Aluminum skid plates + corrosion

[wkel23]

Curious what everyone else thinks. I’ve got a complete aluminum belly pan coming from artec. Should I be worried about galvanic corrosion where the skid plates meet the frame? I’m going to powdercoat the skid plates and obviously the frame is painted, but is paint alone enough to prevent it? Maybe stick something between the two? It will take years to rust, if it does happen, but I don’t plan on parting with my 392 like my defender 90.

 

[Earl 392]

Curious what everyone else thinks. I’ve got a complete aluminum belly pan coming from artec. Should I be worried about galvanic corrosion where the skid plates meet the frame? I’m going to powdercoat the skid plates and obviously the frame is painted, but is paint alone enough to prevent it? Maybe stick something between the two? It will take years to rust, if it does happen, but I don’t plan on parting with my 392 like my defender 90.

There will be no current flowing between the frame and skid plates so you won’t have any issues. IMHO.

 

[Huckle Monster]

There will be no current flowing between the frame and skid plates so you won’t have any issues. IMHO.

No need for current to flow. See plumbing.

Of course I'm a dumb contractor so could be wrong.

 

[wkel23]

Good point on no current flow. Forgot about that. Thanks!

 

[Keithbickford]

There will be no current flowing between the frame and skid plates so you won’t have any issues. IMHO.

Galvanic corrosion does not occur where there is electrical current from an electrical circuit, although it can occur in circuits. Galvanic corrosion occurs due to electrical current between two dissimilar metals. The difference in materials causes the current. For example, Galvanic corrosion occurs at the top of Fox 2.5 DSC shocks between the aluminum adjuster knobs and the steel ball bearings used for the clickers. Definitely no current flowing there.

 

[Keithbickford]

No need for current to flow. See plumbing.

Of course I'm a dumb contractor so could be wrong.

Correct

 

[Keithbickford]

Curious what everyone else thinks. I’ve got a complete aluminum belly pan coming from artec. Should I be worried about galvanic corrosion where the skid plates meet the frame? I’m going to powdercoat the skid plates and obviously the frame is painted, but is paint alone enough to prevent it? Maybe stick something between the two? It will take years to rust, if it does happen, but I don’t plan on parting with my 392 like my defender 90.

I don’t have any working knowledge of corrosion on skid plates, but it seems to be a valid concern. As you mentioned, galvanic corrosion occurs anywhere to dissimilar metals are brought together. Different metals have different electrical properties and electrical charges, and current will flow between them. Moisture between the materials helps complete the circuit and exacerbates it.
Painting and powder coat will certainly help. My questions are: will flex cause the paint and powder coat to break down overtime? Eventually I assume. If so, will mud and moisture get between the two surfaces? If so, could it result in corrosion.
It might be worth having a conversation with ARTEC. They may settle your concerns, or perhaps you will enlighten them. Where there’s an issue, there’s always a solution. Perhaps a ground strap between the two? Perhaps just periodic inspections. No need to engineer a solution for a problem that doesn’t yet exist.

 

[Earl 392]

Galvanic corrosion does not occur where there is electrical current from an electrical circuit, although it can occur in circuits. Galvanic corrosion occurs due to electrical current between two dissimilar metals. The difference in materials causes the current. For example, Galvanic corrosion occurs at the top of Fox 2.5 DSC shocks between the aluminum adjuster knobs and the steel ball bearings used for the clickers. Definitely no current flowing there.

The very definition of galvanic corrosion is the electrochemical process where an accelerated corrosion of one metal occurs when it is in electrical contact with a different metal in the presence of water or moisture. Water ,salt ,mud often finds it self working in between the frame and skids where some corrosion will start.
I need to remove my skids to lube the front drive shaft (pain in the ass) no corrosion yet but I do clean them and the frame plus wipe all surfaces with whatever open container of oil I have left usually 40 wt. left over from VW. days

 

[wkel23]

I did some research so I better understand how galvanic corrosion occurs. From what I saw it requires dissimilar metals, electroylyte (rainwater, mud, salt), and electrical flow meaning electricity can flow between them, not an active electrical current. It still leads me back to my original question, is powder coated skid plates and a painted frame enough to break the electrical current and prevent galvanic corrosion. I also learned the aluminum corrodes not steel. I thought it was the other way around so now I’m not as concerned since it’s not the frame that would get damaged but the skid plates

 

[Earl 392]

I did some research so I better understand how galvanic corrosion occurs. From what I saw it requires dissimilar metals, electroylyte (rainwater, mud, salt), and electrical flow meaning electricity can flow between them, not an active electrical current. It still leads me back to my original question, is powder coated skid plates and a painted frame enough to break the electrical current and prevent galvanic corrosion. I also learned the aluminum corrodes not steel. I thought it was the other way around so now I’m not as concerned since it’s not the frame that would get damaged but the skid plates

Steel is a better skid plate material it will slide over rocks much better than aluminum . As aluminum will gall and hang up . Over time paint and powder coated skids will wear off from grit and flexing they will have contact.

