The Compleat Sculptor
" You supply the talent, we'll supply the rest!" Since 1995

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New expanding urethane product for easily sculpture enlarging.

  • HydroSpan™ works like a 3 dimensional copy machine enlarging any shape or design in perfect proportion and detail. You can increase the size of patterns, molds, art castings, foundry molds, fossil patterns or original art works without sculpting new masters.
  • Original art can now be replicated in various sizes to customer requirements. HydroSpan™ provides you with the ability to easily and accurately increases the size of any object. No sculpting is required, simply cast a part and soak in ordinary tap water. If you are a sculptor or pattern maker imagine the possibilities. Imagine how much time you will save.
Order #
Package Size
3 quart
3 gallons
We strongly recommend the use of Dry Gas Blanket when storing unmixed HydroSpan.
Photo depicts 3 successive expansions with the HydroSpan™ product; each head is 60% larger than previous casting. The largest head (transparent green color) is the actual HydroSpan™ product after soaking in water and reaching full expansion.
  • HydroSpan™ was created for artists wanting a fast economical way to enlarge seashells, fossils and other common items for a museum exhibit. Sculpting larger versions of common objects is tedious and time consuming. Very detailed fossil reproductions are virtually impossible to accurately sculpt. With HydroSpan™ you can simply make silicone molds from small objects and directly enlarge them. When parts cast from HydroSpan™ are soaked in water they accurately increase in size 60%. By making larger silicone molds from the expanded HydroSpan™, you can produce a series of progressively larger molds. The result is exponential growth of your original shape. Using this expansion technique we have expanded a silver dollar to the size of a dinner plate in a series of three HydroSpan™ expansions.
How does it work? HydroSpan™ uses water to create a perfect expansion. Our invention is a flexible urethane polymer, which over time absorbs individual molecules of water deep into itself until it is completely saturated. When liquid water touches the surface of HydroSpan™ , it is attracted to the atomic charge of the polymer molecules. Polymer molecules deep within the HydroSpan™ will pull water away from adjacent molecules closer to the surface and in this way conduct water throughout. As water is absorbed the polymer matrix stretches to accommodate the in coming water. The water is so tightly held in the polymer matrix it appears dry to the touch. Even cutting or crushing the polymer will not easily release liquid water. Migrating water molecules uniformly surround each polymer molecule, evenly stretching the polymer matrix in all directions. Through this process HydroSpan™ produces near perfect expansion of molded shapes by soaking in ordinary tap water.
HydroSpan™ is a safe easy to use 2 component flexible urethane. It is non hazardous for shipping purposes and produces no odor. It has a mix ratio of 2 parts A to 1 part B component by volume, working life is 10-minutes, full cure time 24 hours. Hardness of cured HydroSpan™ (before soaking) is 45 Shore A / hardness of expanded HydroSpan™ (after water soaking for 14 days @ 72° F ) is 35 Shore A. Percent increase in size 60%. HydroSpan™ is packaged in quantities of 1.5 and 7.5 gallons. To calculate size of expanded shape multiply starting dimensions by a factor of 1.6. For example an object, which measures 10 inches tall, will become 16 inches tall after one expansion (10 X 1.6 = 16)
  • Mix ratio: 100 parts A to 50 parts B component measured by weight, 100 parts A component To 54 parts B component measured by volume.
  • Mixing method: Hand stirring or electric drill with jiffy mixer attachment.
  • Color: Transparent blue.
Photo courtesy Phoenix Rising Ceramics

Although we try to keep the most updated prices on our website, all prices are subject to change.