Caulk Question

JeffroNC

Hi
I saw these cracks on my porthole windows. do I need to scrape the old caulk and replace it? What should I use?

[Deleted User]

This is what I used on some other areas. You don't want to use anything permanent anywhere on the camper. You also need something that is UV safe and flexible.  

https://www.westmarine.com/buy/3m--marine-grade-silicone-sealant-clear--190233

N7SHG_Ham

I would check with NuCamp, it for sure should NOT be any kind of silicone caulk, I can't recall what it is off top of my head, but a search might turn up something.

Sharon_is_SAM

Check here:

https://tab-rv.vanillacommunity.com/discussion/comment/184832#Comment_184832

https://tab-rv.vanillacommunity.com/discussion/15424/porthole-window-service

https://tab-rv.vanillacommunity.com/discussion/comment/147741#Comment_147741

manyman297

Just redid the driver side porthole windows on our 400 (that side gets hit with sun in storage). Nucamp uses geocel 2300 (in silver color). Fairly easy to remove the old with a plastic razor blade and mineral spirits. A little tricky applying the new stuff. Just use mineral spirits to tool it. 

The issue I’m seeing are air bubbles that develop (maybe due to temp changes) and bubble up the sealant. Not sure how to combat that. 

One other tip…be really careful scraping the old sealant off. I clipped the vinyl decal in a couple of spots and was left with some tiny tears in one spot.

JeffroNC

Hot off the press:

Hi Jeffrey Masterman,

It would be best to remove the old caulking, then follow up with Geocell ProFlex. 

https://www.amazon.com/dp/B001FC98X2/?tag=vogelrving-20

Best Regards,

manyman297

Interesting. Maybe they've changed but they actually sent me a tube of 2300 for a repair. I don't know if ProFlex comes in silver which all of my other windows have been caulked in. The 2300 comes in silver. 

elbolillo

manyman297 said:

Interesting. Maybe they've changed but they actually sent me a tube of 2300 for a repair. I don't know if ProFlex comes in silver which all of my other windows have been caulked in. The 2300 comes in silver. 

The Geocell 2300 is their OEM-RV industry sealant. They don't supply that to the end consumer directly which is why NuCamp recommends GeoCell ProFlex.

kurt

Hello, I was at the Nucamp 2022 rally and had my roof vent replaced by Nucamp. I asked the Nucamp tech which caulk they use for the vent and the windows, and he informed me that they use: DICOR 501LSD for the roof and GEOCEL 2300 MHRV for the windows.

https://dicorproducts.com/

https://dicorproducts.com/product/self-leveling-lap-sealants/

https://www.geocelusa.com/

https://www.geocelusa.com/product/2300-mhrv-sealant/

dsfdogs

manyman297 said:

The issue I’m seeing are air bubbles that develop (maybe due to temp changes) and bubble up the sealant. Not sure how to combat that. 

@manyman297 I too have air bubbles! Both drivers side windows, mostly on the forward side of the window. The bathroom window is worse. While stored at home, that side doesn't receive any sun. How have you dealt with this issue?

Thank you

manyman297

@dsfdogs Haven’t tackled a re-caulk yet. Thinking of using Sikaflex 221. Comes in gray and is used for RV applications. Lexel is another popular one you can pick up at Lowe’s. Not sure what’s causing the bubbling but I’ll update this thread if the problem persists.

bergger

Here is a video from NuCamp reference caulking.  I just re-caulked the door window in our 400 as it had started to separate from the door.  I removed the whole window, cleaned it up then reattached it with 3m tape and caulked it with Geocell Proflex Rv caulk as suggested in the video.  I also re-caulked around the cutouts for the 3 way fridge vent.  Everything else looked good for now.  I thought the Geocell was very good and easy to apply.  Sikaflex is very, very good stuff.  I've used that as well in another application.  I did find the sikaflex harder to apply and harder to clean up than the geocell.  If using sikaflex I would recommend using painters tape to keep the mess down as I find it is harder to wipe up the excess when smoothing out the caulk bead.  

https://www.youtube.com/watch?v=ztBRqSTNbW0&t=362s

manyman297

@bergger Does the painter’s tape pull up easily or does the Sikaflex tend to pull away with the tape? I know Lexel tends to stick to the tape so it’s hard to get a clean edge. 

bergger

As long as you pull the tape before the caulk dries it should come up easy and leave a nice smooth line.  When I recently caulked our door window, with Geocell, I did not use the tape.  It came out pretty good but wish I had taped it so it would have looked even better.  You'll have so much Sikaflex in the tube that I would do a test run on something else to practice and see how it comes out prior to caulking your trailer.  I also usually use a latex glove to smooth out the caulk.  Keeps the fingers clean.  I would definitely use a glove with sikafex.  It is much harder to get off the skin than Geocell. 

