Headlight Cover Project

General Composites Discussions Composites Talk
#21

I popped off the mold today. It was on there for ~72 hours. Popped off pretty easily. The surface looks great, with the exception of a few small spots in the surface coat which has some small pin holes. I’m not sure what to do about those holes. If I don’t do anything I wonder if it will be an issue with the finished part. I plan on wet sanding and clearing the parts anyhow, so maybe it doesn’t matter. Any advice on how to proceed?


IMG_7446.jpg by Kevin_Doe, on Flickr


IMG_7445.jpg by Kevin_Doe, on Flickr


IMG_7443.jpg by Kevin_Doe, on Flickr


IMG_7447.jpg by Kevin_Doe, on Flickr

#22

Looks fantastic…
I just pulled my first mold and have some of those small pin holes. I posted a question asking how to fix them and no one responded. I’ll watch your thread and hopefully someone will help.

#23

Can you please tell what surface coat and resin you used for the mold. It looks like it’s worth putting in the extra time to make a perfect mold.

#24

I’m not sure if this helps, but you can take a look at this video. They make a repair to the mold, but they did use a gelcoat.

Min 18:12
[ame=“http://www.youtube.com/watch?v=UgKvDw1E60E”]http://www.youtube.com/watch?v=UgKvDw1E60E[/ame]

#25

I used Adtech ES-201-PC surface coat
http://www.adtechplastics.com/pc-38-20-es-201-pc-room-temp-surface-coat.aspx

#26

I use an airbrush needle to fix pinholes in epoxy surface coatings. Even with a low-temp catalyst, epoxy stays open and flows back after a few days. I use a heatgun to flow the fix back and leave it there, but you could block them down.

That said, I wouldn’t touch those pinholes. I think you’ll distort your shape trying to sand the pinholes back down flush. I would try and fill them with a release agent and then work the final part. Especially if you’re going to paint the covers.

#27

When using a wax as a release, I would do nothing. the pinholes will fill with wax.

When using a semi perm, you could try and fill them with a tiny drop of regular resin, but only if you are able to dispense the right amount. Otherwise do nothing.

#28

Will this not cause the new part to mechanically lock itself into place and at worst break a section of the mould when you try to release the newly made part?

#29

Not with these handful of tiny bubbles. If the complete mould is like that, you have a problem.

#30

I agree with herman…the pinholes are so tiny and in such a small area that you don’t have to bother. just fill them with wax and you will be ok.

#31

agreed, also remember they are female on the mold so would be male on the part, so sand it off after cure.

#32

Any further progress on this project?

#33

No, I paused this project due to some other more pressing projects I have going on with the car. I’m redoing the front end, and part of that was a new radiator, oil cooler, and power steering cooler. I am remounting everything with light weight design, and ease of maintainance in mind. Should be ~30 lbs lighter, and have more cooling capacity than before. I’m about wrapped up with that, so it will be back to the headlights very soon. My first SCCA event of the year this April 7th, so thats the deadline I’m working to.

#34

Cool project! I did some for my FC along time ago. I. Made one with a vent but the mounting tabs were a pain to re construct.

#35

Back at it. I figured I’d try a new technique, so I decided to do a wet layup. After reading a thread just now, I feel like I’ve made some mistakes. Hopefully it doesn’t turn out too bad.

I did a wet layup using Adtech 820 resin, which is a pretty low viscosity. I used peel ply, but no perf film. I used two layers of breather, and set vac to 25 inches Hg. I basically did everything wrong. Hopefully there is enough resin still left in the fabric to hold the part together. :nervous:


Untitled by Kevin_Doe, on Flickr

#36

I see nothing wrong with what you have described as your procedure…why would you want to use peel ply unless it was to adhere something to later if you are wet bagging?

Did you put your resin in a vacuum chamber prior to laying up with it?

#37

I used peel ply instead of perf film because that is what I was familiar with using. I also like the visual look of a peel ply surface for the unfinished side of a panel.

I did degas the resin prior to layup, about 20 minutes prior to mixing the resin, and ~2-5 minutes post mixing.

#38

Other than learning a new skill any reason why you chose wet lay up over infusion?

As always great work!

#39

Two reasons. I was getting frustrated by trying to get the laminate stack, peel ply and infusion media to stay in place. I would use spray adhesive, but it appears as if Airtac2 isn’t compatible with Adtech 820 resin. I did a test piece and even the lightest spray of the adhesive remains on the surface after infusion. I was getting irritated so I figured I’d try my hand at a different skill. The wet layup.

#40

Pulled the parts from the mold. They’re a bit dry, and the weave isn’t very straight and nice, but they parts will be functional. I’m not happy with how they turned out, so they’re definitely getting painted to match the car.


IMG_7705.jpg by Kevin_Doe, on Flickr


IMG_7707.jpg by Kevin_Doe, on Flickr


IMG_7708.jpg by Kevin_Doe, on Flickr


IMG_7714.jpg by Kevin_Doe, on Flickr

Closeup of dryness. You can see the resin wicked out of the weave intersections.

IMG_7713.jpg by Kevin_Doe, on Flickr