I am intersted in making or having made a floorpan for my new kart. Right now I am using .048 aluminium I think and am curious what it would take to make some equivalant. It would be 36" X 50" approx. It has to have some rigidity to it needs to be fairly thin. Thanks for any help you all may be able to offer.
I am not sure if the picture link will work but you can see it at www.mattmendenhall.com
You can use 5.7oz Carbon Fibre Cloth to make the top and bottom layers of a sandwich style layup to make an equivalent of the 0.048". You can use a dial caliper to measure each of the materials used to figure out what amount of remaining material thickness you need in the middle.
http://www.icancomposites.com/product_info.php/cPath/21_22/products_id/28
Because Carbon Fibre is pretty expensive you have other options for the material to be in the middle of the layers of Carbon. You can opt for Fiberglass Cloth or cheaper yet, Fiberglass Matting. These materials are much more reasonably priced and with the Carbon top and bottom you should have a very strong sandwich. Being that 0.048" is pretty thin and you are looking for rigidity, I would opt for the stronger of the two which is fiberglass cloth for the center. Also laying the middle layers up at a 45% angle to each other will help in maintaining strength and rigidity overall. S-Glass is a very strong fiberglass cloth and might be a good choice for you. Granted you ought to make a small sample part prior to undertaking making an entire chassis floor to make sure you get the results you are after. Here are some S-Glass Cloths:
http://www.tapplastics.com/shop/product.php?pid=88&
http://www.tapplastics.com/shop/product.php?pid=87&
If the floor of your kart is completely flat that makes things fairly simple. If it has contours or bends then you will have to make some kind of form or mold to lay the part up in that fashion. I would definitely use Epoxy Resin for that application. It is tougher overall and is more suited to what you are trying to achieve. Here’s a good option for Epoxy Resins:
http://www.tapplastics.com/shop/product.php?pid=29&
If you have access to someone with a vaccuum pump setup that will make for a very nice end product that will get sucked down uniformly, but it is not a necessity really. Another good method if it is completely flat is using a hydraulic press.
I guarantee you if you make this part with a Carbon/Fiberglass layup at around 0.048" thick, it will be stronger than your 0.048" Aluminum. At a company I used to work for we made similar carbon/fiberglass cross laminated sheets around 0.050" - 0.060" in a hydraulic press and they were incredibly strong! I think they would have even repelled a bullet …lol.
Cool looking kart by the way 
do maybe 4-6 layers of plain weave with each layer set 45 degrees of each other to get a directional strength. wet lay on so it is perfectly flat under vacuum with separating film and absorbant material so that you achieve a good fabric to resin ratio. if you dont have equipment thats ok. go to walmart and get a food saver with the jar attchment. honestly it sounds funny but ive heard alot of people that use the food saver for fiberglass repairs. i have used it and still do to make cylinders. but anyways lay a bag and seal the jar attachment to the bag and tape the switch so it stays on. then put a heat lamp or a few towels on it and iron.
carbon about 80$
resin about 56$
food saver 50$
vacuum materials maybe 20 bux
so your looking at 200 dollors for this plate done ghettoly right.
you can skip the vacuum but i wouldnt rely on a structural component like that without a good fabric to resin ratio. but thats up to you.
graphite stopping bullets??? no way ive seen pictures of bullet holes on graphite aircraft parts and the stuff explodes. witnessed the aftermath of a bird hitting a speedbrake on a f15 and it was crazy. not even kevlar helmets can stop a .22 bullet at 20 yards. but composites are strong and stiff as heck.
I think you might be referring to kevlar instead of carbon graphite. Carbon yields better strength in term of stiffness but it will shatter under impact. On the other hand you have kevlar which has less strength but superior when it comes to handling stress. For an under body panel, I would recommend a carbon/kevlar material layed in the directions that dallas has stated. I don’t have a caliper so I can’t even tell how thick is .048" but I’m guessing about 3-5 plys of 5.7oz cloth vac bagged.
It was a joke guys …lol
I realize it is not “bulletproof” …just a silly metaphor :lol:
lol i didnt think so but dont want anyone getting any ideas. a guy died tryin to make a vest out of conventional kevlar and needless to say it didnt work. i think 3m is the ones that make the stuff and its a specific type not just plain stuff. but carbon kevlar seems smart too. red would look quite good on your kart.
It was a joke guys …lol
I realize it is not “bulletproof” …just a silly metaphor :lol:[/quote]
see if you cant get a pre preg and lay it on glass and let it cure. soemtimes they can be ordered to the desired thickness and will have a multi directional strength. they can be shipped frozen so all you gotta do is cut it and then lay it out securely either vacuumed to a table or pressed and let cure. very easy and doable.
The only problem with using prepreg is that it has to be oven cured at 350 degrees doesn’t it? A 50 inch long part wouldn’t fit in a traditional oven.
