A Tale of Two Tread Plates, Update

OK, it's now been two years since the original experiment...

Here's how they look now:

 

As you can see, the untreated tread plate on the left is still groady... in fact it is even worse in real life than the picture shows.

And on the right is the plate which was treated with BAC, still looking clean, tho grey.  I said BAC, but for this experiment I actually used a version of BAC that has some silicone functional groups substituted for some of the carbon-based groups.  This version, called "Gold Shield" (sample provided by Drew - thanks!) is considerably more proof against washing out.  In fact it is used by hospitals to sterilize and keep sterile their bedding, even tho it is frequently washed.

I call this experiment concluded, and a success.  I am going to treat the other tread plate, and our bare teak rub strakes, with Gold Shield.

A Tale of Two Tread Plates, Update

A Tale Of Two Tread Plates

A year later

Some of you out there may recall an experiment I started a year ago - using benzalconium chloride (BAC) as a teak treatment.  Well, here are the two tread plates after a year of exposure and neglect.

Clearly, the BAC made a huge difference - the untreated plate on the left still has algae and lichen growing in the low spots and pores in the wood.  The treated tread plate on the right is free of these pests, except at the very top, where I probably didn't get a full dose of BAC applied.

Score!

This was so successful that I just completed spraying our teak rub rails with BAC - these are being fully colonized by the same characters, especially where the rain water from the deck scuppers drains on them - in those places, the lichen has completely covered the wood.  In fact, the coverage is so complete there that I will probably have to reapply BAC, since most of what I applied probably never made it thru to the wood.

Where you can easily obtain BAC?  See my first post on this handy material.

A Tale Of Two Tread Plates

Another Use For BAC

As a prelude to varnishing Eolian's caprail, I always remove the teak tread plates that I made so many years ago.  And this time I looked at them, really looked at them, for perhaps the first time in years.  The bacteria, algae, and worse, lichen had made themselves a very good home in and on the teak.

Now normally I would have just gotten out the sandpaper, but then it dawned on me to try benzalconium chloride.  I've extolled the virtues of this stuff before, and continue to be impressed with it.  So I sprayed some on the right hand tread in the picture above and let it dry in the sun for a day.  Then I gave it a very light (emphasize light) sanding with 220 to remove the corpses.  What a difference!  And because the BAC is now soaked into the wood, I expect it to fend off colonization attempts in the future.  This has now become an annual task.

Next:  I'm going to spray our unfinished teak rub rail with BAC.  It is equally groady looking.

Another Use For BAC

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.

Chemistry Experiment: Results

Another Chemistry Experiment

Remember these spots?

Look close - there's algae there too

Well, I did some research - it is such a wonderful thing to have the bulk of Man's knowledge at your fingertips!

Guess what?  Algae, moss and lichens suffer grave bodily harm when exposed to a particular class of chemicals.  Well I guess that part is not a surprise.  But this part is:  that family of chemicals is relatively harmless to virtually everything else.  In fact, it is the active ingredient in Bactine:  benzalkonium chlorides.

Now here's the next surprise.  No, you don't have to buy 100 bottles of Bactine and distill it to get the benzalkonium chloride - all you have to do is go to the pool/spa section of your local hardware store and buy a bottle of HTH Algae Guard:

And it was less than $10!

This is a 30% solution, and yet a 2% solution is supposed to be adequate for killing algae/moss/lichen.  

So, the first test is a kind Hippocratic one.  Does this stuff harm the Sunbrella canvas on the boat?  I uncapped the bottle and put some of the straight 30% solution directly on a scrap of our Sunbrella and left it to dry.  After rinsing it out 24 hours later, there was no detectable effect on the canvas.  At 30%, the solution has a blue tint - I suspect this is just a dye for appearances, given its intended use. Our canvas is green - if yours is white, you might want to repeat this test.

The next test is underway right now.  I made up a 6:1 dilution (5%) solution in a hand spray bottle and applied it to a section of the deck with the lichen, and a portion of our canvas which has a liberal infestation of winter algae on the outside.  I also applied it to the inside of the canvas directly over our galley vent where we get the most amazing colonies of...  well, life I guess, apparently feeding on whatever the vent delivers to the canvas.

I'll let you know how this works out...

Update:  Results are here.

Another Chemistry Experiment