More practice parts.

First a short video of degassing the resin prior to infusion.


This time I made a 12x12 square, with a 10x10 foam core. I fed from the middle, and pulled vacuum on the sides. I also put 1/8" diameter perforations in the core every 2" from the center outward. I think I probably over-sized the holes, but it worked. I'll try smaller holes next time. That test was to ensure resin would wet out the surface underneath the foam, with just small holes to pass through. I discovered that sealing a resin feed hose in the middle of the bag isn't easy. I ended up with a leak during infusion. I was unable to stop the leak and figured the parts were destroyed. I was wrong. The infusion still went quite well. There is an area where the resin didn't 100% wet out the fiber where there was a significant amount of air, but its not too bad. Nice lesson to learn on a practice part. Next time I'll feed the resin tube in under the bag edge seal like I've done in the past.
Perfectly transparent fiberglass.
http://www.flickr.com/photos/kevindoe/6723472053/http://www.flickr.com/photos/kevindoe/6723472053/ by http://www.flickr.com/people/kevindoe/, on Flickr


Then I also made a 4x12 test panel with a 2x10 foam core, out of carbon. 2x2 3k twill weave. Two layers, core, two layers. This test was to see if carbon infused any different than the glass. It seemed to wet out quicker, but other than that no other issues. The test panel turned out really nice. The carbon panel is super stiff as well. This stuff is awesome.

Mold side
http://www.flickr.com/photos/kevindoe/6723468437/http://www.flickr.com/photos/kevindoe/6723468437/ by http://www.flickr.com/people/kevindoe/, on Flickr

Peel ply side.
http://www.flickr.com/photos/kevindoe/6723470673/http://www.flickr.com/photos/kevindoe/6723470673/ by http://www.flickr.com/people/kevindoe/, on Flickr

Next test will be a small swatch of carbon epoxied on the mold flange, to make sure that wax alone is adequate to release from the gel coated mold surface. If that goes well, then its on to making an actual sunroof. Well, I may do a test to thermoform some of the core inside the mold, but that should be straightforward.

 

We had problems with the mold release too. Our solution was to not polish the wax. We would literally wipe it on *thick* with the applicator and only make sure there were no big clumps. The parts pop off like a champ. Of course it makes for a not-so-nice surface finish, but all of our stuff is meant to get painted. I hope you can get it to work, so you can show off the carbon.

 

Where did u get your materials from, and how flexable is that divinicell does it seem like it can be used on curves or just pretty flat surfaces

 

I got the materials from a variety of sources.

Aircraft Spruce - foam
Fiberglass Supply - peel ply, flow media, bag tape, wedges
Advanced Vehicle Technology - fabric, mixing cups, stir sticks
McMaster Carr - PVC tubing, tees, spiral tubing, polyethylene film (for bagging)
M2 Supply - Resin
Sabic Polymers - Resin

 

I've used this source with good results. They have just about everything you could need. Check out the Aero Mat if you want to do work on compound curves.

 

The divinycell is fairly flexible in the 1/8" thickness. In the 1/4" thickness seems like it will conform to the shape of the sunroof quite well. I'm not sure how well it would conform to the shape or something with a smaller radius of curvature.

 

Test infusion on flange. Making sure the mold release works on the mold surface.
Test Infusion

 

So awesome, keep up the good work!

 

Made up a fiberglass sunroof today to test the fit and whatnot. It ended up weighing 3.125 lbs after trimming to fit. I did notice that my flanges for mounting are not nearly stiff enough. I'll have to add several plys to that area to stiffen the flanges. I also think I may double up the thickness of the foam core in two strips along the edges to increase stiffness. Other than that it was a complete success.

The blue you see is the foam core. The carbon version obviously won't show this through the fabric.
http://www.flickr.com/photos/kevindoe/6752964113/http://www.flickr.com/photos/kevindoe/6752964113/ by http://www.flickr.com/people/kevindoe/, on Flickr

The fit around the edge looks good.
http://www.flickr.com/photos/kevindoe/6752961523/http://www.flickr.com/photos/kevindoe/6752961523/ by http://www.flickr.com/people/kevindoe/, on Flickr

The fit with the stock roof line is perfect.
http://www.flickr.com/photos/kevindoe/6752959205/http://www.flickr.com/photos/kevindoe/6752959205/ by http://www.flickr.com/people/kevindoe/, on Flickr

 

Wow - awesome project! Can't wait to see the finished product

 

Great Work!

