Making Composite Parts
 

So I made this thread to help, ask questions and share ideas about make composite parts out of Fiberglass, Aramid and Carbonfiber.

If you want to make a HOOD lets say, here is pretty much a step by step. Now this is what I have learned in the industry over the past few years
Step 1: Prep the Plug
Clean and make your part how you want (shinny, matte and etc)
Make the flange go at 4"-6" from the part
Wax the part/flange at least 5 times. 1 wax job is coat the part with mould release, wait until haze (10-15 min). Wipe off with clean rag and do not touch part with anything other than a clean rag (hands, gloves etc...) IMPORTANT Then let air dry for 15-20 mins, this will let the micro layer of wax to harden. REPEAT 4 more times
Put modeling clay in the joint between the part and the flange so it doesn't make a mechanical bond (locked together)

Step 2: Making the Mould (Mold)
Spray or bush on 2 heavy coats of Tooling Jell Coat
When jell is tacky (barely leaves a finger print) put on your skin coat of fiberglass which is a 1 or 1.5 oz Mat IMPORTANT Make sure all air bubble are rolled out.
Once the resin is cured look over the part for air bubbles. I some are found, grind them out and do not go in to the jell coat. I use Resin Putty to fill the grinned out areas.
Put on another layer of Glass/resin Mat
Now once there is a skin coat and a first layer, there can be layers of glass be put on at a time MAX: (2) 2 oz layers at a time
Build it up to your needed thickness. Can use foam or wood in between the mould and the last layer to add Stiffness
Put some wedges in between the flanges and work the way around to pop it loose slowly. Don't force it. The best sound is a good release
Now the mould can be wet sanded and buffed to the desired surface
Post all you projects and ask away! :idea:

Here is my newest part I made and currently its still in the works

https://www.miataturbo.net/attachmen...ine=1461804982

https://www.miataturbo.net/attachmen...ine=1461804982

https://www.miataturbo.net/attachmen...ine=1461804982

https://www.miataturbo.net/attachmen...ine=1461804982

https://www.miataturbo.net/attachmen...ine=1461804982

https://www.miataturbo.net/attachmen...ine=1461805172

http://i526.photobucket.com/albums/c...psfqroyxxh.jpg

Attachment 183729

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I like this.

Looks cool. This makes me want to do body panels so badly. The trunk is probably the easiest panel to make but also lower priority for me than things on the front of the car.

Also, what cloth and core material are you using? 2lb 13oz seems a bit heavy for a panel that size. It seems like wet layup and core materials are tricky- like it would be hard to keep the core from taking on a bunch of resin.

Here is a spreadsheet I put together to try and figure out how much weight a carbon prepreg sandwhich core hood could save. I have it as 3 plies right now, might need to be 4. Also, one annoying thing about our hood is that it is wider than a typical 50" roll of fabric.
https://www.miataturbo.net/attachmen...ine=1461870090


Also, what gelcoat are you using on your mold? The stuff I have gives me trouble when I try to brush it on.

I have a 30 yard roll of kevlar (I think 5 oz, loose plain weave) I don't know what to do with.

Kevlar is good to put into body panels that might be shattered at some time like bumpers or fenders, but I would but them in between layers of glass or carbon. Kevlar sucks to cut or sand, so don't take it to the finish edge of your part ( its just going to fray.)

Actually the hood is alot easier, because with the trunk I had to make 2 moulds. one for the top and one on the bottom ( which still needs a part pulled form it) since the trunk seal has to seal the trunk from exhaust. The hood has is what I want to do next :) . I am using coring foam, though for my first part it isn't a bad weight. The foam is closed cell which doesn't suck up much.

