My favorite casting products are Dental Stones shown on the Dental Stone page. I believe these are the best and most durable casting materials to use for your projects.
However, there are many other less expensive products available so I've compiled this list of product reviews from my customers. Please note that I have not tested these out personally, so I can't guarantee that the reviews are accurate. Also, the information on each product may be incomplete because these reviews were given to me by customers from the message board on my web site. Many of the reviews have been edited for space.
If you want to purchase some of these products listed below, it's best to go to your favorite search engine and type in the name of the product you want. Several companies should be listed who carry these products. I would also suggest looking at GypsumSolutions.com. They are a wonderful resource for finding the properties of different kinds of plasters and where stores are that you can purchase them.
If you have information on a product that you like, please e-mail me at firstname.lastname@example.org. so I can add it to the list shown here. The products listed below are in alphabetical order.
I used to use high quality plaster for all my modelling, but later found out that the highest quality plaster is more or less a mixture of cheap plaster and cement. Cement is the binder in concrete without the rocks and you can find it at most lumber yards. I've experimented with this and found that 3 parts plaster of paris mixed with 2 parts cement will have almost the same durability as dental stone, but costs only as much as plaster of paris.
Plaster of paris and cement are about the same price, you just have to buy twice as much for twice the price- even this is usually cheaper than going straight for the quality products. So long as you don't put in too much cement (no more than 2 fifths for walls, etc... and about a quarter for detailed work) it will have the same quality as dental stone. -Toomy
Finally getting back to model building and wanted to try Denstone, 50lbs for $33.57. I love it. I'm never going back to any other material. I'm mixing it thinner than recommended on the net (about 150ml to 300g vs. 60ml to 300g) and it's setting well. Still having a few bubble problems, but that's due to my pouring technique and not the plaster. Overall, HIGHLY recommended, and you can't complain about free shipping for a 50lb box! -Eric
I too have tried the Denstone Dental Plaster and will never go back to PoP or Hydrocal. This stuff is great!!. It does mix thinner than plaster but has fewer air bubbles and is much stronger. The sales rep who I purchased the product from even threw in a vibrating table for free!!!. I use the vibrating table after I pour the plaster and Bruce's Blocks come out bubble free. Dental plaster is definitely the way to go if you can get it. -Brian
I just picked up my second 50 lb. box of DenStone. It on has about half the strength of Die-Keen (9,000 psi vs 18,000 psi), but it only cost me $29.50. It's plenty strong for my tastes. -Tim
I too am using Denstone and I have been happy with it. (Keep in mind that I have been doing this for only one day!) I paid $20 for a 25 lb. box. My only complaint is that it doesn't seem hard enough, I think I will try the Die Keen next time. ($38.00 at my local dental supply store.) -JerekMace
I have been absolutely thrilled with the die stone from orthocast.com. I can mix and pour 3 batches. By that time, the first is ready to be scraped. Buy the time they are all scraped (and pour the scraped plaster into other molds) the first pieces are ready to be demoulded. Once all pieces are demoulded, I start mixing and pouring again. I tend to mix it thick, I seem to get better results that way. -Llama
I have to agree with Llama about the Die Stone. I read about his initial recommendation and ordered 50 lbs last week. The company was incredibly friendly and actually knew what I wanted ("your going to build castles, right?"). It mixes very well and is very very strong. Bruces instructions for Dental Plaster (Die Keen) work perfectly for Die Stone. -Tony
Durhams Rock Hard Water Putty
Having worked with Durham's Water Putty often, I can say the stuff is great. VERY dense, strong enough to drill, but best used with small pieces. Large pieces are a bit more brittle and and will shatter if dropped. Great stuff for making bricks though. -Bryan
I recently went to Home Depot to see what type of alternatives they had. Well I picked up this stuff called Durhams Rock Hard Water Putty. On the back it says it can be used for moldings. I figured what the heck, it is only about $4 for 4 pounds. It is a really fine powder that mixes with water like any other plaster. BUT, this stuff is SUPER STRONG. I was really surprised at how strong this stuff is. I just took one of the 1/2 x 1/2 x 1/4 blocks and stuck a knife in it. It took a LOT of pressure to split the block. It is a lot stronger than the plaster and light weight hydrocal I have been using. -Mike
You can view the manufacture's website at www.waterputty.com (has some interesting suggestions). It is available at Home Depot for $4.93 (plus tax) for a 4 lb. cylinder or in lesser amounts.
