carbon fiber

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tyler_s18

tyler_s18

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i have been looking into carbon fiber and how to do it. it looks like vacume is the best way. ind vacume infusion looks really cool. what have you all done? and what do you do for molds? i have seen blue missile has done some really good looking stuff and not neccessarly used a mold. but what do people on here know that can help me down the road. also where can one go to get all the materials? thanks tyler
 
well i tried with some 50k plain weave cf which is way to strong for little things for cars since its industrial use plus don't form easily. i would use a vacuum but haven't gotten one yet. i did make some sunvisors using a 5:1 epoxy, release mold, 2 large pieces of glass, and weights. i ended up covering them with suede do to the finish on the cf wasn't that great and sanding was almost impossible. your best bet is to contact blue missile and find out everything you need and possibly get the supplies from him.
 
Tyler,
I am not really a supplier in the true sense of the term. I have been making VARTM carbon fiber windsurfing fins for about twenty years. So I do have sources of supplies and I can help you learn about composites. Depending on what you want to make and more importantly how many, it is sometimes simpler to make the part outright rathar than make a mold. Working with basic composites is fairly simple and straight foward. Mold making is an art.
Let me know if I can help and I will be glad to hook you up with whatever suppliers you need.
Andrew
 
ok sweet. i want to do my interior stuff in carbon fiber. kinda like what you are doin but more. mostly for look and being that its so light. so like door panels, dash, package tray, sun visors, hood, trunk lid, maby bumpers, and trim if it can be pulled off. i know its a lot but it will be a ways down the road so i want to practice for now. i tried to fiberglass a simple speaker box and it didnt turn out the best so i need practice on this kinda stuff. the biggest things i want to learn more about is vacume infusion. where can i learn more about it. and also making the vacume machine. also where can i look at getting the fiber, and resin to redo the speakerbox in carbon instead of glass?
 
is there a good way or a way at all to go around a pole and make it look correct with no seem? i am thinking get some of that carbon tubeing and make my roll cage outta it. but i want it to appear it is one piece and maby go into the dash and package tray so its one big piece that i will hope never has to come out lol
 
I don't know how safes cf rollbar would be. As far as the hood and trunk that would take a lot finess and carbon. If you do you could try to use the top of the hood as a mold with a film underneath so carbon doesn't stick. I thought about doing my dash but you would probably want to cover the dash in carbon to have the looks instead of making a 100%carbon dash since a mold would be required. You might want to write down every piece you want in carbon and price it out.

Jon
 
i want it to stay really light so i think i will try to do a mold and do it all like that. i want to learn more then anything. it will be a ways down the road before i actualy make my interior mostly carbon fiber. would it be worth it to make all the sheet metal(i.e. doors fenders and all) outta carbon? or is the metal lighter or close?
 
i have been looking on dragonplate.com at their carbon fiber stuff. they offer veneer and sheets. the sheets look like they are already done and you just cut it to the right size. so that would leave the veneer to be what you put the resin on and form it to your mold or what it will be. is this right? or is the veneer just like a sticker like what they sell at checker?
 
Jon
you first- Please be careful of laminating steel with an epoxy matrix. This goes for carbon or fiberglass. The two materials have very different thermal expansion properties. Since the dash will get very hot it is entirely possible the lamination may pop off the steel. I have thought about doing the same thing and I still want to get together with some of my industry contacts for technical help regarding the issue. I will let you know.

Tyler-
I dont know where to begin.
I agree with Jon about the roll bars,Carbon fiber has one big drawback, unless it is combined with another type of fiber it has poor impact resistance.This is why it is very often paired up with an arimid fiber such as kevlar. Since kevlar and wet applications dont work well together I use a special S glass and carbon fabric with coremat to make my windsurfers.
A carbon roll bar will offer you no protection and you will never be able to make it look seamless unless you paint it. It will also never be accepted at any sanctioned track with a tec inspection.

Vacuum infusion- was invented by Symen Composites- they called it SCRIMP for symen composites resin infusion manufacturing process. It was developed for building very large structures such as boat hulls where wet layup or chopper gun use didnt give them the flexibility to include sub structures in the final part. Through scrimp they could more accurately place the ply schedule and inserts then deliver resin to mutiple points on the one sided mold all at once. The process was still very simple they have a very large vacuum sorce many hoses and plastic five gallon buckets with the mixed resin to draw from.

