How to Make a Plaster Slab for Wedging and Recycling Clay | Mixing & Pouring Plaster w. Measurements
ฝัง
- เผยแพร่เมื่อ 12 ส.ค. 2024
- How to make a 12"x18" plaster slab with full measurements! You can use this to wedge your clay on, or to recycle your clay. Directions, supplies list and measurements below! Please like my video and Subscribe to my channel for more fun art videos!
SUPPLIES LIST:
►No.1 Pottery Plaster (I used 10lbs per mold:: amzn.to/3koocwH )
►*Cold Water (for my 10lbs, I used 14 cups)
►Mold for the cast (I used a 12x18 sheet pan:: amzn.to/2U6KIQj )
►**Mask (for when you are working with the powder, as you DO NOT want to breathe in plaster powder… das bad)
►Metal or rubber rib (for smoothing out the top)
►Spray bottle of rubbing alcohol (for breaking the bubbles at the surface of the plaster)
►Work space (a space you are willing to get pretty messy. I covered my table with a trash bag.)
►Bucket for mixing (I also lined my bucket with a trash bag for easy clean up)
►Gloves (so you can mix the plaster with your hands and clean up easier)
DIRECTIONS:
1. Prepare your work space and have your mold ready. You don’t want to be setting stuff up while your plaster is setting, get all of that ready first.
2. Pre-measure your cold water and plaster mix in separate containers.
3. Add your plaster mix slowly to the cold water. (DO NOT add the water into the plaster mix, DRY GOES INTO WET)
4. Work the mix with an immersion blender or your hands to get all of the lumps out and ensure the mix is well mixed. (I just used my hands)
5. Pour the mix into the pan. (Since I wanted the bottom of the pan to be the top of my wedging surface, I poured in about ½” first and let that sit about 5 mins while working out the bubbles by tapping the sides, to ensure that part was extra smooth.
6. Pour remaining mixture into the mold. (Pouring over your hand helps reduce bubbles and pour the plaster a little smoother.)
7. Smooth the surface with your favorite rib tool.
8. Tap the sides of the mold to bring bubbles to the surface.
9. Spray the top with a couple mists of the rubbing alcohol to break the surface tension and pop the bubbles.
10. Check the plaster every 15mins, tapping the sides and respraying the alcohol until the mold is firm.
11. When the mold is solid (it will still feel a little cool and damp), you can dump out your shiny new wedging board/clay recycling board (or whatever you’re making). For me, this took about 45 minutes, but I am in Texas and it is July. In cooler months and climates, the plaster could take a little longer to set up.
12. After you remove your board from the mold, while it is still a little damp, you can trim it up a bit with your trim tools, rib, or whatever, to smooth out any sharp edges, lumps, bumps and what-have-you.
13. The mold will take 2-4 days to dry completely, depending on how thick you made it, and the climate where you live.
SHOP FOR SUPPLIES:
►Wilton 12x18 Sheet Pan:: amzn.to/2U6KIQj
►No.1 Pottery Plaster, 5lbs:: amzn.to/3koocwH
►No.1 Pottery Plaster, 50lbs:: amzn.to/3yTom3o
REFERENCES:
Plaster Mixing Chart:: www.aardvarkclay.com/pdf/tech...
☼ SOCIAL LINKS AND DETAILS ☼
PATREON: Support my art:: / bluenosetrading
DISCORD: Let's hang out:: / discord
WEBSTORE: Buy things I made:: www.bluenosetrading.com
INSTAGRAM: See what's up on the daily:: / bluenosetrading
MUSIC: Awesome jams, made in house:: "Pleasant Tune" / bird.song.productions
I like the cake pan idea, I need to do this. Thank you for the video.
You are so welcome, thanks for watching 😊
Thank you for your very clear instructions.
You are so welcome! I'm glad to be a help 😊
This was very helpful! Thank you so much.
Glad it was helpful! Thank you for watching ☺️
Great video!
Thank you!!!!!! ☺️
nice, this is exactly what I'm going to do .....we have a plan!👍
You can do it!
Thank you. I think It’s important that the tray / container you are using should having sloping sides. If you use a container with straight sides, it may be very difficult to persuade the plaster cast to emerge because the mixture expands as it sets. I once tried to make a plaster batt in a round cake tin with one of those push-up bottoms. Perfect I thought, I can push the mould out when it’s set. But no, the expanded plaster was completely wedged into the tin. End of cake tin.
That's a good point to take into consideration. The pan I used here did not have any trouble releasing the mold. I do think this pan has a very slight slope as well. Good to know, thank you for sharing!
I like the star bucks apron
Thanks!
Very good video ! Can you tell me where you got the table that you are using for
your video. Are you using saw horses and piece of wood ? It seems nice and solid ! I am starting to
work with clay and need to get myself a small inexpensive work table.
I got it from Costco! They usually have them in stock around the spring time. It's a pretty decent work table. There are definitely sturdier options out there, but it would be a lie to say I don't use it all the time. It collapses into a nice little flat bit with a handle and it's lightweight. It was originally my husband's for woodworking and I adopted it when he upgraded.
