ragnaroek

ive worked with cf, but i have some questions about getting a good finish.

to get that 'gelcoat' appearance, do you paint some resin in the mold, let it set till its nearly hard, and then start lay-up?

when ive done vaccum bagging, the outer surface of resin always gets sucked out, and the end finish is never that glossy appearance. of course, ive never tried the method that i just asked about.

0Synapse Motorsport

When I layup CF, I always brush on a light coat of resin in the mold before putting the fabric down. Then I make sure everything is saturated and vaccum bag it. If you bag the part you have a much better chance of getting air bubbles out, and you can suck out excess resin which gives you a better resin to fabric ratio, thus a stronger part with less defects.

tec_wiz

ok, how do you vacum bag. what items are needed and where can I get them. I've always just brushed and let sit in the mold. will vacum bagging allow for a quicker set-up time due to the less resin. also, i know that when i do fiberglass parts i always have some abnormalities from the mold on the finish. nothing major just little imperfections that i have to sand out. if i do the same with carbon will i have to make sure the mold is mirror perfect on the inside so to get the perfect don't have to touch up finish, or is there a way to get these imperfectins out in carbon also.

0Synapse Motorsport

1st you need a vaccum pump, which are pretty expensive, or you can use a shop-vac, but you need to have it on so long, that you could burn up the motor. You either can make your own vaccum bags, with plastic and a food saver, or go the expensive way and buy doublesided tape and vaccum bagging material. You will also need peel ply which is a barrer between the CF and badding (which sucks up the excess resin). The peel ply is a thin plastic material with a bunch of tiny holes in it to allow resin excess resin to flow through, and be absorbed by the badding. For badding you can simply go to Wal-Mart and buy a bag of it, its used to put in blankets. For the rest of the stuff there are plent of distributors. http://www.fibreglast.com/ has just about everything you need, and a good forum for begginers.

0Synapse Motorsport

Heres a part for an auditt I did, I also have made CF charge pipes and intake pipes.

0Synapse Motorsport

Sorry for the pic, but to answer someones question above, when I lay a coat of resin in the mold before i put the CF down, I do not wait for it to dry like you would if you were gelcoating a part or mold. And for best results you should gelcoat your molds, and then you can sand and buff them to a near perfect finish.

Aquafina

iTrader: (3)

I'd highly recommend buying Grassroots Motorsports. Excellent writeup to just give you the basic idea of what goes on. I went to the store last night at 1 in the morning just to get it. The pictoral they did pulls it all together.

0Synapse Motorsport

I have been working on putting together a whole how to on composites, from simple layups, to overlays, and mold constuction, someday ill get enough time to finish it.

eHoward

Thank you for the tip.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondadesign &raquo;</TD></TR><TR><TD CLASS="quote">First let me say your project looks great and thanks for posting your what you have done.
I found that using a chip brush with the bristles cut down about a third of the way help alot in getting all those bubbles out. You gotta gently pound/pop those bubbles carefully without distorting your beautifully laid out layup. Also this only works best by doing it to the face sheet and then bagging that on its own to assure perfect debulking and tool/part consolidation. I've worked on military, indy/formula, aerospace, concept /show car, industrial design and everybody does it a little different according to how much money and what they are trying to acheive. </TD></TR></TABLE>

eHoward

This kit WILL NOT include vacuum bagging.

However, since there seems to be interest, I could start doing research into affordable pumps to include with a vacuum bagging kit. I think the price of a vacuum bag kit would be in the $300 range. Does that scare everyone off?

I will post some pictures of a vacuum bag lay up.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .nate &raquo;</TD></TR><TR><TD CLASS="quote">Interesting... your kit also includes whats needed for vaccum bagging?

I'm also interested in how this process works.</TD></TR></TABLE>

eHoward

You need a pump, fittings and vac bag materials. The source posted is a source.

Vacuum bagging does take more time, due to the increased number of steps. Cure times are about the same.

You really need to be ultra careful with the carbon because it is not nearly as forgiving as fiberglass is. If you sand it, it will distort the weave. You also cant really use bondo as you could with fiberglass for obvious reasons. The mold making with carbon fiber is probably the most important part of the process.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tec_wiz &raquo;</TD></TR><TR><TD CLASS="quote">ok, how do you vacum bag. what items are needed and where can I get them. I've always just brushed and let sit in the mold. will vacum bagging allow for a quicker set-up time due to the less resin. also, i know that when i do fiberglass parts i always have some abnormalities from the mold on the finish. nothing major just little imperfections that i have to sand out. if i do the same with carbon will i have to make sure the mold is mirror perfect on the inside so to get the perfect don't have to touch up finish, or is there a way to get these imperfectins out in carbon also.</TD></TR></TABLE>

eHoward

I am currently writing composites 101 for our website along with getting an instructional DVD together for the kit.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Synapse Motorsports &raquo;</TD></TR><TR><TD CLASS="quote">I have been working on putting together a whole how to on composites, from simple layups, to overlays, and mold constuction, someday ill get enough time to finish it. </TD></TR></TABLE>

hondadesign

you can use a venturi vacuum generator to pull about 25psi. It runs off your air compressor and is an inexpensive way to start. I found some through Gougen Bros / West System that cost under $100 that worked well, and I also found 1 at Harbor Freight that was under $20 that worked just as well. Its marketed as "Air conditioner tester".

eHoward

You mean inches right? *smirk* I was told the vacuum attachments that work off of compressors were a bad idea. I have zero first hand experience with them.

