Dents in Aluminum Skin Do Not Behave Like Dents in Steel

Steel stretches and returns. Push a dent into a steel van panel and the metal has stretched slightly; work it back and it largely returns, which is why paintless techniques succeed on cars so often.

Aluminum does not behave that way. It work hardens quickly, has far less elongation before it cracks, and once it is creased the crease is a permanent line in the material. On riveted aluminum skin, which is standard on many travel trailers and on Airstream style construction, a dent also loads the rivets around it, so the repair is not just the panel but the fastening.

Fiberglass does not dent at all in the metal sense. It either flexes and returns, or it cracks, or the laminate behind it debonds. A visible depression in a fiberglass sidewall that is not cracked is almost always a bond failure, which is delamination rather than a dent.

So the first thing that happens at intake is establishing what the panel is. That single fact narrows the repair options to two or three before anything else is considered.

Two questions decide it: can you reach the back, and is the metal creased.

Reaching the back is rarer on an RV than on a car. A car door is hollow. An RV sidewall is a bonded sandwich with insulation, framing, wiring and plumbing behind it, and interior cabinetry in front of that. On a cargo trailer or a van the interior may be open, in which case a technician can work from behind. On a laminated coach wall, that access does not exist without removing interior finish, and that removal is often more expensive than the alternative.

A crease is the second question. A soft, round dent with no sharp line has stretched the material gently and can often be worked. A crease has a fold line where the metal has yielded sharply, and worked metal along that line will never be flat again without filler, and on aluminum it may crack when you try.

Where pushing is not viable, the panel is either filled and refinished or the section is replaced. On aluminum skin, section replacement is common and clean, since the skin is fastened in defined panels and replacing one is a bounded job. That is panel replacement work.

Rarely in the metal work itself. On a straightforward dent the metal stage might be a couple of hours, and the rest of the job is everything around it.

Stage	What drives the hours
Access	Interior finish, cabinetry, trim or upfit equipment removed to reach the back of the panel, then reinstalled.
Metal or laminate work	Pushing, shrinking, sectioning or bonding. Fast on a good access job, slow on a crease.
Filling and blocking	Filler applied thin and blocked flat, repeated. On a large flat panel this is where a wave either disappears or does not.
Prime and block	High build primer, guide coat, block again.
Refinish and blend	Colour, blend into adjacent panels, clear to a natural break, then cut and polish.

That is why a dent the size of a dinner plate on a big flat aluminum trailer wall can carry more hours than a much uglier looking dent on a small van panel with a body line beside it to end the repair at.

Photographs and a couple of simple observations tell most of the story.

• Shoot the dent with light raking across it from the side, which shows the true shape far better than a straight on shot.
• Look for a sharp line inside the dent. A crease changes the repair path and the price.
• Check the rivets or fasteners around it for any that have loosened, popped or show a dark ring of movement.
• Look inside the vehicle at that spot for cracked trim, a lifted panel seam or anything that suggests the impact went through.
• Note whether there is a seam, a body line or a trim strip near the dent, since the nearest natural break sets where the refinish can stop.

Collision estimates are written at no charge and insurance walk ins are always welcome. Sibling work sits at fender and quarter panel repair and bumper repair and replacement. Bands are on the price sheet.