A good casting mixture is noticeably harder than plaster of paris. It takes about three times as long as plaster to set enough to remove it from the mold, but retains significant malleability during that time so it is useful for sculpting as well as casting. When dry it has a peach or cream color similar to light adobe. While the resulting cast is strong, you must still be careful in handling pieces thinner than a 1/4" (they are strong, but can still break whereas anything thicker than 1/2" you will have to apply a good deal of force to break). The substance can be sanded, drilled, or carved with ease.
For casting (after extensive testing) I've found a mixture of 50 mL of warm water (or about 1/4 cup) and 7 1/2 Tablespoons (I use 5 flattened measures of 1 1/2 Tablespoons) stirred for at least 5 minutes (preferably until there are no lumps) performs well and produces sufficient mixture to easily fill the Wizard's Tower mold with some left over for other uses (see below). Mixing does tend to introduce a lot of bubbles, but this doesn't affect the casting if you are careful to tap the mold thoroughly and run a paintbrush along all the mold edges immediately after pouring.
After pouring, the mixture should reach toothpaste consistency after 30 minutes so you can scrape off the excess. After 1 additional hour you can remove the blocks from the mold (you can be rougher the longer you wait for the putty to set). The excess putty may be put to several uses, especially between 30 - 50 minutes after mixing. Once it has reached a toothpaste or thicker consistency, it makes a strong and highly effective mortar for bricks, producing a more natural look than normal gluing. Additionally, for any bricks or pieces that come out concave (you scraped too aggressively) you can fill in the concavity and either flatten it now, or let it dry and sand it down later. Lastly, if any air bubbles marred the cast and you have a light and steady hand, you can make impromptu repairs to it.
Aside from the slowness of the hardening process of this mixture (a fact that does prove useful when using it for other things than casting) I find this product superior in all ways to plaster of paris. Not only does it make excellent casts, but it has a myriad of other uses and makes a really nice mortar or faux rocks and rubble. -Adam
Durhams Water Putty is one of the greatest mixtures available for those that cannot afford more expensive dental products. It is about $5.96 for 4 Pounds of the stuff. Using large red dixie cups, I fill it with the amount of plaster I will need for the casting. Taking another cup, I fill it with water.
The amount of water you should use should be half of the amount of putty you are using, In other words, 1 part water to 2 parts plaster. It should be ready for scraping immediatly, and when the putty starts to turn an orangeish color, They are ready to remove. It runs about forty minutes from mixing to removal.
I am never going back to any plaster or hydrocal product. Be careful about spilling the plaster dust, as it is a pain to get it up without it blowing everywere. For a 4lb container, you get about 10 casts on 2 molds. Flex the cup when the putty is dry and it cracks off with no problems. It takes paint well. -Ants
Note for all: The Durhamís Water Putty from Home Depot is now up to $8 for the 4lb container. The cure time for that is 1/2 hour before you can scrape and 1 hour to remove from mold. Now, not only is it just as expensive as some of the better dental stone material, it has the longest cure time of them all.
Extremely hard to sand and if your not careful, youíll tear right through standard sandpaper. Sheetrock sanding screen works better but is more expensive as well. Does not take staining well. Paint yes, stain no. If you have the time, money and desire for all your pieces to be super tough, this is the stuff for you. If not, go w/ any of the dental stone products. Personally, I will not use this stuff again. -Sam
While waiting on more Die stone to arrive I decided to try some Rock Hard Water Putty on a whim (seen in aisle of Ace Hardware) after recalling it mentioned. Since it was purchased at an Ace hardware it was a little more then normal price. $4 for 1lb.
