Talk:Plaster

Plastering Picture

I think the picture (here) previously heading this page may not be of plastering at all, so I've taken the liberty of changing it to one which is quite unambiguous. T'old pic was described as "Gypsum-based plaster used in spray fireproofing", but normal gypsum doesn't stick to what appears to be a metal roof structure, which doesn't in any case usually need fireproofing. Gypsum plaster sprayers normally have a single, large, tube, but the the spray rig shown has two colour-coded (resin and hardener) tubes and one large (air) tube, which is typical of the polyurethane foam sprayers used to insulate metal roofs. I know that a modified gypsum-resin-fibre material is sometimes sprayed on metal structures, but I'm not sure this is it. Could I be wrong? Glynhughes (talk) 11:00, 6 July 2014 (UTC)

[[Image:Fireproofing.jpg|thumb|250px|[[Gypsum]not]-based plaster used in spray fireproofing in a low-rise industrial building in Vancouver, British Columbia.]]

Metal roof structures absolutely need to be fireproofed. Not because they burn but because they expand and deform if heated either pushing the walls out or collapse thus the building collapses. IE: it is a heat-protection. — Preceding unsigned comment added by 202.8.39.83 (talk) 05:06, 15 February 2017 (UTC)

Medical plasters

Some how we need to find a better wasy to deal with plasters used in medicine such as Mustard plaster. I know this is mainly a historical topic but we do need to cover it. I dislike that this whole page be about paster of paris. If I knew anything about these medical plaster I would try and fix it. But I was just looking to link to such information.--Birgitte§β ʈ Talk 01:40, 5 October 2006 (UTC)

Really, this is just a few more articles away from becoming a mere disambiguation page. All thats needed is a good article on the many different cultural uses of the word, set to branch out as chunks become too long. Zaphraud 09:29, 13 January 2007 (UTC)

I think there is a huge need to include the medical orthopedic uses of Plaster of Paris. It is largely used in fracture and serial casting procedures. It is the original casting material and still remains as one of only two largely used products for such a large area of emergency and rehabilitation medical practice in place today.Chubbyblondebabe 21:50, 12 February 2007 (UTC)Chubbyblondebabe

Origins of

Shouldn't there be some mention of this? Jachra 21:14, 20 February 2007 (UTC)

Yes. Here is the reference to history of the name Plaster of Paris

http://www.galleries.com/minerals/sulfates/gypsum/gypsum.htm

SmokesLikeaPoet 16:33, 3 August 2007 (UTC)

Dangers of Plaster of Paris

http://newsvote.bbc.co.uk/1/hi/education/6485481.stm

I'm interested to know more about this. There's not much here about plaster being dangerous! Does the plaster re-heat up when you mix it with water? no not particuraly usually it just fogs but some would argue that it can cause cancer but you would have to inhale or what drug users would say is huff a very,very large Proportion of it to even have a soft case of sneezes.

Hi, Yes there is an endothermicexothermic reaction, although this is not really “news“ as it has been known ever since plaster was first used, which dates back to at least The Romnans ThanxTheriac 18:05, 25 March 2007 (UTC)

I would have to disagree to the Silica / Cancer relationship. Silica is known to cause ( or correlate with, I'm not sure ) cancer in laboratory animals. http://www.cdc.gov/niosh/npg/npgd0553.html

in construction grade plaster of paris the concentration of silica is less than 1% by mass.

http://www.dap.com/docs/msds/english/00071008E.pdf

I highly doubt that apsirating even a large quanity of suspended plaster of paris dust would cause anything greater than a case of the sneezes. I think this wording should be altered to qualify the statements.

