I have a set of vids on basic to advanced fibre material construction for sale.


Modified by SpeedDreamz.com at 8:45 PM 6/28/2005

 

i would recomend for you to work with fiberglass first..

materials need??

-resin
-fiber
-brushes
-etc etc

there is already a thread about this with some good info.. have fun

 

Here is a helpful website for your fiberglass and carbon fiber needs:

http://www.fibreglast.com/fibretalk.php

set up an account and view all of the great ideas from those who know. There's even some automotive specific stuff in there.

 

Guys I have been doing fiberglass for 10 years in the car audio business. Just wanted to start doing some stuff in cf.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 30psiCiv &raquo;</TD></TR><TR><TD CLASS="quote">Guys I have been doing fiberglass for 10 years in the car audio business. Just wanted to start doing some stuff in cf. </TD></TR></TABLE>

hmmm if you have been fiberglassing for 10 years.. you should know how to work with cf then.. i mean its almost the same thing.. they are both fiber

 

carbon works with all resin types, so you can acutally use the cheapo polyester resin. Use the basic priciples of glass but the difference in strength is dependant on constuction. Unlike glass, a bad build will net a weaker property than glass(strength to weight). A core material is also good to have for added strength.

 

I do not suggest using polyester resin (usual fiberglass resin) with CF or armid fibers. It will delaminate. Besides, if your investing in the extra cost of CF or armid cloth why waste it with crap polyester resin??? Plus epoxy resins don't have as harsh and wide reaching of an odor.

I don't even use polyester resin with e-glass anymore. A crappy layup with a good epoxy resin system is better than most perfect polyester resin layups.

~I suggest getting some GOOD shears for cutting the cloth. The armid shears are great but cost alittle extra. They won't dull out as quickly as regular shears.
~one of those Roto-Zip tools works great at cutting cured CF, I have not tried it on armid yet but I doubt the bits will last very long at all.
~a good respirator - CF dust is very very bad for you to injest, inhale, etc. Carbon tends to migrate through the human body.

You will find that the CF layups are much thinner in comparison to some of the glass layups you done before. Good luck

 

Good information. What about vacuum forms?

 

Go by Barnes and Noble and get a copy of "Fiberglass & Composite Materials" by Forbes Aird. Published by HPBooks. Order it on Amazon if you have to. I paid 18 bucks for it.

Wes

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 30psiCiv &raquo;</TD></TR><TR><TD CLASS="quote">Good information. What about vacuum forms?</TD></TR></TABLE>

Do you mean vacuum bagging? or vacuum molds? Check the link to http://www.fiberglast.com to answer your questions so I don't have to retell what someone else has already done.

 

If your looking to do hotbonding wich is the real deal with cf you'll need some pretty expencive ecuipment. you'll need a hotbonder, heatblankets, there is usualy vacume pumps in the hotbonders but it's nice to have backup pumps for bigger moulds. temperatur sensors, and lots of consumeble products, releasefilm, baggingfilm, breather cloth, tackytape, tape and so on

we use products from heatcon and are happy with them, easy to work with.

http://www.heatcon.com

 

What is hotbonding? I have never heard of this. Are you talking about curing cf parts in an autoclave? Vacuum bagging is not always better btw. Sometimes it gives you cosmetic headaches.

I 2nd the mention of using epoxy only. Polyester is crap from every point of view except cost. If you're going to the additional cost of carbon why use polyester. The stiffness of the part falls off as well. The prep is about the same as glass other than choosing the fabrics. That really depends on the complexity of the mold shape. 2x2 twill is good because it conforms easily to complex shapes. Plain weave doesn't work as well. Do not go with a basket or 4x4 twill or you'll be sorry, they are very hard to handle because the cut edges tend to fray and are hard to layup. You do need an accurate scale to weigh out the resin and fabric. I would not attempt to go under a 50% resin content with wet layup. This means 1lb of carbon to 1lb of resin. I have gone as low as 47% but its hard to get the cosmetic quality with that. Practice first with flat plates.

I also agree fiberglast is a good place to buy dry fabric and resin. After you get comfortable you might even want to try the VARTM process. This is (Vacuum Assisted Resin Transfer Molding) and it means you lay the carbon into a female mold and then place a male mold on top, without impregnating with resin. Then you pump resin from a container through a tube and into the two mold halves and then have vacuum pulling the resin out the other side until it wets out the carbon. I have not tried this yet but I hear you can really lower the resin content of the part if you're shooting for weight reduction. I have heard from many sources that the resin content is almost as good as using prepreg carbon. Fiber makes parts strong, resin makes them weak.

One last item I wanted to cover was using Kevlar in parts. You would not like cutting the parts when they are cured. It does not cut well. It sort of looks like melted carpet when you cut it. The edges need to be razor bladed to get the frays off, not fun. With carbon I would use a Dremel tool with a diamond coated cutting wheel, they work perfectly. Also for drilling use carbide drill bits if at all possible, they last longer.