 

Congratulations on your success, any pics of the underside?

 

Very Nicely Done!

Look forward to seeing the finished product.. and will keep this all in mind when I start the widebody for my FB in the next couple weeks.

 

I did a test piece to check out infusing additional layers of fabric. I did 14 layers. I also tested using 3M Super77 to help hold the surface layer where I wanted it. I applied a very light mist to the mold surface (a waxed mirror). The fabric adhered nicely. But after the infusion was complete, the mold surface of the part was very sticky, and still had the residue on it. The mirror surface also had the residue on it. There were tiny dry spots from where the 3M was in contact. I was using Adtech 820 epoxy resin, which may have something to do with it. I will not use it again, at least not with this resin system.

 

Out of curiosity, why are you using an infusion method? Why not just do a wet lay-up and vacuum out the excess?

 

Super impressive work. Can't wait to see the final results

 

Well I made the real thing finally, but unfortunately I had some issues with the finished part.

Anyhow, here is the process.

- Scribe trim line into mold
http://www.flickr.com/photos/kevindoe/6837968033/http://www.flickr.com/photos/kevindoe/6837968033/ by http://www.flickr.com/people/kevindoe/, on Flickr

- Wax the mold, 4 coats of Meguiars Max Mold release.
- Lay in 1.2 oz/yd fiberglass, plain weave. The idea for this was to provide a finer layer on the surface. The glass can also be sanded easier if necessary.
http://www.flickr.com/photos/kevindoe/6837964203/http://www.flickr.com/photos/kevindoe/6837964203/ by http://www.flickr.com/people/kevindoe/, on Flickr

- Lay in two layers of 5.9 oz/yd 2x2 twill weave carbon fiber, first at 0/90 then at -45/45.
http://www.flickr.com/photos/kevindoe/6837961385/http://www.flickr.com/photos/kevindoe/6837961385/ by http://www.flickr.com/people/kevindoe/, on Flickr

- Place 1/4" divinycell foam core mat. I drilled 3/32" holes on a 2" grid. This is a slightly tighter grid than I used on the all glass test panel.
- Lay in 4 additional layers at 0/90 for additional stiffness on the mounting flanges.
http://www.flickr.com/photos/kevindoe/6837958689/http://www.flickr.com/photos/kevindoe/6837958689/ by http://www.flickr.com/people/kevindoe/, on Flickr

- Lay in two more layers of carbon, at -45/45, then 0/90.
http://www.flickr.com/photos/kevindoe/6837953369/http://www.flickr.com/photos/kevindoe/6837953369/ by http://www.flickr.com/people/kevindoe/, on Flickr

- Peel ply
http://www.flickr.com/photos/kevindoe/6837950855/http://www.flickr.com/photos/kevindoe/6837950855/ by http://www.flickr.com/people/kevindoe/, on Flickr

- Infusion media
http://www.flickr.com/photos/kevindoe/6837949079/http://www.flickr.com/photos/kevindoe/6837949079/ by http://www.flickr.com/people/kevindoe/, on Flickr

- Spiral Tubing and Vac bag
http://www.flickr.com/photos/kevindoe/6837947065/http://www.flickr.com/photos/kevindoe/6837947065/ by http://www.flickr.com/people/kevindoe/, on Flickr

http://www.flickr.com/photos/kevindoe/6837945083/http://www.flickr.com/photos/kevindoe/6837945083/ by http://www.flickr.com/people/kevindoe/, on Flickr

http://www.flickr.com/photos/kevindoe/6837942797/http://www.flickr.com/photos/kevindoe/6837942797/ by http://www.flickr.com/people/kevindoe/, on Flickr

http://www.flickr.com/photos/kevindoe/6837940545/http://www.flickr.com/photos/kevindoe/6837940545/ by http://www.flickr.com/people/kevindoe/, on Flickr

http://www.flickr.com/photos/kevindoe/6837937611/http://www.flickr.com/photos/kevindoe/6837937611/ by http://www.flickr.com/people/kevindoe/, on Flickr

The infusion seemed to go great. No real issues. Yesterday I pulled off the vac bag and consumables. The part looked great. Then when I demolded today the surface has a lot of porosity and dry spots. Looks like the dry spots are only in the glass surface layer but its hard to tell for sure. The dry spots are 2" apart, meaning it certainly had something to do with my hole spacing in my foam core.

