Body Fabrication

[Conor]

As a first year team, we're kind of confused on a lot of things, and one of them being how to fabricate a body for our car. We'll probably do it out of fiberglass because it's light and probably the easiest option. How do teams go about building the mold for their body? I've seen pictures of teams using foam and then shaping on that. Can somebody provide me with some more details about this process. Also, is there another way of doing it than using a foam mold and fiberglass? I really have no idea and would like to explore all possible options. Any help would be greatly appreciate. Thanks!

[Conor]

As a first year team, we're kind of confused on a lot of things, and one of them being how to fabricate a body for our car. We'll probably do it out of fiberglass because it's light and probably the easiest option. How do teams go about building the mold for their body? I've seen pictures of teams using foam and then shaping on that. Can somebody provide me with some more details about this process. Also, is there another way of doing it than using a foam mold and fiberglass? I really have no idea and would like to explore all possible options. Any help would be greatly appreciate. Thanks!

[kwancho]

Carbon fiber! http://fsae.com/groupee_common/emoticons/icon_wink.gif

[terra_dactile]

conor,
one way is to take your 3d cad model an slice in like a loaf of bread into section of a certain thickness , say 3/4 in or 1 , plot these layouts on to full scale draing paper and glue this to MDF boards,then cut out each of the section with a band saw for wood, and glue these section together, from their you must sand away the steps between the slices of wood and then coat it with a coating like duratech, then sand this coating really smooth and prepere you mould over this peice witch is called a Plug, once you mould witch is made of some type of fiber is ready you can make your finall peice inside of it, their are steps that i have skipped like demoulding agent and wax, but that info you could find from any shop that works with fiber glass,

i hope this can get you started,

Jude Berthault
ETS Formula SAE
Steering System Leader
Brake System R&D

[Colin]

just a word of warning, do not underestimate the amount of time it takes to make a reasonable body in fibreglass, specially if you've never done one before. So if your a first year team I would suggest keeping the design nice and simple such as a three separate piece body (nose, 2 sidepods).
good luck

[markocosic]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">We'll probably do it out of fiberglass because it's light and probably the easiest option. </div></BLOCKQUOTE>

Bent tin (alloy sheet) also qualifies as light and easy.

Aircraft fabric (just stretch over your spaceframe and warm it up) is even easier/lighter.

Neither look spectacular up close though!

[Nick McNaughton]

Aircraft fabric is by far the easiest, and can be done start to finish in a day. It's not that durable, so count on having to repair it often after overexcited drivers throw the harness around or run into cones. Your time would be better spent on making the other parts of the car work...

[Conor]

Thanks for all the help guys. What do your teams do? If somebody had a photo timeline of their fabrication, that would definetely be very helpful.

[Bryan Hagenauer]

I've just got a suggestion for some easy to make bodywork. We generally go the full mold routine, but our baja team used a different method with suprising results.

They stretched out painters plastic across their tubes so that they had effectively saran-wrapped their car. They then just did a wet layup on that. The finished part wasn't all that pretty, but it worked well and fit the car perfectly.

Just a thought for teams with no time for the mold method.

[Mustang Mac]

I have done some body design and fabrication for a few years. The first body we did was a plug-mold-part process. We wrapped the chassis with plastic (package wrap - like cling film) and glued foam sections to this. I then shapped the foam and used bondo to build up areas and as a gap filler. The we sanded, gel coated and applied a molding release wax. A mold was made from this plug using fiberglass. The mold was then waxed and the final part laid up.

The next year we made section view cuts of the chassis every 4-6 inches and printed them out to scale. They were transfered to mdf sheets and cut out. A spin was made by notching a couple 2by4's and inserting the mdf sections. We then shrink wrapped the whole thing and pored in a 2 part liquid foam. After it dried the plastic was removed and a skim coat of body filler was added and sanded to the desired shape. We then applied a high fill primer, sanded, primed and applied mold release. We then followed the same procedure of mold then final part. If I knew how to post a pic I would.

This year we are looking into machining a mold out of foam on a 5 axis mill and skipping the painful steps. If this is your first crack, I will worn you about the endless hours and days of sanding to achieve perfection, which never seems to come.