Another tip I've heard about, that I have yet to try, is to dip your finger in very soapy water then smooth out the caulk bead.  The soap is supposed to prevent the caulk from sticking to your finger and is supposed to make a nice smooth finish.  

I think there are several good caulks to use on your trailer, Geocell Procell Rv and Sikaflex 221 being to of the most popular and possibly best.  One of the differences I noticed between those two is the Geocell has a very shiny sheen to it while the Sikaflex was much more flat.  I honesty like the finish of the sikaflex better.  But I thought the Geocell was easier to apply and for that I liked it. 

The most important thing, like the video talks about, is to inspect all the caulk lines on a regular basis.  At a minimum once a year but a quick walk around before each trip is a better idea.  Our door window looked just fine at the beginning of the season and for our first couple of trips.  Then the night before our last trip, while packing, I noticed the window caulk cracked and the window loose. I did a quick temporary repair then a more long term repair when we returned home.   

Horigan

Regarding the smoothing with wet finger tip, use water or water/soap for non-silicone caulk and alcohol for silicone caulk.

Basil48192

Just finished caulking mine.  I used the Geocell.  I'm typically halfway decent at caulking...but this stuff was rough.  It seemed to go on nicely at first...but I waited a while to prep the second side.  It seems that the caulk became 'stickier' and more viscous...even though I sealed the nozzle.  TIP:  Prepare and clean all of your joints before you open the caulk...then run all your beads at once.  

manyman297

@Basil48192 When I redid my windows last year I learned that using mineral spirits on your finger to tool it helped. I did this and while my bare finger (I can't caulk with gloves on) took a beating it did help make a decent bead. But even with that it was hard to get a nice bead.

Basil48192

@manyman297 Thank you!  I will try that next time!

manyman297

Sorry to rehash this thread again but I got to thinking about Sikaflex 221. It's used widely for RV applications but nearly every comment/review I see on it basically says it's permanent and very difficult to remove...that's a scary proposition if something needs to be removed for whatever reason.

What other sealants has anybody used? Geocel's MHRV 2300 (What Nucamp used on our 2021 400) is expensive and hard to find. They have a non-RV variant but I'm hesitant to try it. Lexel is another one I've used on my home and people use it on RVs but it's clear..not the end of the world but aesthetically gray would look better. 

Any other sealants people would recommend? 

Mickerly

I used Geoseal. seams to work for the last few months. The earlier warning in correct. Prepare everything. Caulk once. An hour delay will have it setting up in the tube. I will add the temperature was in the low 90's.

The key is to find something UV stable. It's amazing how many caulks aren't. Even the ones marked "RV." 

Slackers

I used Geosel 28101V (White) and it has held up nicely (since Spring 2021).

scott14

I need to re-caulk the porthole windows on our 2019 T@B 400.  The current caulk is black.  I do not see an option for Geocel caulk in black.  What are people doing in this situation?  I am considering removing the black caulk and using the white.  Thoughts?  Thank you.

Follow-up:  after some additional research, I see where the black vinyl decals are causing the black caulk to move and expand.  The solution presented by nuCamp to fix this is the remove a portion of the black vinyl decal (1/2" or so) and then re-caulk with white caulk.  The result is similar to a photo posted by @jimcenname:

Nicomekl

Are there any tips on cutting a properly executed circle on the decal around the portal window and also not cutting into the fibreglass side panel.

AndreO

FYI... I used Geocel 2300 less than 2 years ago on my 2018 400 portholes.  Noticed on my trip latest trip (Sept 2024) they are all cracked already. So suggest trying out the Proflex. I also noted  it dried out more and more as time passed, completely losing its flexibility. Also got lots of bubbles when applied during warm weather. You really need to apply it in the shade or indoors if you can.

Can't say I'm impressed with the expensive 2300 product. Bi-yearly re-application is not a relished task.