SmokesLikeaPoet 16:27, 3 August 2007 (UTC)

New evidence is suggesting that inhaling plaster can be extremely harmful particularly in the long term regardless of silica content. This is taken very seriously in professional industry. Safety instruction on plaster instruct to use gloves when handling dry uncured plaster, and to wear an appropriate respirator when mixing plaster or sanding cured plaster. I'll pull up some sources later. -Verdatum (talk) 18:20, 8 February 2008 (UTC)

Copyvio text from Minerva Conservation

I removed a large amount of text that was a direct copy of http://www.minervaconservation.com/articles/externallimerenders.html. If the topic of lime rendering in historical conservation is pertinent to this article, then the text should be properly cited and written in an author's own words, not directly copied. --Elkman ^(Elkspeak) 19:47, 3 May 2007 (UTC)

History

This article needs a history section explaining the invention/discovery and whatnot. -- Beland 02:12, 31 August 2007 (UTC)

Plaster Vs. Plaster of Paris

I am under the impression that 'Plaster' and 'Plaster of Paris' are not synonymous. I have always understood that plaster of paris is a specific formulation of plaster that is fairly weak and inexpensive. High performance gypsum plasters are almost never referred to as 'plaster of paris'. I will do more research on this. -Verdatum (talk) 18:14, 8 February 2008 (UTC)

The original plaster of Paris is much more expensive and highly refined than normal plaster, and used for casts of sculpture etc, not in building. I agree the article is in a mess over terms. Johnbod (talk) 16:57, 4 October 2008 (UTC)

Plaster vs Faux Plaster

In this article there is mention of plaster being used in the faux painting industry. All of these plasters are actually mixtures with film forming agents in them and should be classified as paints. There is a lot of industry confusion because manufacturers are trying to capitalize on the concepts of "authentic plaster" but I am almost certain that they are not. The term Faux plaster or textured paints would be more appropriate. The images that are shown are veneer textures that were applied over paint and contain poly resins and are technically thick paint made to look like plaster. —Preceding unsigned comment added by 76.25.45.143 (talk) 04:32, 9 March 2008 (UTC)

Split

This article should be split apart, with an overview left here, and the things split off into individual articles. Especially, plaster of Paris needs to be split off and clarified. 76.66.195.159 (talk) 13:37, 12 December 2008 (UTC)

Lime plaster already has its own article, but Plaster of Paris redirects here, and certainly does need its own article. I think the meaning of the term has varied considerably across time and space, which causes confusion. Johnbod (talk) 13:50, 12 December 2008 (UTC)

At this time there is not enough content to justify a split. If someone is able to write a plaster of paris article, that would be wonderful; however it is not currently well defined here. The other sections are all relatively small, and well within the scope of plaster. If any section becomes larger, as to encroach upon WP:SIZE or begins to give the appearance of undue weight, we can split it off at that time. -Verdatum (talk) 18:23, 14 January 2009 (UTC)

How its made

how do you make regular plaster??? idc about all that other stuff i just wanna know how to make it!!!!!!!!!

Assuming you're talking about standard multifinish plaster, it's made out of gypsum (the same stuff that blackboard chalk is made from). Ground into a very fine powder, various other things added. There are different varieties and formulations, but (most) modern plasters are based on gypsum. —Preceding unsigned comment added by 81.107.183.201 (talk) 03:17, 22 March 2009 (UTC)

Chemistry in Lime Plaster

There's a statement in the section about Lime plaster that doesn't look quite right to me:

"the calcium hydroxide turns back into limestone."

Doesn't limestone refer to the rock as it comes out of the ground? I think it would be more accurate to say that it turns back into calcium carbonate, but I might be wrong. Can someone with more knowledge about the chemistry behind it either a) change it to be more accurate or b) tell me that I don't know what I'm talking about? Thanks. EricWesBrown (Talk) 00:07, 6 October 2010 (UTC)

Was it plaster of Paris?

Since I use often (and touch) plaster of Paris (hydrated calcium sulfate) for home repairs, I can'believe the plaster reported in "Safety Issues" to have burned a girl's fingers was pure plaster of Paris. I suspect it was a mixture containing lime, which is extremely dangerous if it is not properly hydrated. The references speak of plaster of paris, but they all are from newpapers, and we all know that if a press agency reports a fact, all newspapers will report the same thing. Does someone have a different source? I think in a safety matter it is important to be accurate. --GianniG46 (talk) 16:07, 23 November 2010 (UTC)

Please re-read the sources again, the answer is fairly obvious from http://news.bbc.co.uk/2/hi/uk_news/england/lincolnshire/8303246.stm - The girl in question had a problem with removing her hands after the plaster set quickly, and the temperatures reached up to (at least known/reported) 60C. Its not uncommon that plaster would reach these temperatures, and higher, when setting. Especially in large quantities near the center. 60C for an extended time certainly could cause issues when the heat has no chance to escape. 198.147.192.8 (talk) 18:39, 1 December 2011 (UTC)

Stenciled plaster?