Layer 1 250 grams/8.8 ounces of 10 ounce Carbon
250 grams of Epoxy Resin
Vacuum bagged at 28 in/mer

Layer 2 250 grams of 10 ounce Carbon
200 grams 20x30 inch 1/4in foam core
450 gram of epoxy resin

I think if I went to a nomex core I would save about 7 ounces, but it isn't cheap. and went to the Triaxial weave Spread Tow Carbon Fiber which uses 20% less resin

Carbon/Kevlar
https://www.miataturbo.net/attachmen...ine=1461885195

Carbon

https://www.miataturbo.net/attachmen...ine=1461885195

For the hood I was looking at only 3 layers. I was going to make a copy of the inner structure and put that into a 3/4 in foam. two layers on top and one at the bottom. With how tough the truck is with just 2 layers and 1/4"foam, I don't think the hood needs much more than 3.

Your reinforcement (Carbon) is your strength and your core (foam/ honeycomb) is your stiffeners(doesn't add to your strength) I read some where that 1/4 foam makes it 70 times stiffer.

The tooling gel is from work and I don't know the company's name, but I'm going to spray it on at my new job (building 26' Carbon fiber boats)

I know about cutting and working with it. That roll started out longer. I used it to make a boat hull. Nice for a thin, anti-penetration skin.

I just want to sell it though. I don't really need it now.

what are the specs on the roll (how much is left on it?) and how much do you want for it?

I will have to get the tag off the box, but what I said above... Hexcel brand, roughly 5 oz loose plain weave. tens of yards by, I think 50ish inches wide. Now that I think about it, it might be much lighter than that.
It was a Hexcel blemish roll but I have never seen what that blem is. I'm certainly not going to unroll it to find out.
I also have a roll of pretty heavy fiberglass chop strand but it's not as long. Great for molds though.
If you're serious, I will pull them out of my basement and get specs and photos. They're buried under a few other things and heavy and awkward.

Suffice it to say that the project it was being saved for never materialized. I'm willing to let the whole roll go for a small fraction of retail plus shipping (it's big).

https://www.miataturbo.net/attachmen...ine=1461945079 https://www.miataturbo.net/attachmen...ine=1461945079


Fun!

I think I want it. Get pictures of the tags and PM me?

Will do by the end of this weekend. cool?

Yeah, Im in no rush.

If anyone is curious on stock NA body panel weights:

Fenders 6.5lb each (not including hardware)
Hood with headlight covers, latch, hinges, and release cable: 22.1lb
Front Bumper without hardware: 14.24lb
Stock door stripped of all removables except triangle glass and the bar that supports it: 31.92lb
Trunk lid with OEM R package spoiler, hinges, springs, third brake light installed. (I still need to weigh the latch and cable): 22.5lb

My guesses at how much very light carbon sandwhich core pieces could be. Assuming a near perfect resin to fiber ratio:
5.5lb hood with 4 aerocatch latches
fenders: 1lb each
Doors: 8lb each - probably not able to mount factory glass/speakers/other crap back in them
Bumper: 6lb?
Trunk lid: 3.5lb with latches

That comes out to roughly 100lb and would require about 10 molds.

That trunk looks great for a first shot at things, nice job.

I've only done basic wet layups, made some small CF parts and planned to get deeper into properly making stuff but then got sidetracked with the whole new drivetrain thing..

What I'm curious about is the vac bagging. That's been the thing I have yet to ever get a full walk-through on from someone who really knows and have the *aha* moment - mostly writeups online that always seem to be just vague enough that I'm left with a few questions. I have a parts list floating around here somewhere of all the bits you need for making a DIY vac setup and all the materials needed like peel ply, breather, etc. but words on a page don't quite cut it, I'm a visual person, just need to see it all in front of me once.

We do a lot of work with a composites shop, but they're busy doing their job and vice versa... I should really carve out some time to go get a crash-course.

Vac bagging is pretty straight forward. Your basic stack looks like this (from bottom to top):

*Tool with release agent
*Fabric/resin

*Release material of some kind. This can be a treated fabric that allows resin to pass through it, plastic films with perforation for resin transfer, or plastic films with no perforation (usually only used with prepreg). Your release film choice affects how much resin gets pulled out of the laminate by the vacuum. Most of the time with wet layup you want take as much resin as possible out of the part.

