Overland Build

Midwestdrifter

Engineer In Residence
Why don't you use stainless steel screws?
The screws are screwed into aluminum. Stainless steel would cause the underlying aluminum to corrode instead of the sacrificial screw. It's much easier for me to replace the screws that is to replace the aluminum brackets. I typically get about 7 years or so before the zinc coating on the screws is exhausted and need to replace them.

Also stainless self tapping screws have a tendency to shear off due to their low tensile strength.
 

filmcan99

Well-known member
The screws are screwed into aluminum. Stainless steel would cause the underlying aluminum to corrode instead of the sacrificial screw. It's much easier for me to replace the screws that is to replace the aluminum brackets. I typically get about 7 years or so before the zinc coating on the screws is exhausted and need to replace them.

Also stainless self tapping screws have a tendency to shear off due to their low tensile strength.
Ahh! Yes, Galvanic Corrosion... Maybe use stainless machine screws with nyloc nuts and nylon insulating washers? Always use a good anti-seize compound when assembling stainless fasteners.

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Midwestdrifter

Engineer In Residence
Ahh! Yes, Galvanic Corrosion... Maybe use stainless machine screws with nyloc nuts and nylon insulating washers? Always use a good anti-seize compound when assembling stainless fasteners.

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As long as there is any electrical contact there will be a galvanic cell. But as you say there are methods to mitigate it. Anodizing, insulating washers, etc.

In my case it was way simpler to just plan on replacing 10$ of hardware every 5-7 years.

I used a handful of stainless fasteners on the solar array just to see. When I removed them after 7 years there was quite a bit of aluminum corrosion at the contact points. The zinc plated steel rivnuts had none for comparison. The zinc plated screws had no zinc on the exposed bits, but the aluminum interface still had some zinc present.
 

rollerbearing

Well-known member
Stainless galvanic corrosion can sometimes really get you. One of the ships I worked on flooded the engine space (at dock fortunately) because at some point someone had removed a bit of thru-hull instrumentation and replaced it with stainless plugs which eventually corroded the surrounding area out.

The exhaust ports of Epars commonly corrode badly from the outside - I believe because of the stainless exhaust piping.
 
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RVBarry

2023 AWD 170 DIY CamperVan
Snapshot of the battery at 79% soc traveling down the highway at 40F ambient. Steady state conditions, headlights on. So much for alternators melting down if you max them out. :p: As the engine bay warms the alternator output will drop, at 100f ambient it will be 145A at the same speed.

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That's Torque Pro, right? What's it reading data from?
 

Roamers

2020 4X4 170 Crew
As long as there is any electrical contact there will be a galvanic cell. But as you say there are methods to mitigate it. Anodizing, insulating washers, etc.
Sorry to infringe on this string, but I have a similar decision to make and no experience.

I'm using quarter round 8020 for the perimeter of my solar rack. Using the attached bracket for corners (cast zinc); joint will be covered with decorative plastic cover. Choice of fasteners is SS or zinc plated steel. After reading these last few posts, plated appears to be better choice than SS, but my concern in damaged plating allowing rust on fastener with potential than for rust drips on roof.

Although 8020 is anodized, the threaded hole obviously isn't. How bad of an idea is it to use SS fasteners? Should I be less concerned about rusting zinc plated steel hardware?

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Midwestdrifter

Engineer In Residence
After 5 years the Dometic 972 portable/cassette toilet has started to leak from one of its seals. Not surprising, and given its cost, a replacement was ordered.

My torque converter oscillation when cold has started to get worse, so I guess dropping the transmission valve body is on the list before winter this year.

The accelerator pedal mismatch code has started to return whenever I mash the accelerator to overtake someone. I ordered a used replacement from KC sprinters. New ones, when available, are something like 600$, which is fairly ridiculous.

Some van enabled whale time.

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ScottWCO

Active member
I ended up with 2 rivnuts each side on the upper frame member. I used those to mount a wood block which is flush with the back of the headliner. The aluminum angle in the picture below is attached to that block.

Woo replying to a post nearly nine years old :D

Curious about this bit and what you're describing. If the wood block is held against the sheet metal to the side, how do you have that aluminium angle iron attached? That metal piece looks like the vertical part of it is flush with the sheet metal. I don't follow the positioning of the two bits (wood block and angle) and why need for the wood block at all. Thank you!
 

Midwestdrifter

Engineer In Residence
Woo replying to a post nearly nine years old :D

Curious about this bit and what you're describing. If the wood block is held against the sheet metal to the side, how do you have that aluminium angle iron attached? That metal piece looks like the vertical part of it is flush with the sheet metal. I don't follow the positioning of the two bits (wood block and angle) and why need for the wood block at all. Thank you!
Hopefully this section view will clear things up. Its not to scale obviously. I counterbored for the bolt heads so they were below the surface of the wood in contact with the headliner.

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ScottWCO

Active member
Ahhh, the wood block is on the outside of the headliner, the aluminium angle is on the inside. That makes much more sense now, thank you!

I was trying to puzzle out if you had cut a slot in the headliner to allow the bottom of the angle iron to poke through... haha!
 

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