Shrinking a Casting
There are different ways to enlarge or expand a resin casting or other materials castings too. Specially formulated compounds such as PanocastTMenable artists to make successively bigger casts of small objects. The enlarged reproduction will be proportionate and detailed just like the original miniature version. At times, even submerging a silicone mold in mineral spirits can cause it to swell physically.
However, is there any way to actually make smaller versions of an original without making successive smaller molds and casts? Can you truly shrink a mold or cast and make it smaller in size?
Some people think that they can use mold making or casting materials like alginate, wax or latex that tend to shrink when exposed to air. You just make an alginate mold or wax/latex cast and let it shrink naturally as it dries out. But this does not turn out as a practicable option because thelack of a proportional contraction.. The shrunk piece may end up quite warped and deformed.. Even if the shape remains the same, this technique requires a lengthy series of repeated casting/molding process to achieve a palpable reduction in size.
Filling a cast with foam and then remolding a smaller version again presents another prolonged procedure. The remolds may also fail to capture the surface details as required. An obvious solution is to take a laser scan of the object and shrink it on the computer before taking a 3-D printout. But this hi-tech method is quite expensive and complicated.
Reducing a Cast to Scale
Well, it is significantly easier to enlarge a piece than trying to reduce it in size. But there actually are some water based urethanes in the market that are made specifically for reducing the size of an already existing original cast. For instance, a three dimensional resin casting can be molded with the special urethane and then left to shrink for a couple of days at room temperature (the amount of shrinkage and days required varies for different compounds).
Apart from this, many artists use a special solvent or even simply odorless mineral spirits to achieve the desired shrinkage. The solvent or mineral spirits is mixed along with the silicone mold rubber. It should be vacuumed properly to eliminate any air bubbles.
Take care to use a mold that is resistant to solvents, else coat it with a solvent resistant spray before pouring the mold rubber mixed with solvent.
The silicone mixture will be much thinner as it has been diluted with solvent and will tend to flow out. It will also take longer to cure. Allow it to cure a bit and then de-mold quickly to let it dry on its own. As the solvent or spirits evaporate, the mold will shrink in size. It can take anywhere from 3 to 7 days to achieve the desired size. (up to 25%)
In this way, you can directly shrink a piece without having to re-sculpt a smaller original!
However, is there any way to actually make smaller versions of an original without making successive smaller molds and casts? Can you truly shrink a mold or cast and make it smaller in size?
Some people think that they can use mold making or casting materials like alginate, wax or latex that tend to shrink when exposed to air. You just make an alginate mold or wax/latex cast and let it shrink naturally as it dries out. But this does not turn out as a practicable option because thelack of a proportional contraction.. The shrunk piece may end up quite warped and deformed.. Even if the shape remains the same, this technique requires a lengthy series of repeated casting/molding process to achieve a palpable reduction in size.
Filling a cast with foam and then remolding a smaller version again presents another prolonged procedure. The remolds may also fail to capture the surface details as required. An obvious solution is to take a laser scan of the object and shrink it on the computer before taking a 3-D printout. But this hi-tech method is quite expensive and complicated.
Reducing a Cast to Scale
Well, it is significantly easier to enlarge a piece than trying to reduce it in size. But there actually are some water based urethanes in the market that are made specifically for reducing the size of an already existing original cast. For instance, a three dimensional resin casting can be molded with the special urethane and then left to shrink for a couple of days at room temperature (the amount of shrinkage and days required varies for different compounds).
Apart from this, many artists use a special solvent or even simply odorless mineral spirits to achieve the desired shrinkage. The solvent or mineral spirits is mixed along with the silicone mold rubber. It should be vacuumed properly to eliminate any air bubbles.
Take care to use a mold that is resistant to solvents, else coat it with a solvent resistant spray before pouring the mold rubber mixed with solvent.
The silicone mixture will be much thinner as it has been diluted with solvent and will tend to flow out. It will also take longer to cure. Allow it to cure a bit and then de-mold quickly to let it dry on its own. As the solvent or spirits evaporate, the mold will shrink in size. It can take anywhere from 3 to 7 days to achieve the desired size. (up to 25%)
In this way, you can directly shrink a piece without having to re-sculpt a smaller original!