This was a great tutorial! Unfortunately, I dropped my mold out too quickly and it cracked, is there any way to fix this without redoing the whole process?
Thanks for watching! Unfortunately plaster is a chemical reaction.. so it can't be undone, and I'm not sure of any way to connect pieces together. Sorry that happened!
Hi, thank you for this detailed video! I followed this to make a plaster slab. It’s been one week of drying, the surface is a bit “powdery” to the touch.. I wonder what it means.. does it mean it isn’t set and need more time to dry, or can I simply wipe the powder off.. is it safe for me to start using it to dry wet clay without mixing some of the plaster powder in it…
Thank you!!!
It's hard to say without seeing it. But if it's solid, it should be fine. A little powdery texture is a bit normal. I'd wipe it down and go for it. Unless it is crumbling. The main thing is that you don't want chunks of plaster in your clay. Sorry I can't be more helpful!
Hi and thank you for the helpful tips!! How did you decide to use 10lbs of plaster? I followed the mathematical instructions of a different video because I wasn't sure where to start with how much water/plaster to use for my specific container and it turned out HUGE. I wasted a ton of plaster and am hoping to try again. Without being able to rely on experience, how can someone figure out how much plaster they should use, given the dimensions of their container? Thanks again!
Thanks for watching! The plaster came in a bag of 10 lbs, and the ratio calculator said it worked out for the pan size. Here's a link to a plaster volume calculator if you're using a different mold or pan plaster.glazy.org/
Thanks a ton for responding!
what's the difference between this plaster and the standard plaster you find in a carton at the hardware store or craft store?
Hey Melissa, great question! There are a lot of different types of plasters. Let's go with plaster of Paris from a hardware store vs the Pottery Plaster #1 I'm using. The Pottery Plaster #1 is made from a higher quality gypsum, and forms a harder mold that is stronger and more suitable for heavy use.
How long after it dries until you can start to use the slab?
I started wedging on mine almost immediately. I'd say it takes 2-3 days for it to be completely dry. The drier it is, the better it will be at absorbing moisture, but it works well enough pretty much immediately after it's set. Give it a nice wipe first to get any loose plaster bits so they don't go into your clay.
just poured mine waiting on it to dry 18L x 26W x H2, four gallons of plaster
Awesome! I hope it serves you well.
@@BlueNoseTrading well I hope so but its not out of the mold yet and I do have a bunch of clay that needs to be dried out and used
did you use a release agent for the pan??
No, I didn't use anything except a pan with plaster straight into it. Thanks for watching :)
well mine is out of the mold a few days ago and looks great but it is taking forever to dry completely. How long does it normally take for one of these things to dry out enough to put it in use?
It really just depends on the ambient temperature and humidity where you live
@@BlueNoseTrading I put fan on it got it dried out and fixing to throw my second batch of clay on it now ....we cooking with gas now baby!!!!
How did you calculate water to plaster ratio??
I calculated the plaster ratio using this chart from aardvark clay :)
www.aardvarkclay.com/pdf/technical/Plastermixinginstructions.pdf
can i put wrap in the mold for ease of removal?
I don't see why not. I'm not sure if it will or won't make it easier, so let me know if it helps!
hi! is it ok to use normal plaster? There's no pottery plaster in my country
There are a lot of different kinds of plaster, so its hard to answer with certainty... I can tell you that pottery plaster is stronger and harder than plaster of Paris. SO if you use plaster of Paris, you would have to be extra careful not to break off any tiny bits into your clay.
The main point of the plaster is that, in general, plaster is porous and absorbent. I would say your best bet is to try out what is available to you, and see how it behaves. If it's absorbing well, and it isn't leaving pieces in your clay, it's probably fine to use. You might have to do some testing, and you may end up just needing to be a little more careful with your plaster slab.
Thanks for watching, I hope you find a solution. If you want to comment again with your findings after testing, it might be helpful for others here. 😊
안녕 Andrea, I had the same problem in Germany and found out that I had to search for calcium sulfate plaster or alpha gypsum- normal plaster is beta gypsum- I ended up finding it by searching for "plaster for slip moulds" or supraduro plaster, maybe you can find a local potter in Korea who makes moulds for slipcasting, they will be using this plaster and maybe can help you buy it? All the best x
I think i’ve seen people just add a layer on canvas to the top of the plaster to avoid any chucks getting into your clay. The plaster still works (any kind really) to pull out the moisture, even through a layer of canvas. Great video I can’t wait to try this!
Will plaster of paris work?
There are people who have used it, but it's a much weaker form of plaster. Pottery plaster would be preferable.
@@BlueNoseTrading thanks for sharing
Wont the plaster dust stick on the clay?
The plaster used is Pottery Plaster No. 1, which is specifically designed to be used in ceramics. It's made to be used for both wedging surfaces and casting molds. If any minute amount of plaster gets on your work, you can just wipe it off the bottom. In my experience, there isn't really any "dust" to speak of after the plaster is set.
I tried ... so far epic fail.
The second time I tried, I messed it up really bad. I think my plaster was too old. The age of the plater matters I think.