Body Work
Rust and Corrosion Repair: Cost, Hours and Process in Hacienda Heights
Rust and corrosion repair addresses surface and cosmetic metal loss on an RV exterior: frame surface rust, filiform corrosion creeping under paint, galvanic attack where an aluminum panel meets a steel fastener, and pitting on bare aluminum siding. It is treatment and refinishing of sound metal, not structural replacement.
What brings this in
- Paint lifting in thin wandering lines rather than in patches, which is filiform corrosion tracking under the film
- White powdery bloom around every fastener on an aluminum panel, the signature of galvanic attack at a steel screw
- Orange staining running down a panel from a bracket, hinge or trim screw above it
- Flaking surface scale on frame rails and outriggers with sound metal underneath
- Pitting and a chalky grey surface on unpainted aluminum siding, worst on the sun facing side
- Corrosion inside a compartment door frame where the seal has been holding water against it
- Bubbling under a decal edge, where trapped moisture sits against the substrate
- Steel bumper tube scaling from the inside out, visible first at the underside seam
This job, by the numbers
$400 to $3,500
2 to 14 hours
RV systems estimate, $150. Covers slide, awning, water, electrical and generator. Credited to an authorized repair.
Parts and assemblies we work with
Lippert, Norco, Alpha Systems, Trim-Lok, Kwikee
Three different mechanisms, wrongly called the same thing
Owners describe all of it as rust and it is worth separating, because the treatments differ. Iron oxide on a steel frame, outrigger, bracket or bumper tube is ordinary rust, driven by moisture and time, and in this region it is usually surface scale over sound metal rather than section loss.
Filiform corrosion is the one owners find most alarming: fine wandering lines of lifted paint spreading from a chip, a stone strike or a fastener. It is corrosion tracking along the interface between the coating and the metal, and it will keep tracking as long as it has moisture and a coating edge to work under. Painting over it feeds it.
Galvanic corrosion is the RV specific one. Put a steel screw through an aluminum panel, add coastal humidity, and the aluminum sacrifices itself around the fastener. That is the white bloom around every screw on an older aluminum sided trailer, and it is why fastener material selection is part of any repair we do on aluminum rather than an afterthought.
- Steel frame, outrigger, bracket and tube scale, mechanically removed and coated
- Filiform corrosion under paint, coating cut back past the tracking to sound film
- Galvanic attack at dissimilar metal fasteners, isolated and refastened correctly
- Aluminum pitting and oxidation on bare siding, cut, refined and protected
- Corrosion inside door and window frames where a seal has held water against metal
- Underbody and chassis surface coating renewal
Why coating over corrosion always comes back
A coating is a barrier, not a cure. Corrosion under a film keeps a supply of moisture and oxygen at the interface, so a fresh coat on top gives it a sealed environment to keep working in. The repair that lasts removes it mechanically back to bright sound metal, past the visible boundary, because the boundary of what you can see is never the boundary of what is happening.
On steel that means abrasive removal, a conversion or etch treatment where appropriate, an epoxy primer that tolerates the substrate, and a topcoat matched to the exposure. Frame and underbody work gets a chassis coating rather than a body finish, because it is going to see rock strike and standing water.
On aluminum the sequence is different and the surface preparation matters more than the coating. Aluminum forms its own oxide immediately, so the window between preparation and priming is short, and a self etching primer is not optional. Getting that wrong produces a coating that looks correct for a year and then sheets off in a single piece.
What California actually does to a coach, and what to do about it
Inland Southern California is a low road salt environment, which is genuinely good news for frames. What this region does instead is UV and thermal cycling on coatings, plus marine humidity for any coach that spends time toward the coast. So the pattern here is not the rotted frame you see in the salt belt. It is coating failure, then localized corrosion wherever the coating opened.
The practical consequence is that the cheapest corrosion work is done at the coating stage, before there is metal loss. A chip in a frame coating treated this year is a small line item. The same chip in five years is scale removal, prep, primer and topcoat on the whole member.
