Carbon Fiber Sunroof Delete Panel - Build
 

This particular project will be to produce a lightweight composite sunroof delete panel for my car. I'll bet permanently fixing it to the roof. I have an existing metal sunroof to use as a plug, with a few modifications.

Here is the sunroof hole.
http://www.flickr.com/photos/kevindoe/6400440125/http://www.flickr.com/photos/kevindoe/6400440125/# by http://www.flickr.com/people/kevindoe/, on Flickr

Another of the hole.
http://www.flickr.com/photos/kevindoe/6400438033/http://www.flickr.com/photos/kevindoe/6400438033/# by http://www.flickr.com/people/kevindoe/, on Flickr

Closeup of the hole.
http://www.flickr.com/photos/kevindoe/6400435725/http://www.flickr.com/photos/kevindoe/6400435725/# by http://www.flickr.com/people/kevindoe/, on Flickr

Sunroof to use as plug.
http://www.flickr.com/photos/kevindoe/6400433065/http://www.flickr.com/photos/kevindoe/6400433065/# by http://www.flickr.com/people/kevindoe/, on Flickr

In this picture you can see two silver parts on the assembly. Those silver parts are nuts, that mount the sunroof assembly to the roof structure. What I did was measure the vertical distance between the contact surface of the nut, and the edge of the sunroof at that location. That way I'd know what the spacing from the edge of the sunroof to the flange I'll be building onto the plug. All 4 ended up exactly 1.1875".
http://www.flickr.com/photos/kevindoe/6413053273/http://www.flickr.com/photos/kevindoe/6413053273/# by http://www.flickr.com/people/kevindoe/, on Flickr

Then I removed the metal sunroof from the assembly and placed it on the plywood table. I then added 1/8" to the 1.1875" so that when the mold is made the flange will be 1/8" too tall. This will make the part that it produces protrude 1/8" above the flush roof line. I am doing this to account for any variations car to car, and my measurements accuracy. I can always add shims to bring it down to flush when I mount it, but I cannot make it stick up higher, so I'm erring to the side of too tall. Here it is shimmed to correct height.
http://www.flickr.com/photos/kevindoe/6413054589/http://www.flickr.com/photos/kevindoe/6413054589/# by http://www.flickr.com/people/kevindoe/, on Flickr

The next steps are to attach it to the wood shims to keep it in place during the rest of the buck making process. Then I'll need to fill in the vertical gaps with something. I also need to make the vertical edges have a slight angle to them, of a few degrees to make the parts release from the mold easy. I also need to slightly extend the sunroof about 1/8" all around, to make the fit inside the roof hole a bit tighter. Right now its about 1/4" gap all around.
http://www.flickr.com/photos/kevindoe/6413056201/http://www.flickr.com/photos/kevindoe/6413056201/# by http://www.flickr.com/people/kevindoe/, on Flickr

I mounted the sunroof to the plywood with expanding foam. I placed a 25 lb weight on each side directly above the shims I used to get the height right. And I put another 15 lbs in the middle. Here it is all trimmed up.

http://www.flickr.com/photos/kevindoe/6434436835/http://www.flickr.com/photos/kevindoe/6434436835/# by http://www.flickr.com/people/kevindoe/, on Flickr

Long story short, foam was a very bad idea even with the weights on top. The force of the reaction is so strong that my plywood ballooned and the sunroof did too. Not great. I had to cut the bottom out of the plywood and pull all the foam out. The sunroof went back into shape thankfully. I also had to cut out some foam on the long edges to get the shape to come back to stock. It did, but I was sweating it pretty good. Here is a pic of the foam all cut out (besides 2" around the edges to keep it mounted).
http://www.flickr.com/photos/kevindoe/6434435511/http://www.flickr.com/photos/kevindoe/6434435511/# by http://www.flickr.com/people/kevindoe/, on Flickr

Then I needed to box in the sides, and make it 1/8" larger all around to reduce the gap when installed in the car. I used 1/8" thick hardboard and glued it with Locktite construction adhesive. That actually worked pretty well. For the corners I had to cut 3/8" wide strips and glue them in place individually.
http://www.flickr.com/photos/kevindoe/6434434497/http://www.flickr.com/photos/kevindoe/6434434497/# by http://www.flickr.com/people/kevindoe/, on Flickr

