Materials Question

[Zerohour]

So I have this 2001 Subaru Outback Sedan, and I've decided to play ecobug for a while to see who much fuel sipping I can get out of it.

I see alot of people have modified bumpers and the sorts and I would love to do the same.

I've done some trolling unregistered and I know there is a Subaru Outback Wagon on patrol here as well.

My first big question is, what do you use to construct body modifications? Thin sheetmetal gets heavy fast. And you can't build everything out of cardboard.

I have fairly creative with fiberglass, but that stuff is nasty. I've also looked at vaccuum forming for smaller aero pieces, but I am under where to get the plastic sheets used.

I am wondering, what do all the cool kids build there aero bits out of?

[Patrick]

I think Coroplast is the #1 material. It's used a lot for making political and other temporary signs.

[aerohead]

Zero,you might consider making a working mock-up out of cardboard and masking tape and run it long enough to evaluate any contribution it might make.
Then,it it warrants it,you can commit to a permanent build.

[Zerohour]

Meh its hard to use cardboard when we're in the rainy portion of summer. It takes me about a week to use a tank of gas, and I would like to slap on 4 aero pieces in the first go. Well Five Aero pieces, 4 are fiberglass products (in my mind at least).

The coroplast seems like an interesting way to build forms for fiberglass though. I am wonder where is a good place to source or individual pieces? I did some quick search and I can buy it by the pallet, but thats a little excessive.

I also know there is a certain type of hobby plastic that works well for vacuum forming, but I need to look that up again. I think vacuum forming over some simple carved foam shapes will yield an item that is replaceable (stones, birds, jackass in parking lots). Not to mention lightweight as well!

[KamperBob]

Zerohour, you don't need to run a full tank. Think quick test. Coast down curves can give a good indication of whether a change is making any difference aerodynamically. ScanGauge (et al) also enable cost effective experimentation such as Darin's recent cross posts on mpg vs speed curves. My SG paid for itself Year 1 with fuel savings BTW.

Cheers
KB

[BamZipPow]

Check with yer local recycling place...they might have some coroplast they can give to you fer free.

I wonder how well fiberglass screen and the roll on bedliner stuff would do...

I've been using luan sheets as my lightweight, low cost, easy to git/work with material.

[3-Wheeler]

For me, foam/fiberglass is the only way to go most of my mods concerning bodywork.

Honda Insight Under-body Smoothing Panels (custom belly pan / undertray)

Jim.

[busypaws]

I used shrink-wrap plastic for my grill block. The stuff you buy in the fall the put on the windows in your house to make poor mans storm windows. It's attached with 3M double sided tape and then use the hair dryer to stretch it tight. $1.79 at home depot for enough to do one house window. Yes -- if you run through the car wash you have to replace it but it has lasted me over 6 months. (I don't wash my car)

[aerohead]

Originally Posted by Zerohour

Meh its hard to use cardboard when we're in the rainy portion of summer. It takes me about a week to use a tank of gas, and I would like to slap on 4 aero pieces in the first go. Well Five Aero pieces, 4 are fiberglass products (in my mind at least).

The coroplast seems like an interesting way to build forms for fiberglass though. I am wonder where is a good place to source or individual pieces? I did some quick search and I can buy it by the pallet, but thats a little excessive.

I also know there is a certain type of hobby plastic that works well for vacuum forming, but I need to look that up again. I think vacuum forming over some simple carved foam shapes will yield an item that is replaceable (stones, birds, jackass in parking lots). Not to mention lightweight as well!

A local library can provide directories for commercial business operations in your local.
Look for a business which deals with vacuum-formed ABS plastic sheet who will sell you small quantities.This sort of material is not sold retail and typically you must be a business to obtain it.It is sold by the pound.In 1986 it was about $2.35/lb.
An electric oven can be constructed at home,along with perforated wooden tooling affixed to a vacuum table.
A small air conditioning vacuum pump from a pawn shop can be used to charge an accumulator tank.A foot-operated air-valve will communicate the large volume of vacuum flow to the vacuum table.
Typically,the ABS is secured to a rigid framework,is pre-heated,then sent to the oven.When it achieves sag,it it quickly transferred to the table,quick-clamped down,all along it's periphery,then the valve is opened,drawing the plastic down over the tooling.
In about 30-seconds the part can be removed and taken to a router station where it is positioned over a trim-jig which guides the router,cutting away the flash.
Remember,you cannot have any straight,90-degree walls on your pattern.A certain amount of 'draft' is required for a proper 'release' after cooling or your part will stick.And freeing it can damage or destroy your precious tooling.

[Arragonis]

Lego.

After all Smart use it.