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amyv
Exterior window caulk
amyv

Is there a brand of exterior window caulk you would recommend over another? Thanks!

ordjen
Re: Exterior window caulk
ordjen

My favorites for longevity, paintabilty. and elasticity are the urethanes: Sonneborne MP1, Vulkem or Quad, in that order.

Mastercarpentry
Re: Exterior window caulk
Mastercarpentry

My go-to for best paintable exterior caulking is "Duo-Sil" by Siroflex. It has superior adhesion and durability compared to all the others I've tried and it skins and cures quickly. The downside is that it is not easy to tool because of it's stickiness so you need to apply it well, tooling it minimally and quickly or you'll get a mess.

Phil

ordjen
Re: Exterior window caulk
ordjen

The urethanes are heavier bodied than the acrylic based products and lay out much better with little need for tooling, good thing to as they are extremely sticky! Being so heavy, they are able to close up a much bigger gap. I am not familiar with the Duo Sil brand.

When using the urethanes, I always have paper towels and paint thinner handy in an attempt to keep my hands and the gun from getting completely gunked up.

The urethanes definitely have to be good and warm too, otherwise you can't get them out of the tube without great force!

Mastercarpentry
Re: Exterior window caulk
Mastercarpentry

Goog "Duo-Sil", It's made right here where I live. It's a mildew-resistant urethane and mean as glue for adhesion. One of the 'big-box' chains here has it here but it may not be nationwide. Removable tips are nice, I have several ones saved so I don't waste a tube cutting for a larger bead. I've seen marginally nailed exterior trim stay up for years because it was caulked with this. Flows OK cold (just above freezing), water clean-up (do that fast, it won't wait!).

Phil

A. Spruce
Re: Exterior window caulk
A. Spruce

I like beutyl caulking, don't have a brand preference, as I've used several different brands with equal and excellent results, the last thing I used it on were the headlights on my truck, which the plastic lens had separated from the plastic case, letting water in and blowing bulbs every time it rained or it went through a car wash. Since using beutyl on the seams a few months ago, the lights have stayed dry and functional.

With beutyl, it is paint thinner clean up, so as ordjen suggests, keep plenty of paper towels handy to keep the tip goop free. Take your time in applying it to avoid gooping and errant beads, and if you do need to lay it off with a finger, I suggest wearing rubber gloves and keep the lay off to a minimum, meaning don't over apply and get the stuff from head to toe. It is better to go back and add another bead or touch up spots than to goober it all over the place, though honestly, this can be said for any kind of caulk.

Beutyl is immediately water proof, skins in minutes, paintable in 24 hours, cured fully in 7 days. It is VERY elastic, so it tends to stay stuck to everything really well, even in large gaps that shrink to small gaps and back again as temperatures swing from one extreme to the other. I used Big Stretch brand in the aforementioned gaps in the masonite siding of my house at least 5 years ago, probably longer, and it's still performing well, it replaced failed acrylic and failed silicone, neither of which have the stick or the stretch needed for such things.

ordjen
Re: Exterior window caulk
ordjen

Like Mastercarpentry Phil, I have actually used Sonneborne MP-1 urethane to physically hold down surfaces which were not actually properly fastened: My first house had aluminum siding. The builder had cheated and not used the J-channels where the aluminum siding butted up against the brick molding on the windows. He had simply caulked it to the brick molding with oil caulk which fell out within a few years and left the siding pretty much floating and unsupported. I secured the siding by kind of toe nailing it into the framing and then put a continuous bead of caulk from the siding to the brick molding. I know this isn't kosher, but I can tell you it held that siding immobile and water tight for about 20 years! I had occasion to remove one of those wooden windows for repairs in later years, and had a devil of a time getting the Sonneborne to break free!

As a painting contractor, I wanted to have repeat customers who trusted I was using the best products available. I knew that when I used Sonneborne, I wouldn't be getting call backs. Many a time I would take the effort to completely chisel out loose oil or latex caulk and replace it with a nice continuous, smooth bead of caulk.

A. Spruce
Re: Exterior window caulk
A. Spruce
ordjen wrote:

As a painting contractor, I wanted to have repeat customers who trusted I was using the best products available. I knew that when I used Sonneborne, I wouldn't be getting call backs. Many a time I would take the effort to completely chisel out loose oil or latex caulk and replace it with a nice continuous, smooth bead of caulk.

Repeat customers or handy DIY, this just makes good sense. As with paint, caulking is only as good as what it is stuck to, if that surface is compromised, then no matter how good the caulk is or how good it was applied, it will prematurely fail. Always, always, always, clean out old caulk, loose paint, dirt, and any other foreign materials that will compromise your work. Do it right the first time and you'll have a lasting project, crap it together and you may as well head to Vegas, 'cause it's a crap shoot as to how long it's going to last, and odds favor the house for early failure plus the added expense and misery to do it all over again.

Mastercarpentry
Re: Exterior window caulk
Mastercarpentry

Cheap butyl caulking is crap- it's the rock-hard stuff we've all had to chisel away in chunks where it has shrunk and split. It's one of the oldest caulks. Commercial grade butyl does great- it's used in building expansion joints where there's nothing else keeping the water out. The elastomers in it are the costly part which is why the cheap stuff is so bad. Silicone does well when it adheres well but we all know it's not paintable, plus it's not usually applied as intended- if it's not thin so it can stretch it will simply pull loose. Urethanes stick like crazy but need care in application- gotta read the directions with them. The Duo-Sil stuff I use is a siliconized paintable urethane- the best of everything blended together.

It's been ages since I used any commercial-grade specialty caulks. You simply don't encounter them in residential work where the environment is not usually so severe, but there are literally hundreds of types and blends made for specific purposes and "Caulker" is a listed trade in many places because it's so specialized when you go beyond the normal uses. It can be a confusing subject with so many answers to one single question, but luckily most of what you find on store shelves nowadays will do OK almost anywhere for awhile at least. It still pays to use the best stuff for the intended application though- that's one thing whilch will never change.

Phil

A. Spruce
Re: Exterior window caulk
A. Spruce

I have not experienced those things with the beutyls that I've used. Maybe they were hybrids such as the ones you're talking about, maybe they weren't actually beutyls, I don't know and it's been long enough that there are no old tubes laying around to refer back to.

ordjen
Re: Exterior window caulk
ordjen

Butyls are used in the RV industry because of its elastic nature. An RV is subject to a lot of stress as it bounces down the road. It is used as a general seam sealer and for setting the windows and doors. It is also paintable.

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