Following mixing instructions gave something similar to plaster of paris a little thicker upon inspection. It flowed into mold about the same as PofP but it held air bubbles like honey. For the first time my floor tiles had air bubbles in them. Vibrating for 15 minutes didn't work out the air bubbles.
Once dried overnight I inspected and found the tiles weaker then PofP (???) and they broke under slight thumb pressure. I tried 6 different batches and all turned out the same. For the price and characteristics I would use another product. -Aaron
Hydrocal VS Extra Lightweight Hydrocal
Having mixed both several times now, I have to say that Lightweight Hydrocal is much more difficult to mix. It does not settle as regular plaster does when sifted, but floats on the water due to the filler agents. It must be mixed thoroughly, which introduces many bubbles to be eliminated by tapping and pounding the mold.
Hydrocal sinks to the bottom, forms an island on the water when complete, and if stirred slowly with a coffee stick in a back and forth motion has little to no bubbling to eliminate after a pour.
Lightweight Hydrocal does meet it's claim of half weight. For my comparison, I filled the same mold with first Lightweight Hydrocal and then regular white Hydrocal. I then weighed the two results. The lightweight Hydrocal came in at just under 45 grams for a full cast. The white Hydrocal came in at just under 100 grams. Lightweight wins, hands down.
Overall, I like hydrocal better, and will be using it in the future. It is more than twice as heavy, but easier to mix, and much cheaper (lightweight is about $4 a pound, white is $.70 a pound). Unless weight is your most important factor and you can pay over 5 times as much and tolerate the mixing difficulties, I would go with the standard white Hydrocal. -Ernie Phelps
Hydrostone is the proprietary name for a gypsum cement product offered by U.S. Gypsum. Other companies offer similiar products. Hydrocal is harder and much finer than standard plasters. This is a good site for details: www.plastermaster.com/usg/index.htm -Andy
Or try Gypsum Solutions -Luke
The recommended mixture for HydroStone is 32% water to product by weight. In my experience though this increased the scraping/drying times significantly when using it in such low quantities as you would for HirstArts molds.
I found 100grams water to 250grams HydroStone works just fine and gives a 5-6 minute scraping time and 25 minute demold time. It is thin enough to flow into even some of the smaller pieces like on Mold #59 and the thin walled pieces like on Mold #85. Though I do use a vibration table for the smaller pieces, I do not for larger pieces like Mold #70 and #204.
So far I have had little to no issues with air bubbles. The pieces that come out of the mold are strong enough that I haven't had much issue with fractures during the demolding process. After about 2-3 hours in a dehydrator set to 122F the pieces are completely dry and have a fine stone-like finish.
I was able to purchase HydroStone from a local storefront here in the DFW area called Brick In The Yard Mold Supply. They have an online store as well. -Matt
Well, I think I've found my favorite casting material... Permastone. Allow me to elaborate:
1.) Material - Permastone is an extremely fine powder in a bright white color. The stuff comes in a canister which I could not open easily, however, I cut a small square just underneath the lid for easy "squeeze" dispensing.
2.) Mixing - Here's where this stuff really shines. The powder dissolves almost immediately upon hitting the water all the way to the saturation point. When you are done with the mixing, you are left with a heavy mixture that has little surface tension. When pouring it, the sediment settles quickly and you will immediately see how much water separation you will have on top of the mold. This is good for estimating how high above the mold to pour an excess amount of material.
3.) Casting - I let the Permastone set for five minutes and then scraped the top of the mold. The Permastone did not compress as I scraped, like Hydrocoal and plaster did. When I say compress I mean that when the edge of the blade goes over the top of the mold you don't feel that backpressure on the blade that makes you feel like the holes in the mold have a lot of air or material in them, which always made me think that the mold was not fully set or formed. I could fully remove the bricks 30 minutes later, and they came out without any residue at all. Permastone does create air bubbles, but they are very, very small and practically invisible and sometimes, they actually enhance the look of the brick. (Gives it a weather-pitted look.). None of the air bubbles caused deformation of any of the blocks, which happened often with Plaster, Hydrocoal, and Water Putty.