All edges bonded on, and the first coat of body filler. I've got a lot of work to do on this to make it a quality surface finish, but I'll get there in a few days hopefully.
http://www.flickr.com/photos/kevindoe/6434430793/http://www.flickr.com/photos/kevindoe/6434430793/# by http://www.flickr.com/people/kevindoe/, on Flickr

This photo shows two things, one is the corner edging. The other is the crosshairs and circle around it. Those are the locations of the mounting studs in the car. That is where I'll drill a hole in my part. I'm planning on putting some sort of spike onto the plywood before I make the mold, that way it will give me a "center punch" on my part so I can drill the holes accurately.
http://www.flickr.com/photos/kevindoe/6434432677/http://www.flickr.com/photos/kevindoe/6434432677/# by http://www.flickr.com/people/kevindoe/, on Flickr

I'm planning on using 2 layers of 6 oz 2x2 twill weave carbon, one layer of Soric XF core, and another layer of 6oz carbon. I'm also planning on doing a vacuum infusion for the part. I've estimated it should weigh 2 lbs. Thats a 20 lb weight savings over the stock metal sunroof.

More as it happens.

You know Ronin Speedworks makes a carbon skin right?

p.s., did you/could you weigh the entire sunroof assembly, including the skin?

I am aware of Ronin's sunroof skin, and thought about using it as a starting point but didn't for several reasons. Ronin's skin is of identical dimensions the stock metal. While this is good for people who want to retain the function of the sunroof and the rubber seal, its not good for me. I want to seal it up fixed. That would then lead me down the path of making some sort of gutter system, or sealing up a very 1/4" gap all around the sunroof. I'm oversizing my sunroof by 1/8" all around to make the sealing gap smaller. Plus I'll have mounting flanges built right in. Should be a bolt in replacement, then seal around the edge. I think this will be a lighter solution as well, for me.

I did weigh the entire assembly as it came out of the car. 22.5 lbs.

Are you going to bondo and paint to make look smooth or are you going to leave carbon fiber look? How are you going to seal?

I will likely just use a UV resistant resin an no paint, for lower total weight, and to show off the part I worked so hard to make. Vacuum infusion leaves a perfectly glassy surface finish (well really as good as your mold is), so there wouldn't be any bondo required if I were to paint.


Small update. Lots of bondo work. I roughed in the visible sunroof surface. I am nearly completed with the sides. I just have a bit of finish sanding to do there. I included a 5 degree angle on the side pieces to give the mold some proper draft angle so the parts would pop out of the mold easier. I also finished squaring off the corners from widening it 1/8".

http://www.flickr.com/photos/kevindoe/6439961029/http://www.flickr.com/photos/kevindoe/6439961029/ by http://www.flickr.com/people/kevindoe/, on Flickr

This shows the widening by 1/8" all around.
http://www.flickr.com/photos/kevindoe/6439959625/http://www.flickr.com/photos/kevindoe/6439959625/ by http://www.flickr.com/people/kevindoe/, on Flickr

And another of the 1/8" widening, and the sides.
http://www.flickr.com/photos/kevindoe/6439958213/http://www.flickr.com/photos/kevindoe/6439958213/ by http://www.flickr.com/people/kevindoe/, on Flickr

Great idea. I've always thought about deleting my sunroof but then change my mind once I'm driving with it open.

The reason I brought up the sealing thing, I would make sure you do something flexible or else it will crack. There will be some definite flexing going on.

For sure. I was thinking some sort of flexible waterproof sealer. Either RTV or some the stuff they use to seal windshields.

Nice place to drop some weight.

Another small update, although this one took me quite a bit of time. I finished out all the surfaces to 220 grit paper. I took it to 80 grit with bondo, then skimmed it with a glazing putty and took to 220 grit. The sunroof was quite a bit rougher than it seemed when it was installed on my bar. Either way, its 100x better than it was, and hopefully will make for some nice parts that I pull from the mold.

