Exterior caulk?

[Star0210]

Looks like we will be looking into sikaflex!
Thanks everybody!

 

[senangsekali]

+1 sikaflex
easy to work with. Use soapy water to smooth out.

 

[BruceK]

+1 sikaflex
easy to work with. Use soapy water to smooth out.

Plastic wrap film over a finger helps too. And mineral turpentine(we just say "turps")to clean up,have a rag or paper towel ready in advance. Also, leftover Sika keeps well in the freezer, but don`t delay getting it there.

 

[Benthic2]

Lexel is mold resistant, can be applied to a wet surface, stays flexible, and is paintable. It requires mineral spirits to clean up though.

I would NEVER use any caulking product by GE. I've been let down too often, and heard the same from others.

 

[steelydon]

You know it was interesting that I agonized (OK, more like waffled) over Sikaflex and 3M back in 2015 and ended up going with 3M 4200. Based on the collective knowledge of the group I am going with Sikaflex when I begin my Spring project list. Thanks for the advice!


Don

 

[Westiculo]

What Sika do you guys use? Mostly I'm worried about UV and chemical exposure.

 

[Star0210]

So once I get all the old scraped out...what’s best to clean and prep the surface for new caulk?
Or maybe I should ask, are there any products I shouldn’t use? I think someone was telling my hubby to use acetone after just scrubbing it good with soap and water.

 

[RT Firefly]

Greetings,
Mr./Ms S. Yup, soap and water followed by acetone will work. What you want is a surface clean of grease, oil or soap residue. Another alternative is xylene (xylol) better de-greaser but it is much harder on the liver IMO.

 

[MV Alchemy]

I have had very good results with TDS (Teak Decking Systems) caulk for this purpose. It is designed for caulking teak decks but I checked with the manufacturer that it is fine for this kind of general caulking as well. One other idea is to use black caulk instead of white - no yellowing or dirt. It sounds strange but actually looks good (IMHO) on our boat.

 

[Knot Salted]

I have begun using Life Caulk polysulfide and butyl tape.
Cures faster when wet, but will air cure as well.
I havent had it out in UV long enough to know if it stays white. It is available in black too. Heard good things about it a couple of years ago here on the forum.

 

[Comodave]

I used to use Lifeseal a lot but found that it yellows so I went to Sika. So far it has not yellowed on me at 2 years. I use 291 for general caulking. I used 295UV when I caulked the plexi wind shield. When I caulk to teak I do use their primer which is expensive at $80 and has a shelf life of 1 year. But I wanted to make sure the caulk stuck to the teak because the old caulk from the PO just peeled up in long strips. It was easy to get off but didn’t seal worth a crap. So far the Sika is doing great.

 

[Knot Salted]

Good.
The Life Caulk cannot be used on plastics either.

 

[CaptRowlands]

Caulk suggestions.

Ditto the sentiment to not use 5200

I have had good experience over the years and use LifeCaulk (not Seal) for joints and butyl tape for bedding hardware and window frames.

In any event, follow the products instructions explicitly.

 

[JeremiahM]

+1 more for Sikaflex. We just had caprails refinished with awlgrip and the yard used sikaflex to seal all of the paint edges. Goes on easy and looks good.

Good luck!

--Jeremiah

 

[adornato]

the lastest issue of Practical Sailor did a big article and testing. concluded 3M 4000 uv was the best for exterior caulking

 

[SteveZ]

caulk

I agree with Pack Mule - 3M 4000UV holds up very well.

Steve Zimmerman

 

[Sailinggod]

My advice is to use either Sikoflex or 3M marine caulk. Do NOT use household caulking, as it does not have enough mildew resistant properties and will soon turn green or black and look terrible (I have experience with it to prove it).

 

[DonnyP]

I think your gooey caulk is because of poor prep by the PO or brokers guys. It was probably wet and/or dirty when they did the quick fix and now you are seeing the results. Moral of the story is that you can use any of the brands recommended in this thread and all will likely fail if you do not prep well. Clean, scrape, cut, get as much of the old stuff out and make sure the joint is dry before applying your new caulk of choice. Use painters tape on both sides of the joint, apply caulk, finger it nice and smooth, and remove tape. I have had good luck with Life Caulk both white and black.

 

[garmstro55]

Here's a helpful chart from Boat/US Magazine.

 

[Westiculo]

I haven't had any issues with the 3m 4000, but I agree there was a lot of bad feedback a number of years ago. See post #11 from https://www.thehulltruth.com/boating-forum/617165-3m-4000-uv-sealant-problem.html - it explains why.

In short, the formulation was messed up for a little bit towards the beginning, which probably gave the product a bad name. I'm assuming it's all fixed now; I haven't had any trouble and have probably gone through a dozen different tubes over the last couple of years.

