Making My Own Clear Headlights from Lexan

[94SubieSVX]

I made another mold using just dish soap this time.





Here it is. It's so much better than with saran wrap.



Won't be too much sanding on this mold.

I can't wait to finish the vacuum form "machine" so I can make a lens

[crazyhorse]

You'll do SOME sanding. You need to reduce the size by 1/8 on all 4 sides. This will compensate for the thicknes of the Lexan.

[superru]

i love it!!! right on the money man!! just make sure you get that plastic hot enough to vac it tight! super job

[Roo]

I spoke with a TAP Plastics store manager about this project, and he brought up a few things which may/may not help.

1. The lexan, when heated past 212 degrees, becomes VERY moisture prone, and will absorb moisture, which is what causes the bubbling.

2. The lexan may/may not melt, given the temperature of the halogen bulbs and the heat that is created...which is obviously how you're forming these in the first place. If you use thicker Lexan, it would simply retain more heat than thinner Lexan, but would last a bit longer before meltdown occurs.

Again, this is the opinion of a guy who's been doing plastics for some time now, and is only meant for informational purposes. I'd like to see you succeed, and would be happy to purchase a set of these when they become available.

[94SubieSVX]

Originally Posted by Roo

I spoke with a TAP Plastics store manager about this project, and he brought up a few things which may/may not help.

1. The lexan, when heated past 212 degrees, becomes VERY moisture prone, and will absorb moisture, which is what causes the bubbling.

2. The lexan may/may not melt, given the temperature of the halogen bulbs and the heat that is created...which is obviously how you're forming these in the first place. If you use thicker Lexan, it would simply retain more heat than thinner Lexan, but would last a bit longer before meltdown occurs.

Again, this is the opinion of a guy who's been doing plastics for some time now, and is only meant for informational purposes. I'd like to see you succeed, and would be happy to purchase a set of these when they become available.

Good info. I could get thicker lexan if needed. But I also, have HIDs so the temperature is alot less than normal halogens.

Now that I know the temperature(212 degrees) that lexan gets soft at, I will put it in the oven at 200 degrees for however long I need it to.

[94SubieSVX]

Did some sanding today. There's a couple of small dips that I will fill in later. I just have to make another mold like this but for the other headlight, and I can start molding.

There's a few things left I need to finish up with the vacuum former then it'll be ready to go.


Getting closer to finishing

[crazyhorse]

Get some bondo glazing putty to fill the low spots. Then glaze over the whole thing for strength.

[94SubieSVX]

Originally Posted by crazyhorse

Get some bondo glazing putty to fill the low spots. Then glaze over the whole thing for strength.

I was thinking of using bondo.

It'sJustEric even gave me the idea of making the whole mold out of bondo. It would be super strong but would take forever to make.

[It's Just Eric]

lol, no, it'd be faster to make. the trouble is the viscosity....It might be too thick to get the right shape, though, you'r not doing a very complicated shape or anything, so Id say give it a try, even if it';s like, the 3rd try doing it

[b3lha]

I keep thinking that you will need more vacuum than a you will get from a vacuum cleaner. A vacuum forming machine sucks pretty hard.

If the shop vac doesn't suck it tight enough around the mould, try with a vacuum pump. They seem to go quite cheap on ebay. Have a look at item 350000857210

[superru]

how much HG does that thing suck? for forming we have a pump that does 60 INhg. that's a suckin fool! but we're also doing huge 4'x6' peices. i hope the old shop vac works for you! i'm still kinda busy around the shop here, i hope to try one before the new year.

[Roo]

Originally Posted by b3lha

I keep thinking that you will need more vacuum than a you will get from a vacuum cleaner. A vacuum forming machine sucks pretty hard.

Go to your local red-light district and hire someone off the corner...

[Tim]

Originally Posted by Roo

Go to your local red-light district and hire someone off the corner...

Make sure you protect the mold

[94SubieSVX]

Originally Posted by It's Just Eric

lol, no, it'd be faster to make. the trouble is the viscosity....It might be too thick to get the right shape, though, you'r not doing a very complicated shape or anything, so Id say give it a try, even if it';s like, the 3rd try doing it

Well in a sense it would take longer because I'd have to do a few layers a a time to get into the tight corners, but I know what you mean.


Yeah, I hope the shop vac works, and if not, I'm goin downtown to get someone

[94SubieSVX]

Got a bit done. Here's a few pics of what I did.

Here's the frame holding the lexan in it. Made it just like a video posted earlier in this thread.




Here's the setup. The oven is just out of the picture to the left, close enough that the lexan doesn't get hard once out of the oven.




The first frmae holder setup. I had to raise it about 3 inches more to allow for the sagging lexan.





I had made a 95% perfect mold at first, but two corners weren't up against the plaster mold good enough. So I raised the plaster mold about 1/2" and re-heated the lexan again.

This is what happens if you re-heat the lexan multiple times at about 375degrees and leave it in for too long. It had sagged so much that it started coming out of the frame and was so long that it got wrinkled as you can see.



I'm going to start fresh with a new piece and make sure to watch it before it sags too much.