In making fins I use a similar process but I use a two sided closed mold. First I create a plug (a perfect fin miced to better than .001" in tolerance), then I cast it in a special low exotherm non shrink aluminum filled epoxy system, one side at a time.I also cast in regestration pins to be able to realign it when in use. I then create a support structure for the epoxy which would crack if not supported when you try to bolt it together.

I then developed a propritary sprew system to get the resin in and out the molds other side. I fill the mold with dry composites of various weights and weaves ( this is called the ply schedule) I draw a vacuum on the entire system which includes the interior of the mold and then inject a very thin special application resin into the miold until it comes out the other end.
This process is called vacuum assisted resin transfer molding VARTM.

I will spend $500-$600 to make each mold it takes a week and the finished parts are .625" at the thickest part and anywhere from 10"-16" long. I went on line and found Ricer Hoods for about $600 and up. Think about the cost of the tooling. If you are going to do this as a buiness the major start up cost will be the R&D for the tooling and the tooling it self. There are also special software packages to figure out ply schedules and resin flow within the mold. You will need these also.

When I said mold making was an art, the art is in making a mold that seperates and releases the part well and one in which the resin fills all the voids fully. Even with vacuum this is not always a given.

Now to vacuum bagging. The beauty of this process is that you are using a one sided mold ,or you are just bagging a freestanding part. Check out the arm rests in my carbon door panels post. They are a complex curved part that would suit itself well to a mold but you would still need to shape the foam or contract it out to be shaped in volume quantities. It was so much simpler to shape them and just bag them with a simple bag.

There have been a few requests for me to make others carbon dash pads. The challange is in making a mold that I can use for the carbon and then later fill with the steel core and a rigid foam. Hand shaping the first one was relativly simple in comparison. The choice of resin is also very important. Some resins will 'blush' without warning. The dash pad has a very small amount of this. so I will not use my thin resin for the finish layer on any more parts. I have a more viscous (1000cps) water clear UV resistant resin I will use from now on.

As far as material suppliers go to my web site www.a-c-designs.com click on the composites portal ,then go to the links page, go to materials they are all listed there. I dont get anything from these companies in the way of a refferal, I put the site together as an informational resource. You can get a vacuum pump at harbor frieght for about $70.

I did go to dragonplate and they have material that could be used to veneer with contact cement onto flat surfaces. But if you are going to set up a vacuum system you could make the same stuff by bagging a peice of cloth on to glass, for much less.

I think you have to decide what is the motivation here. Are you going to be racing for serious money or is this a look good thing. If it is for looks I would stay with the interior parts. The loss of weight= serious money.
I hope this helps.
Andrew
 
never thought about the thermal dynamics of the epoxy vs. steel.

Tyler if i was you i'd really consider which parts you want the carbon fiber to be seen and which parts will be painted, because if you're going to paint the hood and trunk to body color instead of leaving it the carbon then it would be easier to buy an already made fiberglass hood/trunk.
 
wow thats really helpfull. thanks:) it will mostly be for looks and functionality. i want to leave the hood and all carbon fiber look. you cant really cover up something that cool looking lol.

would vacume infusion be good for small parts? and where can i read about how to do it? there is a lot of info on youtube on doing it but none telling you what they are doing just videos of it being done.

would a mix of kevlar and carbon fiber work for bumpers? i dont know how resistant kevlar is to that kind of impact.

thank you again for all the info
 
Tyler,
If I may ask how old are you?
You sound very enthused about carbon but are not listeing to the practicle side of things. Yes SCRIMP will work on all parts small or large. You are starting out with no knowledge-base or experience. I urge you to start simply, rather than jumping into a complex field and process too deeply.
The end result of a bagged wet layup and a SCRIMP layup is exactly the same. You are using vacuum and atmospheric pressure to consolidate the composite part. The best part is bagging is simpler requires less hardware and hence less money.

As far as reading about it try going to "Composites" magazine and looking in their archives. Maybe a supplier like "Airtech" will have some books.

