Off topic E350 gutter rust polyurethane vs Tripolymer vs thermoplastic

[rebar]

Hello new here. I apologize for this "whats the best caulk" question, but figured people knowledgeable about the best caulks available on this cruiser forum might be able to help me make a decision.

I drive work vehicles, so I'm not concerned about how they look. But I recently rebuilt the cummins engine in my ford E350 tow vehicle, so Iv got allot of money wrapped up in it.

My problem is that even though the undercarriage is spotless since the van is from Florida, the rain drip edge gutter has some rust from the salt air.
I will wire wheel the gutter down to bare metal, treat with rust neutralizer, fill any holes with fiberglass patch, and prime and paint with POR-15. I would then like to fill the entire gutter full of exterior caulk with UV protection instead of auto-body seam sealer so that the gutter no longer collects water. The caulk I choose needs to be removable, because the gutter will rust again as this is a temporary fix short of cutting out and welding in new metal which I cant justify.

Can anyone recommend or educate me on the best, longest lasting removable caulks on the market for my painted metal application? Iv read Geocel 2300 (Tripolymer), solarseal 900 (Terpolymer), 3M4200(polyurethane), NP1(polyurethane), Vulkem 116(polyurethane), Sika Flex (Polyurethane), Dymonic (hybrid), Kop-R-Lastic (thermoplastic) are some good choices, but making a decision is difficult with so many products.

I noticed polyurethane caulks dominate my list so I'm guessing polyurethane must last the longest? I don't want silicone because of it's "wont stick to itself" and difficult removal properties.

Thanks!

[roverhi]

At least two coats of POR15 with a UV resistant topcoat should be all you'd need to protect the gutters. Would fear that laying in a caulk would just hide any rusted areas that develop. Any caulk that will seal won't be easy to remove. You'll have to scrape it out of there and sand off the remnants. The 'Debond' liquid may make removing 5200/4200 easier but have never worked with it and don't know if it will dissolves the caulk.

[rebar]

Originally Posted by roverhi

At least two coats of POR15 with a UV resistant topcoat should be all you'd need to protect the gutters. Would fear that laying in a caulk would just hide any rusted areas that develop. Any caulk that will seal won't be easy to remove. You'll have to scrape it out of there and sand off the remnants. The 'Debond' liquid may make removing 5200/4200 easier but have never worked with it and don't know if it will dissolves the caulk.

Thanks roverhi..

But the reason it rusted and failed in the first place is that the gutter collects and traps water. I want to fill the gutter to prevent that. And when I remove the previous seam sealer repair job, I'm sure I will uncover more rust and damage I cant see right now.

[a64pilot]

Your Ford has a Cummins engine?

[rebar]

Originally Posted by a64pilot

Your Ford has a Cummins engine?

Yes sir. And 5 speed. The van cruises 65 mph at 1800 rpm 75 mph 2200 rpm 28 miles per gallon.

[foufou]

I have an older Ford van with similar issues. I sanded and filled rust/low spots with epoxy mixed with aluminum powder. Still solid 5 years later. My oldest truck had silicone caulk for over thirty years. Never failed

[rebar]

Originally Posted by foufou

I have an older Ford van with similar issues. I sanded and filled rust/low spots with epoxy mixed with aluminum powder. Still solid 5 years later. My oldest truck had silicone caulk for over thirty years. Never failed

Thanks foufou.

Epoxy mixed with aluminum powder huh.. I have a bunch of west systems epoxy. Then mix this..

The internet is informational. Sometimes to much so.

[rebar]

Originally Posted by foufou

I have an older Ford van with similar issues. I sanded and filled rust/low spots with epoxy mixed with aluminum powder. Still solid 5 years later. My oldest truck had silicone caulk for over thirty years. Never failed

After manually prying out the body filler the previous owner used, some of the vertical drip edge is completely rusted away and gone. I know how to weld, but am reluctant to tear out the vans custom interior and remove ever bit of combustible material in my garage to prevent a home fire for a work van.

Iv watched a few video's of POR 15 Epoxy Putty and like its firm moldable consistency and ability to sand.

Would the aluminum powder you recommended mixed into west systems I have be moldable and sandable like POR 15 Epoxy Putty?

Here's a video of half the damage. Thanks

[foufou]

I used aluminum powder because I happened to have some. Could have used any of the West System products many of which are softer than aluminum for easier sanding. And do you know about Ospho? A rust converting product that make minor rust into a black, hard, paintable surface. Available in hardware stores in US. Good luck.