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Evaluating Motorcycle
Helmet Visor Anti-Fog Treatments
Methods for Evaluating Visor Anti-Fog Treatments
by Dr. David Salter, Managing Director, Salclear
Edited by webBikeWorld.com
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Visor Anti-Fog Articles | Owner Comments (Below)
Note From the Editor: In our most recent anti-fog treatment comparison
article, we discovered that the anti-fog treatment applied to the visor
during manufacturing can have an affect on the anti-fog coating applied by
the owner, something we hadn't considered in the past. In response to
that article, several readers suggested using a thin layer of
dishwashing liquid as an effective anti-fog treatment. This is spread
on the inside of the visor and then buffed dry.
I asked Dr. David Salter, the Managing Director
of Salclear, about the use of dishwashing liquid as an anti-fog treatment.
We exchanged a series of emails that covered some interesting information
regarding anti-fog coating evaluations with Salclear and other products that
I thought might be of interest to our readers, so I've edited the various
topics of the correspondence and we're presenting it here.
Note that we have no financial interest in
Salclear products, which are featured in the graphs, but the descriptions of
the various methods for evaluating anti-fog treatments and coatings are both
interesting and useful.
Method of Comparing Anti-Fog Treatments
Continuing with our tests of anti-fogs and visors, we thought you'd be
interested in these observations.
A simple test that we carry out on anti-fogs is our so called "Mug Test".
See the photo below; basically we take a cup of boiling hot water and place
the helmet over the cup with the visor closed. Typically the visor
will fog up within about 30 seconds as the humidity rises in
the confines of the helmet.
This test is not rigorous enough to run test comparisons between different
anti-fogs on an extended test basis, but it serves to demonstrate a basic
anti-fog performance parameter (for webBikeWorld evaluations).
We are
aware that most visors and most plastic eyewear comes
with a factory coated anti-fog layer. We've demonstrated in the past that
these anti-fog coatings do not, in our opinion, provide adequate anti-fog
characteristics. They are far inferior to our own spray or droplet applied
products.
The second photo shows a visor in which we removed part of the factory
applied anti-fog coating from, then we used the "Mug Test".
The visor shows three distinct parts, left to right:
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Far Left: Anti-fog layer removed.
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Central Portion: Salclear TT.
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Far Right: Standard visor (with factory applied coating).
The worst fogging is seen on part of the visor with the factory applied
coating removed.
The second worst fogging comes from where the visor remains coated with the
factory applied product.
The clear central portion of the visor has been treated with Salclear TT.
This test serves to demonstrate that factory applied coatings are more
effective than no coating at all, but far inferior to designer anti-fog
sprays such as Salclear TT."
The "Mug Test"
Motorcycle Helmet Visor: OE anti-fog removed (left); Salclear TT (center);
OE anti-fog coating (right).
Anti-Fog Humidity and Water Resistance
We are doing some studies for a UK bike magazine and thought that the
results might be of interest to you, and perhaps your readers.
The results are not complete yet, as there are other
tests in progress, but it gives you a fair overview on the performance of
various commercial anti-fogs for motorbike visors.
We've tested various commercially available products, one or two that are
available in the U.S. and which you've looked at yourselves.
The two criteria we treat as important in selecting a good anti-fog are:
-
Humidity Resistance: basically how well the
anti-fog stands up to humidity
and therefore fogging.
-
Water Resistance: how the
anti-fog behaves when subjected to high levels of
condensation.
I should add that in our opinion, this wash-off test is critical. An
anti-fog works by preventing water droplets forming on the inside of the
visor. Instead, the water forms a completely transparent film.
Nevertheless, condensation and water filming is still present on the visor
surface, and so a good anti-fog should be able to withstand the condensation
and fogging that it is designed to prevent.
We regard these criteria as important because the tests illustrate anti-fog performance
and anti-fog longevity (i.e., how long it lasts, and therefore by inference, its
cost of use).
The data presented here is pretty self explanatory. We included in the
tests:
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6 commercially available
anti-fog treatments;
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2 Salclear products
(TT and DMist);
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Liquid dishwashing detergent concentrate.
The Salclear products score highest in both tests, and the differences are
remarkable in both the humidity resistance test, where both Salclear
products are at least 11 times more effective than a leading U.S. brand; and
in the wash resistance test where after 10 rinses in cold water, the U.S.
product was completely ineffective, whereas the Salclear products were still
100% active.
Humidity Resistance Test
The graph below indicates time (in seconds) to 50% fogging. Yes, these
numbers are in seconds, the problem being that some anti-fogs don't last
more than 5 or 10 seconds in steam, whereas good ones last much longer.
It's a tough test and requires the treated visor
to be suspended in steam over an extended period of time. In this test
-- which we created, I don't think anyone else does it -- the visor is
visibly monitored until 50% of its inside surface has fogged up, a point at
which we deem unacceptable to the motorbike rider. If the rider has
lost 50% of vision, that's not a good thing!
