Repair/Rebuild Prosport rear undercarriage

I started with West Systems epoxy which bonds well to the polyester resin parts but it takes some extra sanding to get polyester gel coat to cure over epoxy.  I now use polyester resin for all Radical body work because it is less expensive and gets the job done equally well.

I have never used carbon fiber for any repairs -- just glass mat and cloth.

The process that I use:

0. First I decide whether a repair is less work than fitting a new part.  I always use a new part if it is less work because I hate doing body work, however fitting a new part and adding vinyl wrap and graphics is often more work than a repair.

1. Get the torn pieces to fit back together well.  I usually use a box cutter to cut the torn mat so that the pieces go back together and are aligned.  Some times it takes some additional tape or pieces of aluminum sheet and temporary rivets to secure the pieces in place prior to laminating.

2.  On the side opposite of the gel coat, use mat and/or cloth to permanently join the pieces, providing sufficient strength and rigidity.

3. Make the gel coat side look nice.  Sometimes this requires some filler and resin first, followed with gel coat on top.  I use silica thickener and resin to fill deep areas.  Where possible, use a chemical bond -- that is, don't wait for the lower layers to fully cure before adding the next layer.

4. Add gel coat, sand, and polish.  It never looks like new, but is functional and is good enough for racing.  For a rear diffuser, I don't spend any time polishing.

I also had to recently do some repair work to diffuser panel.  While I was at it I painted the top side a light color (silver) and clear coated it.  It makes seeing and then cleanup of any leaks easier.  Notice I quickly found one

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