Vacuum infusion composite construction

[cjtpb13]

Just curious if there is anyone else on the TLF utilising Vaccum Infusion for manufacturing composite parts for their Lotus or other vehicles.

I decided I needed another hobby in the limited time that I am at home...lol. So I have decided to try my hand at Vacuum Infusion for person purposes. A quick note to know is that for my businesss I already work with the technique and composite repairs and gelcoat. Yes part of being an International Poolboy.

Reality is that I have become disenchanted with the lack of response to inquiries to businesses that manufacture aramids and carbon fibre parts and their unwillingness to want to take my money for a product.

[pdgessler]

Christopher,

I do have a bit of experience with this -- my school's SuperMileage Vehicle team fabricated our body and main chassis out of carbon fiber. We used vacuum infusion to make sure all the layers of carbon were fully laminated without voids. It also squeezes out quite a bit of excess epoxy, which significantly decreases the weight.

The chassis we made was a sandwich of sorts -- two layers of carbon, a waxy plastic honeycomb in the center for rigidity, and two more layers of carbon. The whole panel supported everything in the car (engine, driver, axle and steering loads, etc.) and weighed about 8 pounds if I remember right. The body was just 2 layers of carbon but was significantly more difficult to make because of all the complex curves. I did have experience with this in the past though, from building a cedar-strip and fiberglass canoe.

What are you looking at making? If you have any questions about techniques or sourcing for supplies let me know; I'd be happy to help.

-Paul

[cjtpb13]

Paul,

Thanks. I have experience in working with gelcoat, fiberglass, and cored balsa in both wet lay up, vacuum bagging and vacuum infusion due to what I do in my business. One reason why I posted was to find people like yourself. What I have to do for my business never has to be the most tidy of jobs, as it is in the mechanical pit or in the return laminar flow tunnels of the piece of equipment I work with.

Though I am wise enough to know that Carbon Fiber and Arimids have their unique qualities when it comes to design and layup. Hence why finding like minded people with experience. If I can learn from someone elses mistakes or experience it has just saved me that much in time and frustration.

The Henry Ford method in a nutshell, " I might not know the answer but give me five minutes and I will find someone that does. "

Just a quick clarification, were you employing vacuum bagging ( where your composite is layed in wet and then the vaccum is applied ) or vacuum infusion ( where all is dry when vacuum is applied ) for your project ?

By chance was your core Duponts Nomex Honeycomb ?

Their are actually numerous pieces on various motorcars of mine that I want to fabricate new pieces for. Specifically on the Lotus there are several cosmetic pieces and a also the cabin air intake plenum. Mine has a particular weak structure, thus creating a terrible seal between the hood and the plenum, allowing water into the front compartment at times.

Edited July 24, 2010 by cjtpb13

[red vtec]

HI Christopher,

There are quite a few videos on You tube covering what you are asking, also www.detailingworld.co.uk has quite a few members into making carbon parts. I have been looking into it, but purley for cosmetic reasons, Therefore I have been looking at 3M dinoc film as I only want the look of real CF.

Good Luck

Chris

[paulwendling]

Hi Christopher,

Where in California are you? If you are near Los Angeles, I have a special effects studio where we do all sorts of things in a similar vein.... even Vaccuforming machines up to 4 feet by 8 feet. I make all sorts of parts using all sorts of manufacturing processes... this link shows an armour suit I designed and built (and ended up doing the stunts in as well).

The dark musculature undersuit was vaccum infused into nomex and nylon matrix.

I am also making many custom pieces (air dams, spoilers, side skirting, quarter window surrounds, custom engine bay venting etc. They are not main structural members, but are strong enough to withstand aerodynamic forces.

I'd love to hear what you were thinking of doing. Oh, and by the way, since I'm near Burbank, there are lots of available surplus Nomex honeycomb panels to be found left over from the Lockheed manufacturing days. (not cheap, though...)

All the best,

Paul Wendling

(951)206-9156

Edited July 24, 2010 by xspeedx

[cjtpb13]

Paul,

Nice work ! I take it you also do quite a bit of styrene plastic work too ? I have actually read many of your threads with interest because of what you do. Originally what you do is what I wanted to do. Instead lifes turns sent me in the direction of international poolboy instead.

