caulk - flowing

[oldyork90]

I'm looking for a brand name. Window installers use a sticky caulk on my windows that is still holding up. It "flows". Silicone is compliant - good for compression but can fail in tension. Hard acrylic caulk just fails. Anyone know of such a product?

[gregz]

Try looking up dap ultra 230 . Been using dynaflex 2300, but I don't know the difference. Ultra is mildew proof.

Greg

[Gunther]

They probably used a Butyl Rubber caulk, purchased through their supplier. If you know where they purchased the windows, probably can make a phone call to see what brand the supplier carries.

[trader4]

For this kind of application an important factor to consider is if the caulk is paintable. I think the butyl rubber is.

[Gunther]

It is paintable. Draw back using it, it's like no other caulk. There's no tooling of it, unless you wet your finger in a flammable liquid. If you're good at caulking, then this is a pretty good caulk. Butyl will crack, after years exposed to the elements.

[DanG]

Avoid silicone unless it is Dow Corning 795.

Any of the commercial grade one part urethanes would be fine. The one I normally use is Sonneborn's NP1.

I have started to use Titebond's Metal Roof Sealant. It is a polymer product that is a bit easier to gun than NP1 and has worked well for me.

[nestork]

You're probably looking for Kop-R-Lastic, which is what most window companies use on the new windows they install:

It's made by the U.S.E. Hickson Company in Canada and the Henry Company in the USA under license from the Koppers Company of Australia.

'Kop-R-Lastic | Henry.com'

I have 66 windows in my building, and I wouldn't use anything BUT Kop-R-Lastic on them. The reasonw why is that Kop-R-Lastic is a synthetic rubber that's got excellent adhesion to most construction materials, BUT, it's cohesive strengeth is even greater than it's adhesive strength, which means that it sticks to itself better than it sticks to construction materials. So, when the time comes to replace your caulk, and it won't come soon, you just get one end of the bead of Kop-R-Lastic started and it pulls out of the joint just like a rubber rope.

Here's a picture of me pulling clear Kop-R-lastic off the Suite 3's dining room window in my building:

[image: You can see that you have to pull hard to get it off, but you can also see that it pulls off cleanly (provided it's had more than 2 years to fully cure) so that applying new caulk is quick and easy because you don't have to spend a lot of time removing the old caulk.

My building is my job, my livlihood and my retirement. I wouldn't use anything except Kop-R-Lastic on the exteriors of my windows. Get it in clear so as to get the most synthetic rubber and hence both the highest adhesive and cohesive strength.

Please don't use:

a) silicone caulk. Silicone caulk works great and lasts forever, but you have to remove it COMPLETELY before any other caulk, including more silicone caulk) will stick to that surface. Kop-R-Lastic lasts as long as silicone, but pulls off cleanly so that you can immediatly re-caulk with any other caulk, including Kop-R-Lastic.

b) butyl rubber caulk. Butly rubber caulk dries up in a few years, cracks and falls off. Contact any company that sells caulk to get an opinion on butyl rubber caulk before using it. I wouldn't use it.

[gregz]

Brackets ? See if this works

Greg