[Didier Beaudoin]

Last year, we used about the same process as Ryan described. I started by designing the bodywork in CAD:

http://www.etudiants.polymtl.ca/fsae/gallery/albums/Construction-2005/test.sized.jpg

Then, we printed sections of the body on paper, glued them on wood panels and cut them out. We then filled the space between the panels with foam blocks that were then roughly shaped with a hotwire and a handsaw.
http://www.etudiants.polymtl.ca/fsae/gallery/albums/Construction-2005/IMG_1424.sized.jpg
http://www.etudiants.polymtl.ca/fsae/gallery/albums/Construction-2005/IMG_1426.sized.jpg
http://www.etudiants.polymtl.ca/fsae/gallery/albums/Construction-2005/IMG_1436.sized.jpg

We then applied a layer of fibre glass and a lot of bondo. After many hours of sanding, we ended with this:
http://www.etudiants.polymtl.ca/fsae/gallery/albums/Construction-2005/IMG_1442.sized.jpg
http://www.etudiants.polymtl.ca/fsae/gallery/albums/Construction-2005/IMG_1443.sized.jpg

We then waxed the plug and applied PVA, gelcoat and a few layers of fibreglass to get a mold.

http://www.etudiants.polymtl.ca/fsae/gallery/albums/Construction-2005/fs006.jpg
Our mold wasn't nearly stiff enough, but as we ere doing only one part that is not that critical, it worked well nonetheless.

After that, we built the actual parts out of carbon fibre. The major error we did was to build the body in one part. It's very difficult to do correctly. The vacuum bagging was a nightmare and it is not really practical to handle a single piece of bodywork. I don't recommend it.

Here is the finished product:
http://www.etudiants.polymtl.ca/fsae/gallery/albums/Lancement-05/IMG_1511.jpg

[Matt Gignac]

We did more or less the same thing as Poly, except for printing out sections of the body, we printed out cross-sections at every 2" longitudinally, which we then glued to either side of a 2" thick foam insulation board (they're always maybe .050" under 2", but the glue should make up for it), and hotwired. Doing this took a LOT of sanding out of the process, as the shape was very close after this step

Matt Gignac
McGill Racing Team

[rjwoods77]

I was thinking of vacumm forming plastic sheets after nearly falling over when i saw ETS mini-bajas' video. We are looking into it right now. Very cheap and very esay to make a ton of panels.

[kwancho]

Link?

[Korey Morris]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Rob Woods:
I was thinking of vacumm forming plastic sheets after nearly falling over when i saw ETS mini-bajas' video. We are looking into it right now. Very cheap and very esay to make a ton of panels. </div></BLOCKQUOTE>

I'd like to know more about what they did. Anyone have info?

Side note... Anyonle else see them on monster garage?

[RiNaZ]

i dont think rob meant the discovery video. Maybe it was something that he saw on ETS website or something. I could be wrong though. But ive seen the show, i didnt see any vacuum baging goin on.

[Didier Beaudoin]

That is the video Rob is referring to:
http://www.mec.etsmtl.ca/club/minibaja/media/2005/film/2005Baja.wmv

[rjwoods77]

Does anyone have that ets video from discovery channel? I still want to see it.

[drivetrainUW-Platt]

my hard drive crashed, so I no longer have it sorry Rob

I'm still looking for the Cornell jet engine built out of a turbo that was mounted on a pedal bike.

[RiNaZ]

hey rob, try checking out your local listing and see maybe they'll show a rerun on it. I think i saw them twice now on discovery. But i dont think you're missing anything much. It's pretty much an intro to mini-baja condensed in 10 min. And plus, some gay dancing at the end http://fsae.com/groupee_common/emoticons/icon_smile.gif.

[Chris Boyden]

Awesome video,
that 2 speed? gear box is cool,
nice work. I love watching it pass people on water,that's pretty cool. The body work
is definetly about 10 times faster than a layup.

[rjwoods77]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Chris Boyden:
Awesome video,
that 2 speed? gear box is cool,
nice work. I love watching it pass people on water,that's pretty cool. The body work
is definetly about 10 times faster than a layup. </div></BLOCKQUOTE>

Hi,low, neutral box. ETS is one of a few teams that have gotten their "thruster" design right. Once ETS got those designed right it was all over. I think there is only 3 teams that can keep up with them. Those guys are just juggernaughts. But their car really isnt all hat complicated. They have a lot less suspension travel than the average baja. They arent super light weight weight like some other teams. Just well developed car with great team behind them. I know some other guys on other teams that do well in the water and those team have been clocked at 10mph in the water. That is just awesome for using the tires as paddlewheels.

