Foggy looking glass (inside) H4 Headlight lens- How to clean

machten · Post by **machten** » Thu Nov 06, 2008 7:10 pm

I spoke to someone last week who has separted roundcase headlight assemblies several times using acetone. It takes quite some hours soaking, apparently.

Macdesmo · Post by **Macdesmo** » Fri Nov 07, 2008 12:44 am

Nottonight,
That stuff is Dichloromethane and is a carcinogenic paint stripper. Maybe any other paint stripper will do the trick. Machten has an idea that can't hurt trying as well. I had some acetone but will try the wife's nailpolish stripper if I haven't got any.
Ian

nottonight68 · Post by **nottonight68** » Fri Nov 07, 2008 1:33 am

in the interests of not ending up in cuba-acetone seems like a good shot
i know these things need to be soaked for hours
if it works the next problem will be-acetone will disolve rubber gasket allowing lens to come off-where to get new gasket?
i also need to find sources of chemicals
at least we're making progress-better than butcher it off with knife
experiments start tomorrow

machten · Post by **machten** » Fri Nov 07, 2008 2:18 am

macdesmo,

as the process was explained to me, it's a bath. Pour some inside and sit the extenal glued interface into a pool of acetone. Leave it overnight. Have a pry and test for separation. If it's not happening, leave it some more, etc etc. I got this info from a 35 year bevel owner and bevel mechanic/restorer. Naturally however, at your own risk!!!

Regards,

Kev

nottonight68 · Post by **nottonight68** » Fri Nov 07, 2008 2:28 am

thanks kev
at your own risk is a worry
i just paid au$425 for a nos complete headlight
needs re-silvering
this was the only h/light i could find in the world

MartinMille BANNED · Post by **MartinMille BANNED** » Fri Nov 07, 2008 2:49 am

Steve are you talking about a CEV head light ? you can still get them NOS and for less than what you paid for it !!!!

nottonight68 · Post by **nottonight68** » Fri Nov 07, 2008 3:02 am

no martin
aprilia-jod-duplo,original equip on ss
no longer avaailable

machten · Post by **machten** » Fri Nov 07, 2008 6:27 am

Unless you have a good condition reflector, acetone is no issue. Even if you do have, the chemical interaction between acetone and the relatively inert reflector surfaces (silver, chromium, (alumininum vapour may be different)) is likely to be close to zero - like wipe it off.

I've never done the procedure, but I have seen a number that have undergone it, and they look pristine. I suggest anyone planning to do this rubs a bit of acetone on a less critical surface first, and leaves it for a day. I'll be very suprised if an acetone chemical has any effect on it, but you should check it out first to convince yourself.

Kev

machten · Post by **machten** » Fri Nov 07, 2008 7:55 am

Steve,

I think at that price, if the glass is as good as looks, you've got a good buy, particularly with the AU$.

Kev

nottonight68 · Post by **nottonight68** » Fri Nov 07, 2008 8:36 am

this is a brand new complete unit-shell,reflector,lens,chrome ring ,adjusting screws-even got both lamps.only thing wrong is flakey silver on reflector

nottonight68 · Post by **nottonight68** » Mon Nov 10, 2008 11:51 pm

i now have complete instructions for separation of lens from reflector <its a long winded explanation and i type slow
anyone want this info

Macdesmo · Post by **Macdesmo** » Tue Nov 11, 2008 12:00 am

Steve,
Let it roll.
Ian

nottonight68 · Post by **nottonight68** » Tue Nov 11, 2008 12:35 am

O.K. I am gonna try this when I get all the stuff together. I will give you the instructions as they were given to me.
I have successfully separated a lens/reflector using acetone. It is available from your local hardware store. Put the lens/reflector glass down and fill up to the the parking light hole. Put it in a polythene bag (some types of plastic will disappear in contact with acetone vapours) and leave it for about 6 days. At that time tip out the acetone but save it because it may have to go back in, get a very thin blade and run it around between the glass and reflector at the front of the light. After a few minutes I put a piece of wooden dowel inside the unit and pushed very gently. I tried to separate the unit after 4 days and 5 days but to no effect. Don't hurry the process. It took 2 or 3 days with liquid methylene chloride but the other problems with it were terrible. The reflector has to be polished with 1000 grade wet and dry before being coated. The process is vacuum deposited aluminium. Be very careful not to polish off the little fingers of the bulb holder that wrap around the hole in the back of the reflector. Once coated don't put your fingers on the reflector while you are reassembling it. Use a neutral cure sealant, not silastic, when reassembling the lens into the reflector. Silicones give off acetic vapour while curing and rot the coating big time.

I am gonna take some pics as I go. Keep me posted. This info should be valuable to those on this site.

Cheers Steve

Macdesmo · Post by **Macdesmo** » Tue Nov 11, 2008 12:49 am

Thanks Steve,
I will keep this and have a go at it when I follow up on exactly what I will do with regards to re-coating the reflector. I was going to have it silvered by an electroplater, but will have to find out about the aluminium vapour process as well.
Ian

nottonight68 · Post by **nottonight68** » Tue Nov 11, 2008 12:58 am

yea
ive done em in the past-silver plate was the go-dont know about ali vapour
i'll just take mine to chromers here in adelaide who specialise in bikes-they'll know what to finish it in
cheers