with the baking soda?

140dave · Nov 3, 2023

Hard to tell with no pictures but baking soda is abrasive so I am betting that’s what did it.

Donn Chambers · Nov 3, 2023

Yeah, pretty sure you did this with the baking soda. Next time, use soap without baking soda.

hen · Nov 3, 2023

Yes and yes. The twisted lugs are made of the same 316 stainless steel as the rest of the watch, but of course scraches show much better(?) on polished surfaces than brushed. My lugs are uniformly scratched exept for the 4 o`clock lug. For some reason that lug is way more beat up than the rest. The reason is my carelessness, as I often just have to weld this or that and "forget" to wear gloves.

Live with your scratches or maybe use som Silvo or Brasso to polish away those swirlies CAREFULLY!

ErichPryde · Nov 3, 2023

Baking soda scratching steel? I'm not sure I buy that given the hardnesses involved, unless the soap also contained another harder abrasive (that was harder than Sodium Bicarbonate). What I do buy: something potentially on the surface of the lugs that acted as an abrasive when the toothbrush was applied; some debris in the toothbrush itself that acted as an abrasive; the lugs were scratched enough and dirty enough that cleaning revealed swirls and scratches on the polished surfaces (which definitely show scratches more easily).

I'd want to know the ingredients list of the soap... could be that I'm incorrect though.

(EDIT TO ADD: I know baking soda is often recommended to remove scratches from kitchen appliances, but from what I understand, the scratch is generally in a clear coat over the steel if baking soda can remove it (and not the steel itself). I'm willing to accept I could be wrong in this, but given just how common silica is in our environment and how hard it is, it seems much more likely that if the scratches were caused during cleaning it was the result of some silicon dioxide grit or dust being present and not sodium bicarbonate.)

artek · Nov 3, 2023

I would be willing to bet that baking soda is the culprit. Pictures would be helpful if you can.

Dan S · Nov 3, 2023

ErichPryde
Baking soda scratching steel? I'm not sure I buy that given the hardnesses involved

I can think of experiment you could try if you want to make a contribution to the forum. Don't forget the before and after pics of your watch. 😁

ErichPryde · Nov 3, 2023

Dan S
I can think of experiment you could try if you want to make a contribution to the forum. Don't forget the before and after pics of your watch. 😁

Indeed, this is a testable hypothesis for sure, and I have to admit I am not particularly willing to test this on one of my watches but I was considering testing it on the same type of stainless steel if I have an object made of 316L. My question remains though, given the hardnesses involved by what mechanism is sodium bicarbonate scratching the steel? Is there some smaller percentage of baking soda that isn't actually sodium bicarbonate, or is something chemical going on between the sodium bicarbonate and the Steels top coating?

PandaSPUR · Nov 3, 2023

ErichPryde
Indeed, this is a testable hypothesis for sure, and I have to admit I am not particularly willing to test this on one of my watches but I was considering testing it on the same type of stainless steel if I have an object made of 316L. My question remains though, given the hardnesses involved by what mechanism is sodium bicarbonate scratching the steel? Is there some smaller percentage of baking soda that isn't actually sodium bicarbonate, or is something chemical going on between the sodium bicarbonate and the Steels top coating?

You're also assuming OP had pure 100% sodium bicarbonate, which is usually not the case for baking soda intended for cleaning. "Food grade" baking soda is supposed to be pure but even then I'm sure theres some small % of impurities allowed under FDA or whatever guidelines.

Vercingetorix · Nov 3, 2023

Throw away the magnifying glass.

ErichPryde · Nov 3, 2023

PandaSPUR
You're also assuming OP had pure 100% sodium bicarbonate, which is usually not the case for baking soda intended for cleaning. "Food grade" baking soda is supposed to be pure but even then I'm sure theres some small % of impurities allowed under FDA or whatever guidelines.

I definitely agree that I am making this assumption, which is why I was wondering if there was an additional abrasive within the soap. I know that there are sometimes compounds that can be present that might do something like this.

@fleetwoodmac exactly what brand of soap are you using?

Commander · Nov 3, 2023

Was the dish soap mixed with water? It seems unlikely to me that a clean, soft brush and water with a little dish soap in it (even dish soap containing baking soda) would scratch stainless steel. That said, I use diluted Dawn and my fingers to clean my steel watches except for the inside of my lugs, where I use a very soft brush.

