Wednesday, September 12, 2012

A little chemistry for non-chemists

So a couple of days ago, I put some chemistry knowledge to work here onboard Eolian.  How you ask?  (Please ask - otherwise this post is going nowhere.)

I noticed that the mirror in our shower was really filthy with soap scum, especially at the bottom.  And so I got out the paint thinner to clean it.

Paint thinner??!?

Let me take you on a very short chemical journey.

What is soap scum?  Well, first let's start with this: what is soap?  Soap is the sodium salt of a long chain organic acid.  Huh?  OK, I guess some definitions are in order.  "Organic" doesn't mean pure, or natural.  Instead it means that it is a carbon-based compound.  Long-chain means, well, it is long, skinny molecule, made up of a chain of carbon atoms strung together.  The acid part means that on one end of this long stringy molecule, there is an organic acid group: C=O-OH, that has been reacted with a strong base, sodium hydroxide in this case.  It is useful for cleaning up greasy things, because the long organic end of the molecule bonds well with the grease, and the ionic acid end dissolves nicely in the water - thus making the grease sort of water-soluble.

OK, so now we know what soap is... what is the scum?  Well, the scum comes from "hard" water - that is, water that contains calcium and or magnesium ions.  See, these ions replace the sodium in the soap molecules, turning the soap into the calcium and magnesium salts of those long chain organic acids.  So what's the rub?  It's this:  the sodium analog is water soluble.  The calcium and magnesium versions are not.  So a precipitate forms:  SCUM.  It feels kind of greasy (that's the organic end of the molecule), and doesn't wash off with water (duh - it's not water soluble). 

People spend lots of money on weird chemicals and abrasives in trying to remove this stuff.  The grocery store remedies all try to work with the tiny ionic end of the molecule; that is not a very effective approach.  The paint thinner works on the 99% part of the molecule: the organic end.  A quick wipe-down with the paint thinner removes the scum amazingly easily.

The scum just wipes off.  Really.

Try it.



I know I've mentioned this before.  But really, it bears repetition.
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8 comments:

Drew Frye said...

I'm always amused when I see the hundreds of cleaners sold in every grocery store, knowing how few products are really needed. The rest are just combinations and repackaging for special cases.

Deb said...

Sorry but I use Greased Lightning. I clean apartments full-time and you could take away every other cleaner and leave me just Greased Lightning and I could clean everything still.Granted, it's not eco-friendly, but then neither is paint thinner. And no, I don't work for them :)

Deb
S/V Kintala
www.theretirementproject.blogspot.com

dave in Kent said...

Does the paint thinner do anything to silicone caulk, or ceramic tile grout sealer? Is there anything it shouldn't touch?

bob said...

Dave -

*NOTHING* does anything to silicone rubber, including paint thinner. Silicone is the next best thing to Teflon when it comes to being inert.

Paint thinner certainly won't harm ceramic tile, but I don't know about the grout sealer. But what's the worst that could happen? Reseal the grout?

bob

bob said...

Deb -

Unless the Greased Lightening is non-aqueous, I'm guessing that paint thinner is better. Have you tried it?

I'd be interested in your professional opinion...

bob

bob said...

Drew:

:)

bob

Deb said...

OK so here's the professional opinion: I took some paint thinner to work today to try it on the soap scum in the apartment I was cleaning. As background, this is soap scum on 4" square tile and it's unbelievably thick, disgusting soap scum from 4 years of showers without cleaning, in an apartment occupied by med students who have zero time to clean. Keeping in mind that I'm comparing it to the commercial strength Greased Lightning, not the household strength, my observations are that (1) It didn't work as well as the Greased Lightning (2)It stinks much worse than the Greased Lightning (3) I have to worry about flammability (4) What the hell do I do with the rags afterward that I can't wash out and reuse like I do with the Greased Lightning rags? Result? Greased Lightning wins hands down.

Sorry, but I'm sticking with my Greased Lightning, which by the way is also way less expensive - $28.96 for a 5 gallon bucket at Lowe's. And as I said before, I don't work with either them or Lowe's.

Deb
S/V Kintala
www.theretirementproject.blogspot.com

bob said...

OK Deb - I'm gonna get some and try it!

bob

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