Why does fixing a dent in a bumper require the removal and repainting of the entire bumper?



Why does fixing a dent in a bumper require the removal and repainting of the entire bumper?

In: Engineering

It doesn’t really but if you don’t repaint the entire thing to the nearest seam you will be able to see the repair.

The main reason is that when the paint is damaged it’s not recommended to paint only one area. The paint work will be extremely obvious. Typically when painting anywhere on a car, you need to paint surrounding panels as well. It’s called blending and there is no really good way to do it in just one area. Bumpers however are the exception as they are typically plastic versus the other areas on the car which are painted metal. The bumpers on colored cars are almost always a shade or two different from the rest of the car.

Sometimes dents can be pulled and repaired without repainting but it depends on the shape and depth of the dent. I have a friend who does this for a living. If you have to paint however it’s way easier just to paint the whole bumper because of many reasons including that paint ages and changes color as it gets older. The cost of the paint is irrelevant. Once you prepare a paint gun for spraying it’s 5 minutes to paint an entire bumper. The cost is always in the prep work.

Matching paint is a bitch. It’s much easier to camoflage if you re paint a whole section rather than just one spot. Your eye has a harder time making a distinction between the two shades if the areas are both larger.

Thank you everyone for your comments! I finally understand it now

It’s doesn’t.

But matching and blending the paint to be seamless takes way more labor (ie costs more) than just painting the whole thing. The materials are cheap, skilled labor isn’t.

Depends on the kind of dent you have. The methods used to pull them out and correcting the surface are fairly rough and violent. There are many different ways you can do it, but none of them are particularly kind. The paint will suffer, and if it won’t come off now, it will start to come off after it leaves the shop.

There’s a few reasons. The first, and most important is that when dealing with insutrance they have an obglation to bring the vehicle to the condition it was before the accident. That means that the resulting repair must be flawless.

If you are repairing your own bumber and are willing to accept something less than flawless than you can get it done for quite a bit cheaper.

So lets understand something. What you call a number is actually a bumper cover. It’s a large piece of plastic or fiberglass that has been painted. The actual bumper is made of metal and is under the bumper cover.

When a bumper cover is dented or damaged in any way there’s a few concerns. First is that the plastic under the paint has cracked. The plastic is not actually very flexible and tends to crack rather than just bend or dent. If you just paint over this, the vibrations from the car will cause the paint to crack over and over.

So you sand away all the old paint and can now see the cracks underneath. Depending on how large the cracks are, you may or may not be able to repair them with some kind of bonding material. If the cracks are to large, the whole bumper cover needs to be replaced. If the cracks can be repaired then it’s possible to save the bumper cover.

An insurance company will often replace a bumper cover if there’s even a hint of a crack in it. A do it yourself type job looking to save money can repair a lot of cracks that insurance companies would demand a replacement for.

So the bumper cover is now repaired or replaced and now you need to paint it. The problem is, the paint on your car has been faided in the sun form what it was at when the car was brand new. So even if you use the exact dealers paint there will be a slight paint mismatch.

In addition, auto paint is actually 2 (or more) layers of colored paint and clear coat on top. You can’t just paint colored paint on top of clear coat and expect it to look OK. So painting a small section is very hard because at the edges there will always be overlaps on the colored paint layer and the clear coat layer.

It CAN be done, but it requires some advanced painting techniques that actually take longer than just painting the whole damn bumper cover. So when being done to insurance company standard it’s actually cheaper to paint the whole panel.

In addition to this paint, you are still going to be able to notice a slight color mismatch where one panel meets another. So sometimes they do a little feathering around those edges so that the paint translation is not as stark.

But again, if you are doing a DIY job, you might settle for “good enough” and that’s a totally different standard than what an insurance company is going to do.