Monday, March 9, 2015

Chemistry Experiment: Results

When I did this experiment, I promised you the results. Here they are:

Before

After

The benzalkonium chlorides definitely killed the lichen.  But it did take a mild scrubbing with a brush to remove the corpses.  Please note that previous scrubbing with the same brush and bleach had no effect on the spots.  I apologize that I used a washer for the sizing comparison - I didn't have a dime in my pocket.  The washer is a little bigger than a dime and a little smaller than a nickle.

I also applied the 5% benzalkonium chloride solution to a portion of our dodger canvas.  Please note that this canvas is more than 10 years old, and has lost most of its water repellant qualities.

Untreated

Treated
The "After" photograph does not do the results justice.  The mold, mildew and algae are all dead.  A couple of rainstorms washed the bulk of the corpses away, except at the seams.  But more rain is coming (of course).

Conclusion

This stuff works!  And Jane tried it on the moss on our driveway at a 3% concentration, as another experiment.  It worked there too - the moss is all dead.  In fact, using a 5% solution was probably overkill - my next application on Eolian's canvas will be at 3%, but I think I'll retain the 5% level for the tough-to-kill lichen on the decks.


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3 comments:

Steve Stark said...

Thanks for the follow-up, Bob...
For the last couple of years, at the advice of several near our Marina, I have been spraying the boat with a product, procured at Ace Hardware, called Wet and Forget. The active ingredient is Alkyl dimethyl benzyl ammonium chloride 9.9%. Being an electronics engineer rather than a chemist, this sounds to me to be suspiciously close to the compound in the pool product. The Wet and Forget, sprayed on all the hard surfaces, has not only killed the algae, but prevented re-emergence for some months. I have hesitated to use it on the canvas. I tried a piece of scrap Sunbrella, and it indeed did work without color change, but significantly degraded the water repellancy which required 303 retreatment. I have been warned that the product is not recommended for in the water use as there is some speculation that the runoff can be harmful to some sea-life, but have no evidence of this.
Sorry for the long story, but to the question... did you notice on your scrap fabric test whether the pool product decreased the water repellancy of the Sunbrella?

Robert Salnick said...

Hi Steve -
Yes, some of my research did disclose that Wet And Forget's active ingredient is benzalkonium chloride. Compare prices - my half gallon of 30% cost $7.99 (I think). I also believe that 30 Second Cleaner contains BA chlorides, but I cannot prove it.

As for water repellency, I cannot comment. Our canvas lost its repellency a long time ago - I'd never notice if it changed. I am on an annual retreatment program anyway.

Bob

Robert Salnick said...

I should add that Jane also sprayed some of the 3% solution on moss growing in the grass in our yard. Yup, it killed the moss, and pretty much left the grass alone. But next time we will reduce the concentration to 2% for application where there is grass.

bob

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