I am actual Located in California, Maryland ( near Patuxent River Naval Air Test Center, Naval Air Warfare Aircraft Division, home of Test Pilot School ) and believe it or not it is right below Hollywood, Maryland. Claim to fame was Hollywood, California sued them about 20 years ago. Judge said forget it as Hollywood, Maryland been around since 1700's

Yes those are the types of parts I am heading towards. Some due to the fact that composite material fabrication is much better now than it was back in the 90's. Also on a few of my other cars the carbon fibre brings out a bit more of an appeal.

One idea I want to do is a CF engine cover for the S4. I have used my CNC carving machine to carve a reverse Lotus emblem that I will reverse mould and allow to then be placed in relief in the CF engine cover. Also a few interior piece I want to update to actual CF as opposed to the CF stickers that Lotus utilised. I figured with my travel schedule it was a perfect hobby to do. I already own majority of the equipment and supplies. Travel will keep me from rushing to release a part from a mould before it is ready...lol.

How did you like working with the Dupont Nomex Honeycomb ? Thinking of that for the engine cover. Front splitter on the S4 I am going to use Aramid layers between the carbon fibre. Also Buddsy on here used a ceramic heatshield material that I need to figure out how to adhere to the engine cover and maintain a service life.

Chris,

I have caught numerous videos on Youtube. Thanks for the one link in the UK. I found that some of the videos were humourous in the aspect that they try to take lots of shortcuts in the manufacturing process. Like nothing being free in life, when it comes to making something there seems to be very few genuine shortcuts in the manufacturing process that does not cause issues of quality in the final product. I guess I have a lot of perfectionist attitude in my personality. The method you are looking toward works well too in my opinion. My dash and door trim still looks good in my Lotus from what I can remember of it. ( slight joke after 8 months of not really seeing it ). I just want to replace them with 2x2 twill and have the fun of making the pieces. I found of quite interest the UK company, CarbonMods and their skinning technique. I might try that for certain parts. Seems like they have a nice kit to start with for small practice pieces.

In general a majority of the pieces are going to be reversed moulded. The moulds will be finished in black tooling gelcoat ( far superior to orange tooling gelcoat when it comes to the quality of the finish and it will survive the rafters for storage of the moulds when not used. I have decided to go with extra cost and time of making the moulds for two reasons. First because it really is the right way to do it, and secondly I can always make the piece again of needed. Especially true for the front splitters.

Vacuum Infusion just seems to be the best technique and I am familiar with the process. Though be nice to be doing it it on my garage rather than out in the field.

[pdgessler]

Just a quick clarification, were you employing vacuum bagging ( where your composite is layed in wet and then the vaccum is applied ) or vacuum infusion ( where all is dry when vacuum is applied ) for your project ?

By chance was your core Duponts Nomex Honeycomb ?

My mistake, I read this way too quickly -- we did use vacuum bagging for this past year's car. But we had a meeting with a sponsor we are potentially bringing onboard for this year and he has vacuum infusion capabilities in his shop that he said we are welcome to use. This is exciting because we will be able to use a faster curing resin which is much stronger than what we used in the past.

Our core was not Nomex, I believe it was some type of poly honeycomb but I can't remember exactly what it was. We had problems with our panel flexing from the heat of the engine. At the beginning of a run it would be virtually rigid and by the end the back corner of the panel would sag under the loading. Next year we are looking into different core materials to avoid this along with the vacuum infusion. I'm hoping to do a monocoque body with minimal honeycomb support where needed, but obviously this is a much more complex / risky design process than a simple panel would be, so the team needs to decide what we are capable of.

Let me know how your projects go, I'll be interested to hear about them!

[paulwendling]

Hey Chris, Give me a call at (951)206 9156

One way to prevent heat warping issues is to do a heat soak cure. On your negative molds, what are they going to be made out of? If they can take extended high temp, like up to 250 degrees, then you can heat cure the vaccuum injected pieces in an autoclave / One technique that works well with CF layup is to use the higher temp clear resins, I believe you can still get them from Reynolds Advanced Materials. Some of them have a longer cure time (over 20 hours), but if you do a layup into the mold with the resin, then vacuum CF cloth over it, with a biscuit material of high temp material behind it should give the rigidity. In High temp areas, unless things are made out of exotics (ceramic, metal, etc) you will Always have a sagging issue. The way to minimize this is with actual material thickness under the CF film. Adds a little weight, but in the end prevents those issues. Also when you do an in-mold cure, pour sand into the hollow area, smooth, and put a heavy plate on top. This will continually force the material against the mold as it is heat curing for a perfect shape.

