$9.23
CLICK THE "LEARN MORE ABOUT THIS ITEM" LINK JUST BELOW TO READ THE FULL DESCRIPTION FOR THIS ITEM.
*************************************************************
PROMPT REBATE ON ORDERS WITH 3 OR MORE “FreeShip” ITEMS! WANT TO KNOW YOUR TOTAL REBATE BEFORE PURCHASE? CONTACT US!
Please note the "instructions" are in this description.
--> For other related cement materials: <--
https://www.etsy.com/shop/NorthernWestStuff?ref=hdr_shop_menu&search_query=cement
Brief instructions (see below for more details at "More on how to use"):
Please note that this material has a recommended proportioning of 19 (some sources say 18 to 20) parts of water to 100 parts of drystone. It is a thick paste like mix, but if you tap the container it will flow down in the cup (or mold) and level off. As with all gypsum cements and plaster, it's much more accurate if you proportion it by weighing. It eliminates any guesstimating and results in the optimal end product.
Gypsum cement shares the basic principles as plaster mixing: Always add the cement to the water, never the other way around.
Slowly sift the powder into the correct amount of water, let the water wick up the mound of powder and wet it, then start stirring. Use cold water at first, it will extend the working time. Use disposable plastic cups to mix it in (if you reuse a container it will accelerate the set so you won't have time to mix).
This is a gypsum cement. USG is the largest manufacturer of plasters and gypsum cements in the world and this is one of their products. There are maybe a dozen different gypsum cements. Think of them as "super" plaster. You mix them with water using the same tools and methods as plaster (if you're not familiar, the basics are: sift the plaster/gypsum cement gradually into the correct amount of clean water, then mix. Those last two are crucial. You must use the correct water/plaster ratio or your end product won't be as strong, and the better you mix it the better the physical properties will be. A jiffy mixer on a drill is preferable). There are charts from the manufacturer that give the water/plaster ratio for each type of plaster/gypsum cement.
I should mention that if you've used plaster but never the higher grades of gypsum cements, you're going to be surprised with how "thick" they are. One of the things that make them so strong is the relative-to-plaster low water ratio you need to use. They've added deflocculants so they will flow with a very little added water (if you know something about clay and slip, you'll know what deflocculants do). As a result of the low water usage it is very much a thixotropic material: stirring it (making it move) will allow pouring it, but if it sits motionless it will become paste-like. You just need to get it moving by stirring it so you can cast it.
Here's a nice brief chart giving essential mixing info (from Laguna Clay):
http://www.lagunaclay.com/support/plaster-mixing.php
Here's a good page from USG on Drystone:
https://www.usg.com/content/usgcom/en/products-solutions/products/industrial-and-specialty/art-and-statuary/usg-drystone-casting-media.html
Here's a very technical pdf on plasters and gypsum cements from USG:
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&ved=0ahUKEwj_iqqoxN3OAhVB2WMKHU_uDB0QFgg3MAQ&url=http%3A%2F%2Fwww.usg.com%2Fcontent%2Fdam%2FUSG_Marketing_Communications%2Funited_states%2Fproduct_promotional_materials%2Ffinished_assets%2Fplaster-mixing-procedures-application-en-IG503.pdf&usg=AFQjCNF7ckKZCt9Ad99M16sXqZZjjZN5aA
More on how to use ("instructions"):
Weighing is always the best way. If you have a digital lab scale that will measure grams (they are very inexpensive nowadays, check Amazon), weigh out the water and the gypsum cement powder. These types of gypsum cements want to be correctly proportioned. They are deflocculated like clay slips are (thus the thixotropy) to minimize the amount of water needed.
If you don't have a scale?
Forget about all of the above and do this instead (it's a bunch of guesstimating):
Start with just a 4 or 6 oz container with a small amount of water (couple tablespoons or so) in it and start sifting hydrostone into it. Keep adding until you've got a mound of powder a half inch or so out of the water. Wait some seconds to see how high the water wicks up the mound for future reference (it should be just high enough to suck about all the water up into the mound), then start stirring. It should be paste-like but still stirable, and still be able to wet all the powder into a smooth consistency. If it stirs too easily you don't have enough powder in it. Sprinkle a little more in, since this is just a test. It should take some noticeable effort to stir. When you think you're there, pour it out of the cup onto some flat surface. Tap the cup as you pour. If it was a larger amount (like a quart), gravity would provide some force to keep it moving and pouring. It should form a thickish puddle on a flat surface and then stop flowing as its momentum slows. If it all flows off the surface you used too much water. If it won't pour out of the cup with tapping, just spoon it out onto your surface, then tap the surface. If it stays as an unmoving blob of cookie dough and doesn't spread out then you used too little water.
It would help if you repeat that a few times with just very small amounts until you get a feel for how far you can push the water/drystone proportion towards very viscous, but still being able to flow with tapping. The setting time is dependent on temperature, thickness of the casting, and the proportion of water/cement you ended up using. Poke at the puddle over the next hour or so to get a feel for how fast it sets. Using warm water speeds the set.
All of the above guess work is eliminated if you have a scale.
And there is a wealth of sources about these materials on the internet above and beyond what I'm citing. (Please note that I have other materials in my shop which could fit into this 'cementitious mixes' category. To locate them do a shop search on "Colloidal", "Thixo", "Cab-o-sil", "Cement", "Kaolin", and "Calcium": Calcium Chloride is a cement accelerator and Calcium Sulfate Dihydrate (raw gypsum) is a pozzolan).-
=======================================================================
1-2 business days
I'll do my best to meet these shipping estimates, but can't guarantee them. Actual delivery time will depend on the shipping method you choose.
Buyers are responsible for any customs and import taxes that may apply. I'm not responsible for delays due to customs.
But please contact me if you have any problems with your order.
We're sorry, but at this time we do not ship internationally.
If you would like a smaller or larger quantity of a raw material, click the "Request a custom order" button and tell us how much you would like. Or just contact us and let us know what you'd like. We'll get back to you ASAP.
This problem usually occurs with multiple items. We have free shipping on many of our items. In your cart items will have the sum of all embedded shipping costs. If you place an order for 3 or more "FreeShip" items, you will receive a "rebate" for the excess shipping. The more items you have the greater the shipping refund will be. You can also message us to ask what the total cost of your order will be when excess shipping is refunded before you purchase.
Or, if you see "Request a Custom Order" or "Message Seller", you can request a custom order and your items will be put in a custom listing with the correct shipping. You would purchase it like any other listing.
If you have a technical question about an item we've listed, please don't hesitate to ask. We enjoy helping people out with a material or a process.
We give anecdotal information in our listings if we have any. If you disagree with it or think we're being inaccurate or misleading please let us know that, too.
If there are discrepancies in any of our listings let us know, we make mistakes like everybody and we'd like to be set straight and get those mistakes corrected.
May 18, 2021
Shipping was cheap and fast, got a rebate back on it too, and the powder is high quality - seller was very polite and answered my questions promptly and descriptively. Absolute legend of a shop, highly recommend!
Laura
Aug 8, 2019
Fast - and the owner is very helpful
N M
Oct 29, 2017
BigFluffy Bear
Aug 25, 2017
This is a great and thorough seller! About the fastest shipper in the universe! I can't wait to use this material in my work. With his great instructional page, I know I'll do well!
Ellen R. Willingham
