Cleaning up milky headlights
Posted: Tue Feb 02, 2016 9:13 pm
Whilst fettling a few other bits and pieces on the bike I decided to have a go at sorting out the milky headlight cover. There are many suggestions on the interweb ranging from highly expensive special polishing kits through to mosquito repellant, via toothpaste. The crux of the matter is getting the thing apart in the first place. This is where heating it up comes in.
Some people will have you believe that the entire headlight assembly will melt at the slightest provocation, and others point out that you car park your car/bike in the desert sun and the little greenhouses on the front are just fine and dandy. I choose to believe the latter point of view.
The glue / sealer that is used to stick the headlight unit together softens when warm, the question is how warm to get it malleable but stop short of doing harm?
This is the offending headlight, as you can see one side is pretty cloudy. I'd tried reaching in there using the old rag on a stick approach and the cloudiness didn't mark so it was more than condensation or a little surface dirt.
The observant amongst you will notice the somewhat manky mountings. 3 out of the 4 were broken when I got the bike to I used some nylon sheet I happened to have around and a soldering iron with a nail in place of the tip and knocked up some new ones. Not necessarily pretty but functional.
So having removed the clips and all the odd screws etc it was time to get things warmed up. The value of 115 C for 5 minutes seems to be conistent amongst those describing headlight dismantling so I started there.
Using the trusty sword in the gap at the sides of the housing and gently twisting the lens did indeed start to ease away from the body. Working along the top and bottom edges the parts were coming apart, you can feel when the glue / sealer cools as the 'give' suddenly stops. Another spell in the oven and repeat and the parts separated easily.
The grey glue / sealer goes a bit stringy as it pulls apart hence the lumpy look where it has contracted back in on itself.
Popping the screws out and the inner mask from the lens gives you the three parts separated.
I had borrowed some 2500 and 4000 grade polishing compound from a friend who is into 'detailing' (I just chuck a bucket of water over the car once in a while) and about 10 minutes work with those and a few bits of old T shirt gave this.
Which is a whole lot better than it started out. Although this was taken in artificial light, it's falling across the surface pretty similarly to the original view.
Now to clean up the old glue, run a bead of silicon around the joint and clip it back together.
Yes one of my home made mounting lugs broke off, but I can fix that in just a few minutes too!
Oh yes, I mentioned mosquito spray. Apparently some people advocate the use of solvents such as acetone or thinners. The idea seems to be that as the surface melts you wipe away the milky / yellowed crud and leave the lens wet. The solvent then flows the plastic smooth and restores a smooth finish.
Some people will have you believe that the entire headlight assembly will melt at the slightest provocation, and others point out that you car park your car/bike in the desert sun and the little greenhouses on the front are just fine and dandy. I choose to believe the latter point of view.
The glue / sealer that is used to stick the headlight unit together softens when warm, the question is how warm to get it malleable but stop short of doing harm?
This is the offending headlight, as you can see one side is pretty cloudy. I'd tried reaching in there using the old rag on a stick approach and the cloudiness didn't mark so it was more than condensation or a little surface dirt.
The observant amongst you will notice the somewhat manky mountings. 3 out of the 4 were broken when I got the bike to I used some nylon sheet I happened to have around and a soldering iron with a nail in place of the tip and knocked up some new ones. Not necessarily pretty but functional.
So having removed the clips and all the odd screws etc it was time to get things warmed up. The value of 115 C for 5 minutes seems to be conistent amongst those describing headlight dismantling so I started there.
Using the trusty sword in the gap at the sides of the housing and gently twisting the lens did indeed start to ease away from the body. Working along the top and bottom edges the parts were coming apart, you can feel when the glue / sealer cools as the 'give' suddenly stops. Another spell in the oven and repeat and the parts separated easily.
The grey glue / sealer goes a bit stringy as it pulls apart hence the lumpy look where it has contracted back in on itself.
Popping the screws out and the inner mask from the lens gives you the three parts separated.
I had borrowed some 2500 and 4000 grade polishing compound from a friend who is into 'detailing' (I just chuck a bucket of water over the car once in a while) and about 10 minutes work with those and a few bits of old T shirt gave this.
Which is a whole lot better than it started out. Although this was taken in artificial light, it's falling across the surface pretty similarly to the original view.
Now to clean up the old glue, run a bead of silicon around the joint and clip it back together.
Yes one of my home made mounting lugs broke off, but I can fix that in just a few minutes too!
Oh yes, I mentioned mosquito spray. Apparently some people advocate the use of solvents such as acetone or thinners. The idea seems to be that as the surface melts you wipe away the milky / yellowed crud and leave the lens wet. The solvent then flows the plastic smooth and restores a smooth finish.