I just purchased a domain http://www.racingcomposites.net and will soon have a forum that specifically covers this topic. Should be good.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JCracer723 &raquo;</TD></TR><TR><TD CLASS="quote">i would recomend for you to work with fiberglass first..

materials need??

-resin
-fiber
-brushes
-etc etc

there is already a thread about this with some good info.. have fun </TD></TR></TABLE>

for example, i need to cover my dash--as i have sand down surface to smoothen imperfection; do i need to apply any kind of base coat before laying over with carbon fiber sheet?

 

Well if you just want to build a an overlay I would still build a mold for it. You could just lay the carbon fiber on top of the dash but then how are you going to unsure a smooth finish on the dash cover. You could just lay the carbon fiber on the dash and wet it out but you would have all of the resinmigrate close to the factory dash causing the carbon fiber texture on the outer surface. It would not look like you want. To fix this you would have to coat the dash cover with multiple coats of resin and sand it smooth between each painting, then probably topped off with a couple of coats of clear coat paint. Not fun and pretty heavy. It would be best to sand your stock dash smooth and then paint the entire thing and have it buffed to a decent polish. Now you can rub a release agent all over the part, there are some good waxws used for building wet layup part like this, make sure you get at least two coats of wax maybe 3 or 4. Make sure all wax is removed before going to the next step.

Now that you have this done you can paint the entire surface of the dash with resin, brush is fine here. This can be used as a gel coat. Let the gel coat get tacky before doing anything. Test the time before hand. The resin is ready when you can touch an edge and you just barely see the fingerprint in the gel coat. It should nto be sticky and gooey but just tacky. Now paint on another coat of resin and the start laying down fiberglass veil. Veil is just very low weight fiberglass. Start with this and then add heavier glass layers as you work your way out. I would use 4-5 layers as you want the mold to be self supporting. Afte the mold has cured you can you can remove the mold from the dash assuming you released it well. Its always a good idea to run a test plate using the same paint, release, and resin used on this mold. I almost forgot its a good idea to build a flange around the stock dash edges beforehand so that when you lay the carbon into the part you can release it easier. I would need diagrams and a lot more writing to explain adding mold flanges.

Now you can release your mold and start laying carbon fiber into your mold to build the actual part. One other thing is you should look at the verticle edges you are dealing with and buy some thicker resin if you have high verticle walls. A vacuum bag might not be a bad idea if you don't get good results with your first part.

These are just some very quick instructions. Practice makes perfect!

 

Not to tare apart your post, but I have some differences of opinion.

I can think of lots of reasons not to use a polyester resin, but delimitation is not one of them. Having said that, I use epoxy almost exclusively. The last time I used polyester resin was over 2 years ago to repair bodywork.

I would recommend good but cheap shears. Like the 3 for $10 variety from sears tin snips. So you can cut the fabric when it's green and not worry about ruining a good pair of shears with epoxy.

If you use aramid, there's no way around the expensive shears.

A crapy lay up is a crapy lay up.

I recommend a good respirator also. I use 3M with the charcoal filters, but because the resin system will cook your brain if you don't use it and not for dust. Please don't tell me you can barely smell epoxy. For dust, I wear a dust mask. I do agree that carbon dust is nasty to inhale.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BROOD &raquo;</TD></TR><TR><TD CLASS="quote">I do not suggest using polyester resin (usual fiberglass resin) with CF or armid fibers. It will delaminate. Besides, if your investing in the extra cost of CF or armid cloth why waste it with crap polyester resin??? Plus epoxy resins don't have as harsh and wide reaching of an odor.

I don't even use polyester resin with e-glass anymore. A crappy layup with a good epoxy resin system is better than most perfect polyester resin layups.

~I suggest getting some GOOD shears for cutting the cloth. The armid shears are great but cost alittle extra. They won't dull out as quickly as regular shears.
~one of those Roto-Zip tools works great at cutting cured CF, I have not tried it on armid yet but I doubt the bits will last very long at all.
~a good respirator - CF dust is very very bad for you to injest, inhale, etc. Carbon tends to migrate through the human body.

You will find that the CF layups are much thinner in comparison to some of the glass layups you done before. Good luck </TD></TR></TABLE>

 

I really like Competition Car Composites.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Wes V &raquo;</TD></TR><TR><TD CLASS="quote">Go by Barnes and Noble and get a copy of "Fiberglass & Composite Materials" by Forbes Aird. Published by HPBooks. Order it on Amazon if you have to. I paid 18 bucks for it.

Wes</TD></TR></TABLE>

 

Yeah, when you vacuum bag correctly you get pin holes! Try explaining that's better to rice boys!