Now, another way to get a great piece out of Aluminum is to create your own press mold. For an engine cover size piece, you would probably use less than $500 in materials. Make a negative (start with a workable negative out of ren-shape or other smooth polishable material, then make a positive rubber casting mold. Then fill the positive mold box with a hard metal filled epoxy (used for tooling applications). You now have a press mold negative which will hold up to having 020 or 040 softened aluminum sheet pressed into it multiple times. You next need to make a positive press mold using same techniques, with a hard steel plate on the outer side (top and bottom) of both mold pieces, make sure you take metal thickness into account for proper fit. Then, (this is the only tricky part) find a metal fab shop with a 5 ton or bigger press that has a table size to accommodate the mold. Press the softened Auminum plate in it, and voila, you have a beautiful part. (If you can't find a large press, the I have actually done the "trailer park" thing and we drove our work Suburban onto a mold (with appropriate ramping on either side), back and forth until it was pressed) You still need to anneal it by heating piece to dull glow, and then dunking in a high temp rated oil which should be cool (if none is available, use highest viscosity transmission oil you can buy). If you don't have access to an oil dunk tray/tank then the next best thing to do is heat a section of the Aluminum piece with a torch to a dull orange glow, then spray freon refill bottles you can get at any auto parts store and flash freeze the section you just heated (takes a little practice to not over-temper the metal and crack, but with a little practice on a scrap piece of aluminum, you can get the hang of it.). You now have a piece which is Aluminum, weighs LESS than any CF layup you could ever get, is hard, and will never sag in heat..

Here are some pics of metal work that I have done, using some of the above mentioned techniques, just to show you what is possible on the details.

Paul

[cjtpb13]

Paul W,

I travel on Monday for most of the day. May I ring through? And is there a good time to call you during the day in your time zone. Would be great to chat. If weekday is bad I can always ring through over next weekend.

Nice work in the photographs by the by. Interesting about the aluminium molding. I just finished reading a book on that technique. Ironically because of something else I have the ability for a 10ton press up to a 4 foot square area.

Paul G,

With the CF sagging due to heat, did you at any time attempt to utilise reflective heat tape or a material similar to the ceramic heatshield that Buddsy used in his restoration? Just wondering if that would help. Sounds like I am going to have to experiment a bit with heat.

[Jonathan]

I do a fair bit of moulding on test pieces and so on, made my own roof, regard...

http://www.flickr.com/photos/jonhimself/3977247804/in/set-72157619732521668/

I dont use any kind of vacuum, I just can't be bothered, I know it would increase the wetting of the mat and the strength vs weight but I just dont bother with it.

I use a long pot life resin which is superb imo, doesn't gel for about 90mins which enables it to wet the mat well....works for me anyways.

CF engine cover is the holy grail imo, Kylie had one iirc. I've often thought of just doing it, it doesn't have to be that strong and CF is a good heat shield as it is without any fancy pants underneath - the only thing I would add is a turbo shield, I done this on my GT3, made it from grp / stainless sandwhich

If you want performance out of the CF and not just looks then vacuum / oven baking is the way - but tart up bits and so on I just wack it on

Reminds me I need to finish my carbon sills, I'd love to have a decent CNC to make embossed moulds but I'l just sticking with decals.

[paulwendling]

Hi Christopher,

Give me a call anytime.... phone is always on (951)206-9156

Paul

[Bibs]

Christopher, I found them!

[cjtpb13]

Paul W,

Thanks...my number will have a 301 or a 203 exchange depending which phone I am ringing from. Speak soon. I look towards it.

Jonathan,

Yes having a CNC carving machine to assist with mould making is a nice luxury. I am trying to plan an embossed Lotus logo on the engine cover of my S4. I had removed a few bits whilst I was meeting with Lotus Cars USA and the dealership in the attempt to get my car completed to my satisfaction. Once you use the CNC unit there still is a bit of fine cleanup needed before the mould is ready to be taken from it I have noticed.

Bibs,

Thanks for the attached photographs, nice thing is the v8 cover looks a lot more simple to reproduce in CF than the S4. Appears the transitions are a lot smoother. Will give me something to strive for. Yes that is some of the look I would like to achieve, fashionable but not gaudy....lol

[Jonathan]

Is it CF or is it just covered in CF ?

Pod covers crack me up...no-one sees them

CF in the interior just makes me feel like I'm sitting in an anechoic chamber.