You have an image captioned, "Example of a stenciled plaster design" but do not discuss/describe this anywhere within this article, although you detail a number of other techniques. If this is part of the "plasterwork" section, then perhaps list it there -- I did look at the plasterwork article, and it isn't there either. However, it seems like an interesting technique, so, I'd like to see a bit more info, e.g., what kind of plaster, where was it used historically, is it used today, is it part of the original plastering or applied later, etc. Zlama (talk) 03:52, 10 February 2012 (UTC)

Types of plaster used in building work

It would be really useful to have sections on the different types of plaster used in building work such as Undercoat plaster, Bonding plaster, Multi-purpose (one coat) plaster, Finish plaster etc. They are presumably made in subtly different ways and probably have additives. Anyone with the required technical knowledge who could add the required sections ? Thanks  Velella  ^{Velella Talk}   20:22, 2 February 2014 (UTC)

plaster/ σοβάς in greek. please add this

Ο σοβας (ή σοφας) είναι το γνωστό σε όλους μας επίχρισμα που εφαρμόζεται πάνω από εσωτερικούς και εξωτερικούς τοίχους για την προστασία και τον καλλωπισμό τους, κατά τη διάρκεια της εργασίας που ονομάζεται "σοβατισμα". Οι ρίζες της λέξης είναι τουρκικές, όμως σαν υλικό είναι γνωστό εδώ και εκατοντάδες χρόνια, με παραλλαγές βέβαια ιδιαίτερα τις τελευταίες δεκαετίες, όπως θα δούμε στη συνέχεια.

Αυτό ακριβώς λοιπόν θα αναλύσουμε, τις διάφορες παραλλαγές σοβα που υπάρχουν πλέον διαθέσιμες στην αγορά, τις εφαρμογές τους, αλλά και τη σύσταση του παραδοσιακού σοβα, που ακόμα επιλέγεται από πολλούς κατά το σοβατισμα. Άλλωστε είναι σίγουρο πως η ποιότητα του υλικού παίζει μεγάλο ρόλο στο τελικό αποτέλεσμα!

Ξεκινώντας λοιπόν την ανάλυση για τον σοβα, να ξεκινήσουμε από την πλέον γνωστή λύση, τον παραδοσιακό σοβα. Πρώτα από όλα για όσους δεν το γνωρίζουν μπορεί να εφαρμοστεί τόσο με ειδική μηχανή για σοβατισμα, την επονομαζόμενη πρέσα, είτε και με το χέρι. Για πιο μεγάλες επιφάνειες βέβαια επιλέγεται ο πρώτος τρόπος, αφού είναι πιο γρήγορος αλλά και οικονομικός, ενώ αν γίνει με προσοχή θα είναι και ένα αρτιότερο αποτέλεσμα εμφανισιακά.

Ο παραδοσιακός σοβας λοιπόν αποτελείται πρωτίστως από 3 υλικά, την άμμο, τον ασβέστη και το τσιμέντο, τα οποία αναμιγνύονται με νερό. Βεβαίως σχεδόν πάντα το τελικό μείγμα ενισχύεται με πρόσμικτα, όπως ρητινούχα γαλακτώματα, ενισχυτικές ίνες και latex, ώστε να αποκτήσει επιπλέον ιδιότητες και αυξημένες μηχανικές αντοχές. Επειδή όμως ως γνωστόν το σοβατισμα γίνεται σε 3 στρώσεις, σε κάθε στάδιο συστήνεται διαφορετική σύνθεση του σοβα, για βέλτιστα αποτελέσματα.