I cannot just toss this piece and start over, since I've gone way over my anticipated budget already. What is the best course to fix the spots? I have a few ideas.

1. Sand through the fiberglass down to the carbon and hope the carbon was fully wetted out. If that is the case, I will just clear coat part and all will be well.
2. Paint on some epoxy and use a heat guy to help it flow into the voids and pull out the air bubbles. I'm not confident this method will work. There is wax probably transferred to the surface, plus I don't know how well the resin would wet out the cloth.
3. Fill in with glazing putty and paint. I'd rather showcase my hard work, so this will be a last resort.

Any ideas, I'm open!

 

I say, try to get as much of the wax out of the pores as possible, then paint in some resin by hand. Then try your best to sand it smooth. Clear and call it finished.
If you decide to make another one, try what I said in post #40.
Good luck.

 

Interestingly enough I was talking with my friend last night about the upcoming GT bodywork I am making for the FB.
We were discussing all the methods I ahve done in the past with layup, and what we used to do on his formula car chassis, and bodies, as well as the newer methods he is using the last couple years.

Infusion is the ONLY way he does composite now.

The issue I see with how that setup was done.. from all the info I gathered last night was the very very very first step.

He stated very clearly.. you pre-cut all your glass/carbon.. get it all laid out and ready to apply. The works.

Then you ***spray on a layer of gellcoat into the mold FIRST***** be it clear or colored!

Then lay in all your material.. set up the infusion setup, and then you keep on with the procedures as normal. This gives you a good surface finish, that adds a boundary between the material.

Im having a brain fart.. but he buys a type of glass that is stitched.. not woven. Its at angles.. but its stitched... so you dont have the tiny small voids where the fibers overlap.. which is a small spot of resin... that shrinks.. causing patterning on the final surface.
The kind he buys.. I forget the damn name.. patterns very very minimally.

SOooooo food for thought if you decide to make another go of it.

 

I sold this carbon one with the blemishes. I'll get another chance to do it right. I'm happy.

 

is it just a plug or can it mount to the stock sunroof carriage?

 

Love the progress. Look forward to seeing your next one Kevin.

 

I think you're talking about unidirectional? They also make fabric that is two layers of unidirectional stitched at different angles. That's fine for thick parts, but they come out heavier and thicker for a given strength because you now have two layers instead of one.

Have you started the new one, Kevin? Interested to see how it comes out and what you do differently. I am sort of copying your process to make one for my FC, but using a hand layup and then vacuum bag to get the excess out. I've never been successful with an infusion outside of small laboratory test samples. I'm also going to epoxy it to the Inside lip of the sunroof hole rather than bolt it in. This way it'll also be completely sealed in the event of rain and I won't need any weather stripping

 

Ive spent a fair time messing with this stuff, very time consuming.

I would never have put the glass as my first layer. I would have sprayed in some clear then started my layup. I dont use a vac tho.

When you dont have an autoclave you need to come up with whatever tricks you can to end up with a final piece that looks like the real deal.

For what your doing there you may want to look into a resin that sets when heated. You can build an oven with a space heater and 4x8 sheets of rigid insulation. Pre-infuse the carbon or coat the mold, lay in your carbon, finish the layup, pull a vac, slide it in your oven once you got a solid vac and leave the motor running while it sets up. The heat setting stuff gives you way more time to dork around.

Spent a day with a guy that makes parts for some of the guys in Rally America. Humble guy with a tiny shop making first class stuff. Even he pulls parts that look just like yours. They still go on the car since they serve their purpose and will end up getting crashed anyways. He had some Porsche hoods that were kevlar/carbon, absolute perfection, actual metal integral so the hood latch bolted on as well as the hinge mounts. That guy had a million tricks, but none of it could be done without the heat setting resin.

Good luck.

 

Hell, for a sunroof, you could use the oven in your house.