Stretchy fabric bumper cover?

[Red Lion]

http://www.youtube.com/watch?v=kcs1hz8z-9k

The video was posted in THIS THREAD and got me thinking about mocking something up with fabric that could easily stretch around the front bumper and hold in place for easy removal, instead of corrugated plastic or cardboard covers. It would have a sort of inner skeleton to keep it in a certain shape (like a tent has), but it could easily be removed and packed away when not needed.

Thoughts? Good idea, bad idea? Here's an idea of what my car looks like:


Any ideas on what type of fabric to use? It'd have to be something that is dense enough and rigid enough to not let air through easily, but at the same time light enough and cheap enough to make it worthwhile. It should probably be water resistant too for rainy weather so it doesn't retain weight.

[Bicycle Bob]

You can buy spandex by the yard at fabric stores, and get quite a bit more by stretching it. To get it to bulge a bit, put some cardboard behind it, and shoot in some insulation aerosol foam. Pat it down as necessary as it cures. With or without the foam, a coat of resin firms it up, and then you can add layers of fiberglass to get what you want.

[blueflame]

Canoes have animal skin and canvas(hemp) stretched over lightly built wood skeleton frames. Great canoes to use I believe, really light. Great idea!

I'm thinking no frame just stretched across existing bumper top and bottom radius. How to make it very stiff? epoxy or polyester or corn resins and hemp for the greenies

[cfg83]

Red Lion -

I am trying to figure out how the "skeleton" would be stored. I imagine something like an umbrella or one of those unfolding outdoor canopy tents :



However, in your case the geometry is much more complex. A bumper *is* similar in shape to a canoe, so maybe blueflame is implying your tent structure.

For a 1.0 version, I wouldn't think in terms of an inner skeleton. I would combine Bicycle Bob's and blueflame's suggestion. I would get spandex and see how it stretches over the shape of your bumper. Kind of like a car bra, but without the emphasis on form-fitting.

This is not a stow-away option, but as someone else suggested, getting a used bumper and turning it into an aero shape is a great idea. That way you can keep your original bumper in storage while making as much of a mess as you want with your aero-bumper.

CarloSW2

[Christ]

Depending on what fleece you get, it's usually only stretchy in one direction. I have to imagine that's what was used in that video, since it's a pretty normal use for polyester fleece.

A little polyester resin will set it permanently, if you want to hold the shape. You can make a frame to the shape you want out of any tough wire, or thin strips of wood. You can lay wax paper over any area you don't want the fabric to stick to once you apply the resin to it. Afterward, application could be as easy as dzus fasteners in strategic places, and removal would be just as easy.

This is how really cheap body kits are made in your driveway, BTW. You can make the frame out of chicken wire and put papier mache over it, as well, which will keep a better visual of the final shape until you put the fabric on it.

Not sure how permanent of a mod you want to make, though.

[Christ]

Just watched part of the video... seems like they're using lycra? or some nylon-type fabric. I have no experience with using those for fiberglass techniques, other than dacron as a peel-ply...

[Red Lion]

Originally Posted by cfg83

Red Lion -

I am trying to figure out how the "skeleton" would be stored. I imagine something like an umbrella or one of those unfolding outdoor canopy tents :



However, in your case the geometry is much more complex. A bumper *is* similar in shape to a canoe, so maybe blueflame is implying your tent structure.

For a 1.0 version, I wouldn't think in terms of an inner skeleton. I would combine Bicycle Bob's and blueflame's suggestion. I would get spandex and see how it stretches over the shape of your bumper. Kind of like a car bra, but without the emphasis on form-fitting.

This is not a stow-away option, but as someone else suggested, getting a used bumper and turning it into an aero shape is a great idea. That way you can keep your original bumper in storage while making as much of a mess as you want with your aero-bumper.

CarloSW2

I think you're right, I should do a 1.0 version and just test it out before I attempt to make the skeleton to go with it. Luckily (or not?) the guy that had my car before me had tore up the front bumper to fit an intercooler there (something this car won't see again), so I need to replace it anyway and I can play around with it.

Originally Posted by Christ

Not sure how permanent of a mod you want to make, though.

Just watched part of the video... seems like they're using lycra? or some nylon-type fabric. I have no experience with using those for fiberglass techniques, other than dacron as a peel-ply...

I'm not sure what they used in the video but searching around, it sounds like if I want to use a cheap, stretchy fabric maybe lycra is the way to go since it can stretch in four directions instead of just two.

As far as permanence goes, I kind of want something I can wrap the bumper in for highway driving and take off for city driving or auto-x, hence the idea of something I could easily stretch around the bumper and take off quickly.

[TomO]

There's always MonoKote.

[Red Lion]

^I'll look into that too!

[moorecomp]

As an airplane mechanic, I suggest dacron like this:

DACRON FABRIC <BR>FOR HOMEBUILT AIRCRAFT from Aircraft Spruce

Glue it in place with fabric cement that you can find on that sight too. Then heat shrink it up nice and tight. Seal it and paint it for a good looking finish!