By the way, about the divesting liquid, how well does it work and is it expensive? I was doing mechanical divesting of Formula and I cannot say that it can win any stars in the favourite activities competition. -LOL! I feel the same way. I felt like a paleontologist removing rock from a new fossil specimen. My guess is the rough surface quality may be caused either by residual ash left over in the cavity when pouring the metal, or the cavity walls are cracking and breaking during the expansion of the material. I've consulted a few people who theorize the photopolymers may be interacting chemically with the investment during burnout, causing the rough surface textures, but I'm not sure how to confirm that.

Here's some info on divesting from Ganoskin:

Removing the castings from the investment can be a challenge. The investment, which is baked at very high temperatures, turns into a glass-like substance that can be difficult to separate from the cast pieces.
Most manufacturers use hydrofluoric acid, which is extremely dangerous and must be handled with utmost caution. Always use rubber gloves, a rubber apron, and a respirator that filters small particles from the air.
A small shop may wish to consider a safer devesting agent for platinum investment as a substitute for hydrofluoric acid. Ask your tool supplier; there are many brand names. You can also mix your own substitute using the following formula (percent- ages are given by weight): 25 percent sodium hydroxide, 25 percent potassium hydroxide, and 50 percent deionized or distilled water. (The sodium hydroxide and the potassium hydroxide should be in pearl or flake form.) Combine all three solutions in a stainless steel container, and heat (do not boil) for 25 to 40 minutes. Be careful mixing, since the three ingredients will naturally heat up when combined.

Here's a link to a safer divesting solution but it's still a bit pricey. It's a hazmat item so shipping will be more expensive as well: http://www.ishor.com/casting/investment/safe-d-vest-investment-remover


I usually soaked it in the divesting solution until the investment started to loosen up, then put it in an ultrasonic. Repeat until all investment is removed. Make sure you have good ventilation in the area you're divesting.


@survivalist
I've always used Castaldo for my molds. It's pretty durable stuff in my experience. Haven't tried any of the alternatives.