First and foremost I would really like to thank everyone for the ideas, they are great. I should have clarified a little better when I asked my question but I truly didn’t think Iwould get so much help.
The main reason I would be doing it would be to cut down on weight. Making it from kevlar to keep it from shattering is a very good idea because we do tend to drag the bottom of the kart occasionally.
I had made one for my old kart out of kevlar but it wasn’t strong enough. This could have been due to not enough layers, not turning the layers 45 degrees to each other and if I understand your ideas correctly you should only be laying up one layer at a time and let it cure to a certain degree.
Could I use the Carbon/Kevlar weave on the top to incorporate the blue kevlar or is going to make it harder to do. Again, the lighter the better. I would have to estimate that a 1 foot by 1 foot peice would need to support 5 pounds without too much sag. Betwwen the main frame rails and the nerf bars on the sides there isn’t that large of an area that isn’t supported.
Again thank you all for the help.
I would say if you are after lightweight and stiff and you don’t mind spending a little cash to get what you are after I would go with using standard kevlar as the bottom layer and the hybrid kevlar/carbon blue for the top if you want the visual effect. Then the middle would probably be best using raw carbon fibre cloth to add the rigidity. You could use the option like the others here stated by building the entire floor out of the kevlar/carbon hybrid alternating the middle layer weaves 45 degrees and leaving the top and bottom layer weaves inline with the length of the cart (50"). If you get most of your force to the floorboard in a twisting motion more than a straight front to back flex, that is where the 45 degree angles will benefit you.
For the most part Kevlar adds the durability, while Carbon Fibre adds the stiffness. Both are very lightweight materials with great strength. Hope this helps clarify things.
Remember, it is a very good idea if you are after specific properties in a finished part, there are general rules and properties for each material used, but it is always a good idea to make a test piece before wasting expensive materials trying to achieve a basically unknown end result.
I am currently building a carbon/kevlar floorpan for my oval kart. It is only about 24"x24" but I am also considering making a full pan for my briggs endro kart. I am using 2 layers of 5.7oz carbon with a layer of 11oz carbon in between and a layer of 1.8oz kevlar on the bottom for abrasion. I’m using epoxy. I have wondered if this will be strong enough but it sounds like from the replies it should be. I hope!!
The original piece is made of fiberglass and has little wingletts that bend up to follow the shape of the chassis. I made my mold out of plexiglas that I cut to the proper shape and then used a heat gun to heat it up and bend it to the shape of the original. I then glued it to a wood frame that I made. I cut the material last night and I hope the lay it up this weekend pending the path of hurricane charlie :? . The plexiglas should give me a very smooth and nice finish.
This will be the third and biggest carbon piece that I have made. I have also made a steering wheel flairing out of carbon for my oval kart. It turned out very good for being my second piece. I used 3 layers of 5.7 oz for it and used the original plastic piece as the mold. After I finish the floor pan I’m going to make another steering wheel flairing for my enduro kart. I will post pictures of my floorpan mold and the finished flairing later tonight.
Matt-That is a nice looking laydown kart. Where do you race? I will be racing the briggs enduro kart in the Big South and the Southern Road Racing Series here in the southeast. Another option you may want to consider for the floorpan is using a piece of UHMW polyethylene. They call it “poor man’s teflon”. It has a very low coef. of friction and is basically unbreakable on impact. I’m either going to build one out of carbon/kevlar or more than likely make it out of a 1/8" thick piece of UHMW. It costs about $75 or so for a 48"x96" piece and can be cut using woodworking tools.
Thanks for the compliment on the kart. I wished it still looked that good. Had a little altercation at Kershaw with another kart so I am now in the proccess of getting ready to hang a new body on it and it is why I have chosen now to make it as lite as possible.
I have used the polyethylene for the wheel wells(next CF project) and some other peices but it is too heavy for a floorpan.
Did you let your peices cure a bit between each layer? The reason I ask is that I did a couple of peices in kevlar with the right epoxy and laid all 5 layers at once and it didn’t come out as stiff as I had anticipated. The could have also been caused by the fact that I ran them all the same direction.
I to run the BigSouth Series and Sothern Road racing series(even played race director last weekend) along with all of the national races.
Again I would like to thank everyone for their help, it is truly apprecaited.
Letting each layer cure will not produce a stiffer part, it will only complicate the process and drag it out much longer. Then you have to sand between each layer and could make the part more susceptable to delaminating also. Kevlar by itself is anything but stiff. It is actually quite flexible. Kevlar merely produces a lightweight and very tough product. The rigidity will come from using Carbon Fibre. Carbon Fibre is more brittle and less durable on the surface than Kevlar in most forms, but is makes a very strong and rigid part when laminated. I would advise using a hard curing Epoxy that uses about a 4 to 1 mixture. Those Epoxies typically are structural Epoxies and dry much harder.