Κατά την πρώτη στρώση που είναι γνωστή και ως "πεταχτό", αναμιγνύουμε μόνο άμμο, τσιμέντο και νερό, με σκοπό να δημιουργήσουμε ένα αρκετά λεπτόρευστο υλικό που θα δουλεύεται εύκολα με το μυστρί. Η συνήθης αναλογία για αυτό το σοβα είναι 25 κιλά τσιμέντο (1 σακί) με 75 κιλά άμμο (3 σακιά), ενώ προσθέτουμε λίγο λίγο το νερό, μέχρι να πετύχουμε την επιθυμητή σύσταση

Στο δεύτερο χέρι που ονομάζεται λάσπωμα οι αναλογίες αλλάζουν, ενώ βεβαίως προσθέτουμε και ασβέστη. Πιο συγκεκριμένα για κάθε 25 κιλά τσιμέντου (1 σακί) χρειάζονται 225 κιλά άμμου (9 σακιά) και 125 κιλά ασβέστη (5 σακιά), ενώ προσθέτουμε και νερό. Τέλος για την τρίτη στρώση του σοβα (το μαρμάρωμα) το τσιμέντο που μπαίνει είναι λευκό - αντί για γκρι - και για κάθε σακί 25 κιλών μπαίνουν 225 κιλά μαρμαρόσκονη (9 σακιά) και 125 κιλά ασβέστη (5 σακιά).

Αυτές είναι σε γενικές γραμμές οι αναλογίες του παραδοσιακού σοβα, όμως προσοχή χρειάζεται και στην ποιότητα των υλικών αυτών που θα συνθέσουν το τελικό υλικό. Έτσι λοιπόν συστήνεται να επιλέγονται πιστοποιημένα υλικά όταν είναι εφικτό και να προτιμάται άμμο χονδρόκοκη αντί για ψιλή, μαρμαρόσκονη επώνυμη, ασβέστης καλά σβησμένος και βέβαια ποιοτικό τσιμέντο χωρίς τσιγκουνιές στην αναλογία.

Από την άλλη τα εργαλεία που χρειάζονται για το σοβατισμα με παραδοσιακό σοβα δεν είναι και τα πλέον σπάνια και συγκεκριμένα θα χρειαστεί μυστρί, σπάτουλα λείανσης, δράπανο, τριβίδι, αναδευτήρας και ένα δοχείο για την ανάμειξη και κατασκευή του επιχρίσματος

source: http://www.sovatismata.gr/sovas — Preceding unsigned comment added by Atsimas (talk • contribs) 16:47, 1 January 2015 (UTC)

Please observe that this is an ENGLISH article! — Preceding unsigned comment added by 202.8.39.83 (talk) 05:18, 15 February 2017 (UTC)

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Lead

Err...@Johnbod:....the lead hasn't changed much.....Cas Liber (talk · contribs) 21:16, 20 January 2016 (UTC)

Merge discussion

I suggest separating out the material from the uses of it, and having one article on plaster of various sorts, and one or more on its uses (decorative, functional, historical uses?). Large chunks of material would need to be moved between articles, with a good scope definition with link to the other pages in the lede, so the overlap doesn't happen again. HLHJ (talk) 13:08, 13 February 2016 (UTC)

Oppose on the grounds that the overlap doesn't seem excessive, and sections are already adequately linked to their main articles. Each of the 3 pages, Plaster, Stucco and Plasterwork, has its own distinctive character. Klbrain (talk) 22:06, 13 February 2018 (UTC)

faux paint and stucco

What's the durability of stucco and faux painting plaster Kuforiji ayoade (talk) 21:59, 15 March 2018 (UTC)

The plaster is made of plaster

"Cement plaster is a mixture of suitable plaster, sand, Portland cement and water". What is meant here by "suitable plaster"? Is there an extraneous comma (i.e. is it supposed to be referring to sand suitable for plastering)? Iapetus (talk) 09:33, 21 February 2022 (UTC)

"Hydrocal" listed at Redirects for discussion

The redirect Hydrocal has been listed at redirects for discussion to determine whether its use and function meets the redirect guidelines. Readers of this page are welcome to comment on this redirect at Wikipedia:Redirects for discussion/Log/2024 October 29 § Hydrocal until a consensus is reached. Utopes _{(talk / cont)} 07:18, 29 October 2024 (UTC)