Caulk???

Topic: Caulk??? (Read 1580 times) previous topic - next topic

Caulk???

June 13, 2012, 03:43:38 pm

I've never really figured out the caulk thing. When I go to an RV store or Home Depot or wherever they seem to have hundreds of choices! Can anyone recommend a specific brand and type for various jobs on the rig. e.g.

1. The photo is of a little grommet deal for the fuel tank drain plug. The original caulking was white and real rubbery. You can pull off a piece of it and stretch it. I see this type in a lot of areas throughout the rig. What is that stuff?

2. I need to caulk the vent pipe deal for the black tank (took it off to check for obstructions in the pipe). What to use?

3. Above the compartments there are lots of trim pieces all of which are caulked. If I take trim off, what caulk would be best?
Thanks.
jor

Re: Caulk???

Reply #1 – June 13, 2012, 06:13:42 pm

I like 3M Marine products. Use their job selector page.
Adhesive Sealant Product Selector

Re: Caulk???

Reply #2 – June 13, 2012, 10:34:03 pm

John, it was probably a urethane caulk, such as Dicor or Sika. For vertical surfaces use a High Modulus, thicker, caulk. On a horizontal surface use a Low Modulus or Self Leveling caulk. I have also found a product called Geocel, available on line, that I like very much. Lap caulk is another generic name for caulk that is also a good adhesive with decent elongation.

I would suggest staying away from residential type acrylic caulk for most applications on a motorhome. Some acrylic/urethane caulks are OK but generally choose a urethane for best adhesion and elongation, followed by silicone or silicone hybrid like silicone/acrylic. There are some acrylic lap caulks that are pretty good, I have recently been testing Lexel Clear thanks to Dick S, but the traditional filled acrylics like DAP or Red Devil you use around the house should be avoided for use on a moving earth quake like an RV.

I agree that 3M sells some of the best caulks/adhesives that are available. A good caulk should cost at least $5.00 per tube.
.

Re: Caulk???

Reply #3 – June 14, 2012, 12:13:45 pm

Kent,we are officially changing your name to URETHANE MAN.

Re: Caulk???

Reply #4 – June 14, 2012, 01:39:32 pm

If you think you will be removing the caulk, use silicone. If you think the next owner may be removing the caulk, use polyurethane. If you think it will remain forever, use Shoe-Goo. Polyurethane is great stuff, but it is hard to remove. Silicone removes easily, but is not permanent. Shoe-Goo is forever.

Matt B

Re: Caulk???

Reply #5 – June 14, 2012, 03:11:12 pm

FWIW
having been a boater for some time, I think this only reinforces what has already been said but...
If you want to remove or feel that you will remove, use silicone
If you want to be able to remove, but think you never will, use polyurethane (I like Boatlife)
If you want it to stay put, I like 3m 5200.

I think it certainly cost more, but always get my caulk for boats/motorhomes from Marine places. The enviornment is similar. Home stores caulk when I have used have pretty much been short lived and unsatisfactory performance (so only use that stuff at my home).

Re: Caulk???

Reply #6 – June 14, 2012, 04:46:25 pm

Nobody can figure out the caulk thing. The choices of materials and brands are endless. So don't feel alone.

Calk is more difficult to talk about than religion & politics as everyone has their favorite which is probably passed down in their genes.

For over 30 years of RVing, we have settled on GE Silicone II clear Kitchen & Bath and usually go through several cartridges every year. We use it inside and outside. It makes bumpers for knobs that hit things. It attaches things together. It seals holes, screws, wire runs. We used it on our roof to but things back together after painting, like air horns, fridge vent, solar mounting screws, etc. We have filled in large holes with silicone.

A GE tech told me the Kitchen & Bath is the same silicone as the Door & Window products. Only the label is different as they are marketed to different users. Same product for two markets.

100% silicone sealants are not paintable, but do come in colors. We find clear the best for looks and sealing. Cartridge can be reused over and over until empty.

Silicone is commonly available, even in Walmart.