Next step is high build primer, 400, 800, 1000, 1500, 2000, buff.

http://www.flickr.com/photos/kevindoe/6457568367/http://www.flickr.com/photos/kevindoe/6457568367/ by http://www.flickr.com/people/kevindoe/, on Flickr

The sunroof was really a complex surface to finish out nicely, curves in every direction, and transitions from convex to concave, etc. These next two pics show the shape of the sunroof.
http://www.flickr.com/photos/kevindoe/6457566187/http://www.flickr.com/photos/kevindoe/6457566187/ by http://www.flickr.com/people/kevindoe/, on Flickr

http://www.flickr.com/photos/kevindoe/6457564923/http://www.flickr.com/photos/kevindoe/6457564923/ by http://www.flickr.com/people/kevindoe/, on Flickr

And this one shows the corner edge blends. The inside corner is just to ease the layup. The outside corner will be somewhat visible, and I tried to match the radius of the corner of the sunroof hole.
http://www.flickr.com/photos/kevindoe/6457563421/http://www.flickr.com/photos/kevindoe/6457563421/ by http://www.flickr.com/people/kevindoe/, on Flickr

Primed with many coats of high build primer. Should be sufficient to get sanding up to 2000 grit and then polishing/waxing. I was in a rush and ended up painting right over my mounting hole location marks before I center punched them. Looks like I'll be sanding down to the wood to find my marks and then touching up those areas. Won't matter too much though since it won't be visible when installed, but it pisses me off when I do stupid shit.

http://www.flickr.com/photos/kevindoe/6469084839/http://www.flickr.com/photos/kevindoe/6469084839/ by http://www.flickr.com/people/kevindoe/, on Flickr

http://www.flickr.com/photos/kevindoe/6469083667/http://www.flickr.com/photos/kevindoe/6469083667/ by http://www.flickr.com/people/kevindoe/, on Flickr

http://www.flickr.com/photos/kevindoe/6469082339/http://www.flickr.com/photos/kevindoe/6469082339/ by http://www.flickr.com/people/kevindoe/, on Flickr

Awesome work! but a little surprised you don't have something keeping the dust off the seven....

You might be able to sell the mold when you are done for someone to produce these!

Bah, all the dust washes off. :lol:

And sanded to 2000 grit. Then buffed with some meguiars polish on the surface that will show when installed. Bare primer just doesn't buff out that nice, I suppose since there isn't any clear.

http://www.flickr.com/photos/kevindoe/6480434189/http://www.flickr.com/photos/kevindoe/6480434189/ by http://www.flickr.com/people/kevindoe/, on Flickr

Like the work so far. Keep it up!

I prepared the plug for laying up the mold. I attached some angle aluminum for flanges to add some stiffness to the mold. I then waxed the whole thing with 6 coats of Meguiars #8 Max Mold Release Wax.
http://www.flickr.com/photos/kevindoe/6503312361/http://www.flickr.com/photos/kevindoe/6503312361/ by http://www.flickr.com/people/kevindoe/, on Flickr

Then went w/o PVA and sprayed the gel coat on. Then a few layers of 0.75 oz mat, with some plain weave cloth draped over the corners at a 45 degree. Then 6 layers of 1.5 oz mat, and put some foam in there for added stiffness. Here it is all cured up with the green being the foam ribs.
http://www.flickr.com/photos/kevindoe/6503310737/http://www.flickr.com/photos/kevindoe/6503310737/ by http://www.flickr.com/people/kevindoe/, on Flickr

I removed the aluminum strips and they popped right off no problem. I was feeling pretty good about not using PVA at this point. Then shoved a bunch of wedges under and it started to pop quite nicely.
http://www.flickr.com/photos/kevindoe/6503308433/http://www.flickr.com/photos/kevindoe/6503308433/ by http://www.flickr.com/people/kevindoe/, on Flickr

