Viki Posted February 15, 2020 Report Share Posted February 15, 2020 The old plaster wedging tables in our guild studio are chipping around the edges, and worn down unevenly in the middle. I'd like to pour new plaster on top (after removing all the loose pieces, of course). Should I smooth the old plaster before adding a half inch or so on top? Or should I rough it up so it adheres? Other suggestions? Link to comment Share on other sites More sharing options...
liambesaw Posted February 15, 2020 Report Share Posted February 15, 2020 Remove all of the old plaster and use a durable plaster like hydrocal Link to comment Share on other sites More sharing options...
neilestrick Posted February 15, 2020 Report Share Posted February 15, 2020 The new plaster is not going to adhere well to the old plaster. A 1/2 inch layer will probably end up cracking. Your best bet is to remove all the old plaster and start fresh. Like Liam said, Hydrocal or Hydrostone will be much more durable than #1 Pottery Plaster. Link to comment Share on other sites More sharing options...
Viki Posted February 20, 2020 Author Report Share Posted February 20, 2020 Several years ago I did put ¾ inch of new plaster on top of a very old 3 inch thick plaster wedging board. It worked well until recently, when pieces started flaking off. As I repaired the table again, I discovered my mistake from those years ago. Back then, the ‘first’ pour of plaster was not sufficient to fill the space. Within a half hour, I mixed up another batch and finished the pour, overlapping and levelling the surface. So, the problem was that the two pours did not make for one working surface. Through normal use, the overlap areas weakened and flaked. Surprising to me, I was able to lift the entire ¾ topper in one piece. It did not adhere to the old plaster. It is still very strong. I’m going to cut it and use it for bats. A few days ago, I cleaned the old surface once again, and poured a single pour of new plaster. Letting harden for several days before using. I’m optimistic it will last for a longer time than the last time. Thanks for your thoughts. Link to comment Share on other sites More sharing options...
Liz A Posted May 29, 2021 Report Share Posted May 29, 2021 How do you remove the plaster? I made a wedging table and the plaster was apparently too wet. It now has quite a few gouges. The plaster doesn’t flake, but the indents are more than annoying. I would like to remove a few inches and pour more plaster. Suggestions? Link to comment Share on other sites More sharing options...
Chilly Posted May 31, 2021 Report Share Posted May 31, 2021 Old chisel? Leave the surface rough, with some undercuts for next layer of plaster to grab hold of. Link to comment Share on other sites More sharing options...
Jeff Longtin Posted June 2, 2021 Report Share Posted June 2, 2021 On 5/29/2021 at 1:29 PM, Liz A said: I made a wedging table and the plaster was apparently too wet. Can you attach a picture? What kind of plaster? Link to comment Share on other sites More sharing options...
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