Tech Tip: Plastic Body Panel Repair (If You Dare)

Hey first gen fans, it's time to talk about one of the biggest issues with our favorite cars, the plastic body panels.  I don't know about you, but if I didn't love these cars so much, I would avoid them like the plague because of this issue alone.  I appreciate Honda's decision to keep the car light by using plastic body panels, but they weren't considering their enthusiasts 30 years down the road.  The sad thing is, when most people see first gen CRX with cracked, chipped, or missing body panels, they walk away, or worse, scrap the car altogether.  Since Honda no longer makes replacement body panels, and the few companies that did re-manufacture them aren't making them anymore, we're left with only a few options.  Heeltoe Automotive is a great option.  They manufacture front quarter panels, lower door panels, and rocker panels.  They are all well made out of fiberglass; a bit pricey, but a great option none-the-less (My own CRX sports Heeltoe fiberglass body panels).  Kevin Sousa also makes fiberglass panels including front quarter panels, a custom spoiler and nose panels.  But if you've priced out ordering new panels and have realized that they will cost more than what you paid for your car, there's still one last option, and that's repair the ones you have.

This is not an easy task because most of the factory plastics are very brittle and crack easily.  This tech tip will show you how to reinforce the plastic on the factory body panels, stop cracks from getting worse and show you how to repair smaller pieces that have already cracked off.

Panel Assessment:

There's no point in spending the time repairing panels that are so brittle, they will literally crack, or even shatter during removal or installation.  The simplest test is taking them off the car.  This is a strenuous task for the plastic parts and if they don't fall apart during removal, there's a good chance that they will qualify for repair.

Panel Reinforcement:

The best way to reinforce your panels is with fiberglass.  You can pick up some fiberglass mat (or cloth) and a can of resin at your local auto parts or hardware store.  While you're there, grab a box of heavy duty rubber gloves, and respirator (if you're working on this indoors).  Depending on how many panels you are going to be working on, you might have to find larger quantities of mat at a specialty store.

First, position your body panel with the inside facing up.  Next, lay out your fiberglass mat over the inside of the body panel.  Make sure you press the mat up against back of the panel so you can confirm whether or not you have enough to cover the entire panel.  With the mat covering the inside surface of your panel, trim the excess mat around the edge of the panel.  Leave at least 2 inches of mat, outside the edge of the panel to allow for mistakes or folds.

After you've prepared the fiberglass mat, remove it from the panel.  Then cover the inside of the panel with a layer of resin.  You can use a paint brush to apply the resin.

Once you've covered every inch of the panel in resin, take your mat and lay it over the fresh resin.  Position the mat back into its original position when your trimmed the edges, and then begin pressing into the resin.  Make sure the mat has been pressed into the resin across the entire panel surface.

Next, apply another layer of resin on top of the mat.

You may repeat this process (adding additional layers of mat) to increase durability, but keep in mind that the panel still needs to fit over the body.  If you make the panel too thick, you might have to go back and trim/sand the fiberglass back in order to reinstall the panel properly.

Once you've finished applying the mat and resin, allow to dry (see instructions on can of resin for dry times).  After the fiberglass has dried, trim back any mat or fiberglass that extends beyond the edge of the panel, and sand down any sharp edges.

This process should keep your panels in the game for a long time, but that doesn't mean you let anyone lean on the front of the car. :)

Panel repair:

If your panel has a section that has cracked off, and you still have that piece, all is not lost.  It is possible to reapply the broken piece, and here's how.

Before you start, you'll need to pick up some plastic weld, denatured alcohol, sand paper, a rasp, a file or wire brush, masking tape and a dust mask.  All of which your local auto parts or hardware store will have.

Start by 'roughing up' the cracked edge on both the loose piece and the panel with a file or wire brush.  Take the file or wire brush and drag it along the cracked edges at an angle (image the panel, or loose piece as the neck of a violin, and the file/brush is your bow.  Do this lightly because you don't want to take off enough material where the two pieces don't contact each other when pressed together.  You just want to round off the cracked edges.  This allows for the welding material to rest between the two plastic pieces.

Next, clean the two cracked edges.  Brush off any visible dirt with a dry rag and then wipe them down with denatured alcohol on another clean rag.

Then secure the loose plastic piece to the panel with painters, or masking tape, by taping one side.

On the side you haven't taped, apply your plastic weld.  Apply it liberally.  Make sure it's in the crack, and don't worry if there's excess amount of weld, you will be grinding it off later (at least on the outside of the panel).

Once the first weld is dry, take the tape off and weld the opposite side.

When both sides have dried and it feels secure, take a rasp and scrape the excess weld off the outside of the panel.  Make sure you don't take off any of the original plastic, the point of this step is to reduce sanding time.

Then with 220 grit sand paper (on a power sander, or sanding block), sand the weld down to the level of the original part surface.  Afterward, sand the surface again by hand with 600 grit or higher to smooth the plastic out.

Below is a repair I made to a factory body panel.  In this case, I did not have the piece that cracked off, so I used a Dremel tool to cut out a piece of plastic from another panel I wasn't using.  I shaped the piece with the Dremel tool to fit into the cracked panel. (Note, in the image below, you can see I had already applied some fiberglass strips to reinforce the panel.)

Above, I welded the part onto the panel, but then I had to eye-ball the shape from the opposite panel and draw it onto the new plastic piece.

I then took the Dremel tool and cut the plastic to match.

Here's what the final product looked like after a lot of sanding.  Turned out ok.  

So for those of you that are stuck between a rock and a broken body panel, I hope this posting gives you hope.  These are the cards we are dealt, so let's make some lemonade! ;)