Shortly after this point, I heard what I thought was the mold popping off the plug, but I was wrong. It was the plug breaking in half. The sunroof and hardboard sides had pulled off the plywood. I had the mold pulled off the plywood and the rest of it stuck inside my mold. Not good. I chipped the hardboard and bondo sides and was then left with just a sunroof at the bottom of the hole. At this point I was thinking about how screwed I was, and then decided to have a beer. Thankfully I widened the whole thing 1/8" and that gave me a small gap to grab onto the sunroof lip. I rigged up this prybar with some vice grips and a wedge. It popped off super easy.
http://www.flickr.com/photos/kevindoe/6503306299/http://www.flickr.com/photos/kevindoe/6503306299/ by http://www.flickr.com/people/kevindoe/, on Flickr

Disaster averted. I was sweating bullets. Looks like everything turned out nice besides tons of primer sticking.
http://www.flickr.com/photos/kevindoe/6503303959/http://www.flickr.com/photos/kevindoe/6503303959/ by http://www.flickr.com/people/kevindoe/, on Flickr

http://www.flickr.com/photos/kevindoe/6503301681/http://www.flickr.com/photos/kevindoe/6503301681/ by http://www.flickr.com/people/kevindoe/, on Flickr

So now here is my question, how do I remove all the primer w/o damaging the gel coat. The gel is a Fiberglast Orange Tooling Gel coat. The primer is this stuff.
http://www.flickr.com/photos/kevindoe/6503299567/http://www.flickr.com/photos/kevindoe/6503299567/ by http://www.flickr.com/people/kevindoe/, on Flickr

Mild success, after a big scare was the overall feel tonight.

I cleaned the mold up with lacquer thinner. That got 95% of the paint off. There was some paint embedded into the gel, so I wet sanded with 1000 grit paper and it came right off. I do have one concern though. Seems as the wood grain texture transferred to the mold, even though I had it filled and sanded/primed. The wood grain texture is on a part of the mold that won't be critical visually on the part. I am concerned about the vacuum bag sealing though. I'm not sure the bagging tape will be able to seal in those tiny nooks and crannies.

Here is the mold mostly cleaned up. I still need to get into the inside corner, but other than that its about all cleaned up.
http://www.flickr.com/photos/kevindoe/6509063811/http://www.flickr.com/photos/kevindoe/6509063811/ by http://www.flickr.com/people/kevindoe/, on Flickr

If you look closely at this pic, you can see the wood grain texture I'm talking about. I also did a polish test with some Meguiars M205 Ultra Finishing Compound I use on my cars. Polished it up pretty good even just by hand in that small spot.
http://www.flickr.com/photos/kevindoe/6509091641/http://www.flickr.com/photos/kevindoe/6509091641/ by http://www.flickr.com/people/kevindoe/, on Flickr

looking good :icon_tup:

I was sweating bullets along with you as I read.

Didn't have a beer though. :(

I didn't do much with the mold, but I got started on other equipment required for vacuum infusions. I need a vacuum pump, resin trap, and degassing chamber. For simplicity's sake, I figured I'd mount them all on a platform so they'll be packaged neatly. I'm not finished yet, but here is what I've got done.

The resin trap is 5" pipe, sch 10 stainless steel. I welded a 0.125" plate to the bottom and drilled some mounting holes. The degassing chamber is a 8" tube, 0.069" wall. These are just items I had around so I figured they were close enough to what I wanted so I went with it. I put some 1/4" NPT half couplings in them to hook them all together. Each chamber has a SS 1/4 turn valve. The resin trap has a 3.5" vacuum gauge to monitor the vacuum in my part during cure, and will be used to leak check the vac bag.

http://www.flickr.com/photos/kevindoe/6535399039/http://www.flickr.com/photos/kevindoe/6535399039/ by http://www.flickr.com/people/kevindoe/, on Flickr

http://www.flickr.com/photos/kevindoe/6535396893/http://www.flickr.com/photos/kevindoe/6535396893/ by http://www.flickr.com/people/kevindoe/, on Flickr

http://www.flickr.com/photos/kevindoe/6535394689/http://www.flickr.com/photos/kevindoe/6535394689/ by http://www.flickr.com/people/kevindoe/, on Flickr

I took my time welding to ensure I had no pinhole leaks.
http://www.flickr.com/photos/kevindoe/6535392513/http://www.flickr.com/photos/kevindoe/6535392513/ by http://www.flickr.com/people/kevindoe/, on Flickr

