Headlight baking

[gybe]

I have polypropylene housing and lexan glass, typical plastic protege headlight. anyone already baked it in an owen? I have to take it apart so I need some tips if anyone got them.
what's the appropriate temperature? something about 200 F?

[bigbully0110]

I have seen it done at 300 for 3 to 4 minutes on youtube. This is for a projector retrofit. Looks to be a mazda 3 headlight. There are 4 videos. http://www.youtube.com/watch?v=imIiglkq7HA

[gybe]

nice, I'll probably bake it longer on lower temps. lexan an PP start to soften radically at around 280 F.

[monoxidechild]

i dont like using the oven, or even a heat gun. i just use a 5 inch putty knife. does ZERO damage. you cant even tell you opened it up when you go that route. ive installed 2 HALO kits on mazda's now by just using a 5 inch putty. it even takes 1/4 of the time, is cleaner, and doesnt risk melting your headlight.

[gybe]

lol last weekend when I wanted to do the headlights I bought a reasonably wide putty knife coz they were cheap. now tell me something, how on earth did you manage to squeeze it in the slot??? did you pry it or slide the plate right between the edges and literally cut/massage the sealant?
have you ever done it on a second gen?

I need headlamp repair really badly and it has to be done over a course of weekend. need as much info as possible. I don't want to melt the lamps either, they cost fortune.

[gybe]

was that a soft knife you have used or stiffer one?

[monoxidechild]

it was a metal one. i just put it in the crease, and pryed slowly, taking my time. but still took less then a minute each.

the putty is nice, cause if you try that with a flat head screw driver, it just messes up the plastic. but the putty spreads the pressure evenly, so it doesnt **** up the headlight at all.

[gybe]

okey so I have got a polyurethane sealant for windshields that is perfect for this application because of the operating temp. range and relatively low melting point (=200 deg F). it will be perfect.

I am starting tomorrow morning and will see what will happen. yeah screwdrivers sucks I didn't even bother that....
what was the oldest headlight you have done dry prying on it? don't forget mine's 1995 (well the other one is actually younger, but this particular one is original and still factory sealed) so I think it will take a bit more time. anyway I still wanted to bake them for a while. I noticed that after a long ride in summer everything gets properly hot under the hood so I'll give it a bit of heat treatment first.

I have a foggy headlamp situation on this one and I already checked the vent but it looks clean and okay. also because of that the projectors are a bit faded but paper towel wipe test showed clean and shiny underside. no visibile corrsion either.

thanks for tips and sharing!!!

[3ni_tricksta]

i've baked my 2nd gen headlights; @ 250 or so.. for 5minz.. on a properly preheated oven and the lense came right off; heated it back up and pressed it together.. after painting and never had any condensation issues;

[grey1]

200 F will do ....maybe less

make some balls of tin foil to prop it up on. ...you dont want any part of the headlight touching anything but the foil balls it is sittig on

touching metal pan or or rack will melt/deform the case.

dont need any extra glue, in fact Mazda used too much. Discard any that seems extra.

[gybe]

I'll be discarding all of it. I couldn't position the headlamp into the oven because the oven is too narrow. it just half an inch but I didn't want it to touch anything. I left it in the sun for an hour and it went nicely with a putty knife. next phase is to somehow remove the old sealant. I cannot reuse it because it's already dirty after the putty knife therapy.

anything on cleaning the projector lense itself? I was thinking about regular window cleaner with factory added alcohol? some people rub it with pure alcohol but I don't have it at home.

[gybe]

it's done. I rinsed old sealant with a thinner. it was horribly messy, but I tried to stay in the mood. when this sealant gets on your hand it just sticks and sticks. not even the superglue is so annoying!
the projector is nice and shiny. hope the light won't fog up anymore.

[renesis_z5]

what kind of projectors did you use?

[gybe]

the stock one, I just cleaned it in and out.
I only sanitized one headlamp as the other one is very shiny and no fog problem either.
did a bit of polishing this weekend with Xerapol and the results are satisfactionary. it will probably need some fine sanding but mostly they are starting to look alike.

forgot to add that luckily the sealant does work and there is no moisture trapped in the light anymore.

[CaymenEGT91]

just dont do what one of my ex gfs did .... she was baking a cake, instructions said bake @ 350.... she waited til 10 of 4 in the afternoon to put it in... I'm 100% serious.