We always prep-clean all surfaces to be silicone with denatured alcohol.

GE Caulk: Waterproof Caulk Keeps Water Out in Kitchens, Windows, Doors, and
GE Silicone II Kitchen & Bath Adheres and Seals Fast, Providing Mold Protection

There are 20 other sealants that come in cartridges that can do the same job. Some are paintable, some are stronger bonding (just try to take them apart and clean up the residue), some more flexible, etc.

We tried to work with urethane, but always come back to silicone. Urethane was harder to remove, and it was not always possible to reuse cartridge after it had been closed up for a while.

Re: Caulk???

Reply #7 – June 15, 2012, 10:22:17 am

Thanks for all the replies. We just got back and I've got a few projects lined up, some of which involve removing old caulk and replacing. As I progress I'll post what I use and the results.
jor

Re: Caulk???

Reply #8 – August 19, 2016, 04:30:57 pm

I know it's an old thread but I needed some suggestions. The variety of sealants and adhesives is mind boggling and I am sure much has changed in 4 years.

I peeled and scraped all of the old caulk out, inside the shower. I'm soaking the residue in odorless mineral spirits overnight to get the last of it up. I will have a clean surface to reapply fresh the caulk. What I peeled out was flexible so I assume it it silicone.

I am a bit nuts so I am using clear on the two sides where the metal meets the shower pan, and almond on the two sides where the wall meets the shower plan.

I was going to use this: Amazon.com: Momentive Performance Materials GE286 Silicone II Premium...

Any feedback would be appreciated. This kind of project is one of the rare ones when I can confidently say that price is not object. I want the best.

Thank all, hope everyone has a great weekend.

Jeff

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Re: Caulk???

Reply #9 – August 19, 2016, 09:49:56 pm

I did two shower pans and ended up using plain old Home Depot almond bath-shower caulk. It came out great. I just made sure I had a very clean and dry surface. I also use tape when I caulk for a clean, straight edge.
jor

Re: Caulk???

Reply #10 – August 19, 2016, 11:47:50 pm

Jeff & Sandy,

Repeating our previous posting, that is exactly what we use and will be using this week. We buy from Home Depot / Lowes & even Walmart carries it. We do look for the latest expiration date on the cartridge, and want it to be about a year out.

But we only find white & clear in smaller tubes, like your Amazon link, at big box stores. So we buy the regular size larger cartridge that us used with a cartridge gun for other colors. Two days ago we paid $5.92 for Almond cartridge at Lowes, so their cartridge price is lower than Amazon tube price.

We generally use several cartridges of GE II Clear each year to keep the motorhome sealed up, for door bumpers, etc.

GE has two different colored packages marketed to plumbing and weatherstrip. A conversation with GE customer service years ago said both products are the same, but packaged differently for marketing purposes.

Re: Caulk???

Reply #11 – August 20, 2016, 12:14:03 am

3m 4200 would be getting my vote, even though I have not used it yet. If the 4200 ( for remove able seal) is as good at doing its job as the 3m 5200 is, well let's just say the 5200 seems amazing. Resently used the 5200 for sealing the GV cap to dash problem and holding so far. There will be a write up comming shortly after I finishing flex sealing the area. ( waiting on new defroster ducting ).

Roger listed the 3 to use in recent post. Search " what caulk is used on Foretravel".

Re: Caulk???

Reply #12 – August 20, 2016, 12:16:19 am

Here it is.

Re: Caulk???

Reply #13 – August 20, 2016, 09:21:17 am

Silicone caulks require a very clean surface to adhere well. Silicone does not stick well to silicone or silicone reside. There are slicone removers to clean and remove the silicone film left from earlier caulking. We used the GE almond and clear silocones on our shower because of color match. I am not sure how well the 3M 4200 sticks to previously caulked surfaces. It is an interesting question. You can get it in smaller tubes whick makes fine line caulking easier. Using tape for a sharp edge is always a good idea. 3M 4200 is likely a good choice. I have 3M 5200 in tan color (I used it to glue my deck boards down, no fasteners) so the 4200 is probably available in colors other than white and black. Some of the really good latex caulks are easier to remove and recaulk as needed.

