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Construction adhesive for backblocking?

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  1. #1
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    Default Construction adhesive for backblocking?

    G'day, Happy new year and all. May '21 be better than '20.
    I'm plastering a set of cathedral ceilings, approx 8 sheets across so backblocking definitely required. Mixing a small batch of backblocking cement for each sheet join and cleaning up after is a major PITA.
    Any reason fast grab construction adhesive couldn't be used for backblocking?
    Regards
    CA

  2. #2
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    Hi, i used to cut 200mm to 300mm wide strips of gyprock sheet from scraps, and i would place small blobs of stud adhesive along both sides of each blocking piece and fix that over the sheet joints to strengthen the joint before starting the jointing work, and it always seemed to work, sometimes i would use Parfix Maxi nails glue, which also seemed to work very well.

    This youtube video shows the plasterers doing a huge ceiling, at the 2 minute mark you will see them back blocking, using offcuts of plaster sheets with back blocking cement on one side....... https://www.youtube.com/watch?v=yL0O0tfpsBY

    I have seen blokes cutting blocking strips from plywood bracing sheets, as well as cutting blocks from left over stud framing, and these idiots would just screw those blocks in place along the tapered joint edge of the sheets, some would use stud adhesive, others would use stuff like liquid nails.

    I have never used the proper blocking cement myself, only because i already had stud adhesive or Parfix Maxi adhesive at hand, and used those instead.

  3. #3
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    To slow the setting of the backblocking cement you can add lemon juice.

  4. #4
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    Quote Originally Posted by droog View Post
    To slow the setting of the backblocking cement you can add lemon juice.
    Will this lemon juice cause any issues with the adhering properties of the backblocking cement ?

    Backblocking cement appears to be very similar to cornice cement, however i still think stud adhesive would be a better way to glue backblocks, would be quicker as well.

  5. #5
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    Quote Originally Posted by Bridgyguy View Post
    Will this lemon juice cause any issues with the adhering properties of the backblocking cement ?

    Backblocking cement appears to be very similar to cornice cement, however i still think stud adhesive would be a better way to glue backblocks, would be quicker as well.
    Check out here.
    https://www.how2plaster.com/

    Rod Dyson is a member on here, adding citric acid to slow down, and salt to speed up any of the setting compounds is a common practice. Has worked well for me.

    Stud adhesive is quicker, but if you experience cracking latter on I am sure the small gain will be very quickly forgotten.

  6. #6
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    Quote Originally Posted by droog View Post
    Stud adhesive is quicker, but if you experience cracking latter on I am sure the small gain will be very quickly forgotten.
    Not sure what you mean in the last part of your reply ?

  7. #7
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    Gents, thanks for your responses. The essay question to be answered is not about slowing or accelerating setting of backblocking compounds, it is about whether or not alternative adhesives will work. Droog suggests use of stud adhesive - hadn't thought of that - might result in cracking. Why? And same question for construction adhesive?
    Almost anything is better than mixing and cleaning up small quantities of backblocking cement - which certainly looks like cornice cement to me - for each next sheet to be installed.

  8. #8
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    Have always used cornice cement for backblocking.

  9. #9
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    Quote Originally Posted by phild01 View Post
    Have always used cornice cement for backblocking.
    I would have thought cornice cement would have been the ideal choice over mixing backing cement, especially if cornices are going to be fixed to the ceilings, no need to buy blocking cement.

    When i was doing all my own gyprock work i rarely used cornices, most of my work was square setting around the ceilings, and for me stud glue or cheap construction glue like Parfix or liquid nails was what i always used for blocking out.

  10. #10
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    Cornice cement, i use for back blocking make a small batch when you need it, a builder doing a knock down next door taught me while i was doing up the hallway

  11. #11
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    I think Liquid Nails or similar is going to win this time. When you put up sheets - as the family plastering team does - at a rate of about 1/hour, mixing either cornice cement or backblocking stuff for one set of joins just adds another cleanup task. If I had a spare hand for the camera phone, I'd record the next daunting task for Funniest Home Videos .... the family stick up a 90mm cornice 4500mm long on a cathedral ceiling, high part 3700 off the ground. Give us all patience.

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    ....dont like the idea of liquid nails. Skins over too quickly. Have tried that in the past for patch up jobs but never really happy with the results.
    Last 2 jobs I'd done, we used the same blue gyprock stud adhesive on the back blocking and seems to work really well. Going up into the ceiling days later to check and its stuck rock solid. Long work-ability times.

  13. #13
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    Quote Originally Posted by Bart1080 View Post
    ....dont like the idea of liquid nails. Skins over too quickly. Have tried that in the past for patch up jobs but never really happy with the results.
    Last 2 jobs I'd done, we used the same blue gyprock stud adhesive on the back blocking and seems to work really well. Going up into the ceiling days later to check and its stuck rock solid. Long work-ability times.
    OK, that's a possibility I hadn't thought of. Any adhesive that doesn't require mixing and can be slapped onto one edge then the other ... I likes that. Forum folks in general, any objections to using blue bog for backblocking?

  14. #14
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    you can get actual backblocking adhesive. boral and csr both make it.


  15. #15
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    There would not be a plasterer that at some time or another that has not used stud adhesive to back block, myself included.

    FYI I did an inspection of a home that had been back blocked using stud adhesive where all the joins had cracked. The joins were taped with fiberglass tape. You can guess what my recommendation was. The fact is that back blocks must be adhered to the sheet over the entire surface of the back block not just a dab here and there.
    GREAT PLASTERING TIPS AT


  16. #16
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    Quote Originally Posted by Compleat Amateu View Post
    I think Liquid Nails or similar is going to win this time.
    If, somehow, liquid nails or equivalent does win please be aware that I have had old liquid nails (or other construction adhesive) deteriorate and lose its adhesion after a couple of years. In some jobs this may not be a problem but I would think in your application that may be a real problem. I'm sure that not all construction adhesives deteriorate over time but do you know which ones will and which ones won't?

  17. #17
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    Quote Originally Posted by Compleat Amateu View Post
    OK, that's a possibility I hadn't thought of. Any adhesive that doesn't require mixing and can be slapped onto one edge then the other ... I likes that. Forum folks in general, any objections to using blue bog for backblocking?

    ...Not a possibility, it just wont last the distance.
    Also when back blocking the links below gives you an idea of just how much adhesive you would need which is why it comes in a bag to mix up. Check out the 1.20 mark of the first link
    Like I said, for an amateur job if you didn't or wont use the proper back blocking adhesive, then your next best is stud adhesive...use plenty like in the link

    https://www.youtube.com/watch?v=8sl-_WbySDk
    https://www.youtube.com/watch?v=P8fFsnZVEL8

  18. #18
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    While stud adhesive can work it can create a further problem if it bleeds through the sheet joins. Just use the powder whether it be cornice cement or what Sol pic'd.

  19. #19
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    I watched the guys when they do my jobs. They screed the adhesive on with a notched trowel. looks like theyre tiling.

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