Im gathering the material to diy a supermiata s2 style front bumper. I've read the other threads, but they more focus on the thickness of the undertray to handle operating as a splitter. With the S2 style front end nothing is cantilevered past the air dam. My local Home Depot, lowes, and 84 lumber motorsports shops all carry 1/4" birch and 1/2" birch. Several recommendations say 3/8 is the way to go, but I can't find it locally. Will the 1/4" hold up in this application? Maybe add some aluminum angle to stiffen? Or do I need to go 1/2"? Any other cheap options?

 

3/8 Birch fine for undertray.
If extending into a splitter, 1/2". If it doesn't support your weight, add struts.
10mm Alumalite can be run out to 5" without struts on some cars.

 

It's great to get info on this.

Wingnut.