Love the exterior door trim though, classy.

Edited August 8, 2010 by Jonathan

[rogerch]

I've reduced overall weight by 14 kilos at minimal cost.

[cjtpb13]

Jonathan,

I will actually be producing made of CF, not covered. Been in the process of making the moulds.

In my case, my light pods are seen during the day. I always run with the headlamps on. Far too many times have I had some minivan ( people carrier to you ) pull right out in front of me. I have found many people have the tendency to look " over " the car and not realise how close I am actually to them. The height of the vehicle lends to them an optical illusion. Plus the originals are flimsy and have splits in them and gives me the opportunity to make the headlamp pods a bit more weather tight.

I have gotten use to having tasteful other CF bits in and around me with the other motorcars I own.

Roger,

How much did the wing weigh.?. LOL !

Not always being done for a weight saving reason but rather for a better look and replacing some of the older plastics that are showing their age.

Plus just another excuse to try another hobby in life.

[Jonathan]

Yeah I was commenting on the yellow car, on whether that was covered or not.

I you manage to get the engine cover done it'll be worth marketing.

Paint the car a brighter colour then you wont have to worry about people not seeing you

[cjtpb13]

LOL about the brighter colour. I think more to do with the stereotypical minivan driver....

All the CF work that you have done, has it all been wet layup covering or have you made yourself a mould? Have you been doing any more CF work lately? I believe me dive into it is the same as your own. Hassle at times to get anyone out in the market place to want to do anything or reply to oneself.

And in reference to the engine cover, being a business person I have given it it some thought. Want to master the technique first and foremost. Would be easy enough to create a third business and let it run where it wants.

After much research, by the by Jonathan I hold you responsible for this whole route ( it was your thread that had the carbonmods UK video links that has had me reading and experimenting with CF ). So you are entitled to a wee bit of royalties...lol

All of my moulds I have planned will be done up in black tooling gelcoat and CSM ( chopped stranded mat ) with two layers of fibreglass cloth to give it more strength. This will allow me to store the moulds in the attic of my 4 car garage. Of which I am taking one bay to turn into an enclosed CF room. Moving one of the motorcars up to my CT house.

[Jonathan]

I've only done about 1sqr foot of CF, the rest is GRP small repairs to the body of the GT2, roof and some test pieces / moulds for other bits.

Whether or not the mat is GRP / CF - same thing different material imo.

Ya it's much easier DIY and you save cash which is my drive, I'm time rich, money poor but I also like working with engineering stuff.

Usually I make a soft wood prototype (usually balsa, cus it's easy to sand and cut) then PVA / latex it, then make a GRP mould of it, or one I have been working with lately is fabric gauzed soaked in latex - works well but shrinks (hence the gauze to bind it).

I might just go over my engine cover, tbh carbon fibre is not that light - thats not it's property, it's property is strength. The key with carbon to make it anywhere near worth it's while is to get the least amount of resin in the weave to achieve the same strength.

Otherwise GRP'ing a part and then putting the top coat in carbon is much more cost effective. An effective way to do the engine bay cover is simply to sand the bugger down until it's as thin as possible and then get a whole layer of CF over the top. Making a whole new mould seems too much for me.

If you're taking it to McLaren F1 levels where the mats are baked and so on thats where it's worth the investment. But again there the investment is in structures, not finish.

Thing is to get something like a good, well made light engine cover that weighs 1/2 of the GRP one will cost a lot of cash becuase of the prep work.

[Günter]

yellow one is from the German owners group as far as I see ..the owner loves some notable 'pimp it up' style ...the engine cover is thinner layed, it's CF and costly

[birdseye]

How do they prevent heat warping in the mouldings they use in F1 cars or is this why companies other than Red Bull are having difficulty with using the exhaust gases aerodynamically.

[Jonathan]

Easy, high temp resin

Most of the stuff I use is a general purpose resin, the glass and the carbon can withstand huge temperatures but the resin I use will probably start to soften or catch fire at exhaust gas temp (I've had it ignite when using too much hardener, thermal runaway, very smelly).

I saw a program on the McLaren F1 which I think was the first all CF production road car ?

Very interesting watching them make a car from what looked like a dressmakers outfit - they hand place the weave on the mould and then painted the resin in before baking it at some silly temp which increases the strength of the resin.

[cjtpb13]

Paul,

Attempted to send you a PM. Bounced back. Email me when you have a chance.