Asked on Nov 20, 2018

How do I remove spray-on insulation foam?

Nancy TurnerHandyGirlOliva


I recently bought a window air conditioner which had that spray on insulation all around where it fit in the window. It's rock hard and I had to use a knife to pry it out of the window. Needless to say, there is some left on the unit. How do I remove the rest of the foam from around the air conditioner without destroying the unit?

3 answers
  • Oliva
    on Nov 20, 2018

    Hi, Phyllis,

    You'll need a box knife or scalpel (available at college stores where biology labs require dissection tools) to carefully remove the remainder.

    It's tedious work, and requires use of protective gloves. You can cover areas without foam, using paint tape or similar, that won't mar the finish, yet allows you to easily see where you need to trim.

  • HandyGirl
    on Nov 20, 2018

    My can says acetone if it’s still tacky but must be mechanically removed once cured. I’m not seeing the unit but I’m assuming the outside edges are metal or hard plastic. Cut as much as you can off with a knife then use your palm sander with a 60 grit then up to 220 grit. Once you are satisfied you got enough off, you can spray paint the areas you sanded.

    • Phyllis J Holman
      Phyllis J Holman
      on Nov 20, 2018

      So sorry, I forgot to take a picture. The foam is on all four sides. It's going to take a lot of effort, but I'm a stickler when it comes to appearance (even if it is going in my garden shed.)

  • Nancy Turner
    Nancy Turner
    on Nov 20, 2018

    A safety razor blade in a holder may do the trick, just make sure the blade is sharp and undamaged and change it as necessary if it gets full.

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