Angled upward for your viewing pleasure.
http://www.flickr.com/photos/kevindoe/6535389951/http://www.flickr.com/photos/kevindoe/6535389951/ by http://www.flickr.com/people/kevindoe/, on Flickr

Not a lot of progress today. I managed to get the thing all plumbed up, and all the pieces mounted to the board. Up next, lids.

http://www.flickr.com/photos/kevindoe/6547125081/http://www.flickr.com/photos/kevindoe/6547125081/ by http://www.flickr.com/people/kevindoe/, on Flickr

When I make my molds, I use TR mold release wax. I have heard horror stories with Meguiars wax. Typically, I use 3 of the TR waxes and then coat the crap out of it is Rexall Coverall PVA. These products are the best on the market and what I used before.

BTW, I use the same pump. For my resin trap, I just use a modified dessicator. What you have is a badass set-up nontheless. Eventually I will be using a venturi for hooked up to an air compressor as my "pump".

I finished up the lids for the resin trap and degassing chambers. The resin trap uses a stainless lid, 1/2" thick. The degassing chamber uses a Lexan lid, 1/2" thick. I machined an O-ring groove into each lid, 0.160" wide, 0.250" deep. I am using Viton o-rings in the grooves. The atmospheric pressure seals them tighter as the vacuum increases. On resin trap lid had 350 lbs of force holding it closed at full vacuum. The degassing chamber has 740 lbs of foce holding it down at full vacuum.

I added a tube to the resin trap lid to channel resin into the cup that I'll place inside it. I did this to make sure the trap works as intended. I doubt anything will make it up into the tube, but better safe than sorry.

I pulled a vacuum on the containers and turned the ball valves to closed. Zero vacuum loss over 10 hours. Perfect. I was a bit concerned about the force of the lids smashing the o-ring so I measured the height of the lid while free, and while full vacuum. The o-ring compresses 0.020". That seems pretty optimal really, so no limiters need to be added.

http://www.flickr.com/photos/kevindoe/6598180559/http://www.flickr.com/photos/kevindoe/6598180559/ by http://www.flickr.com/people/kevindoe/, on Flickr

http://www.flickr.com/photos/kevindoe/6598184077/http://www.flickr.com/photos/kevindoe/6598184077/ by http://www.flickr.com/people/kevindoe/, on Flickr

http://www.flickr.com/photos/kevindoe/6598185991/http://www.flickr.com/photos/kevindoe/6598185991/ by http://www.flickr.com/people/kevindoe/, on Flickr

http://www.flickr.com/photos/kevindoe/6598182465/http://www.flickr.com/photos/kevindoe/6598182465/ by http://www.flickr.com/people/kevindoe/, on Flickr

After I did the vacuum test I found out that even with the ball valve on the pump open, vacuum won't bleed down. So the lids were stuck on with the force of god. Luckily I just have the top port of the resin trap plugged with an NPT plug. I was able to just thread that out to relive vacuum. Given that, I need a better way to do that. In this picture you see a half coupling next to a tee fitting. I'll be welding the coupling to the fitting and drilling a through hole. On that I'll thread in another ball valve with a breather fitting on the end to keep debris out when I relieve vacuum.
http://www.flickr.com/photos/kevindoe/6598178969/http://www.flickr.com/photos/kevindoe/6598178969/ by http://www.flickr.com/people/kevindoe/, on Flickr

I also started polishing the mold. I am using Meguiars polish that I usually use on car paint. I tested an area and it works pretty well. I'm only done with step one, but its coming along nicely. This is with M105, Ultra Cut Compound. The gel coat is pretty hard so I had to up the speed and pressure accordingly.
http://www.flickr.com/photos/kevindoe/6598155775/http://www.flickr.com/photos/kevindoe/6598155775/ by http://www.flickr.com/people/kevindoe/, on Flickr

http://www.flickr.com/photos/kevindoe/6598157305/http://www.flickr.com/photos/kevindoe/6598157305/ by http://www.flickr.com/people/kevindoe/, on Flickr

Here is my modified t-fitting with quarter turn ball valve and breather vent all put together.
http://www.flickr.com/photos/kevindoe/6609057907/http://www.flickr.com/photos/kevindoe/6609057907/ by http://www.flickr.com/people/kevindoe/, on Flickr

