Very good explanation.

Put any material between the parts and you're guaranteeing "loose" hardware. The galvanic corrosion is due to using "stainless steel" or zinc-dichromate hardware and/or shitty trailer/truck wiring and improper grounding of electric trailer brakes and lighting. With aluminum/steel "composite" trailers you must run "full" wiring to every electrical load and not just "ground" brakes and lights to the "frame" and count on the "ball" to ground the trailer to the truck. ESPECIALLY with "bolt-in" and/or "hide-a-ball". Back in the "good old days" when you'd weld a "plate" to the frame and weld the ball into the plate or at least have it threaded into a nut welded to the plate and incandescent bulbs were the only option and brake controllers were add-on accessories and trucks and trailers had "real" wiring, even aluminum trailers were "grounded" good enough to prevent galvanic corrosion providing the manufacturer had half a clue and didn't "cut corners" on materials substituting "shiny" hardware for "rust magnet" plain or phosphate steel. And they used actual BOLTS with NUTS instead of CAP SCREWS threaded into "weldments". There are hundreds of thousands of "composite" semi-trailers and especially livestock "pots" that hold up fine for decades and decades because they're engineered, built, wired and operated correctly from the word go and are pulled by tractors that are the same way. But there are also fly-by-night "shops" that perform shoddy or outright "wrong" inspections/maintenance/service/repair/parts replacement and either "discover" non-existent "problems" to "fix" and/or in the process of "fixing" actual "problems" create more problems and usually fail to "fix" anything correctly. "Horse people" and "RVers" in particular make good targets for crooked and/or incompetent "shops" because it's their "pets" and/or "loved ones" who they haul around the countryside and who "live" in those trailers anywhere from days to months per year. Any "trailer" that needs major structural repair and/or replacement really "needs" to be "scrapped" and/or returned to the manufacturer for "failure analysis" by the "engineers" who built it along with the owner/operator and tow vehicle for a "whole system" inspection and diagnosis. 90% of the time the real "problem" is "human error" in putting the trailer and tow vehicle into service originally and/or subsequent to some kind of "service" when the FIRST "symptoms" of the disease of improper "setup" show up. "Intermittent" or "insufficient" or "non-existent" trailer brake and/or lighting operation, blown fuses and/or tripping breakers and/or melted visible links and/or burned out flasher on the toe vehicle, etc etc etc. Any "shop" that used "Scotch-Lok" and/or common, cheap and "unsealed" electrical "connectors" and will "set up" a tow vehicle not factory-equipped or at least "factory equippable" to pull any given "trailer" using a strictly "plug and play" OEM/OEM-quality approach is highly likely to "discover" all sorts of "problems" with the "engineering" and/or "construction" of the trailer, tow vehicle or both "down the road".

Thank you the information, it is helping me out a lot. I cant really seem to find any information like this. When I research using the web all I get is Trump aluminum and steel. So finding your video was a surprise. Question I have "Does the aluminum corrode away first if the aluminum is against steel? Or do both metals equally corrode?". I'm new to working with metals so please bare with me. Working on my first pickup truck and I am currently fixing rust holes. I used aluminum pieces as a form to adhere bondo product, in which is new to me as well to clean up the rust holes. I am not really a fan of bondo but this is a band-aid until I can purchase quarter panels and learn to weld them on. I recently discovered that aluminum against steel is a no no. So will the aluminum go away first or will the steel? Thanks again, stay safe.

So your saying don't waste the money on a aluminum trailer but buy steel or a galvanized steel trailer ?

Could you put nylon shims in between all the contact points and then also use some type of sleeve over the bolts to avoid the corrosion from occurring or is the technology not there to do that in a cost effective manor?

I have some corrosion on the exterior panels of my 2011 Autumn Ridge, almost look like blisters. What could be causing that?

Hi! I need to replace some steel skin on my old trailer and i was able to get auminum for cheap..... i was gonna use pop rivets to put them on. So if i do that its gonna corrode a way? Any way to go about doing that with out corrosion?

Steel wins