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Found 20 results

  1. Hi, has anyone ever converted a woodworking lathe to make plaster models for casting? I'd like to try turning a few models in plaset, but reluctant to fork out £2.5k for the machinery. Curious to know if anyone has used a table-top woodworking lathe for this purpose and any tips on how to do it? Becca
  2. Hello. I have a hige problem with bubbles in my work. It is slipcasted porcelain in a closed mould. Does anyone know what the problem could be? The air shouldn't be trapped as there are enough holes in the highest places. The bubbles are inside and on top and bottom of the casting. I would really,really appreciate any help!! Anna
  3. Hello everyone, I am hopefully going to be embarking on a journey soon enough of selling some log cabins. I am hoping that I can figure out a way to make a mold of the design so that I will have an easier time producing them. Here is a LINK to some pictures of one. I am wondering if, with some modifications, a mold is able to be made of a complex shape such as this? The roof is separate and I would be making a separate mold for it. Are the amount of details added, such as the window panes and door frames too much detail for a mold master and would be better added afterward? The windows themselves would not be cut out yet of the mold master but is the hollow inside a problem? I am thinking since it is hollow than it would have to be a slip cast mold but since there are so many over hangs I am guessing it would not just slide out easily? Would a two piece slip cast mold work though - that is split horizontally? This way it just pops off? As for my slip cast mixing question. I've been doing some research and see that sometimes people say it has to be mixed for hours while other instructions only mix for 10-30 minutes maybe. Are hand drills with say a jiffy mixer used often and successfully in mixing slip or do industrial mixers need to be used? Thanks in advance for any advice and I hope this makes sense.
  4. Hello, I'm no artist or sculptor but a classics graduate with a passion for Classical art and sculpture. I am in need of advice from professionals regarding a recently acquired a bust from a car boot sale. I purchased this for £16 and was hoping it might be possible to refurbish it for a Grey stone/marble look like the traditional classical sculptures and busts. I have taken this to an antique dealer who did not particularly care for it and appeared to want me gone knowing he would make no money from me. He believes the material is plaster as it was cold and sounds hollow. I also have taken this to the local Warhammer store where the staff were very interested and friendly and appeared to be knowledgeable. They remarked that the hair, base and drapery appear to be a kind of putty added after while the rest appears to be ceramic. He sanded a little off the bottom of the bust and when the paint underneath came away he was almost sure it was ceramic. I would like to restore the piece because of the numerous brush strokes visible all over and the rather haphazard painting where certain parts have been left bare. The Warhammer chaps suggested I begin with Acetone to reduce the brush marks down and then gentle sanding if that fails and they have kindly offered to paint/spray it in store with me when I reach a stage in which it can be done. My main questions are: Can anyone identify this material purely from the images I've provided? (I'm located in Cambridge UK if anyone local can help) Is the advice of Acetone and sanding good? I don't want to risk losing detail or damaging the piece overall, but I'm aware once I begin this process there is no going back. Is there any other recommendations for what to do? Apologies if any of this sounds stupid, I simply have no idea when it comes to painting, stripping paint, sculpting or materials. I'm only familiar with art styles and forms of the ancient world. While this is clearly neo-classical inspired, it's modern so I know virtually nothing on how to approach this.
  5. I am new to ceramics and have recently started teaching art is a school two days per week. The other art teacher is also not a ceramicist. The current practise in the school it to discard clay ‘waste’. This is loads of clay so I have been working on recycling. I have dried discarded clay and rehydrated it for over a fortnight in a large bucket and made two large plaster bats to dry the rehydrated ‘slip’. Two questions: 1. Despite having been cast five days the plaster bats feel slightly cold to the touch - does this indicate they are still drying and not ready to use? 2. I have used one of the bats to begin the ‘drying’ process of firming up the rehydrated clay over night and flipped it onto the second bat this morning. All seems to be fine but the original bat now is damp from the clay sitting overnight. I have more rehydrated clay to process. Should I wait before sitting the next batch on the plaster and if so how do I know the plaster bat is ready to use again? Hope this makes sense!! John
  6. Greetings good people please help me. I am an apprentice potter who's master works almost exclusively in porcelain and I've stained her plaster wedging table with a completely different clay body. I don't know it's name but it's a red clay, much stiffer, which fires to cone 11 where her porcelain is fired to cone 6. Is there a way to clean the pigment out of the plaster, and if I can't is there a risk it will contaminate her white clay in the future, will the pigment dredge up out of the plaster as she wedges? Part if me thinks it's harmless but I'm afraid I've ruined her table. When I've made reclaim in the past white crystals have formed on the surface as the plaster dries, will the red remove itself that way if I add water to the affected area? I really don't know what to do.