As far as bumpers go, is the car for the track only, or will it be run on the street?
If it is for the track, have at it, impact resistance won't matter.
If it's for the street stick with steel, yes kevlar has great impack resistance. But to have the type of impact protection you will need and to be legal or sane there will have to be alot of engineering done.
If you are thinking of laminating the steel bumper with carbon, there is a second problem to Dustar's of thermal expansion which is a dielectric moment between the carbon and steel. In an exterior wet invironment the carbon will rot out the steel at an alarming rate. I know this from applied experience!!! Kevlar won't have this problem, It has the problem of not being UV stable!!!
Hope this helps
Andrew
 
ok thank you. i am 18 and get overwhelmed with all the science so i tend to not understand it all right off the bat. sorry. but i will look into all that and see. the car will mostly be for the street. so there is not an easy way to get carbon or carbon/ kevlar bumpers. is there any way to have steel inside the carbon fiber. say for braces inside a hood? i thought i had seen manufactures doing this but with what i know now it seems like it would not work at least not for very long
 
Tyler there is no crime in being young, and as far as getting overwhelmed, just take it a step at a time, which is what I was talking about.

It seems that you have your heart set on a carbon bumper. Heres what i would do. Go get an already manufactured fiberglass bumper for your car. Then sand it down to get a good mechanical bond and vacuum bag a layer of carbon on it. I dont think fiberglass bumpers are street legal, but that's your fight.

Yes there is an easy way to get a carbon bumper, contact the people who make the fiberglass ones and write a big enough check for them to break their production line and make one for you.LOL

Putting inserts inside of a composite piece is where infusion processing has its advantage, Those inserts are usually brass or stainless steel for reasons already stated. I have read about hoods where the inserts strip out. These pieces were probably made with a one sided mold and laminated with a chopper gun after the carbon was put on the face. This leaves voids around the inserts.

Dont give up the quest, but you should probably ask Adam to transfer this thread to 'Body & Paint' so there will be more participants.
Andrew
 
ok thanks:) i am not set on one thing just like the idea. here they really dont check how safe you are just as long as you dont huet the ozone layer lol. if i were to get some material and the vacume bag stuff what would be a good way to learn? like what is easy to make? or is vacume bagging the best way to learn?

i think i will see about moveing this to body to look for it there thanks
 
OK Tyler,
heres what I would do,

First get a vacuum pump, the one from harbor freight will work well, I got two rotary pumps off of E-bay, either will work for you.

Second contact any one of the material suppliers and get a vacuum port/ thru the bag fitting. For most anything you are going to bag one will be enough. From the same supplier get say ten yards of 'Peel-Ply Fabric' make sure its coated prefferably with teflon. Also get some medium weight 'Bleeder Cloth" Ten yards will also do.

As I said earlier go to Home depot or Lowes and get a roll of 3mil painters plastic. Experience has shown me that any thinner painters plastic will have microscopic holes in it and you will never make a 'good' bag out of it. You will also need some 1/4" cheap plastic tubing and what ever brass fittings needed to get you from the pump to the hose. The bag fittings are already 1/4".

Then get some fiberglass cloth and some epoxy resin and something to bag, A piece of scrap plywood would be fine.

Next find a metal roofing supply house and get a few rolls of 1.25" wide 'Tacky Tape' or similar product. It will have two thickened edges and a thin center. This stuff makes the best bags.

Next you will make a test panel by cutting a piece of plastic twice the size of what you need , it will be folded in half to make the bag. Then run a layer of the tape in a 'U' shape at the perimiter of the botttom half of the bag without pulling off the paper backing tape. set the ply in the middle of the bag inside the tape and fold the bag over to make sure there is enough room for the bag to contract. then unfold the bag, mix the epoxy and saturate the cloth on top of the ply. Next cut a piece of the peel ply big enough to cover the panel and put it on top of the panel. Then cut a piece of bleeder cloth the full length of the panel and half the width and put it next to the panel on top of the peel ply. Pull the paper tape, and seal up the bag, Make sure to clean up any epoxy where you are trying to seal the bag before you pull the paper. Tacky tape and epoxy will not stick to each other.

Next take a razor blade and cut a small cross just big enough to get the thru/bag fitting into the bag on top of the bleeder cloth far enough away from the panel so as not to suck resin into the fitting. Seal the hole with tacky tape and evacuate the bag. Wait until the resin is either hard or very tacky before you turn off the pump. I usally keep the brush and whats ever left over to let me know at what point I can shut down the system. When the brush is hard or very tacke its time. If you do get resin in the fitting shut the system down and clean it out with laquer thinner and try again.

Hope this gets you started.
Andrew
 
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