 

[bgillroy]

3m4000 for exterior good UV color stability. 3m4200 and 5200 aggressive adhesive caulks for interior bonding applications not for exterior trim, good adhesion poor uv.

 

[sdowney717]

Anyone ever used DUCT SEAL?
It is like butyl, grey in color, waterproof, formed with your hands. supposedly lasts a very long time. Stays soft and flexible and its cheap!
I have a Lexan window in a hatch and thinking of using this.
https://www.homedepot.com/p/Gardner-Bender-1-lb-Plug-Duct-Seal-Compound-DS-110/100212441

https://www.rectorseal.com/rectorseal-duct-seal-compound/

It is used for keeping water out of exterior electrical boxes.
1. Product Description
RectorSeal® Duct Seal Compound is a
gray, permanently soft, non-toxic, putty
type compound which will adhere to most
clean dry surfaces. Duct Seal Compound
is asbestos free and will not adversely
affect other plastic materials or corrode
metals, it also has no adverse effect to
human skin.

Excellent adhesion properties
• Temperature usage range
(recommended) 25° F to 120° F
• Temperature tolerance range: -30° F
to +175°F. Will not slump at +275° F for brief periods.
• Unlimited shelf life
Paintable
Non-irritant
Remains permanently soft
Non-toxic
Non-staining
Non-corrosive
USDA acceptable
No vehicle bleed out
FDA approved
UL(R) classified
Dielectric strength to 100V per mil

 

[RT Firefly]

Greetings,
Mr. s. The problem I've found with duct seal is the surface tends to harden over time AND it is not as flexible as butyl tape. I would suggest for a critical application such as your hatch light, go with butyl tape. The heck with the extra $20...

 

[sdowney717]

Greetings,
Mr. s. The problem I've found with duct seal is the surface tends to harden over time AND it is not as flexible as butyl tape. I would suggest for a critical application such as your hatch light, go with butyl tape. The heck with the extra $20...

It can be painted, that may keep the surface from cracking, likely dries out a little over a long long time. You may find it on top meter boxes where the wire goes in on top.

I can paint it with a small brush and some white acrylic paint.
The Lexan window sits in a recess in the hatch and has about 3/16 gap all the way around. The seal has broken after several years, I thought about silicone, but I am leery of it a little. I suppose the Ultra black Permatex silicone RTV that comes in a cartridge would work ok, I have experience using it on engines, and it sticks quite well, made for a caulk gun. That RTV may be different form other silicone caulks made for houses. I have never had a problem with using it.

 

[spinoeca]

I have read the posts here with interest since we are getting ready to reseal the exterior teak quarter round molding at the junction of the pilothouse and the teak deck. It seems as though this is a no brainer to use butyl tape on. My question is whether or not the SS screws I removed are sufficient to squeeze the butyl tape enough to get a good seal. They seemed to have a good grip when I removed them and my expectations are that BT is the way to go. Any thoughts please.

 

[Westiculo]

I have read the posts here with interest since we are getting ready to reseal the exterior teak quarter round molding at the junction of the pilothouse and the teak deck. It seems as though this is a no brainer to use butyl tape on. My question is whether or not the SS screws I removed are sufficient to squeeze the butyl tape enough to get a good seal. They seemed to have a good grip when I removed them and my expectations are that BT is the way to go. Any thoughts please.

It's a good thought. Personally I'd use the teak decking systems sis-440 for that. The butyl tape might work but it's a bit more susceptible to breaking down from chemicals like teak cleaners. On my boat, the teak was too worn down to be strong enough to compress the butyl tape even though the screws were still good. No reason you can't try it; if it doesn't work, you can just pull it up again and remove the butyl tape.

 

[spinoeca]

As I look at the TDS products I see that there are two colors which got me to thinking about whether I should seal to the deck with black and to the house with white? Seems like that could be messy but my partner is the painter/caulker and she has made it clear that I am NOT to do this without her supervision.

 

[bgillroy]

Investigate 3m4000 or contact 3m for tech solution. 3m produces superior marine products.

 

[Comodave]

As I look at the TDS products I see that there are two colors which got me to thinking about whether I should seal to the deck with black and to the house with white? Seems like that could be messy but my partner is the painter/caulker and she has made it clear that I am NOT to do this without her supervision.

The white and gray TDS caulk will take longer to cure than the black. No problem unless time is a factor. I just used 27 tubes of black on my deck seams.

 

[Cigatoo]

As I look at the TDS products I see that there are two colors which got me to thinking about whether I should seal to the deck with black and to the house with white? Seems like that could be messy but my partner is the painter/caulker and she has made it clear that I am NOT to do this without her supervision

Mark a line or tape above and below the teak before removing. Then clean and tape well before caulking. This will give you a nice clean joint. I am thinking the black TDS on mine. I don’t think the screws would allow enough compression for the butyl tape.