Cosmetic Caulks, Sealants, and Adhesives

[Eggbert]

First-timer preparing to be a full-timer and the body seams on my 2003 40' Alpine Coach are due for a refresh.

What are your experiences and recommendations for products/techniques for visible body seams?

I'm in SW Florida so good Sun/UV and mold resistance is important. I prefer to avoid products containing silicone.

Advice on how to properly remove old sealant and prepare the joint for new sealant without damaging the paint is also highly appreciated.

This will be my home, so I want quality, long lasting results. Thanks for your advice!

[andy29847]

On the body belt seam, I use Pro-Flex clear because of the color changes along the line.

On the roof seams, I use Pro-Flex white.

Cleaning the old sealant and mold is hard! It hasn't turned out good enough for me to offer advice. I'll be watching your thread.

[Cuda67bnl]

NP1……NP125 is clear…… wash well, allow to dry, then clean area with alcohol, acetone, etc. Apply bead, smooth/tool with finger. Test first in a small inconspicuous spot, allow to cure for a couple of weeks, then try to pull off.

[Eggbert]

Originally Posted by Cuda67bnl

NP1……NP125 is clear…… wash well, allow to dry, then clean area with alcohol, acetone, etc. Apply bead, smooth/tool with finger. Test first in a small inconspicuous spot, allow to cure for a couple of weeks, then try to pull off.

NP1 is a new one for me. Elastomeric polyurethane sealant from BASF for exterior active construction joints (high flexion) and can be used as an acoustic sealant. Takes a week to fully cure. Sounds similar to other polyurethanes like 3M 4200 and 5200.

Originally Posted by andy29847

On the body belt seam, I use Pro-Flex clear because of the color changes along the line.

On the roof seams, I use Pro-Flex white.

Cleaning the old sealant and mold is hard! It hasn't turned out good enough for me to offer advice. I'll be watching your thread.

Thanks, Andy! Your suggestion lead me to AZ Expert on Youtube where he removes the old sealant along the roofline of a fiberglass roof Winnebago and reseals it with Proflex. (For those interested in technique, I suggest watching it at 1.5x speed to get through the dialogue, but there's useful info interspersed throughout.)

What's everyone's experience with Proflex? How has it held up? How easy is it to remove parts bonded with Proflex? I presume I might need to remove the beltline trim at some point in the future..

https://www.youtube.com/watch?v=jDd3NrdWSQA

[Cuda67bnl]

I’m a roofer by trade. Pro flex will work. NP1 is a better product. Neither will stick to silicone worth a dang. Neither should be applied to a wet surface, despite what is said in that video. Both will have to be cut away to be removed if they bond to the material. Both cure in about the same amount of time. I sealed mine with NP1. I always have it on hand because I use it almost daily. Proflex may be easier to find for you. They have a proflex and a proflexRV. Same thing. Geocel2300 will also work good.

[Mitimet]

Saw your question and you've got some darn good advice like using Proflex. I've been watching a YouTube guy, AZ EXPERT who inspects, repairs all sorts rv issues. His roofing inspections have been discussing what to look for but even better is his discussing various sealants, adhesives caulking, etc for various surfaces. Eg; Wash and wax our fiberglass roofs at least once a year. You don't need to hand wax but just car wash/wax liquid to protect your roof. Hes very detailed and im learning a lot. Good luck
Mark

[Eggbert]

Excellent advice indeed! Thank you Cuda, Andy and Mitimet.

Geocel ProflexRV /2300MHRV sounds like the easy choice and the goto for most RV folks, but it seems like I'll be repairing sections semi-annually and removing & replacing all the sealant every couple years at best. Is that a realistic expectation for an RV that will be outdoors 100% of the time?


Jimmy, Mr. Cuda, Sir. How does your experience with polyurethane sealant like NP1 compare?

Polyurethane and polyether sealants would seem to last longer and have much better adhesion, but I don't want to end up with a sealant that I can't easily repair and replace when needed.

Some of the stuff they use on Boats like Sikaflex 291 seem to last for 10-15 years in harsher conditions than ours.

I'm leaning towards the more durable polys, but how much more durable and how much trouble am I making for myself down the road when the sealant inevitably needs to be removed and replaced?

[Cuda67bnl]

If you want something that’s easy to remove later, use silicone. Otherwise, seal it up with the expectation that it may be a b*t*h to get off later. Anything you use, may decide it doesn’t wanna stick well. That’s why I recommended trying a test spot earlier.

My coach had previously been sealed with silicone. I resealed it a couple of months ago. Some of the silicone peeled right off, some had to be cut and scraped off. I cleaned it off as best I could, and redid it with np1. A month later, I noticed a section didn’t look stuck well. I grabbed it and peeled a long piece off. I cleaned it off again with alcohol, and sealed it again. That time it bonded well.

That can happen with anything you choose to seal with. If your coach has never been previously sealed, you’re in great shape. Anything you choose will work well. Run a small bead along the seam with the product of your choice. Down the road if you need to redo it, you can just go right over it with a slightly bigger bead, which will seal over it and grab fresh surface to bond too.

I think a lot of the things recommended for RVs actually suck… Dicor is one of them. The only good thing about it, is that it comes off easily down the road. I’d rather seal with something that sticks, and worry about getting off later. Chances are, if it sticks well, you’re not gonna need to get if off anytime soon……

[bcbowers]

Years ago I had an RV service center in PHX remove & replace all caulking on the roof. I discovered that they used C10 self leveling caulk that is expected to last at least 10 years . Since that time I've been using it as when I replaced the shower done.