*Breather fabric- Basically just a soft fabric material that allows air/vacuum to be distributed everywhere in the bag. Its also good for sharp corners to prevent the bag from tearing under vacuum

*Vacuum bagging film. This is basically plastic sheeting. The most common films are the stretchlon products. Some of them can stretch really far before rupturing. Depending on how your mold is made, you will either seal the film to the mold with tacky tape or you can envelope bag the whole part.

The biggest thing to keep in mind with all of this to prevent any bridging from happening. You want your carbon completely pressed into all small corners, and you need your entire bagging stack to be able to conform tightly. Any bridging will result in either a void or poor fiber compaction. Often times you will see people add pleats to their vacuum bags in order to have more material to fill in large concave areas.

Also, generally as a workflow you want to have your entire bagging setup figured out, all your materials cut and tested for fit before you start mixing resin. Dealing with bagging leaks is a pain in the ass and it can take a longer than your resin pot life to get it all set up. If you have a good pump that can do continuous duty you can get away with some small leaks.

Bagging is pretty easy to practice on small parts. We bagged the boat pictured above. It wasn't terribly hard and came out pretty consistent.

I know some people like to use a big vacuum reservoir like a hot water heater and venturi vacuum pumps to keep things simple.

I've found the videos from easy composites to be pretty good.

Another tip- don't buy from fiberglast. Most of what they sell is hugely overpriced and all of their private label stuff is just other products relabeled. For example, their system 3000 epoxy resin is just aeropoxy. $200 a gallon from fiberglast, $140 a gallon everywhere else. I buy fabrics for wet layup from soller composites.

I'm working on the bottom part of the trunk

https://www.miataturbo.net/attachmen...ine=1462408492

And if anyone was wondering what I do for a living, well I worked for one of the biggest composite tooling company in the US (Marine Concepts/JRL Ventures). Now I make Carbon Fiber and Kevlar/fiberglass boats for Barker Boatworks

Vacuum Infusing A Fiberglass/Kevlar deck (from today)

https://www.miataturbo.net/attachmen...ine=1462408492

Foam core about to go down over the Kevlar

https://www.miataturbo.net/attachmen...ine=1462408492

Just done Carbon Hull

https://www.miataturbo.net/attachmen...ine=1462408492

I made a hood with the headlight covers built into it (since the head lights no ,on get exist).

I used normal twill weave set (2x2?) top and bottom, 411 x 2 layers and then a 3mm core.

it came up very stiff, and I have track tested it several times.

I also only only did the top of the hood, so there is no bracing and no hinge mounting points.

Mmmmmm Barker. Beautiful boats. How'd the performance of the boat with the 7marine and a tower turn out?

Sorry for going off topic

83 or 85 MPH, not bad for a $130K engine lol

Subscribed. I've got a fiberglass 1/2 bumper front air dam I need to make a mold of so I can make me some more in carbon fiber. Been struggling with how exactly to make the mold and flanges. I'm thinking I need to separate the air dam from the rest of the front bumper but I worry that it will not be rigid enough if I do that. I think originally they may have taken a splash while the entire front bumper was mounted to the car. I also need to get all the vacuum bag stuff like bags, connectors, etc. for my vacuum pump. I'd also like to try my hand at vacuum infusion process at some point.

KYLE please come buy / take my roll of fiberglass matte to make your molds. It is clogging up my basement.

https://lh3.googleusercontent.com/Y4...=w1475-h830-no

Oh, I never paid you for the kevlar. Im not in a rush, just let me know when you have the total with shipping and send me a PM.

Is it partly stock bumper with added air dam? maybe post #3 might inspire you
Post your DIY Aero - Time Attack Forums

How much did it weigh?

