Table of Contents
Technical Properties
| Technical Properties | English | Metric |
|---|---|---|
| Density | ||
| Wet | 110.0 lb/ft3 | 1.76 g/cm3 |
| Dry | 90.0 lb/ft3 | 1.44 g/cm3 |
| Set Time (Machine Mix)* | 25-35 min. | 25-35 min. |
How long does it take Ultracal 30 to dry?
ULTRACAL 30 Set Time is 25-35 minutes.
When can I Demold plaster?
No less than 24 hours. To get a fully cured part you may want to wait up to 72 hours. De-molding too soon can cause surface damage or if a larger part can break. The longer the cure the harder the finish on the part, the cleaner and easier the de-molding process will be.
How long does plaster take to dry out?
Plasterboard takes on average 2-3 days to dry when plastered, whereas backing plaster takes 4-6 days. No matter what material you have used, it is advisable to wait at least a week before painting new plaster. Sometimes it may even take up to a month for the fresh plaster to be completely dry.
How do you mix Hydrocal?
The mix ratio for use as a bore coating is approximately 1.5 (powder) :1 (water) by volume. The mix ratio for use as a high temperature (HT) reinforced coating is approximately 2.5 (powder) :1 (water) by volume. For slurry application, add powder to water and mix until desired consistency.
What is the difference between Hydrocal and Ultracal?
Ultracal 30 is more dense and harder than Hydrocal and is advertised by USG as a tool making plaster. Hydrocal is a casting plaster that hold detail well. Hydrocal is easier to work with post casting for corrections. Ultracal is more durable.
Can Hydrocal get wet?
Allow soaking for 1-2 minutes. HYDROCAL Brand White Gypsum Cement should be fully dispersed in the water prior to mixing.Technical Properties.
| Technical Properties | English | Metric |
|---|---|---|
| Dry Compressive Strength | 5,000 psi | 34.5 MN/m2 |
| Maximum Setting Expansion | 0.390% | 0.390% |
| Density | ||
| Wet | 110.0 lb/ft3 | 1.76 g/cm3 |
How strong is Hydrocal?
The USG specs say something like hydrocal will hold 5,000 pounds per sq inch compressive strength, sounds impressive doesn’t it? but one little ‘”tap” on a hard surface and corners, sharp edges or fine details break off pretty easy.
Can you sand Hydrocal?
Hydrocal is very strong but still retains some of the working properties specific to plaster. May be sanded and refined with steel tools. Great for mother molds and support shells.
What is the hardest type of plaster?
PURITAN POTTERY PLASTER – Unique, specially designed for use with mechanical clay forming machinery. Absolutely the hardest, most wear-resistant plaster made for molds, and a favorite for jiggering molds. STATUARY HYDROCAL – A basic HYDROCAL cement with a lower use consistency of about 40 lbs. of water per 100 lbs.
What is Hydrocal?
Hydrocal White is a multi-purpose gypsum cement ideal for both solid and hollow casting of lamp bases and figurines. Designed for thin sections, its high green strength minimizes breakage during removal from the most intricate molds.
Does plaster adhere to wood?
Plaster will not properly adhere to wood on it’s own – so a physical key is needed. You first need to fix either metal lathing or wooden laths to the timber. Unless you have to, or want to stick to traditional methods, Expanded Metal lathing (EML) is generally the easiest option to use.
How hot does UltraCal get?
The maximum temperature at which USG Ultracal 30 Gypsum Cement molds are safe from calcination is 120 °F (49 °C). With substantial free water in the mold, a higher drying temperature can be used initially without difficulty.
What is stronger than plaster of Paris?
Hydrocal is much stronger than plaster of paris. The sloughing of plaster results in lots of dust and chips on a continuous basis.
What UltraCal 30?
Harder and stronger than HYDROCAL A-11 and HYDROCAL B-11 cements, UltraCal 30 cement has the lowest expansion of any rapid-setting gypsum cement available. Has a gradual set and long period of plasticity. Ideal for splash-casting molds and models for phenolic, polyester and epoxy resins.
What happens if plaster is too watery?
If too much water is present, the mix will take an extra long time to reach the creamy stage and then, all of a sudden, it will set overly fast. The piece will still have good homogeneity, but the set plaster will be softer than it would have been had the desired ratio been used.
How do you strengthen plaster?
How can I make plaster of Paris stronger?
- Step 2: Mix Water and Glue. Place 1 1/4-cup water in a plastic mixing bowl. Add 1/4-cup white glue to the water.
- Step 3: Add the Plaster. Slowly pour 2 cups of plaster of Paris into the water.
- Step 4: Rest and Mix. Let the plaster rest for about five minutes before mixing.
What is Hydrocal made of?
Hydrocal is mainly composed of plaster of Paris and a small amount of Portland cement. It has a similar formula as hydrostone, duracal, and ultracal. They are all used for casting sculptures and well as making art objects and molds.
Does Hydrocal expand?
USG White Hydrocal® Gypsum Cement : Offering twice the compressive strength of plaster, it is especially suitable in thin, delicate sections where high green strength is required. Offers long workability; setting expansion twice that of molding plaster and pottery plaster.
What can be used instead of plaster of Paris?
Gesso is a mix of plaster of Paris and glue used as a surface for painting and as a base for low relief or carved surfaces before painting or gilding. Alternatives include chalk and water, lime and water, soy powder and water, acrylic undercoat from the hardware store, matte medium or gelatin.
Is hydrostone waterproof?
Re: Hydrostone/Hydrocal/Polymer gypsum It pours and looks like plaster, but is weatherproof and fireproof and one of my friends has had a large geobond sculpture out here in the Sonoran desert for 5 years with no sign of damage. It has actually been used by NASA for the flooring of rocket staging.
Can you carve plaster?
Carving. Plaster can be cut and carved with all manner of tools. You can do a lot of rough shaping when the plaster is at the semi-hard cheese stage, but finishing is done when the plaster is completely dry.
Is Ultracal waterproof?
Accepts paint, is waterproof, weatherproof and scratch resistant.
