Post by notoes on Jun 20, 2018 13:28:33 GMT -5
Got a "double check my math" question on the ratio for shrinking a mold question. I've seen (and saved the info) on how to make a mold shrink by adding Odorless Mineral Spirits at like 1/3 the total weight (or is it volume?) of liquid mold material and after de-molding, the Mineral Spirits evaporate after seven days and the mold shrinks by somewhere around 1/3 of its original size.
What I'm trying to do is this: I am making my own personal set of clay alphabet stamps in resin in at least two fonts - a cursive type and Times New Roman font. And I need them no bigger than 1/4" tall. And I'm making them myself because none of the stamps (for clay or ink) I've found have deep enough pockets to make nice deep letters. I need them deeper than you'd find normally because I'm imprinting on clay which I then make a mold of to cast resin in so I have a resin casting to make the food safe molds from (instead of a clay one) and for the lettering to show up very well on the candy/chocolate made in those molds it has to be a bit deeper than normal. And not only are all stamps (for clay, ink, AND metal) are fairly expensive and most times they are also larger than I want. Plus I want at least two different fonts and that just adds to the problem.
So my math on doing this is:
Using 3oz (total) of liquid mold rubber, I add 1/3 oz of Odorless Mineral Spirits, mix well and pour into mold box with castings glued to bottom. Then after de-molding the castings, I wait 7 days and the mold should have shrink about 1/3 less than the original size.
I'm figuring that if I have castings that are about 1" tall, once shrunk the cavities should give me somewhere around 3/4" tall castings. Hopefully. Can anyone verify my math will work out anywhere close to what I hope for?