What to use to seal plywood

Discussion in 'D.I.Y.' started by fuz940510, Jan 14, 2019.

  1. fuz940510
    Offline

    fuz940510 Noob

    • APSA Member
    65%
    Joined:
    Aug 3, 2018
    Messages:
    23
    Likes Received:
    1
    Trophy Points:
    13
    Location:
    Weltevreden Park
    Hi everyone

    I'm curious about plywood aquariums, more specifically what to use to seal the plywood.

    A lot of forum posts and Youtube videos that i've seen use an epoxy paint, or fibreglass weave, or a liquid pond liner. Would it not be possible to coat all water-facing surfaces with a thin layer of aquarium safe silicone? If not, why not?

    Thanks,
    Kean
     
  2. Dirk B
    Offline

    Dirk B Aquascaper

    • APSA Member
    73%
    Joined:
    Aug 19, 2006
    Messages:
    2,004
    Likes Received:
    1,092
    Trophy Points:
    173
    Location:
    Somerset West, South Africa
    Hi Kean,

    Silicone can be punctured a lot more easily than epoxy or fibreglass which is one reason why you would not use it.

    Second reason you cannot apply it nice and flat and evenly over a surface.

    Third reason it is much too expensive.

    So go the Epoxy or fibreglass route if you must. In my opinion glass is cheaper and much easier to keep water-tight so why bother with plywood...

    Kind regards,

    Dirk
     
    postrus likes this.
  3. fuz940510
    Offline

    fuz940510 Noob

    • APSA Member
    65%
    Joined:
    Aug 3, 2018
    Messages:
    23
    Likes Received:
    1
    Trophy Points:
    13
    Location:
    Weltevreden Park
    Thanks Dirk

    The first and second point make sense, but would the cost be that bad?

    If you have an area of 150cm x 100cm, and you want a 3mm layer of silicone, you would need about 4500ml of silicone (assuming no waste, even layer etc) which would cost about R986 (17 tubes of 280ml sealant at R58 each).

    My experience with fibreglass is limited, so i have no idea how much resin would be needed, or how heavy the fibreglass weave would need to be.

    Maybe the costs will start to make more sense once you get into the mega-tank range - 500 litres and up. Plywood should also be a bit lighter than glass of the necessary thickness.

    Thanks,
    Kean
     
  4. Dirk B
    Offline

    Dirk B Aquascaper

    • APSA Member
    73%
    Joined:
    Aug 19, 2006
    Messages:
    2,004
    Likes Received:
    1,092
    Trophy Points:
    173
    Location:
    Somerset West, South Africa
    Hi Kean,

    Let us say that you install that layer of silicone and now algae starts growing on it. Now you have to scrub it and it is soft, so you scratch it and the whole tank starts leaking. This is the point I want to make regarding that it is not hard wearing enough.

    Fibreglass is basically applied by laying down a mat of glass fibre and painting it with a resin which is applied with a brush, and can be done quite rapidly. It dries nice and flat and smooth and is hard, and hard wearing. You could scrub it with a brush and would have no problems. The advantage of glass fibre is that you could also take the fibre around the corners thereby strengthening them considerably.

    I have never even considered making a tank of plywood, but I have used fibreglass and have fibreglassed boards for applications, and have found it to be very hardwearing and tough.

    My 2 cents worth.

    Kind regards, Dirk
     
  5. fuz940510
    Offline

    fuz940510 Noob

    • APSA Member
    65%
    Joined:
    Aug 3, 2018
    Messages:
    23
    Likes Received:
    1
    Trophy Points:
    13
    Location:
    Weltevreden Park
    Oh yes, maintenance...silicone would be no good on that front, no matter how many amano and nerites you have.

    Thanks for the assistance Dirk, my curiousity is sated.

    Cheers,
    Kean
     
  6. Dirk B
    Offline

    Dirk B Aquascaper

    • APSA Member
    73%
    Joined:
    Aug 19, 2006
    Messages:
    2,004
    Likes Received:
    1,092
    Trophy Points:
    173
    Location:
    Somerset West, South Africa
    You know that aquarium silicone rubber contains silanes which directly bond two glass plates together. The actual silicone rubber hardens when you push it out of the tube, but it does not have a huge amount of strength, and that is the actual problem.

    And then, besides the softness, the amanos and nerites that you mention are actual illegal imports, but every Tom, Dick and Harry seems to import them regardless.

    Kind regards,

    Dirk
     
  7. fuz940510
    Offline

    fuz940510 Noob

    • APSA Member
    65%
    Joined:
    Aug 3, 2018
    Messages:
    23
    Likes Received:
    1
    Trophy Points:
    13
    Location:
    Weltevreden Park
    Really? That's annoying...they do such a good job of cleaning up
     
: plywood

Share This Page