DIY Help Please - Quick Question about Silicone

Hi,

Sorry for the noob question, but what silicone does one use to seal a kitchen sink?

Noticed some minor water damage and mould on the shelf below our kitchen sink, upon inspection it appears water must occasionally seep through between the bench and under the lip of the sink if we don't wipe the bench dry; i.e. the sink was not sealed with silicone completely or parts have disintegrated since.

Just wondering what silicone sealant I should use? Just basic 100% silicone? Something like this? Or something else?

I'll ask the "experts" at Bunnings if all else fails…

Any other tips welcomed…

Photos attached if interested.

Photo 1
Photo 2
Photo 3
Photo 4

Thanks in advance,
DJK

Comments

  • +1 vote

    Yes, that'll do fine. Getting a smooth clean line will take a few tries so practise first and be prepared to wipe it off quickly.

  • +4 votes

    Yes, that's the exact silicone I'm using to redo my sinks and tiles. You also need to buy one of those guns for a few bucks. For extra points, get one of those little plastic scraper thingy so you'll have a nice finish too. Your sink looks like it will want the clear silicone instead of white.

    Edit: here is the scraper from Bunnings.

    • +1 vote

      And inject the silicone ahead of the gun
      Working right to left like this

      <—
      /________

      don't drag silicone behind, like this

      <—
      \________

      It sounds illogical, until you do it. You get a better job straight out of the gun and you're pressuring silicone into the gap rather than pulling it out of the gap as you progress.

  • +1 vote

    The silicone you linked will work but sometimes kitchen sink manufacturers sell specific neoprene seals. Those work betterer.

    •  

      Hmmm, retrofitting something like that (if it is what I think it is) seems way over my basic skill level…ha

  • +1 vote

    It needs to be taken out, clean old sealant off than reapply and set sink back in place. Then put something heavy in sink until silicone dries.

    •  

      😫 I suppose that would be the most prudent way to do it, but I was planning to just scrape away as much of the old sealant from underneath the lip of the sink on the top of the bench and redo that…then also try and add/patch up the parts around where the dried water marks are underneath the bench…taking it out and doing from scratch seems like a lot of effort and I would likely do a crappy job or damage something else in the process…the kitchen reno was "professionally" done only about 18 months ago! 😡

      • +1 vote

        id be contacting them as 18m for a professional reno to have an issue is too soon.
        says a bit about workmanship etc. perhaps even a product failure, if it has a seal strip, perhaps it split etc.

        •  

          Well they haven't come back to finish and fix other stuff despite constant emails, so not holding my breath.

      •  

        As above this is really the only proper way to do it. You will get the best seal and cleanest finish. Lifting the sink out isn’t that hard and you just put the sealant in and squeeze it out and clean the edge. Given it was done by pros a year and a half ago call them and get them back.

  • +4 votes

    I use breast implant grade silicone as I like to play around with it first

  • +1 vote

    It’s super straight forward.

    Scrape away old silicone (around the entire perimeter)

    Apply new silicone (the linked one is fine) with a caulking gun

    Use a scraper (or credit card) to get that nice consistent profile.

    Allow to dry for a day or two.

    You can’t go too wrong, if you stuff it up, simply scrape away and start over. You can also do a test application on some piece of scrap timber to get use to how the caulking gun and scraping works.

    There’s tonnes of silicone in that tube, put some cling wrap over the nozzle when you’re done to help it last a bit longer, but it generally cures and then you get a tube of solid silicone.

    •  

      Yeah, I assumed so. Only issue is the lip is super thin, like 1-2 mm (see photo 4), so I doubt a scraper/credit card would work.

      • +1 vote

        Hmm I see… could also try lifting out the sink, applying the silicone underneath the lip and then dropping the sink back in. In order to get the sink out you will have to disconnect the bottom drain/pipe (?maybe unscrew at the u bend/trap) can’t see if the tap spout is connected to the sink… but this is probably too much dicking around, and I’m unsure if this will work. Maybe a last resort.

        Nice sink and bench top by the way, ceasarstone? How’s the CR-V?

        •  

          Yeah, definitely last resort I think.

          The CR-V is good, drove up to Port Macquarie and back a few weeks ago…some torrential rain in parts, but we survived.

          Had to do the 20k service early again in Jan at about 16k because of the warning light though :(

          • +1 vote

            @John Kimble: I’m guessing you didn’t get a year in between services… 10k, 12months, or when the maintenance minder kicks in, whichever is the earlier… it’s pretty expensive for what it is. The 1.5L turbo engine takes less than 4L of oil per change.

            My one is chugging along. Has about 12300 on the odometer. We did our 10k service at 10.5k, my wife drives it and she reached that mileage in about 8 months. Her workflow has since changed and she only does short trips these days, we might get to 12 months, although, i’m guessing her local commutes will trip it into the ‘extreme driving conditions’ category and the maintenance minder might kick in early.

  • +2 votes

    My tip for getting silicon perfect.
    Apply masking tape in a stright line to both surfaces. Apply silicon. Dip finger in soapy water and wipe once. Remove masking tape. Now you have the exact correct quantity of silicon. Wipe again once with soapy finger. Resist temptation to touch again - you will make it worse. If there are any gaps or holes wait until it has dried and repeat. Perfect results every time

  • +1 vote

    I can’t find it on bunnings website but you can also buy a small tube of sealant that you squeeze out by hand like toothpaste. Perfect for small jobs and it comes in clear and white. In the caulking section. Save you buying a gun you won’t need again and is about $6 for the tube.

  • +1 vote

    I used this
    https://www.bunnings.com.au/kinetic-assorted-size-sink-seali...

    Lifted up the sink, scraped off the old tape, put it back down.
    It was a lot easier said than done.
    The cut-out for the sink was a bit big, so getting it aligned so the tape sealed was difficult (took me many attempts).

  • +2 votes

    My suggestion would be to get a plumber out who can disconnect the pipework underneath the sink, detach the clips holding the outer lips of the sink to the bench top, and then reseat the sink in a silicone bead underneath the sink. You’re much better to do this can stuff around trying to silicone over the top of the sink and the bench top because it will look shitty, and the silicone will just wear away.

    Sinks come with a seat of rubber foam that sits between the bottom of the sink and the top of the bench, it’s possible that the foam might have been disturbed in places, or might have some missing pieces that has allowed water to get through.

    Honestly, after doing a hell of a lot of siliconing myself, it’s an absolute pain in the arse to get a clean finish, so if it was a small job, and a focal point I’d just hire a plumber because it will be done heaps quicker, and you’ll get a good finish.

    Just my thoughts.

    If you do go down the DIY route and you do lift the sink from the bench, use turps to clean up the bottom of the sink, and the top of the bench, wait for it to dry, and then use a clear wet area grade silicone, like a Sika or Selleys would be fine, and wipe up any left over before it sets because it can be a pain to remove afterwards.

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