Prestige ORO 5Lb Premium Jewelry Making Casting Powder Lost Wax Investment Powder for Gold, Silver ETC

After your sticker shock, just don't even think about trying wall plaster (yes, I did). Now-a-days it's so full of 'easy sand' and 'lighter than the other guy' additives that it just can't be used for any kind of molding that involves heat. Plaster-of-Paris has it's own tradeoffs you can read about elsewhere. Compared to either, this stuff requires about 1/4 the water while still being very pourable. Moreover it doesn't take on air bubbles unless you are VERY aggressive with the stirring. You don't want (or need) to use a high speed drill - use a variable speed and keep RPM rather low. It does set fairly quickly. You want to be done pouring and de-gassing your mold within 10 minutes of adding water but unless the object has a troublesome crevasse I rarely get more than a bubble or 2 during de-gassing and the surface itself never rises a bit (like some plasters do). Surface rise indicates fine bubbles that will never come out. So even if you don't have a vacuum chamber, very few products have any hope of giving results even close to this and if you have one (recommended) this should easily stack up to any similarly priced products. For planning purposes I wish they told you what volume to expect. I only used it twice so far and estimate I'll get somewhere around 50-55 cu.in from a 5 lb. bag. That's something short of 900cc or 30 fl. oz. My casting flask is 3"x4" and I expect to be able to fill it 3 times. 4 if I measure really carefully and don't need it completely full every time. You may not have time to scrape the dregs from your mixing bowl before setting prevents de-gassing so expect a little waste unless you are dexterous. Update. Since my molds are typically 3d prints, I've converted to metric. To calculate use: 5lbs = 2268g. You need1.37g of powder per cc of volume so my 70mm ID x 95mm high flask takes 365cc to fill times 1.37 = 500g powder. Water = powder x .39 or 195g. So all measurements are perfect and easy by knowing these 2 numbers. A 5lb bag yields 1658cc or 101.2 cubic inches.

I am happy with my item and well packaged

Followed the instructions suggested by the manufacturer, cast a clean copper part. Make sure to fill your investment casting flask all the way to the top. Didn't do that on my first attempt and the mold blew out the moment I pulled a vacuum. Second attempt I filled the flask all the way and had no issues.

Makes great casts if the directions are closely followed. Wish investment was cheaper in general though. The inner bag wasn’t sealed properly too and some on the plaster was wasted.

Excellent investment worked exactly as it has in the past so product is consistent however, if you have a dry place to store by the 25 pounds

Perfect best plaster out. Shipping and updates were always on time and was actually a day early would buy again and again from them

Mixes the same as the optima, but 100% not near as fine or able to fill voids completely under vacuum. Tried it to see if this cheaper version was as good, and was far disappointed, it failed to capture important relief holes of 5mm in 3 spots leading to a ruptured cast due to internal pressure under cooling. going back to the higher grade tossing this junk out.

solid powder