Tool to cut plaster?


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Old 01-03-09, 03:58 PM
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Tool to cut plaster?

I need to make staight long cuts on plaster walls I try a brick chissel 2.5 wide but it does not make a clean cut, also it is very slow,I m wondering if there is a ''plaster'' cutting wheel that I can use with a grinder
Any ideas?
Thank you
 
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Old 01-03-09, 07:12 PM
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If the plaster is over wood lath it his harder to cut than if it is over gypsum lath or metal lath. If either gypsum or metal lath an abrasive masonry blade works well but raises an unimaginable cloud of dust. You will have dust everywhere and you will need a respirator to breathe and you might not be able to see the line to complete the cut in one operation. A shop vac held close to the blade will capture some of the dust until the filter clogs up.

Now if it's wood lath it's harder to cut the lath with the abrasive blade and in addition to the dust you will have smoke. But almost any other way of cutting the lath will vibrate it and some of the plaster will loosen and you will have a nice straight line in the lath but the plaster will be jagged. This is easy enough to fix but it will happen. A reciprocating saw will shake the lath worse than a circular saw.
 
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Old 01-04-09, 09:22 PM
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Thanks for reply, the plaster is over wood lath .
Im drywalling the DR as the plaster ceiling and two walls were beyond repair due to the removal of asbestos wraped heating ducts . I would like to save the beautiful plaster moulding . I need to cut the plaster clean and true to transition to the drywall and also to box a ceiling beam
Cheers
 
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Old 01-05-09, 12:02 PM
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Make the cuts well away from the molding then use a utility knife to score the plaster several times next to the molding. Change blades as often as necessary. Carefully separate the plaster that remains after your saw cuts from the lath. Then remove the lath up as close to the moldings as you can. The last lath may or may not be embedded behind the molding. Now on the ceiling side some of the lath will run perpendicularly to the molding. Those are the ones you want to be very careful not to vibrate for they hold the molding up. And if you cut them close to the molding the only thing holding them up is the end that is behind the molding. So I think, if I understand you rightly,
maybe what you should do is leave the lath in place on the ceiling and cut them at the first joist away from the molding. Then save some of the other lath and use them to fur down the rest of the joists so the ceiling stays flat. Screw all you can and use nails as little as possible to minimize vibrations. I hope this is clear.

Now you might find that the moldings are lathed separately from the walls and ceilings. This is good. It will give you better separation.

Can you post some pictures?
 
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Old 01-06-09, 09:37 AM
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I saw the picture you poster with reference to a header in the other forum. Now in that picture do I see the molding you reference here? See what I mean about the lath running behind the molding? Score the plaster next to the molding very well then remove the plaster and lave the lath out to the first joist. use some of the lath that you have removed to shim the joists down to the same level. Oh, now how do you attache the drywall next to the molding? If you screw into the lath they will probably split. Maybe use adhesive and some screws to hold until the adhesive sets. Maybe you can get to the area above and add a 2 X 4 nailer where you can screw the drywall next to the molding?
 
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Old 01-06-09, 08:53 PM
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<img src="https://i543.photobucket.com/albums/gg447/romeotango2009/mouldingl.jpg" width="768" height="1024" border="0" aPhotobucketlt="Photobucket">Thanks again tightcoat yes this is the moulding that i like to save Im sure I can find a way to attach the drywall nex to the moulding but I mnot sure yet how to finish the transition between the two,maybe JC sand and prime?
The bad part is that the moulding was taken down comletly from one wall and have no idea how to replace it,also as you can see there is a22'' piece missing where the duct is so saddly at the end I may have to get rid of it
 
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Old 01-06-09, 09:12 PM
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How are you dealing with the asbestos contamination the you are creating from the dust from the plaster and browncoat..
Why did you open the walls to expose the old duct..
Who said there was insulation on the old duct?
 
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Old 01-06-09, 10:44 PM
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Thanks for your concern about asbestos,
what you see are NEW DUCTS ,the old ducts wraped in asbestos were removed by a certified asbestos removal company,a type 2 removal .
Plaster in ceilings and walls were testd for asbestos before and NONE was found but lots of horse hair
 
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Old 01-07-09, 09:31 AM
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You didn't ask but I can tell you a little about plaster moldings. What you have were run in place. A real art. But you have enough molding that you can make molds and casts of some existing then attach the casts to the places that are missing. I don't know anytihng about molding and casting but there are plenty of people who do. Start looking around for them. You make the molds, make the casts, let them set and dry then you can cut them like wood moldings and stick them in place. You might have to deal with some joints for you want the sections to be of a length you can handle without them breaking but that is not too difficult. A setting type joint compound will fill the joints.

You are right to try to preserve this detail.
 
 

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