The second consequence is fasteners and seals. Nearly every corrosion site we open on a coach body traces to a fastener penetration or a seal that stopped shedding water and started holding it. Where we repair corrosion, we address the water path that created it, because treating the metal and leaving the path means the same site is back in front of you in two years.
Cost, hours and the coverage question
The band on this page is 2 to 14 hours at $210 per hour, and it is one of the more predictable numbers on the program because the work is bounded by area. Body supplies run $5 per body hour and refinishing is quoted separately when the repair crosses into a finished body panel rather than a frame member.
Coverage is where we have to be blunt. Corrosion is a wear condition and carriers do not pay for wear. Where corrosion is the reason a covered repair costs more, for example a bracket area that will not hold a fastener during a storm damage repair, that portion is normally the owner's and we write it on its own line rather than burying it. That separation is also what keeps a legitimate claim clean.
The RV systems estimate is $150 and it is credited against an authorized repair. On corrosion it buys a real boundary: how far the affected area actually extends once the coating is cut back, which is almost always larger than what is visible and is the only number worth planning against.
Scope
What this line item does not include
- We do not treat over active corrosion. If it is not taken back to sound metal it comes back through the coating, so a cosmetic pass on a rusted member is not something we will sell.
- Frame members that have lost section are structural repair, not corrosion treatment, and are scoped and priced separately.
- Corrosion is a wear condition and carriers do not generally cover it. We do not write it into a claim as impact damage.
Being explicit about the boundary is faster than discovering it at pickup. If the work you need sits outside this line item we will say so at intake and point you at the right one.
Questions
Rust and Corrosion Repair questions
Why is the paint on my RV lifting in thin wandering lines?
That is filiform corrosion, tracking along the boundary between the coating and the metal from a chip, a stone strike or a fastener. It spreads as long as it has moisture and a coating edge to work under, so coating over it accelerates it. The repair cuts the film back past the tracking to sound material, treats the metal, and rebuilds the coating from primer up.
What are the white powdery rings around the screws on my aluminum trailer?
Galvanic corrosion. A steel fastener in an aluminum panel with moisture present makes the aluminum the sacrificial metal, so it corrodes around the screw. The correct repair cleans the site, isolates the dissimilar metals or changes the fastener material, and reseals the penetration. Left alone the hole enlarges until it no longer holds the panel.
Can rust on my RV frame be treated, or does the frame need replacing?
Most frame rust we see in this region is surface scale over sound steel, and that treats well: mechanical removal to bright metal, an appropriate primer, and a chassis coating rated for rock strike and standing water. A member that has lost section is a different scope entirely, and that is structural repair written and priced separately rather than a corrosion line item.
Will insurance cover corrosion repair?
Generally no. Corrosion is a wear condition and carriers exclude wear. Where a covered repair is complicated by existing corrosion, we split the file so the covered damage and the owner's corrosion work are separate lines. That protects the claim, and it means you are not paying a deductible on something that was never going to be covered.
How do I slow corrosion down on a coach stored outdoors here?
Keep the coatings intact and keep water off metal. Touch in frame and underbody chips the season they appear, keep seals rebounding so they shed rather than hold water at frames and brackets, and stop using steel fasteners in aluminum. In a low salt inland climate those three habits are worth more than any treatment applied after the fact.
Related work
Often done at the same time
$500 to $4,500
Bumper Repair and Replacement
Rear tube, fascia and cover repair or replacement on towables, van chassis and Class A caps.
$2,500 to $25,000 plus
Aluminum Skin and Sidewall Replacement
Riveted Airstream shell panels and stick built aluminum siding replaced by segment with correct rivet practice.
$500 to $3,500
Chassis and Underbody Respray
Frame, crossmember and underbody surfaces cleaned, rust treated and recoated with chassis grade protective finish.
$200 to $1,800
Compartment and Baggage Door Repair
Baggage door, hatch and access panel repair including hinges, struts, latches, locks and seals.
Get a firm number on rust and corrosion repair
The band on this page is honest, and the rv systems estimate at $150 turns it into a firm number. Covers slide, awning, water, electrical and generator. Credited to an authorized repair. We are 18.4 miles from Hacienda Heights.