4.) Curing - Permastone cures to a bright white, porcelain like object. It is hard as a rock and I tested the strength by repeatedly dropping one on my workbench from 4 feet. No chipping, even when dropped on a corner. To separate the blocks in the Dragon's Inn mold, I had to score the groove about 10 times with the back of an X-acto blade, then simply break it along the edge. Clean break, no crumbling. Once broken, the inside of the cured block can easily be shaved down with the back of a blade or heavy grit sandpaper. When there is no break, shaping the block will take a bit more effort with sandpaper, but still achieves a good finish.
5.) The con... Price. I found Permastone a bit pricey at 6.50 for 2 pounds at a craft store. It took about 3.5 pounds to finish just the Wizard's Tower. Considering you can get other casting materials for much cheaper, I'm not sure this is an exceptional value. BUT, If you factor in the frustration of working with other materials, it just may be worth the price. I will say that except for my learning curve with Permastone, once I got the mix down I did not have one bad cast afterwards. I would definitely recommend Permastone for wargaming structures due to its extreme durability and good looks. -Kizarvex
I have been using polyurethane resins like Por-A-Kast for years with great success. Por-A-Kast is a liquid urethane casting materia that comes in two parts, a polymer and a curative, both of which look somewhat like vegetable oil (although one is a slightly darker amber color).
The two parts are measured at equal volumes and quickly cure at room temperature to a rigid white or ivory solid. I usually allow about 10 minutes cure time before removing parts from the mold and curing is complete after 30 minutes. That means I can cast blocks three times faster than when using plaster!
The cured resin can be tooled, turned, drilled, ground, sanded, pigmented, stained, and filled. The tensile strength is higher than regular plaster, not as high as dental plaster, but cured resin is flexible and therefore good for more delicate casts.
I have excellent results gluing resin parts together with a gap-filling CA glue like Zap-A-Gap. Por-A-Kast is the original product, cures to an ivory color, and gels slightly faster than Por-A-Kast II, which cures to a stark white color. Both cost about $65 for a two-gallon kit and are available from Bare Metal Foil Co. -Dave
I just got a 50lb bag of Tufstone from Douglas and Sturgess Art Supplies at www.artstuf.com. Compared to normal plaster of paris: Tufstone is a finer grain and casts much better detail. Tufstone doesn't bubble as much and dries much harder.
The service from D&S was top notch. I ordered the bag on Monday morning, and it arrived at my place (outside Seattle - they're in San Francisco) on Thursday. However, due to the weight, shipping was nearly the cost of the product: $17 on a $22 order. Overall, I like it MUCH better than PofP and will be using it on everything from now on. -Eric
I happen to live in San Francisco, and just recently bought some Tufstone from Douglas & Sturgess (their shop is on my way to work). I fully agree with you: Tufstone is the finest grained, low bubbled, and hardest type of plaster I have tried. Once you try it, you'll won't use anything else.
By the way, those of you who plan to ship their finished castings, I definitely recommend using Tufstone or similar material. -YDune
I am very familiar with Douglas and Sturgess from my vacuum forming days and using Ultracal 30 for making our Stormtrooper molds. After trying StrongCast Plaster from Michaelís ($4.50 or so for a 2 pound tub) I wanted to use something more economical and stronger. After researching shipping costs of other products I decided to try TufStone as D&S is less than an hour drive from me. Their staff were top notch (as always) and very helpful.
After several castings I had only one bad tile and that was because I didnít mix it enough (lumpy batch). It is very strong and I can see the reinforcing fibers when I scrape the molds! So far after 20+ batches I only had two pieces that werenít perfect.-Tracy
Here is a phone number for the USG (United States Gypsum) distributor # 1-800-487-4431.
