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Water and casting investment ratio


How much water is added for 1 cup of investment?


I use a ratio of 2.5 grams of investment per each milliliter of
water. I use Kerr’s Satin Cast 20, but I have used other similar
investments and this process seems to work.

I don’t make bulk quantities of investment.

Somewhere on the Orchid files is my casting Silver document. When
used there is very little waste of investment.

Otherwise convert your cup of water to milliners then multiply by
2.5 to get the amount of investment needed.

Good luck,
Ken Moore


Brian- Til it’s the consistency of Belgian Waffle batter. Not
pancake batter but a tiny bit thinner like belgian waffle batter.
Always use cold water. Mix thoroughly with your fingers to remove the

I am very casual about my investing technique, but it’s worked for
decades and I rarely if ever have any casting problems.

If this bothers you don’t worry. You’ll get some much more technical
answers from my compadres here. Measuring weighing, thermometers for
the water, electric mixers, timers etc.

Have fun and make lots of jewelry.

Jo Haemer


Do not use volume measurements to mix investment use weight. Weigh
the investment and weigh the water otherwise you are just guessing.
As long as you are close the investment will set up but for best
results you need to be within a few percent of the correct ratio.

100 parts investment to 40 parts water. You can vary the water a
couple of percent either way to get thicker stronger investment for
less detailed work or thiner, weaker but more fluid investment for
very fine detail.

James Binnion
James Binnion Metal Arts


Related Articles from our archives:

Casting Notes for Silver Lost Wax Casting

Getting Optimum Performance From Your Casting Investment Powder

More articles: Library > Casting > Lost Wax Casting


For me, it’s more of a “by feel” kind of process. Add a little bit,
mix, add a little more, mix, etc. It should be about the consistency
of pancake batter and lump-free.

How much water is added for 1 cup of investment? 

Weigh the cup of investment on a gram scale, and add 40% of that
weight in water.

NEVER just go by “cups”–each cup of investment you measure you will
contain a different amount because it’s never packed into the cup at
exactly the same density. I was taught to mix investment by cupfuls
when I first started casting. I had innumerable casting problems
until I started weighing the investment and water. The casting
problems all vanished immediately.

Kathy Johnson