Donn Chambers · Nov 3, 2023

Commander
Was the dish soap mixed with water? It seems unlikely to me that a clean, soft brush and water with a little dish soap in it (even dish soap containing baking soda) would scratch stainless steel. That said, I use diluted Dawn and my fingers to clean my steel watches except for the inside of my lugs, where I use a very soft brush.

Since normal dish soap (like dawn) doesn’t contain baking soda, I bet this is one of those gels used for dishwashers that is a lot grittier. I used to use a liquid Cascade soap meant for the dishwasher only that was like that.

Aroxx · Nov 3, 2023

I think those polished surfaces are just scratch magnets. I don’t think you need something harder than steel to scratch the polish. Mine is covered in micro-scratches and I’ve never cleaned it other than wiping with my t-shirt or a microfiber.

ErichPryde · Nov 3, 2023

Aroxx
I think those polished surfaces are just scratch magnets. I don’t think you need something harder than steel to scratch the polish. Mine is covered in micro-scratches and I’ve never cleaned it other than wiping with my t-shirt or a microfiber.

I have never independently confirmed this but one statement I often see tossed around on gemology websites is that quartz is highly abundant in random dust particles you encounter on a daily basis, which is an argument for using harder gemstones as opposed to softer ones. This could just be marketing buzz to sell diamonds and sapphire/ruby, but silicates do make up a huge percentage of the Earth's crust. Even a tiny piece of dust with a higher hardness than stainless that settled onto your T-shirt or just onto the surface could scratch it if pressing force is applied.

ALSO to add, metallurgy is not really something I understand well, but if the finish of stainless steel is chromium that has reacted with oxygen to form chromium oxides (I've read this but I'm not sure) then you should need something harder than not only the steel to scratch the finish, but also harder than chromium oxide (which I think is near an 8). Since it gets scratched fairly easily it can't be this one dimensional, but I don't know why the finish would actually be softer than the stainless. But- let me make it clear that I don't know.

chiefenergy · Nov 4, 2023

Never use abrasives including hard water. I suggest white vinegar applied to a micro-fiber cloth for occasional cleaning.

Donn Chambers · Nov 4, 2023

I’m not going to test whether a paste of baking soda will scratch my watch, but I know for a fact that nylon scotch rite pads and NATO straps can scour steel and leave marks on high-polished steel surfaces. And neither of those materials is harder than steel. Whether it is considered a “true scratch” is moot, but it definitely can mar the polish.

PandaSPUR · Nov 4, 2023

Scratches are inevitable, especially swirls on polished surfaces. OP, just enjoy your watch.

Also, never get a gold watch if micro scratches bother you lol. I was amazed how fast the polished lugs on my speedy got covered in swirls.

ErichPryde · Nov 5, 2023

Donn Chambers
I’m not going to test whether a paste of baking soda will scratch my watch, but I know for a fact that nylon scotch rite pads and NATO straps can scour steel and leave marks on high-polished steel surfaces. And neither of those materials is harder than steel. Whether it is considered a “true scratch” is moot, but it definitely can mar the polish.

Yeah, I've had green scotch brite pads scratch plenty of things that are made of iron or steel. The blue ones are less abrasive, and apparently 3M has them all color-coded for abrasive level. 3M does state those should not be used on polished surfaces because they are abrasive enough to leave swirls.

I can't confirm through 3M's material sheet specifically what is in the green pad, but they definitely aren't just nylon. The spec sheet for the regular green pad states they contain "Cellulose, Fiber, Mineral, Resin, Soap" ( https://www.3m.com/3M/en_US/p/d/v000367222/ ). I've read that there's a small amount of Aluminum oxide contained within the nylon structure. 3M does state that both titanium oxide and aluminum oxide are used in some of their pads. If Aluminum Oxide is the mineral they contain, that's chemically sapphire, and absolutely will abrade steel.

That posted, I think there's more going on with hardnesses that I don't really understand, because I know that some resins, like melamine (which is contained in magic eraser) can hit rockwell hardnesses of 120- which is WAY harder than steel. Could very well be that there's no aluminum oxide in the green pad but whatever resin is present is doing it.

Zman4eva · Nov 5, 2023

An entire thread and no pictures of said "swirlies"?

Are twisted lugs scratch magnets or was I just careless?

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