I guess the problem even if they do work well, for the kit, would be people would have to have air compressors for it to work for them.

I have two pumps. Both used. One's an oil-free one that's loud(the work horse). And the other one is an oil one that smokes. I have many, many lay ups on that oil-free one. Deals are out there if you're looking.

After I get these basic kits shipping, I'll begin evaluating stand-alone pumps.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondadesign &raquo;</TD></TR><TR><TD CLASS="quote">you can use a venturi vacuum generator to pull about 25psi.</TD></TR></TABLE>

eHoward

to get that gel coat appearance, use clear gel coat with polyester resin. Seriously.

If you want more of a glossy appearance when vacuum bagging, don't use peel ply or perforated release film. Use unperforated regular release film or the pourous teflon that's not really pourous.

I don't paint the mold. I have done tests using the exact method you descriped. Zero pinholes, but I did end up with bubbles in the painted on resin layer.

My best advice is to do a bunch of small test parts and pick what you like the best to do the final part.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondan00b &raquo;</TD></TR><TR><TD CLASS="quote">ive worked with cf, but i have some questions about getting a good finish.

to get that 'gelcoat' appearance, do you paint some resin in the mold, let it set till its nearly hard, and then start lay-up?

when ive done vaccum bagging, the outer surface of resin always gets sucked out, and the end finish is never that glossy appearance. of course, ive never tried the method that i just asked about.</TD></TR></TABLE>

PrecisionH23a

Would somebody like to make me a CF moon roof plug for my 96 EK civic?

J_nicks

to carbon fiber!

95db8GSR

has anyone tried making just a hood skin out of CF, as opposed to doing the skeleton/underside as well?
i'm pretty experienced w/ CF and have a vacuum bagging system, but haven't had the ***** to make a hood yet. When you make a hood, is it really necessary to make a female mold of the top and bottom and then join the 2 parts made from the molds? or can i just male mold the top of the hood and reinforce the part so it doesn't sag? I understand that making just a skin would eliminate the possibility of a stock-type hood latch or hinges, so i would plan on hood locks on 4 corners and removing the skin everytime i need to get under the hood.....any thoughts/suggestions?
very nice CF work BTW

92integra_gs

bookmarked

BETO736

I'm sure you guys know about this site, but just in casehttp://www.fibreglast.com/cate...fiber

eHoward

I dont see a problem with that. I would use a core material(honeycomb or something) for strength though since you wont have the skeleton.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95db8GSR &raquo;</TD></TR><TR><TD CLASS="quote">has anyone tried making just a hood skin out of CF, as opposed to doing the skeleton/underside as well?
i'm pretty experienced w/ CF and have a vacuum bagging system, but haven't had the ***** to make a hood yet. When you make a hood, is it really necessary to make a female mold of the top and bottom and then join the 2 parts made from the molds? or can i just male mold the top of the hood and reinforce the part so it doesn't sag? I understand that making just a skin would eliminate the possibility of a stock-type hood latch or hinges, so i would plan on hood locks on 4 corners and removing the skin everytime i need to get under the hood.....any thoughts/suggestions?
very nice CF work BTW </TD></TR></TABLE>

eHoward

I made another this weekend and took a couple shots with the vac bag:


Just toss the part in your vacuum bag.


Hook up the vacuum.


Pull some vacuum.


What your bag should look like if you do it right.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AccidentproWn &raquo;</TD></TR><TR><TD CLASS="quote">how does the vaccum bagging work? i want more shots of that</TD></TR></TABLE>

CarbonCreations

ummm.... you should be pulling from multiple buckets of resin (cant see in pic), good placement on the vaccum source...

also you need a resin trap otherwise youre going to ruin your 300-800$ pump. Expect to spend 600-1000 dollars on a quality vaccuum setup.

CF is ~ 20-35$ per yard (52" wide).. takes ~3 yards per layer = 60-115 per layer.. which is atleast 120 for a hood right there....
Resin is the REALLY expensive part. Quality resin can be on the plus side of 80.00/gal. There are cheaper resin systems available though.

So just to make a hood you're going to be spending 1,000-1,400$ for a vaccuum system (pump, bags, lines, buckets, trap) and the stuff to make it (mold, resin, cf, kevlar, fiberglass etc)

Pure cf hoods are weaker than CF+kevlar or CF+fiberglass hoods. CF+fiberglass = heaviest, but strongest (for str to $ ratio)

Rolled molds are important too for release and looks.

Brushing resin works.. but definitely is not professional (hobbyists is ok and under a few special occasions for odd shapes)

My advice... if you just want a hood, buy it.

CarbonCreations

Not to mention for really professional systems... freezer and heater system for pre-preg and curing.

Oh and I forgot about clear coating prices (you MUST find a good UV protectant, otherwise your stuff will fade)

And space... lots and lots of CLEAN work space.

it all adds up really quick.. i wish i hadn't bought my stuff lol

Aquafina

iTrader: (3)

I don't think people who actually research then make their own hood care about looks or whether it can hold a model at a car show. Most people who actually do this will be making it for their race car.