And re-installed.
http://www.flickr.com/photos/kevindoe/6609060199/http://www.flickr.com/photos/kevindoe/6609060199/ by http://www.flickr.com/people/kevindoe/, on Flickr
I was unhappy with how much the whole thing vibrated even with the pump mounted on factory rubber bushings. It would vibrate so much that the whole thing would slowly slide off the workbench. So I ordered up some rubber mounts that would put more rubber between the pump and the plywood. 4x the rubber thickness to be exact. I also bought some rubber feet for under the plywood that are really soft and made for vibration damping. The whole thing works great. No vibration at all transferred to the bench its on.
http://www.flickr.com/photos/kevindoe/6609061847/http://www.flickr.com/photos/kevindoe/6609061847/ by http://www.flickr.com/people/kevindoe/, on Flickr

Very cool/good project. please keep it update it


J

Thanks for doing this, now maybe I won't have to (if you decide to sell a few) :icon_tup:

I did my first infusion yesterday. I did a sample to make sure I understand the process, and work out any issues on a smaller scale.

Here is the setup I did. Its a 4x12" piece, with a 2"x10" piece of 1/8" divinycell. I feed resin from one side, and vac on the other. I put the feed line right at the edge of the fabric, and left ~3" of peel ply on the vac side as a resin brake. Since the part was so small I did not use any flow media. I used 2x2 twill, 8oz glass. 2 layers, core, 2 layers. Then peel ply, then 4 mil polyethylene. I was using Adtech 830 with the medium hardner (45 min).
http://www.flickr.com/photos/kevindoe/6698682293/http://www.flickr.com/photos/kevindoe/6698682293/ by http://www.flickr.com/people/kevindoe/, on Flickr

I vac checked the part overnight. I had 29" vac, and lost zero vac over 12 hours. Then I mixed my resin up, and degassed it for ~2 minutes. It was still "boiling" when I removed it. I wasn't sure if it would boil forever or what, so I figured it was good enough. As you can see in this picture, I don't think the resin was degassed well enough. There are what looks like air bubbles pulling through, and boiling inside the vac line.
http://www.flickr.com/photos/kevindoe/6698683417/http://www.flickr.com/photos/kevindoe/6698683417/ by http://www.flickr.com/people/kevindoe/, on Flickr

Here it is completed. It took about 10 minutes to fully infuse the part. Seems pretty long for a part of this size. For my sunroof project I'll need to speed up the rate of resin travel, which I think flow media will accomplish.
http://www.flickr.com/photos/kevindoe/6698684737/http://www.flickr.com/photos/kevindoe/6698684737/ by http://www.flickr.com/people/kevindoe/, on Flickr

Here are a few of the finished part, trimmed up with a cutoff wheel (not the best tool for a nice edge). The glass is super transparent.
http://www.flickr.com/photos/kevindoe/6698685755/http://www.flickr.com/photos/kevindoe/6698685755/ by http://www.flickr.com/people/kevindoe/, on Flickr

In this one you can see the peel ply texture on the surface, as well as what appears to be small voids in the surface of the part. I assume this is from not degassing the resin well enough. I did not see any of those "bubbles" till ~6-8 hours after infusion, then they started to appear. Odd.
http://www.flickr.com/photos/kevindoe/6698687017/http://www.flickr.com/photos/kevindoe/6698687017/ by http://www.flickr.com/people/kevindoe/, on Flickr

http://www.flickr.com/photos/kevindoe/6698687937/http://www.flickr.com/photos/kevindoe/6698687937/ by http://www.flickr.com/people/kevindoe/, on Flickr

Absolutely perfect surface finish on the mold side.
http://www.flickr.com/photos/kevindoe/6698688655/http://www.flickr.com/photos/kevindoe/6698688655/ by http://www.flickr.com/people/kevindoe/, on Flickr

And a short video of the resin boiling/bubbling in the vac line. I am positive I had no vac leaks in the bag, so I assume this is from a poorly degassed resin???
http://www.flickr.com/photos/kevindoe/6698750059/