Chemical Forums

Specialty Chemistry Forums => Citizen Chemist => Topic started by: billnotgatez on October 08, 2006, 11:35:18 AM

Title: Plaster of Paris
Post by: billnotgatez on October 08, 2006, 11:35:18 AM

Plaster of Paris once it is set up is not very soluble or reactive. Is there anything that reacts with it to form soluble products? Preferably not producing something noxious like sulfur dioxide. Maybe something like drain cleaners would be nice, but I get the feeling they will not work.

Plaster of Paris or calcium sulfate hemihydrate
http://en.wikipedia.org/wiki/Plaster_of_Paris#Use_in_sculptural_arts
is related to
Calcium sulfate
http://en.wikipedia.org/wiki/Calcium_sulfate
and to
Gypsum or calcium sulfate dihydrate
http://en.wikipedia.org/wiki/Gypsum

Title: Re: Plaster of Paris
Post by: Yggdrasil on October 08, 2006, 12:55:42 PM

Since acid rain can cause damage to many statues and monuments, I assume that some type of acid would work to dissolve plaster.  You can try some small scale experiments to see which acids (if any) work safely enough and act at a fast enough rate.

Title: Re: Plaster of Paris
Post by: Bakegaku on October 08, 2006, 08:18:29 PM

Ick... I tried using plaster of paris for some moulding recently to no avail  :-\

Anyway, Couldn't you turn it back into an anhydrate by heating it, similar to the way Copper (II) sulphate would.  That way it would be similar to the original substance, if you were planning on remoulding it.

Title: Re: Plaster of Paris
Post by: billnotgatez on October 09, 2006, 03:11:23 AM

I am more interested in cleaning up and unclogging drains. From reading the Wiki sites I posted, I am not sure that acids will work especially phosphoric acid.