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  1. #1
    Join Date
    Jan 2014
    Posts
    1

    Default what is sheetrock mud made of?

    I cannot get anyone to answer this question, even though I have contacted many mfg's. Are sheetrock mud and plaster the same thing? Is one superior to the other? Is current plaster very different from 1840 plaster? How do you patch old plaster from the Texas frontier, when they likely burned their own limestone rocks to make it? What is the best plaster product to use? Keep in mind that NO-ONE in Texas has plaster normally, so finding a suppler is iffy. What we have is sheetrock. I used sheetrock mud to patch this plaster,and wonder if I can skim coat it if necessary and have it last. Thanks for your help.

  2. #2
    Join Date
    Jan 2008
    Posts
    1,093

    Default Re: what is sheetrock mud made of?

    For the final skim coat and patching nail-holes, sheetrock mud can be used over plaster with good results, but the deeper plaster coats are entirely different products. Wikipedia has info on drywall mud here http://en.wikipedia.org/wiki/Drywall_compound and you can look up plaster there as well. With plaster rarely being used these days, many stores no longer stock anything but the smallest size bags or boxes for repair work, but all can order what you need.

    Phil

  3. #3
    Join Date
    Dec 2010
    Location
    Houston Texas
    Posts
    2,358

    Default Re: what is sheetrock mud made of?

    Plaster has white portland ceement in it. Drywall compound has none or very little. Plaster is much harder durable surface due to the ceement. Drywall mud is made largely with gypsum, a much softer, cheaper material.

  4. #4
    Join Date
    Jul 2010
    Location
    SoCal
    Posts
    5,066

    Default Re: what is sheetrock mud made of?

    "I cannot get anyone to answer this question, even though I have contacted many mfg's. Are sheetrock mud and plaster the same thing? Is one superior to the other?"

    The answers are as above, and can be found on line. They also differ in their uses.

  5. #5
    Join Date
    Jun 2009
    Posts
    253

    Default Re: what is sheetrock mud made of?

    The difference between plaster and sheet rock is the paper.
    Sheet rock is a mixture of gypsun , sand and water placed between two layers of paper and cooked in a kiln.
    The same mixture can be mixed on site and applied to the wall by hand.

  6. #6
    Join Date
    May 2008
    Location
    Pacific Northwet
    Posts
    1,356

    Default Re: what is sheetrock mud made of?

    Gypsum wallboard is a slurry of powdered gypsum and water with other additives, which is sandwiched between paper and dried. Premix gypsum "mud" is essentially the same stuff. Most if not all of the water is lost through evaporation as it dries.

    Plaster, while it looks similar to gypsum, is a cementitious product. To produce the plaster, limestone must first be baked to remove water (it becomes anhydrous). When mixed with water, it forms a chemical reaction where the water becomes a binding agent (it becomes hydrous), remaining a part of the plaster as it cures and hardens. While some of the water is lost through evaporation, most of it remains in the finished product. Plaster isn't dried like gypsum; rather it is cured.
    The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.

  7. #7
    Join Date
    Jun 2009
    Posts
    253

    Default Re: what is sheetrock mud made of?

    Plaster as used for interior work is a Gypsum product.
    Moulding Plaster , Keene Cement , Hydrocal Gypsum Cement & Gauging Plaster are all made from Gypsum rock.
    White finish plaster is a combination of Lime and any of the above Gypsum products most commond would be the use of Lime & Moulding , Gauging & Lime , Keene Cement & Lime very fine sand can be added to this one.
    Hydrocal & lime but this is very hard to work with as a finish.

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