Re: Caulk???

Reply #14 – August 20, 2016, 09:27:49 am

Yes, tape can give even a novice "caulker" a fine line:

Tape (blue painters tape works well) both sides of what you want to caulk.
Apply the caulk reasonably liberally. 3-4' section at most.
With a gloved finger smooth the caulk, forcing it into the gap/crack. This will leave you with a uniform thickness of caulk, with some on the tape.
IMMEDIATELY remove tape.
IMMEDIATELY smooth the caulk with your finger. This removes the ridge at the edge of where the tape was.

Re: Caulk???

Reply #15 – August 20, 2016, 11:03:35 am

Don't forget UV resistance when choosing an exterior caulk.

Re: Caulk???

Reply #16 – August 20, 2016, 11:49:37 am

I had some leaks in the shower, removed old silcone cleaned surface and recaulked, it leaked again. Re did everything with 3M 4000 no leaks or mildew in 3 years.

Re: Caulk???

Reply #17 – August 20, 2016, 11:53:04 am

Quote from: bbeane – August 20, 2016, 11:49:37 am

I had some leaks in the shower, removed old silcone cleaned surface and recaulked, it leaked again. Re did everything with 3M 4000 no leaks or mildew in 3 years.

Inside or rooftop?

Re: Caulk???

Reply #18 – August 20, 2016, 04:03:52 pm

Another style of "caulk" I have used is the brand name Sika,it is used to seal windshields,it is the same size as a regular caulk tube
but you have to have a special gun .

Re: Caulk???

Reply #19 – August 20, 2016, 04:05:51 pm

Yup, Sikaflex 221 is a very good caulk/sealant/adhesive. I have used both their white and black.

Re: Caulk???

Reply #20 – August 20, 2016, 04:26:05 pm

I hope this is some el cheapo caulk, I have to stare at it every day, and it's getting to me. It's all around the coach. I'm going to try the same stuff that has worked for my pitch problems.

Re: Caulk???

Reply #21 – August 20, 2016, 05:01:15 pm

Wow, that IS awful. Suspect the body shop that painted it did that. At least it is my understanding that it was painted after we sold it.

Agree, hope it comes off easily.

Whoever did it CERTAINLY did not use tape!

Re: Caulk???

Reply #22 – August 20, 2016, 05:30:24 pm

Quote from: wolfe10 – August 20, 2016, 05:01:15 pm

Wow, that IS awful. Suspect the body shop that painted it did that. At least it is my understanding that it was painted after we sold it

The body shop did a perfect job on the paint and stripes. I suspect the PO was a "Mr. Fix-It" and decided to "caulk the seams" He even ran out of white & used grey and slopped that all over, as well.

Re: Caulk???

Reply #23 – August 20, 2016, 06:27:54 pm

Quote from: Jeff & Sandy – August 20, 2016, 11:53:04 am

Inside or rooftop?

Inside at the wall and shower at the hall corner between the curb the shower pan.

Re: Caulk???

Reply #24 – August 21, 2016, 06:08:45 am

Quote from: mike leary – August 20, 2016, 05:30:24 pm

The body shop did a perfect job on the paint and stripes. I suspect the PO was a "Mr. Fix-It" and decided to "caulk the seams" He even ran out of white & used grey and slopped that all over, as well.

Mike.
What are you using to " clean" the caulk seam. I re sealed the belt line seam earlier this year and although it will prolly seal it just fine. Seams to be a DIRT magnet and already looks old. I'm just glad I had not re sealed the end cap seams yet with the same stuff. ( caulk was something recommended buy Sherwin Williams clerk ). I'm thinking the 3m 4200 would be better.

Does anybody know if it was the silkaflex that they used on the wet Bay Area. That stuff does not seem to hold on to dirt at all.

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