Hi Baker, I use Fuji-vest 2 investment which is a ringless system and fast burnout. I presume the problem is when you are fitting the casting to the die.
Adjustment of the expansion of the investment is done with the ratio of water to expansion liquid.
Remember that as the alloy cools it shrinks onto the form of the coping in the investment and different alloys will shrink at a different amount, that is why we need different water-liquid ratio's for differnt alloys.
For non precious alloys I use 15ml liquid to 6ml of water for a 90 gram ring. For the 52% AU alloy I use mainly for PFM's I use a 50/50 mix, The same for high noble > 80% AU.
For the alloy I use for AU crowns ( 60% AU)I use 5ml liquid-16ml water and mix it for two minutes instead of the normal one minute to help improve the strength of the investment as any ratio with less than 50% liquid reduces the stenght of the investment and the ring may crack.
I will put up to 5 copings into a 90g ring or 3 gold crowns.
Hope this is of some help. Cheers Malcolm
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