How to Repair RV Auto Body Damage?

The most common materials used in RV construction are wood, aluminum, or steel. The smaller-sized motorhomes are mostly built using wood, but this material has a weakness in the form of termites. You can’t expect them to last a lifetime, which is why wooden trailers are quite rare nowadays.

On the other hand, steel is strong and has no apparent weakness except corrosion, but it is too heavy and adds a lot of weight to the structure. It is unfeasible; hence not many manufacturers use it for an RV’s frame.

The most common material nowadays is aluminum, which companies use to build motorhomes. It is lightweight and sturdy enough to support the RV on its weight. However, aluminum, wood, or steel are only used in the frame’s construction. The outer body of an RV is made of Fiberglass, which is extremely lightweight and moldable.  

However, fiberglass material is prone to damage, as it cannot withstand too much force or the sun’s radiation. Sometimes it bends out of shape, but it can also break into pieces on impact. When that happens, you must repair the RV at the first possible convenience.

How To Repair Small Cracks?

Fiberglass cracks easily when exposed to too many UV rays or if it is hit hard with something. If the damage is small you can repair that with a special material called fiberglass Bondo. The material expands in the affected space and covers all the cracks and openings on the body. It is waterproof, which protects the RV’s frame from corrosion or damage.  

However, there is a drawback with this quick and easy fix. The fiberglass Bondo filler doesn’t work too well when you apply it to a large area. The fiberglass constantly shrinks at colder temperatures, and then cracks start to appear on the edge of the space where you apply the filler. Subsequently, water starts to seep in, and more unnecessary damage occurs.
You use an angle grinder to grind out the coating just a little bit. But make sure you don’t go too deep, or you would hit the frame. Once you are done, the affected area would be lower than the fiberglass surrounding it. That’s good because in that hole you will place a fiberglass mat.
The next step would be to cut the fiber mat to the same size as the hole. Then, you cut a piece that goes on top of the edges, and then another that goes beyond.
When all the pieces are cut and kept aside, you will need to make a mixture of fiberglass resin and hardener. You need eighteen drops of hardener for an ounce of resin liquid, so keep that in mind. Then, you will use an acid brush or a regular paint brush to apply the coat.
Use the brush to apply the resin to the affected area and place the first piece of mat on top. Follow the same process for the second and third pieces of fiberglass mat. Now you should leave the area to dry for an hour or two.
Use the angle grinder again to smooth out the affected area and, on top of that, a high-grit sander to perfectly prepare the area for the following procedure.
You need polyester filler for this next procedure. Again, you have to add a hardener to the filler, but this time of a different kind. Polyester takes a cream hardener, so you need to mix it using an auto-body spatula.
Quickly apply the polyester over the affected area and ensure you even out the spread. Once that is done, you should use a 180-grit sander to smooth the surface.
It is time for the primer, which you will apply in the affected area to prepare for the paint.
It is time to apply two coats of clear coat followed by three coats of paint. This allows the paint to set in and the color to match the rest of the body.

Voila! You are done!

Now, you must be wondering, what do I have to do for a large affected area?

How to Repair a Large Damage Area?

If there is too much damage to the RV, then that means it’s not just the fiberglass that is affected. The frame holding the fiberglass in place is also damaged. For something like this, you would cut out the affected area and install a new piece. After that, you place a fiber sheet on top, followed by primer and paint.

It is that easy!


Yes, if you have the expertise to undertake such a repair job.

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Ever since I was a kid, I've been fascinated by travel. I inherited this passion from my parents. Since my college years and to this day, I have had a passion for traveling in a motorhome. I am here to share my experiences with you.

1 Comment
  1. Thanks for the reminder that it’s essential to also look into the coatings that will be used when planning to get RV body repairs. I’d like to get my RV repaired soon because I will be going on a couple of summer trips soon. I will be the driver on both instances so I have to make sure that my RV will be in its best condition.

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