I was able to purchase 100lbs of Ultracal 30 for about $17.60. It sets fast (when mixed right), is VERY strong, and does not chip like Plaster Of Paris. The only thing is water puddles form when the Ultracal sets, so before you scrape be sure to dabb that off with a paper towel. It also is a little heavier too, but it is a good trade-off. I mix mine to about the consistancy of thickish pancake batter. Any thicker and it sets up in my cup, any thinner and when you dabb the water off, you may end up with a short block. -Prepaid Sanity
Vatican Art Stone
It's very intersting stuff. It has an aggregate in it that will add a luster to the dried cast if you polish it with very fine grit sandpaper or steel wool. The stone is pretty dense and the aggregate takes a little getting used to. Just mixing the stuff in your normal disposable plastic cup is quite noisy (don't do it when your significant other is watching Tv).
After figuring out that you should let the stuff sit for 2 or 3 minutes after combining the plaster and water (like the directions said) the casts came out much more air-bubble free. It's not particularly strong stuff - I could still break pieces with my hands without working too hard at it (I was mixing it pretty thin because I wanted to make sure that I didn't run out before I had enough stuff cast to do a few projects), but it removes painting from the process and solves the "chipped structure shows white" problem with plaster. The stuff will chip, but it'll be the same color on the inside and won't be as noticeable.
It comes in a variety of colors: grey-green, black, brown, white, & terra-cotta. It was $22 / 25 lb bag and shipping 75 lbs from New York to Oregon was not cheap ($50), but that still left the overall cost at just a little over $1/lb which I don't mind. It's available at Sculpture House Casting at www.sculptshop.com/cart/s...vstone.htm
I definitely plan to use the stuff again. I thought the grey-green color was pretty cool. I would recommend the stuff if the price is not a problem. -Jim
I ordered a 25 pound box for $32.00 (price included shipping to Michigan from New York). Got it today and cast a few test molds using the Crypt Mold. I gotta tell you the stuff is beautiful. After drying about 30 minutes the pieces are ready for handling and finishing. With a little steel wool smooth surfaces shine like polished stone! I donít think I even want to paint this material!
The brick surfaces hold the detail great and I think I will dry brush them, but any smooth arch, tile or such surface I will keep clear. A tip sheet came in my order and one tip was to apply red or brown shoe polish to help bring out the details. The mixture is similar to plaster of paris and I mix to a milkshake consistency. The mixture need to set about 3 minutes but is still very liquid. The mix also has a gritty, like sand, texture in the cup. This looks like fine grains of quarts or some other reflective material. In the settling process this "grit" sinks and with a little steel wool shines through, great effect.
Iím letting a set air dry, I oven dried a set and the came out a milky brown (raw, no finishing) and I didnít like that look. The stone is heavy, heavier then plaster of paris but really hard and difficult to scratch. Anyway, if you want to check it out hereís the site: www.sculptshop.com/cart/s...vstone.htm -Augury
I gotta say this stuff is awesome! Psi is 15,000 - set time is about 13 minutes, time enough to pour 5 molds and still run a toothpick in the dragon accessories mold (barely). It mixed alot smoother than anything else I've tried, and as I just tap the top of the mold with a spoon as I fill it, I had less bubbles than normal.
It comes in a variety of colors. I bought the blue which comes out more like a slate grey. I just restarted casting for my dungeon pieces - I had started with some old plaster but this stuff is way stronger. The pieces come out almost glassy smooth. The mixing ratio was like 1 cup plaster to 1/2 cup water, better than the last stuff I bought! -Chase
Many of the above customer reviews are not complete. If you want to purchase some of these products above, it's best to go to your favorite search engine and type in the name of the product you want. Several companies should be listed who carry these products. Below are a few sources for casting and mold making material.
Gypsum Solutions. A wonderful resource to find out the properties of different kinds of plasters and where the stores are that you can find them.
Smooth-on. They sell all kinds of mold making and plastic casting products.
Douglas and Sturgess, Inc. Click under the "Plasters and Gypsum Cements". They have a good number of casting materials, along with detailed descriptions of each.
The Compleat Scuptor. They also have an online catalog with casting and mold making materials.
The Sculptors' Place. They also have an online catalog with casting and mold making materials.
Plaster Master Industries. A very strange looking web site - but it has tons of information on various plaster types and uses.