Wanting to build an upside down boat (a car)

I am new to this site, so please be nice just like the title says I want to build an upside down boat. That would be a car, yes I know this is a boat site and I have one (jet boat), anyways who knows better, then boat builders, on how to build things that work right? anyways I have had this in my mind for some time and want to actually build it. I came across the idea about 20 years ago and feel that it is time to give it a go. I made the design in clay and looks awsome. Not sure what my next step would be. What I was thinking is to buy foam from home depot or? this is the kind that will get eaten up by polyurethane resin. I figure it would be cheap to use as a plug. I would coat the foam with a water based paint and then lay the glass over the mold. Does this sound like it would work? and any hints you guys could throw my way. This is something i would really like to explore further. Or should I just give up

 

buy a corvette, they are fiberglass...and fast

 

Yes, I know that they are available, thank you for the useless reply.

 

if you are building a car, first start with a chassi, you can build one, or buy a good handling car, like my old nissan 240sx, and strip it down to the chassi. That is probably the most realistic bet, b/c then you have an engine/drive tran that bolts right to the chassi, to boot suspension brakes etc. plus, all of the cars parts you can buy from auto zone. For cars, I suggest toyota supra, nissans 240sx, hell even a civic. They all handle great and have tons of after market parts. if you want to go american, the ford mustangs from the 80s could use some cosmetic help, and they are fast. then after you have a chassi, you will have to make several molds for fiberglass body parts, like fenders, hoods, doors, the cockpit, etc. I can't really help you on mold making don't know to much about it. good luck it is quite a project, you really might want to consider the vette

 

Did you see monster garage last week they did just that , Upside down tunnel hull on a frame . Looked good, interesting concept and saved a fortune by using a dismantled hull. Check out some bone yards .this would be the most inexpensive way. But if your set on building your own concept design the cheap foam would work but it is suseptible to snapping in tight contuors but if your going to stack it and start carving and make a solid plug I don't see why that would.nt work for a one-off format.you might have too do this in sections depending on the complex curvature or just trash the cheap plug from with-in
Scrap the latex idea and check out a cheap faring putty ( Bondo Like) and a good release agent .
Have fun

 

Thank you for the last reply, that was really one I was looking for. I am actually planning on building the Chassis myself. I have thought about bolting it to an existing chassis, like a kit car, but am more apt to making it like a Nascar chassis (Tube) due to it being lighter. I am looking at a mid engine design with a Buick 231 powerplant. Really on this site I am however leaning on mold making tips, thanks for the tips on the Chassis though. The Vette is out of the question, the idea here is to drive something, no one else is.....

 

let me know how your doing post a picture of your model check out several on the net one I can lead you to for a good beginning one one-off format is www.Glen-L .com

 

I did not see the episode, but heard about it on the Hot Boats site, not a lot of happy campers over there on this subject. for the car I am looking at making it in 3 sections, forward, mid, and aft(engine bay). I know it sounds like a half baked idea, but so was the Wright Flyer. I was thinking of doing the stacking, and then carving it out with a hot wire, then sanding it down. The original can be made from a male mold and then a female can be made from a male mold. The problem I am running into is the materials. since this is a first time thing, I want to keep the cost down. If I descide it is a waste of time, I do not want to feel too bad about throwing it in the dumpster. The type of bondo type fairing putty, will it eat the expanded foam of the plug?

 

As much as I would like to post pics, I would like to keep it on the DL (Down Low) for right now. I will try to e-mail some (to you only) though when I get my digital camera back. They say that everyone needs a hobby, I guess this could be one of mine. Building a car, it could be something bigger like a house One good thing in my corner is my neighbor builds race cars (Dirt track) so I may be picking his brain for ideas on chassis design.

 

you don't want to use expansive foam that would cost you a fortune!!!
What I was getting at if you want cheap , use sheet foam not the white stuff you'll have that stuff every where The blue dense foam is good but check out Airex products
they may cost a little more but it is intended for just what your trying to do.
Also check out the waxing method instead of farring puttys now this is where you might be able to save some money As I think about it as I write you may be able to use a latex to seal the foam without a chemical melt down of all your hard work and then wax the surface for a one-off .
Not positive on this but its fun to Experiment in low volume. try it on a piece 12x12
you'll only learn something
good luck

 

There are some good people on this forum I've not meet a bad one yet.
They are helpful and will answer alot of ???'s for you .Thats what this sight is all about
If your serious these guys will help you to the ends of the earth .
I suggest you browse through the sight I'm sure your going to pick up a boat load of information. Don't ever be afraid to ask ???s Thats when mistakes happen that could have been avoided. Just because its a sight for people who are interested in boat building don't mean you can't learn how to turn one upside down on a chassis
and have some fun , a little unothadox but hey! At least you'll learn the basics of mold making.
Good luck
Donjames

 

check out other forum sights for fiberglass fabrication of street rods there you'll find more specific information on your concept with additional information on the auto subject your more than welcome to e-mail me on your progress
djvcwg@yahoo.com

 

Thanks for the reply; I believe Home Depot caries the foam sheets you are talking about. I will check it out. I also have some Epoxy resin that I got from Fiberglass Coatings in Florida. It is left over from the transom replacement that I did a last summer on my jet boat. If that will not eat the foam then I may coat it with that. Thanks for the replies on the subject. I can understand why some people may be reluctant to reply to this thread, as it is something that is incomprehensible for an average person to pull off without billions of research and design dollars like the big 3. It is something that only plan to build for me, not production. The thought of something this cool looking would definitely turn some heads on the street.

 

I know you are looking for mold info, which I can't help you with, but I do have my own project car, which is on hold right now, b/c of my boat project. some quick things to think about, when making your own chassi, you have to fabricate it some type of after market suspension. this could get real costly, esp if you are looking for full independent. my father raced F3 cars in the scca in the 70s, and he made the car simularly to what your doing, build the chassi, mold the body out of glass. and it was costing him about 10 to 15 gs back then to build a car. as for the 231 buick engine, one quick question, was it for a frontwheel drive car or a rwd? a fwd would not work unless you want it to be rightover the rare wheels. also, if it looks cool, you want it to be fast, make sure that there are alot of aftermarket parts, intakes, efi/carbs, headers, roller rocker arms, radical cams, etc. if you use an engine that isn't common in streetrods/sports cars, it will be tough to find the parts and expensive.

 

Thank you, for the response. It makes a lot of sense to build the Chassis to accept production parts, which is what a lot of kit car builders themselves do. I am planning on doing that myself. I threw the Buick 231 out there since it is light and had enough power to make the Grand Nationals compete neck and neck with the V8's. I am also tossing around the idea of a Chevy 350 due to the availability of parts and low $$$. I am planning on setting up the car as a mid engine design. I plan to start the chassis design using a 3D cad program that I have. I am also not sure what transaxle to look at. I will have to check on that also, preferably one that can accept the powerplant and size of the car. This project will be done slow and over time, as I do not want to make any mistakes along the way, since that could = $$$$$