It’s been a while, but I’m finally starting to start a project that will require several lost wax casted parts. The parts need to be dimensionally accurate, so I assume I need to account for shrinkage. I googled it, and read that casted aluminum shrinks between 6 and 8 percent. Another site said to make your molds 5 percent bigger. I just wanted input from people who have been doing this for a while. Do I need to make my patterns 5% (or 6) bigger? Do lost wax castings really shrink that much? thanks for any info, Scott
Not even close. 1.3% for sandcasting aluminum. That's 5/32"/ft. You may get some additional shrinkage from molding your wax, and perhaps firing the investment depending upon what you are using though the latter is usually negligibly small. Best, Kelly
They might have been referring to total volume when talking about shrinkage, 5% by volume equates to about 1.6% linear shrinkage in each direction.
