Help with cleaning the inside of a H4 headlamp

Hi:

Hoping that someone can offer some advice on this.....

I have an old style standard "Stanly" 7 inch (I think) H4 headlamp. Over
the years the inside of the lamp seem to have become a bit foggy. I pulled
the bulb out of the lamp housing and washed the inside out with some
detergent and alcohol. There are patchy bits of a foggy film left on parts
of the reflector surface. Anyone else tried cleaning one of these lamps
out. What did you use as a cleaning product? Thanks for any advice.

 

Oh, yes. I tried the same things you tried, and it didn't work. I
thought about vinegar as well, but maybe that's not such a good
idea...

Perhaps something like Lime-Away or CLR would work, but using them is
completely at your own risk,
don't blame me if the inside of your headlight reflector is worse
afterwards.

The deposits you see are probably probably stable mineral salts
derived from an acid by replacing hydrogen with a metal or
electropositive radical.

Stable seems to mean that the mineral salt will not react further to
acids and bases. Is there a chemist in the house? You can never find a
chemist when you need one...

The salt of an acid ending in -ous is indicated by
the suffix -ite, the salt of an acid ending in -ic is usually
indicated by the suffix -ate.

For instance, carbonic acid is a weak, colorless acid (H2CO3) that can
only exist in a water solution. The carbon comes from the carbon
dioxide in the air, and it combines with the calcium in the water to
form calcium carbonate (CaCO3), a white salt which everybody has seen
in the bottom of pots or on glasses.

And, I suppose the hydrogen that doesn't escape into the atmosphere
with a metallic smell forms hydroxylates that stick to whatever they
can find.

I wonder what dishwashing detergent would do to the reflective
surface? It gets the deposits off your drinking glasses. Trying
dishwashing detergent would be at your own risk.

Dishwashing detergent may deposit borates from the ingredients used to
soften hard water...

Back to calcium carbonate...

Calcium is a metallic element that leaches out of the limestone laid
down decomposing plants and animals hundreds of millions of years ago,
and calcium causes hard water.

You might also have a little calcium chloride in the headlamp because
of the chlorine that's added to drinking water.

Why does alcohol leave a white film on parts that have previously be
exposed to washing with tap water?

Alcohols contain a hydroxyl group which forms esters in reactions with
organic acids. Carbonic acid is, obviously, an organic acid, like
acetic acid, which causes the pungent smell of vinegar.

Ester is contraction of a German word that meant
vinegar + ether.

An ester is an organic compound, comparable to an organic salt, formed
by the reaction of an acid and alcohol, with the elimination of water.
The organic radical of the alcohol replaces the acid hydrogen of the
acid.

Operators of high pressure boilers that have internal pressures above
200 psi go to great lengths to soften and de-ionize and demineralize
the water that is used to make steam.

I've been told that demineralized water has so little
mineral content that you don't need soap to wash your hands in it, it
just dissolves whatever is on your skin...

 

Good.

A reflector is a mirror, right? They sell mirror cleaning stuff in
hardware shops. I'd start with that.

 

Not always. The reflecting material in a mirror is on the back, and the
front is just glass. Looking at my naked 1st-gen SV-650 which has a
similar headlight as the poster, the reflecting stuff appears to just be
aluminized plastic with no protective coating of any kind. In my
experience that stuff is sometimes fragile and the "silver" comes right
off if you get rough with it.

I'd try an outside edge first.

I used isopropyl alcohol and some toilet paper wrapped around a finger.
I had a pretty large opening after taking the bulb out, and the paper
towels I had available were pretty rough.

I dread ever having to clean the DL-650. Those are some large and
complex lens cavities, in addition to there being two of them. On the
other hand, the coating looks much thicker and tougher.

-gc

 

I think vinegar is a *great* idea... much gentler
than CLR, I'll guarantee that! This thing is probably
toast, anyway... but here's a tip... put some cooking
oil in, roll it around so it coats the reflector surface,
then get the excess out... now you can try vinegar
on wooden cotton-tip swaps or perhaps stronger
stuff... wash with soap and water afterward.
__
Steve
'06 FXDI
KI5YG
#0627
..

 

Ah yes, good point. Sorry I spoke :-/

 

Thanks for everyone for suggestions.

Just a clarification. this is a glass headlamp. I believe the reflective
surface is on the back of the lamp (just like a regular mirror) - but it's
hard to tell

The rice idea is a good one, I'll try that. Thanks again.

 

If it is glass, and the surface is on the back, then --most likely--
the reflecting material is a thin layer of aluminium,
sealed on the back with
some other material or
paint.
The fog then would be corrosion of the aluminium at the place
where is touches the glass,
and there is nothing you can do to polish that because you
cannot reach that spot.

Live with it, or buy a new reflector when you find you don't
have enough light on the bike.

Rob.