I wanted to see if anyone has worked with Spread Tow Carbon fiber. I was woundering if I could use 2 layers of 160gr/m with a 1/4 honeycomb use for a trunk could be doable

http://www.easycomposites.co.uk/#!/f...ain-weave.html

It would be no heavier than 2kg.

Yes, sir! Absolutely! What flavor beer do you accept as payment? Maybe I can swing by sometime this weekend?

Yes it is stock urethane upper, fiberglass lower. Thank you for the link.

sent you some gmail.

This what I mostly work with 1800 18oz/yard 0,+45,-45 triaxial. It is a good structural for things like splitters, floors etc...

https://www.miataturbo.net/attachmen...ine=1464053573

It is also used in the BMW i3 and i8. you can see it in the door sills

http://i526.photobucket.com/albums/c...pskyhudbps.jpg

Wow that looks like great material.
I have a hobby ski press and would love to find some of that triax. Any idea what it runs per yard? And can you get 10 yard quantities?
PM me if you'd like to share your source; no one I deal with carries stitched 18oz carbon...

Man and that foam core for the boat... do you cnc mill the entire core?

Some random pics:
https://www.miataturbo.net/attachmen...ine=1464104175
Urethane moat pour in the core
https://www.miataturbo.net/attachmen...ine=1464104175

https://lh3.googleusercontent.com/-X...0/IMAG0503.jpg

Here is some links Triaxial
Multiaxials | PRF Composites

and some other places for other types of carbon

Composite Reinforcement Fabrics : Carbon Fiber Panels/Sheets, Fabric/Cloth, COLORED Carbon/Kevlar, Composite Envisions

http://www.easycomposites.co.uk/#!/f...-reinforcement

http://www.sollercomposites.com,carbon fiber,carbon fiber sleeve,Kevlar sleeve, fiberglass sleeves,carbon fiber fabric,epoxy,west system epoxy,nitrile,gloves,nitrile gloves,aramid,fiberglass,kevlar,tape,biaxial tape, biaxial sleeve

Here is a new radiator shroud for my aerocatch latch conversion. Its a 1/16th balsa core layed up wet with 5.7oz twill and envelope bagged with a stack on either side. I won't get a nice glossy surface this way but I will get maximum resin extraction:
https://www.miataturbo.net/attachmen...ine=1464188607

I have been trying to come up with a plan to make a high quality hood without going the prepreg route- The materials cost on a prepreg hood is huge and you would need a 60" wide roll which is generally more expensive/harder to find than a 50" roll. I want to do wet layup and I don't want to do infusion. I also want to make the part as light as possible and extract the maximum of resin that I can out of the part.
My current plan looks like this:
Two layers of 5.9oz 2k twill vac bagged and cured. After curing, lay nomex honeycomb into the mold and one additional layer of carbon. Vac bag again. I think this will work well since I can get maximum resin extraction on each half of the part while still getting a glossy tool surface.

Suggestions for a resin? Carbon in the sun + engine bay heat means it needs to be higher temp than most RT cure epoxy. I have been using aeropoxy and am looking at pro-set. The hood is too big for my oven so I would need something I can RT cure and then do some crude post cure on using either a polycarbonate/wood box and the sun, or some light bulbs/heat gun setup. The pro-set Lam135/224 combination lists a TG of 223f with post cure but the work time on that is marginal for a part so big. I don't want to deal with handling vinylester or polyester resins in my attached garage.

The top is easy, paint it a solid color. Or if the rice factor is too strong, a uv protecting clear. Temp wise, insulate, gold foil is probably enough.

I'm going to paint it to match my car in montego blue, its going to get pretty hot with a color that dark. I have seen reports of carbon parts getting up to 170F in the sun. 220F TG ought to be enough with DEI foil bottom but more headroom is better. my header is getting ceramic coated as well so that will cut down on radiant heat.

Most heat cure epoxies need to be pressed at 180F+ to reach full strength. I don't think heat would be an issue for any of those.
There's a little boat company in florida, Raka, that carries some resin that I've used with great success in snowsports. It's a room temp cure, but with heat it develops into a better material.