Matt- I was at Roebling last sunday watching the races. I plan on running both series next year. I have also done a Porsche Club drivers school at Kershaw in a friends (also my instructor) porsche race car. Kershaw is a great track. I was hoping to do the last Roebling race or the RA race this year but I don’t think they are going to happen.
The weight was my only concern about the UHMW but the expence is my concern with the Kevlar/carbon option which for reasons you said my be a better way to do it. Maybe a FG/Kevlar floorpan may be a happy medium. The pieces I have made so far I waited about 25-30 min between layers to allow the epoxy to gel. They have turned out good but very small air bubbles are the biggest problem I have had.
I thought I could post pictures but I don’t have a HTTP. If you would like to see then let me know and I can drop you an email.
You do not want the Epoxy to gel or setup at all between layers. You want to have all the layers wet so that they bond together in one layup. You sacrifice strength when you do it the way you are describing and as you also have seen you can easily create air bubbles between layers. You will get a much stronger end product if you have minimal resin between the layers but have enough there to fully saturate all of the fabric completely and also eliminate all air bubbles. That is why if you can vaccuum bag it, it will produce a very uniform part with the layers drawn together as tightly as possible. Having the layers competely adhered to each other tightly is where you get the strength from these types of materials. Remember you are fabricating a structural part, not simply slapping a repair on the side of a boat hull or car body.
I hope you don’t take offense to the way I have put it explaining this procedure. Yes, there are a few different ways to do this project, but I just want to emphasize why things are made using certain proven procedures and deviating too much from those methods will create unsatisfactory results for you and more than likely waste your time.
ok i like the idea of carbon kevlar sandwiching the carbon. do not let resin cure between layers at all. lay 3 layers pour a resin and then lay the last 3. then wet it all out and let it sit for like 5 minutes lay on some separtation film and then your absorbant material. then vacuum. this will pull air bubbles out and make a super strong part. too much resin will create a part that can be too brittle. do the wet lay up on a glass table and then bag over the whole part that way it will be perfectly flat. i would use west system epoxy. i think the guy talking about 4 -1 epoxys is talking about an adhesive. they are like resin but at the same time turn very brittle but bond very well. also they tend to not wet out very well. we use hysol 956 and “triple m” adhesives. sometimes we use them to wet lay fiberglass on a/c repairs but never for wet lay up. you need a low viscosity resin for that. good luck and pm me if youd like some one to do it for you. im in the va area.
Drummz - No offence taken! 
Any advice you have for us beginners is great! I am still very new to this and the reason I did it that way was because I read it on another forum. I very well could have misunderstood the process also.
So it is best to lay up the layers right after each other with no wait in between? I hope to layup my floorpan this weekend.
Thanks for all of the great information!
do it all at once. not one at a time. lay the first 3 layers with the 45 degree angle and pour resin. lay the second over it and then either do it the proper way with a vacuum bag process to achieve the proper resin to fabric ratio. or you can just lay some barrier over it and squegee the rest out. i wouldnt recomend it though. for a race car you want to have it lightweight and also have an even strength cross section. meaning its basically very uniform for its thickness strength and weight. having indentions from starved areas and concentrations of resin will make the part weak. but it is only a go cart.
No not referring to an adhesive at all, actually a Resin. I know that most Epoxy Resins that are 2:1, 3:1 or 4:1 are typically harder and usually used for more structural laminations. The 1:1 Epoxy Resins usually are too flexible for what he is wanting, atleast speaking from my exposure to what I have used in the past.
Here is a 4:1 Epoxy:
http://www.tapplastics.com/shop/product.php?pid=27&
Use the B-Side Hardener • 109 • Medium
The West System is also a popular choice.
…And yes do NOT wait for any period of time between layers. Coat the glass (your form molding surface) with a good release agent prior to starting and let it dry. Then brush a layer of resin by itself down on the glass first, then add the the first fabric layer. Work the resin into the cloth by dabbing your resin filled brush onto the fabric which will push the resin into the cloth. This will help set the cloth and saturate it fully with resin eliminating air bubbles. You can brush it out lightly to even things a little after the cloth is fully saturated. Then add the next layer of fabric and so on…
Simply brushing resin onto cloth typically will not saturate fabric fully and it is always best to have enough resin down on the prior layer so that there will be resin enough to start absorbing into the next follow-up layer. Worry more about the final layer and removing excess resin then. Certainly don’t starve the cloth of resin. That will also weaken it. There is a fine line between weight savings having cloth that is too dry and having enough resin to fully bond the lamination. I worked for a model airplane manufacturer with very high standards and weight savings was of the utmost importance as well as making the parts as cosmetically perfect as possible. You get a knack for the right amount of resin with a little experience. Vaccuum bagging helps in this regard because it does help eliminate excess resin build up by pusing most of it outwards and makes for a uniform and strong part.
The best epoxy resin I’ve used is PTM&W. It’s a 100:18 ratio by weight.