  7. Hi there! So my question is very basic but I just want to know the best way to fix a plaster mold that has broken. I have used in weld to fix all my broken ceramics and it has worked beautifully, but I wasn’t sure if it would work on plaster? Another thing I was going to try was to use plaster to glue it back on, but wasn’t sure if that would work either so just wanted to ask for some advice first. Thanks! Nate
  8. Hello, this is my first post so apologies if my question is greener than Robin Hoods long Johns! I have created a plaster (Crystacl-r) mould, originally cast from a newplast (oil based clay like plasticine) sculpt I made. The aim is to paint thickened silicone into it to make some animatronic skin for a creature I'm creating. Anyway, I am having a right old time cleaning the plasticine out of the plaster mould. I've tried casting a layer of latex to pull the bits out, using a hair dryer to attempt to melt the plasticine, using wooden tools to try to scrape it out (which ends up scarring the plaster ) all to no avail. I read somewhere that you can use water and detergent on the mould, but as it is basically a plaster of Paris will this not get absorbed into and ultimately wreck the mould? Can anyone suggest an effective method of cleaning plasticine out of crystacl-r plaster mould, that will not damage the details on the plaster at all? All suggestions welcome... Many thanks in advance! J
  9. Hi, I want to make a slab of pop for wedging. How thick should the plaster be so that it doesn't crack? I want to make a wooden frame and fill with plaster. Thanks in advance. Have a good week Andrea
  10. Hey! any advice on how to hang this or product recommendations would be great! The piece is about two feet across and as you can see in the pictures is made up of five pieces. The center piece has a crack down the middle. I was instructed to repair this with plaster. My local Lowes has a Plaster of Paris. Is this plaster good to use? My plan on hanging the piece was to mount it to a piece of wood or plexiglass(?) with glue, although I'm not sure what type of glue would be best. I also was planning on putting a satin or glossy coat over the outside pieces - any recommendations? Thanks!
  11. Hi there, I thought someone here may have the answer to this frustrating issue. I have been slip casting and all of a sudden some of these molds started transfering layers of plaster to the porcelain slip after using them for some time. Some of these moulds were a couple of months old some were a couple of years but they all started doing this at the same time. I made new moulds and they started doing the same thing after about 15 casts.They all staretd ddoingit at the smae time again. Loosing fine layers of the plaster onto the porcelain slip cast clay. I have attached some images below both of the moulds and the porcelain with the plaster attached. Also some extra into Also there is no other obvious deterioration of the mould on the outside. Only the small fine layer that has peeled off inside. I am casting a piece a day. It is winter here, but I have a heated studio. I'm using imperial porcelain slip. These moulds I made myself out of potters plaster and are part moulds. I cast very fine works 2-3mm thick They are from different batches of plaster the first and second time. I alowed the moulds to completely dry before using them (no dampness transfered onto newsprint overnight) The moulds that I use plastic clay in are fine! Any ideas? I have asked around a bit in my circle but so far everyone seems perplexed. One thought is that I'm not letting the moulds dry out enough between times. That maybe casting once a day is to much for a plaster mold to take? I' needing to make a lot of work using these designs so I am casting daily and letting the moulds sit over night empty, but it is cold. I'm desperate to keep using them.
  12. From the album: Monoprinting with plaster

    Tile I made using a plaster slab, underglazes and porcelain casting slip, learned technique in Andrew Wandless' book 'Image Transfer on Clay' and also Joanne Veevers on CAD. This is still in greenware stage, not entirely sure how all of those colors will look as bisque and then glazed
  13. I am looking to support a biscuit fired lattice structure so i can machine it. I will then need to remove the plaster any advice appreciated. If I enclose it in paster of paris and fire it will the plaster fall away from the fired ceramic if i submerge it in water?
  14. I'm interested in experimenting with alternative porous materials suitable for slip casting, with useful properties such as flexibility, faster drying, increased durability, machinable, etc. Can anyone suggest plastics (foamed PVC, polyurethane, etc.) or other plasters (eg: Hydrostone) worth looking into? Thanks!
  15. Hi guys, I have some pieces I want to cast in plaster for a mould. The pieces will not be particularly flexible and I worry they wont release properly. Its a basic vase shape that narrows in at the top like a pair- this taper part is a 6cm diameter x 8cm long pipe that I feel the plaster will grip too tightly to release and slip out. I haven't had much luck with soft soap and I'm wondering could I rub a candle on my piece to give it a shiny and slightly slippery surface for the plaster to cast? I worry it will ruin the porosity of the mould though. Has anyone done such a thing? Other solutions are welcome but I'm mostly wondering if wax will ruin plaster or there are similar products that wont. Cheers!
