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How was asbestos insulation put on pipes?

bwroga Member Posts: 44
We just had the asbestos insulation removed from the steam pipes in our basement and I got to wondering...how did they put it on in the first place? Was it installed as premolded forms, or was it a paste that was layered on? There were a lot of weird tight spots that I was unable to reinsualate with fiberglass.

And... was it just pure asbestos, or did it have other ingredients mixed in?


  • Jamie Hall
    Jamie Hall Member Posts: 23,415
    In most cases it was preformed sections for the pipes, which were strapped around them and attached with metal bands. Joints and the like were covered with a paste-like material containing asbestos.

    I'm honestly not sure whether it was pure asbestos, but I doubt it. I'd have to really look closely at some I've got left around here, and I'm not really keen on doing that!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Jellis
    Jellis Member Posts: 228
    It was the wonder material! The article about the guy who liked to use a square of asbestos under his hard hap to keep cool is something else!.
    JUGHNE Member Posts: 11,074
    An uncle said the powder was like flour, they would pour some in a bucket, (with a cloud of dust rising), add water to mix to a paste/sticky mud.
    It was then applied, for the most part by hand, to the fittings and odd tight spots you speak of.

    I have a 1961 school with fiberglass clam shell insulation on the straight pipe section and then the asbestos mud mix on the fittings. Perhaps that was about the transition time of insulation materials.
  • pecmsg
    pecmsg Member Posts: 4,880
    As a 1 st year apprentice we mixed it once. Dry powder add water make a paste.

    I know too many coworkers that died from it!
  • Intplm.
    Intplm. Member Posts: 1,992
    The stuff was used in cigarette filters. Back in the old days when they said smoking was good for you.
  • Docfletcher
    Docfletcher Member Posts: 487
    edited January 2019
    When I worked in a power plant long ago, We would crawl along on top of asbestos coated super heated steam pipes to vacuum the soot off. We waved a broom ahead of us in case of a super heated steam leak. It was said the broom would burst in flame even if just a pin hole leak. I was very young then so I'm not sure if they told me the whole truth. :) After all they had no problem sending me to the tool room for a can of instant steam and six feet of umbilical cord. :(
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
    I'm pretty sure it has plaster of Paris in it. Dry powder, add water to get whatever consistency you want and work it on by hand. They also used rags or something similar to layer it kind of like a cast for a broken limb is done today.
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
    JUGHNE Member Posts: 11,074
    Tarenton (spelling?) cigarettes, IIRC, had the special Micronite pellet in the filter which was rumored to be the finest grade of asbestos......I think some of the ads showed a guy with a black eye with the wording "We would rather fight than switch" (brands that is).
    That I recall this, shows the impact of TV ads of the 60's...and why one of the first anti-smoking measures was to ban TV ads for cigarettes. It was thought any brand of cig ad showing a light up would cause all smokers watching to automatedly reach for a smoke...I know from personal experience. :/
    These ads benefited all the tobacco companies.

    I thought the straw broom theory was the steam could cut the straws in half, giving you warning to not walk there.
    EBEBRATT-Ed Member Posts: 15,605
    Just like @pecmsg mentioned I started in 73' I can remember going to the supply house and buying a bag of "loose asbestos" to cover the boiler fittings.

    Dumped it in a pail and mixed with water. You mixed it as stiff as possible and put it on the fittings with your hands. Usually more fell off onto the floor than you got on the fittings. It was a mess.

    When it dried it tended to crack. We used to mix in some Portland cement with it so it dried harder.

    Luckely, I didn't do much of it.

    Still alive....so far.

    As I recall it was late 70s-1980 when it was sort of baned

    The old "snowman" or "robot" boilers we busted it off with hammers when we changed a boiler. no masks...no nothing
  • mattmia2
    mattmia2 Member Posts: 9,734
    I've seen both pipe and duct fittings wrapped in an asbestos soaked canvas tape (and newer stuff that maybe isn't asbestos) that i assume you soaked in water then unrolled as you wrapped it around the joint.

    There is a web site that has pictures of thousands of different asbestos products out there somewhere.
  • mattmia2
    mattmia2 Member Posts: 9,734
    Aircell looks like it was sheet that was wrapped around then secured with a metal clamp.