Fiberglass or vacuum molded grill plug?
 

I have a Toyota Yaris that I want to fabricate a grill block for. If you've ever seen the Yaris, it shouldn't be too hard.. I could theoretically just cut a piece of coroplast, zip tie it and be done, but I'm looking at it as an opportunity to try to make something asthetic as well as functional. What I'd like to end up with is a "plug" that I can sculpt to follow the body lines and in the end paint to match the car so that it appears factory. I don't think it would be terribly difficult for me to do (with a few tries) using some of the exemplary fiberglass molding instructions I've found kicking around on this site, and if I were careful and did a plug, then a mold from that, and finally laid up my final piece in the mold I'd be able to do a gel coat and hopefully get something that would look stock without too much effort. The tough part, I think, would be vacuum bagging it. That got me thinking, though. In my old model building days, I remember vacuum forming small parts such as this and it was super simple. In some cases, the plug I used remained with the vacuum formed part, so that the outside was mostly just a skin of plastic over my carved foam plug. I've never done anything larger than a small scale model part that way though, so I'd have to learn how to do it on a larger scale and make the equipment.

From those of you with experience and skill working with these sort of methods, which would more realistically accomplish my goal of a part that looks as though Toyota put it there having not much experience working with either? I understand my artistry would have something to do with the final result, but I'm talking about the relative merits of the methods.

I know most people would sculpt some foam to get the shape they want then just cover it with fiberglass and sand it out smooth .. Facume forming etc is probably above what people are willing to do .. but if you got the skills go for it .. its your project do it as you wish.. more power to ya..

Just take pictures to educate the rest of us

I would think fiberglassing a foam mold would be simpler than vacuum molding such a piece without having the proper setup. I can imagine using a shop vac and peg board for a MacGuyver'd up contraption, but unless you were planning on making more molded pieces for the car (or others) it might be more trouble than its worth.