  16. Hi All, I have just finished making over 200# of plaster molds for our local Art Center and have come up with a few questions. This is not my first time to make , but with the quantity I made, I seemed to have a variety of different ‘problems’. I actually only ‘lost’ about 5 pieces of 50, so I feel quite successful as I do not work with plaster that often. With your help, perhaps what I perceived as ‘problems’ will not repeat in future mold attempts. For my molds I used new pottery plaster. I weighed out my water and pottery plaster, as directed with my molds, to the ratio of.7 . Plaster was sprinkled over the water and then left to slake for 2 minutes. I then mixed gently from the bottom, getting rid of all lumps. Then I let sit a couple minutes more, gently mixed, and poured it gently into silicone sprayed molds. (Most of the time the plaster settled/slaked under the water but several times not all of the plaster settled so I had extra mixing – I did not notice any difference in my water temps or time – any ideas why it did not settle – plaster set up quickly). I learned that water should be cool rather than warm or it sets too quickly. Several times, altho the plaster was mixed well, as it set in the molds, a thin layer of water formed on top – what did I do wrong? (I just laid a paper towel on the plaster to soak up the water.) Also, twice the plaster did not even get warm - why? But it set up and appears OK. I thumped my molds on the floor after filling to get rid of air bubbles but occasionally I had a few, very small, bubbles show up. They don’t look large enough to cause surface problems in my clay – we’ll see. I have been told to wait to fill the molds until you can draw a finger across the mixed plaster leaving a slight indentation in the mixed plaster surface – is that right? At times it then seemed to set very quickly once I started to pour. I did learn that different brands of silicone release differently. Molds have dried nicely by placing them in the area of our wood burner – can do a lot more at a time rather than in an oven! However they do take about 4 days to dry. Thanks for your comments! They are always appreciated! I learn so much from this forum!!
  17. Hi, I am having problems with some plaster slip- casting molds that I use regularly. I made the molds in March this year and suspect I have cast into each around 30 times. Over the summer they have sat unused for two months in a dry cupboard. I have gone back to use them and I'm finding the casts are now more reluctant to pop out. They seem to be sort of sucked in there and the plaster doesn't want to release the cast. They are five part molds and sometimes just one side seems to stick on, as if it can't take the moisture out of the slip - even if the rest of the cast is relatively dry. The casts will come out in the end but they are taking longer than before and I risk ripping the casts when removing them. Does a mold have an expiry date? Could there be anything I could treat them with? Please help! Thanks, Elle
  18. Hello, This is my first post, so please be gentle I just finished making my first plaster wedging table, and I'm experiencing something odd. No matter how much I sand, scrape, and clean the surface, little specks of plaster are contaminating my clay as soon as it hits. I've attached a photo. As far as I can tell, I followed the instructions for mixing the #1 pottery plaster. I also vibrated the mold to remove bubbles, and I've waited several weeks for it to fully dry. Has anyone ever had this problem? I know I could switch to another surface material, but I've always preferred how the clay moves on plaster, and I cherish it's quick-drying qualities. Any help would be greatly appreciated! Thanks, Matt
  19. Greetings all, I have been making mugs with tiki faces carved in them. I have made molds that have been working so I can reproduce them fairly quickly. The problem is that the molds chip very easily, leaving holes in the mold which then create unwanted that then have to be smoothed out after the pouring and drying. My question is: Is one plaster better or more durable than the others? I have been using pottery plaster #1. However, at my ceramics supply company that I order from I see that they have a number of different types of plaster: Plaster, Hydrocal White with 4500psi compression strength Ceramical Gypsum Cement with 6500psi compressions trength Puritan Pottery Plaster with 2400psi Compression Strength Pottery plaster #1 has a 2000psi compression strength. I'm going to go out on a limb here and guess that the higher the compression strenght, the harder the plaster. If someone could confrim this, that would be great Second question: Who has used a "harder" plaster for mold making and what are the disadvantages or advantages you have found? Still kind of new to the mold making and production process and trying to avoid the years of trial and error, so any information would help a bunch. Thanks, Brian
  20. Hi there, this is my first post on this very helpful site. I can't seem to find much information anywhere about using rubber to make mold masters for recreating slipcast molds. I have been experimenting with making rubber masters of my molds (mostly 2 to 3 piece molds). But I find that whenever I pour a new mold from the master, they don't quite fit together as well as the original. I have experimented with a few different types of rubber, but am limited to products that don't need degassing. Is there any one particular product that is recommended for use in this situation? I've attached a couple of photos to show how I am constructing my masters. The blue handle mold was made using Smooth-on Oomoo 25 (which is very soft), and the light colored one was made using Polytek Polygel 35. Any little tips or tricks would be greatly appreciated. Thanks
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