[Chris Boyden]

How thin are you going with the plastic sheets? if you don't mind me asking.

[rjwoods77]

Dunno really. Havent have an opportunity to test. The nice thing about the vacumm forming idea is that the plug/mold that you make will be defined by the inner surface, and the outer surface is just an offset of that inner surface, so once the plug/mold is made you can just try it out with one thickness and keep walking it back to where you want it. It is also dependant upon what the material is too. My personal take on things: the body cant be thin enough. The body is purely cosmetic since it isnt used for armor so who cares how thin is is. Depends on what you are looking for. I suggested doing a dope tension fabric or a snap on tonno(spelling?) cover like in trucks beds but everyone looked at me weird. Since the body doesnt do anything but add weight, a ton of fab hours and other general hassles I prefer to make it is easy and light as it can be. Obviously the car has to look good so there is the comprimise but i am a big fan of exposed spaceframes (ala Ariel Atom) so i wouldnt even have a body if i didnt have to. The coolest part of the car and it gets all covered up. What a shame.

[Chris Boyden]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">[quote]I suggested doing a dope tension fabric or a snap on tonno(spelling?) </div></BLOCKQUOTE>

That's a pretty good idea IMHO, but hey I also would like to see the frame blued or a very lightweight coating like black oxide, not 5 to 10 pounds of powder coat.

A velcro or snap system with a spandex/elastic fabric that stretches tight would be light and easy. We used lizard skins (I think that's right) for our coil overs in '04. They were a nice way to protect the coil overs from brake dust and debris and they were just spandex/elastic fabric with velcro. Although that has nothing to do with body work, velcro is a lot easier than those damn dzus fittings.

The aircraft fabric is cool, just more delicate than alloy sheet or glass/carbon fiber composites. Spandex would would definitely be a flexible and forgiving alternative....just difficult to put your stickers on.......and it may look a little weird....very light weight though.

[rjwoods77]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Chris Boyden:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">[quote]I suggested doing a dope tension fabric or a snap on tonno(spelling?) </div></BLOCKQUOTE>

That's a pretty good idea IMHO, but hey I also would like to see the frame blued or a very lightweight coating like black oxide, not 5 to 10 pounds of powder coat.

A velcro or snap system with a spandex/elastic fabric that stretches tight would be light and easy. We used lizard skins (I think that's right) for our coil overs in '04. They were a nice way to protect the coil overs from brake dust and debris and they were just spandex/elastic fabric with velcro. Although that has nothing to do with body work, velcro is a lot easier than those damn dzus fittings.

The aircraft fabric is cool, just more delicate than alloy sheet or glass/carbon fiber composites. Spandex would would definitely be a flexible and forgiving alternative....just difficult to put your stickers on.......and it may look a little weird....very light weight though. </div></BLOCKQUOTE>


Bet you nobody has thought of this one. Copper plating with a clear coat of two. That would look so sick. Make the fuel tan look like an old steam boiler. Brake balanace adjustment knob look like a valve knob for a water line. Think espresso machine pulling 2 g's.

[Chris Boyden]

you're crazy man,

That sounds like an old school Jules Verne style of race car. Imagine the Wisconsin aluminum mono in copper.......nice. While your at it, you can get the EE's to integrate the circuit board as part of the chassis. That would look really modern and make one hell of a chassis ground and no stupid wires, just a few connectors.

[RiNaZ]

I love seeing that ETS car have a go at the rest of the competitors. I was there at the east comp. but didnt drive coz my feet wont fit in the cockpit.

But boy that competition was fun! Maybe we can have the same side to side racing in formula and forget about all the complaints about unfair judging http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

hey rob, were you there at the comp? i was too busy to go around looking at other cars, so not sure how your team turn out.

[drivetrainUW-Platt]

ETS was kickin some major ass at the Midwest competition I went to, till they rolled it like 5 times going over a big hill, not sure if they got it going again after that

[kozak]

what hill was it cuz i flipped someone by "accident" on the back stretch. and that trach was so fun i can't even explain it.