[rickz07]

Basically, most sunblocks/sunscreens will have some form of zinc oxide or Titanium dioxide. OXIDE is RUST!!! so what happens when u mix a metallic element in a rusting process with salt water (AKA SWEAT!)? The sweat works as a catalyst, accelerating the process. Add to that, that most clothes are knit, and the following happens:

You sweat off your sunblock, if drips into your shirt. The metallic particles get 'locked' into the knit fabric. After you wash them and dry them, those metallic particles have completely rusted. If you wet it, it will pretend to vanish, but once it dries, there it is again: An orange stain!

SOLUTION: you need something to break down rust in order to release it from the knit, and then something that pulls it out. Try finding a tub and bathroom cleaner, like The Works, which specificlaly removes rust. Apply it dry, rub, leave for 10 minutes. Then wash the garment with Oxyclean. This should atleast make the garment wearable again!.

[clothier]

Hey Rick,

I'm not a chemist, I'm just a simple clothing buyer, so I think I missed something here.

Are you telling me that the reason sunscreens work is because we are putting rust on our skin? Rust is what's prevent all those harmful rays from burning my skin and they keep me from getting skin cancer?


That just doesn't seem right.

[rickz07]

Sorry, I oversimplified it:) anyway, here's how it goes:

Zinc can't be placed on your skin, because it would irritate you. The oxidation process which leads to zinc oxide involves the loss of electrons, which changes the chemical structure of zinc, and allows it to be more "skin friendly". When zinc (or any other metal) loses enough electrons, it rusts,and eventually bio-degrades. To put in in other words, sunblock uses a metallic agent in a debilitated state to protect your skin.

Now, if you add a catalyst, like salt water, the oxidation process speeds up. Normally, you dont wear clothes when you go to the beach. You put on your sunscreen, then you go out to the sun, and sweat without clothes on, so the zinc oxide just fallss off (it erodes). However, with clothes on, the knitting patterns trap that zinc oxide, which has been affected by sweat, and it stays there. After sometime, the oxidation process advances, rusting the zinc.

So, to answer your question, no.. You are not putting rust on your body (that would irritate because of the PH levels). You are putting on an oxidized zinc mixture which has already initiatied the oxidation process.

[clothier]

that makes more sense.

thanks

[DLiver]

I believe rust is the term specifically for iron oxide, IIRC. Oxidized zinc isn't rust, it isn't red nor orange.

[strataboy]

I thought it is the "avobenzene" in sunscreen which causes the staining...

[imsocrabby]

whoa. this is way too deep and 'sciencey'.


i'll let myself out.

[daidee]

too much hastle. I just apply shout stain remover when i get home and leave it in the washer. For whites, i use shout then clorox bleach, works great!