Generally when 50% is quoted, it means you have a 50% FIBER VOLUME. That's why it's called a fiber volume fraction.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by crx12 &raquo;</TD></TR><TR><TD CLASS="quote">Vacuum bagging is not always better btw. Sometimes it gives you cosmetic headaches.

I would not attempt to go under a 50% resin content with wet layup. This means 1lb of carbon to 1lb of resin. I have gone as low as 47% but its hard to get the cosmetic quality with that. Practice first with flat plates.


</TD></TR></TABLE>

 

i believe you missed my point. i was implying a perminently wrapping the dash with carbon fiber...not using the dash as a mold.

 

Yes I know that. Read the first paragraph where I explain the results you would get. I agree Competition Car Composites is a great starter book.

I know what you mean about pinholes. Given the choice I'd go with autoclave cured prepreg parts but the main problem there is you have to build molds that will hold up to that heat and pressure. When we cured the Vette hoods for the Corvette program we went to 300F and over 100psi and 24" mercury and still had porosity problems, but we were also using uni-tape for the whole hood. Ohh and then ther'e that small problem of cost with a clave. LOL

 

Cytec has some great stuff for tooling you might want to check out. In your environment it might reduce cost. One of their systems only needed 150F or so initially and then was A-OK to do an elevated temp free-standing post cure. Only twice the price of normal prepreg too. I'd really like to do an order of it, but can't afford their minimum quantities.

We cure the pinholing by lowering vacuum under 20 inches on the parts that need it.

btw, the twill sticker on the vette hoods

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by crx12 &raquo;</TD></TR><TR><TD CLASS="quote">

I know what you mean about pinholes. Given the choice I'd go with autoclave cured prepreg parts but the main problem there is you have to build molds that will hold up to that heat and pressure. When we cured the Vette hoods for the Corvette program we went to 300F and over 100psi and 24" mercury and still had porosity problems, but we were also using uni-tape for the whole hood. Ohh and then ther'e that small problem of cost with a clave. LOL</TD></TR></TABLE>

 

I'll have to look into that material. Thanks for the pinhole tip, makes sense. What's your composites background anyway? On the Vette hoods I agree, that was idiotic! You have the highest technology available for a hood and you go and do that to it. It's just because nobody thinks its carbon if its not fabric. We actually didn't have anything to do with them after curing and bonding. They were sent off to be primered, painted, and (stickered) back east. I think the sticker package was an option anyway. Its interesting because GM eventually used uni-fiber as a marketing tool which is sort of contradictory if you have a fabric sticker on there. We had 6 layers of uni-tape in the top side and even after several coats of primer, paint and clear you could see each layer of fiber direction. Lets say we used 0/90 and 30 deg fiber directions you could see each different directional layer. From the top side you could see the bottom layer, it was very starnge and you could only see it in a special light room or if you knew what to look for but it was there. Fiber reed through hasn't really been solved by anyone.

I thought it was very funny when I opened up a Sports Car Illustrated magazine and they did a review of the anniversary Z06 and they said we just left the center of the hood unpainted so you could see the fabric. Gimmie a break. Don't believe everything you read. LOL At least you knew it was a sticker. You should be a magazine writer. LOL

 

Lots of hands on experience. Tiny bit of graduate MatE work.

http://www.cytec.com/business/....shtm is the material. I recommend speaking directly with an engineer because their sales people are awful.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by crx12 &raquo;</TD></TR><TR><TD CLASS="quote"> What's your composites background anyway? </TD></TR></TABLE>

btw, fiber print through gets solved with gel coat *smirk*


Modified by eHoward at 1:56 PM 10/21/2004

 

smartass I think they were trying to keep cost and weight down. I don't know if they make cheap gel coats that can stand 300F in an autoclave, in fact i have never heard of using a gel coat with prepreg materials. Have you ever seen this done? We actually ended up using a resin veil to minimize it, Simskin from Loctite. It seemed to do a lot for voids and dry fiber spots. We constantly fought with hairline dry fiber areas, so small you had to use a magnifier to pick them up but they were too large for the primer to fill. Using fabric on the outer layer helped a lot to but that would have been too expensive for GM. We did a couple of test hoods like that though. I actually have one of the hoods out in my garage. Of course it as defective and thats why I have it but its a cool momento.

Thanks for the link to the tooling prepreg

 

cool tread

 

No. It was a joke.

Although I have tried using regular RTC epoxy as a clear gel coat and ended up with bubbles which to me is just as bad as pinholing cosmetically.

I wasn't aware Loctite sold product other then thread locker, but from a quick glance at their website, looks like they do a whole lot more. I'll have to check into that.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by crx12 &raquo;</TD></TR><TR><TD CLASS="quote">Have you ever seen this done? We actually ended up using a resin veil to minimize it, Simskin from Loctite. It seemed to do a lot for voids and dry fiber spots.

</TD></TR></TABLE>