Entropy resins also carries a bunch of options in their supersap line that will cure at room temp.

Per the Easy Composites Page:

Vacuum resin infusion is a sophisticated technique for manufacturing high performance, void free composites even on large or complicated moulds. The process is ideally suited to the manufacture of carbon fibre composites and is widely used by professional manufacturers for the production of carbon fibre body panels such as bonnets and by marine manufacturers for the production of boat hulls. In resin infusion, reinforcement is laid into the mould ‘dry’, i.e. without any resin, and then enclosed in a specially configured stack of bagging materials (such as peel ply, infusion mesh and bagging film) before being subjected to vacuum pressure using a composites vacuum pump. Once all the air has been removed from the bag and the reinforcement has been fully compressed under this pressure, liquid epoxy resin (mixed with hardener) is introduced to the reinforcement through a pipe which then infuses through the reinforcement under the vacuum pressure. Once the resin has fully infused through the reinforcement, the supply of resin is cut off (using a pipe clamp) and the resin is left to cure, still under vacuum pressure.

Advantages of resin infusion

Resin infusion, when done correctly, can produce parts of incredible strength and quality of appearance. The combination of vacuum pressure along with carefully placed vacuum consumables (such as peel-ply and infusion mesh) mean that the finished composite will have absorbed resin at the optimum resin-to-reinforcement ratio, avoiding resin-rich composites or variations in performance inevitable with traditional wet-lay manufacture. The resin infusion process also eliminates some of the problems that can blight wet-lay composites, such as air voids (caused where the reinforcement has bridged around tight corners) and tiny air bubbles caused by air trapped within the laminate. The quality of epoxy ‘infusion resins’ means that resin infused parts can be made with strength to weight ratios that can rival parts made using pre-impregnated (pre-preg) reinforcement systems




Most well thought out VIP setups will run about 30%-40% resin content. On the hood mould I'm making is going to be a VIP setup and I will do a UV epoxy in the skinning layer. When I was making another trunk I would rather work with 10.9 oz instead of using 2 layers of 5.7 oz, do to the 5.7 likes to unravel easily. The hood has to built strong its going to with stand 120-160 mph, so at 100 mph there is 140lbs of uplift on the hood and at 150 mph 210 lbs. If you have no problem standing on it, then it should be built strong enough.

I built a oven at work 8'x8'16' and used 2 propane room heaters. The heaters move the hot air long the back wall in a counter clock rotation around the room. The air exits near the bottom since heat rises. The room was contructed with plywood wall, 2x4 framing and 1" foam insulation board.

If its a small oven like for a hood, a heat gun could be used with a thermal coupling under the center of the mould.

BTW the hood measures 52"x 49"

Here is a new video I made

The textreme definitely sucks up a lot of resin. Since it has a binder, how well does the textreme conform? Part of what I like about 5.9oz twill is that it is so lose and will conform to complicated compound curves easily since the fibers are free to slide around.

Also, where are you buying it and do they make a triaxial spread tow as well?

For a break test setup, what about a shop press + corner balance scale?

The Textreme sucks up 20% less resin, but what I think happen was that the Textreme is so light that the absorption in the foam was a big part of that percentage. 10.9 contorts to curves just about the same as 5.7, but Textreme acts about like a piece of paper.

I am buying it from Composite Envisions

I looked at going to breakage, but I will do that in a later video

Part 2
Plus my hood project where it will be going step by step, so please Subscribe for more info

It is hard to draw conclusions about strength to weight without testing both pieces to failure. Maybe instead do a test comparing a twill weave to a textreme part where the number of plies is adjusted to reach a similar weight?

I found this interesting for people who what to make their own splitter. I doubt its strong enough to stand on but would be good to add another layer

Project ASS2000: Custom Splitter Build Part 2 | Speed Academy

Thanks for the link. I will have a read when I get time and comment.