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Community and Q&A

Understanding sealants – Is there a comprehensive article?

mikeysp | Posted in General Questions on

Hi. I am interested in learning about sealants. 

I have come to understand that there are some very good sealants on the market. Silicone works great for glass to glass for instance. I used Vulkem 116 several years ago in a metal tube skylight right through a metal roof. The sealant is submerged in part everyt time it rains because of metal ridges on roof panels. The roof gets blazing hot in summer and frigid in winter; yet, it is as sound as the day I installed it besides a little algae on the surface. 

That skylight manufacturer comforted me when I expressed worries about future leaks that he ha sbeen using Vulkem 116 and Quad sealants for close to two decades and never a leak. I was not sure which Quad, so I ordered some Vulkem 116 and it was awesoe in that application. 

Great, I can follow instructions…. but, if I had to selecrt a sealant, I would not know the difference between an apple and an orange. Which one’s are good for A and which for B. For instance, I hear that NP-1 from Masterseal is similar to Vulkem 116. I called and asked, and I may be mistaken, but I think the tech guy said fine for metal roof, but not submersion (again, I may have forgotten). 

So, I really want to be able to select from the shelves what are equals and best for applications. 

Surely that article has been written if it merits one?

Thank you. 


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  1. Jon_R | | #1

    This should be of some help:

    Shorter answer, Dymonic 100 or Spectrem 2 (for glazing).

    1. mikeysp | | #5

      Thanks Jon, but that does not educate me beyond Tremco. If the store carries different brands I want to be able to know what to use.

  2. this_page_left_blank | | #2

    Very few sealants are rated for submersion. Some polyurethane ones, some MS polymer ones. Very few (if any?) silicone ones. The application you're describing is not submersion, it's just getting wet when it rains. It dries out afterwards.

    Edit: I just looked up Vulkem 116, and it is NOT silicone. It's polyurethane, and rated for "some applications of submersion". I'm pretty sure none of the Quad line of sealants are submersion rated.

    Edit again, I reread your post and I guess you weren't necessarily saying Vulkem 116 was silicone; it seemed like it because there was no segue between your comment about silicones and talking about how you used Vulkem 116. NP-1 is also a polyurethane sealant, also rated for submersion.

    1. Expert Member
      BILL WICHERS | | #7

      GE makes a few silicones that they list as suitable for use in aquariums, which would mean they’re ok for submersion. As far as I know, no silicones can cure underwater, so you have to wait to submerge them until after curing is done.

      Presumably there are other sealants rated for submerged use, since there is a need for that, but I’m not aware of any standard building sealants that are.


    2. mikeysp | | #9

      Trevor, you are absolutely right. I appologize for the very confused wording. I needed to reread and edit my post for clarity and brevity not only to get my question answered, but out of respect for others. Unfortunately the popst wasn't meant to be about silicone, vulkem 116, or submersion. I was trying to locate a caulking tube bible guide that would arm me with wisdom when I am looking at a 100 tubes in the hardware store. I blew it. I am going to give this post a few days to see if it answers the question. If not, I will attempt to do it right next time. Cheers. -Mike

      1. Expert Member
        MALCOLM TAYLOR | | #10


        I'd be surprised if Fine homebuilding hadn't done an article on this at some point.

  3. Expert Member

    Perhaps a bit peripheral to the main topic, but I'm trying to think of a building assembly that I would design to rely on caulking being regularly submerged. Relying of sealant, rather than flashing, for a roof penetration, makes it much too vulnerable over time.

    1. mikeysp | | #4

      I am sorry for the confusion gents. I did not communicate well. Let me try again.

      I just want to learn about all the types of cartridges that I can load in my gun and not feel so ignorant every time I walk down the isle with all the caulk gun tubes. At this point I am pretty ignorant with little exceptions. I mentioned two sealants I have worked with and that I was familiar with from my experiences. I am wanting "a guide to different sealant types and their applications". I want to know the types and uses as well as the applications and how well they work.

      When I walk into my local hardware store, they do not have vulkem 116, but they have 50+ products. Do they have an equivelant? I have no way of knpwing because I do not know sealants, their applications by types and results. Best sealant for the job, longevity, etc... I want to learn about all different sealants from a painter's latex to construction adhesives, to everything in between, so I can walk in a store with a need and make use of what is available and be armed with wisdom.

      I will check that link out to see if that is what I was thinking.

      Thank you for your help.


    2. mikeysp | | #6

      Hi Malcolm. I agree. But I did that in 2013 to the 21" skylight at the manufacturer'srecommendation. I was very leary, but he assured me it would old up. It made a believer of me... not to do that again; but, to be a champion of that Vulken 116 with metal to metal. That stuff worked so well. I think I examined it every year and it was like the day I caulked it. I did apply a VERY thick layer on the uphill side because I knew water would sit on it for day at a time in certain weater periods. I do not like skylights, probably less on a metal roof, but my kitchen design was not very wise and it really brought some wonderful light in.

      1. Expert Member
        MALCOLM TAYLOR | | #8


        I'm looking forward the advice you get here too. I only use three or four different sealants, and am not convinced it isn't out of habit rather than any specific knowledge.

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