Humidity resistance. NOTE: Larger numbers are better.
Water Immersion Test
The second test, illustrated in the graph below, relates to the water
resistance of the anti-fog. A quality anti-fog will resist water, or
condensation, and therefore by definition, be resistant to the thing that
its preventing, i.e., fogging or condensed water. What use is an
anti-fog that gets washed away by exactly the thing that it is preventing:
fog?
The second reason for looking at this property
is that visors leak, and it would be a lot of hassle to have to reapply an
anti-fog every time your visor leaked in rainwater.
Another reason might be that some riders at low
speed run with their visor up. In light showers a good anti-fog would
not be washed away by the rain.
This data is really showing the key properties
of Salclear products -- they are not water soluble. So dunking a
treated visor in water often removes normal anti-fogs, as the data shows,
whereas with ours the Salclear products remain 100% active and effective
even after 10 complete submersions in water.
Percent of visor unfogged after wash. NOTE: Larger
numbers are better.
Degrease Test
The graphic below represents a "degrease" test that we also perform.
This is a typically "over the top" test that we normally conduct; in other
words, when we test our products, we don't just pick a test that is easy to
pass.
We smeared half the inside of a visor with
Vaseline petroleum jelly/wax. Why do this?
Well, the majority of anti-fogs you can buy are
just anti-fogs -- that's all they do. We wanted to create a product
that was multifunctional, and we decided that it would be better to create
an anti-fog AND cleaner/degreaser in the same product. So the biker
does not have to buy a separate product to remove squashed bugs or finger
marks from the visor.
So this test evaluates how good current
commercial anti-fogs are at both degreasing AND defogging. And we
tested the defogging AFTER the degrease test just to show that the anti-fog
performance is not badly affected by the degrease test.
In the data above, you are looking for + + in
the degrease/defog test. A - degrease and + defog means that it left
the visor messy with grease, but still worked adequately as a defog.
A - degrease - defog means that it failed both
tests. A + and + obviously means that it cleans very well, and acts
well as an anti-fog; i.e., Salclear TT, Salclear Dmist, dishwashing liquid
and anti-fog brand C (but note in the other tests that anti-fog C has
modest/good humidity resistance, but poor wash off resistance).
In summary, apart from the Salclear products,
only normal dishwash liquid performs well in all of these tests, which is
pretty sad considering the number of so called motorbike anti-fogs on the
market!
By the way, we are always happy to look at any
other tests that your customers/readers would think of as being appropriate.
Degrease Test
Dishwashing Liquid Anti-Fog and the Smear
Test
You are right about the dishwashing fluid -- many motorcycle riders (and
scuba divers) use it. Giving it a good buff works. We did not
include this in the mirror smear test, but you'll find that any mirror with
buffed up dishwashing liquid is a real mess; I'd guess it would score a 5
after buff. You'd get all sorts of streaking and weird colours.
Scuba divers (bearing in mind that this is
another core market for us), often claim that dishwashing liquid is good,
except when they get water in their masks and then it drips in their eyes!
Dishwashing liquid degreases frying pans very well, but not sure about
eyeballs...
One other thing we need to consider, Smear.
We've already demonstrated that dishwashing liquid is a good overall
performer -- a good degreaser, a good anti-fog, good steam resistance.
But dishwashing liquid and other thick gloopy anti-fog products may have
poor smear characteristics.
They perform ok, but make the visor look
terrible. What's the point in having a good defog, if when you apply
it, it makes your visor streaky, smeared and messy? So we looked at
smear characteristics, illustrated in the graphic above.
We tested initial smear and after
buff/wipe/polish smear on a mirror. The mirror bit is important
because any blemishes or streaking are far easier to see on a clean mirror
than a curved plastic visor.
Here's what we found: The initial
application of most defogs scores low; nearly all are messy. A spray
product, such as Salclear TT scores high, because it spreads wide and
thinly. After buffing or polish, some spread well and the streaking
disappears or is reduced
We marked the cleanliness of the surface of the
mirror out of 10, so 10/10 is perfect. Something like 5 or 6 is quite
badly smeared.
Smear Test
Squashed Bugs Test
We also discussed the "squashed bugs" test. We mix fat (butter),
carbohydrate (honey), protein (minced beef) and smear it on a visor and bake
it in the oven for 15 minutes to dry it on the visor. All this just to
test if our products get rid of squashed bugs!
Conclusion
So to summarise, as a producer we think the consumer, our customers, need to
consider several performance characteristics in their visor treatment:
-
Anti-fog performance
-
Cleaning
capabilities
-
Wash-off resistance
-
Humidity resistance
-
Smear/streaking
Our tests are tough, but nothing so far that we
looked at came close to Salclear TT. Perhaps that's why it's the
product of choice by racers in the TT races!
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