 

[Keithbickford]

The very definition of galvanic corrosion is the electrochemical process where an accelerated corrosion of one metal occurs when it is in electrical contact with a different metal in the presence of water or moisture. Water ,salt ,mud often finds it self working in between the frame and skids where some corrosion will start.
I need to remove my skids to lube the front drive shaft (pain in the ass) no corrosion yet but I do clean them and the frame plus wipe all surfaces with whatever open container of oil I have left usually 40 wt. left over from VW. days

Steel is a better skid plate material it will slide over rocks much better than aluminum . As aluminum will gall and hang up . Over time paint and powder coated skids will wear off from grit and flexing they will have contact.

Hi Earl — good research, and you’re mostly on the right track. A few clarifications that may help.

First, a small terminology point: flow is current. There doesn’t need to be an external power source or “active electricity.” When you put two dissimilar metals in contact, you’ve already created a voltage (a difference in electrical potential) between them. Once an electrolyte is present (water with minerals, mud, road salt, etc.), that voltage drives electron flow — that electron flow is the current.

Think of it less like household wiring and more like a tiny battery that forms naturally. The metals themselves create the voltage; the electrolyte just completes the circuit.

Regarding coatings: powder coating on the skid and paint on the frame can significantly slow galvanic corrosion, but only as long as the coating remains intact. Any scratch, bolt hole, compressed area, or fastener that breaks through the coating can re-establish electrical contact and allow corrosion to start locally. That’s why isolation washers, gaskets, or non-conductive spacers are often used in marine and aerospace applications — they’re there to maintain electrical isolation even when coatings get damaged.

You’re also correct that in a steel–aluminum pairing, aluminum is the anodic material, so it corrodes preferentially while the steel is protected. That said, “less concern” is relative. Aluminum corrosion can still be an issue over time — especially around fasteners — and the corrosion products can swell, loosen bolts, and trap moisture, which can create secondary problems for the steel nearby.

So in short:

• Dissimilar metals create the voltage
• Electrolyte completes the circuit
• Electron flow (current) causes corrosion
• Coatings help, but aren’t a permanent guarantee
• Aluminum corrodes first, but that doesn’t mean the system is problem-free

None of this means aluminum skids are a bad idea — just that isolation and good installation practices matter if you want them to last long-term.

As another user pointed out, aluminum gets dinged up and becomes resistant to sliding. That’s what ARTEC makes their special surface material.

 

[Earl 392]

Hi Earl — good research, and you’re mostly on the right track. A few clarifications that may help.

First, a small terminology point: flow is current. There doesn’t need to be an external power source or “active electricity.” When you put two dissimilar metals in contact, you’ve already created a voltage (a difference in electrical potential) between them. Once an electrolyte is present (water with minerals, mud, road salt, etc.), that voltage drives electron flow — that electron flow is the current.

Think of it less like household wiring and more like a tiny battery that forms naturally. The metals themselves create the voltage; the electrolyte just completes the circuit.

Regarding coatings: powder coating on the skid and paint on the frame can significantly slow galvanic corrosion, but only as long as the coating remains intact. Any scratch, bolt hole, compressed area, or fastener that breaks through the coating can re-establish electrical contact and allow corrosion to start locally. That’s why isolation washers, gaskets, or non-conductive spacers are often used in marine and aerospace applications — they’re there to maintain electrical isolation even when coatings get damaged.

You’re also correct that in a steel–aluminum pairing, aluminum is the anodic material, so it corrodes preferentially while the steel is protected. That said, “less concern” is relative. Aluminum corrosion can still be an issue over time — especially around fasteners — and the corrosion products can swell, loosen bolts, and trap moisture, which can create secondary problems for the steel nearby.

So in short:

• Dissimilar metals create the voltage
• Electrolyte completes the circuit
• Electron flow (current) causes corrosion
• Coatings help, but aren’t a permanent guarantee
• Aluminum corrodes first, but that doesn’t mean the system is problem-free

None of this means aluminum skids are a bad idea — just that isolation and good installation practices matter if you want them to last long-term.

As another user pointed out, aluminum gets dinged up and becomes resistant to sliding. That’s what ARTEC makes their special surface material.

I agree electrolysis is really more the terminology with current flow and dissimilar metals say copper and aluminum. That is really my background.
I don’t think a steel frame and aluminum skids painted ,powder coated or not would make much difference