in Liquid Rubber & Plastic for Moldmaking & Casting

Prototypes & Tooling

Getting Crazy with EasyFlo™ 60

     Liquid Poly Urethane casting resins are inherently versatile. When shopping for the "right" plastic, many questions need to be answered. What pot life do I need? How fast should it demold? Should the casting have a lighter or heavier feel? Does the resin need to be tinted or filled to simulate the appearance of another material?
     It is probably true that no one Poly Urethane liquid plastic will fulfill all your needs. This is exactly why Polytek^® has developed such a wide array of products—from our many Poly 15 Series resins to our water-clear Poly-Optic^® systems. Our newest Poly Urethane casting resin, EasyFlo™ 60 has some unusual characteristics, making it more versatile than most liquid casting plastics.
EasyFlo™ 60 Is Versatile
     EasyFlo™ 60 has superlow viscosity, 1:1 mix ratio by volume, and a 2-3 minute pot-life, and it cures to a white, tough, Shore D-65 hardness, nonbrittle plastic often demolded in just 10 minutes.
     Since EasyFlo™ 60 has such a low viscosity, it easily accepts high filler loading. Powdered metals can be added to obtain "bonded bronze." It is also easy to make your plastic part look like marble or another stone-like substance instead of plastic. This effect is often achieved by adding fillers such as calcium carbonate, marble powder, aluminum trihydrate or fly ash to the liquid plastic.
Ivory or Alabaster Appearance from Off-Ratio Mixing
     Where a semitranslucent, stone-like appearance that has some depth is sought, it may be desirable to take advantage of an unusual property of EasyFlo™ 60. By off-ratio mixing this resin, a less-brilliant white color can be achieved, providing a depth and feel similar to alabaster or ivory. This effect alone can dramatically reduce the "plastic look" of the casting. In addition, fillers like those described above can be used with off-ratio mixes of EasyFlo™ 60 to achieve even more substantial effects, since the slight surface translucency permits greater visibility of filler particles.
Invent Your Own Recipe
     Off-ratio mixing of EasyFlo™ 60 involves some experimentation, so here are some guidelines. The above effects are achieved by the use of more Part A than typically suggested (1 Part A to 1 Part B, by volume, is normal). A mix of 1.5 Parts A to 1 Part B by volume is extreme, but still possible. It should be noted that the use of excess Part A increases both the pot life and demold time. Smaller objects or castings with thin sections may need to be left in a mold longer to avoid distortion. Color and translucency may vary with the size of a casting due to the heat (exotherm) associated with a given mass of resin. Since conditions can vary greatly, we suggest you complete careful testing to determine the suitability of these techniques for your own application.

     Polytek^®'s Manual & Catalog explains on page 20 how we built our own vacuum chamber and which pump we like best for vacuum degassing.  We are often asked where one can obtain pumps and chambers. Here's some information.
     Vacuum Equipment Company, Inc., Philadelphia, PA, is a 40-year-old company specializing in the design, manufacture, and re-manufacture of vacuum pumps and vacuum-process equipment. VEC offers an entire line of vacuum chambers in sizes ranging from 6 inches in diameter up to as large as 48 inches in diameter; the 14-inch diameter size, with a 5-gallon capacity, is the standard model. Configurations are either cylindrical or square.
     The cylindrical systems are designed with less-expensive plastic chambers or stainless steel chambers. The square systems are made with carbon steel or stainless steel.
     The systems (including a see-through top and the required piping, gauging, hoses, and valving required, but not including the vacuum pump) cost approximately $495 to $1,395 (for a 5-gallon stainless steel system) or more, depending on the size and the control complexity desired.
     Vacuum pumps commonly used for degassing range from 1 cubic foot of air per minute (cfm) to 65 cfm and vary in price from $395 to $1,595 for a 5-gallon system pump (20 cfm) up to $3,500 for larger pumps. The pumps may be new or re-manufactured. The re-manufactured pumps cost approximately half the price of a new one.
     For complete information and free technical advice call: Vacuum Equipment Company, Inc., 841 N. Holly Street, Philadelphia, PA 19104; (215) 222-1550 or (888) 707-6904. 
     Other companies offering vacuum pumps at reasonable prices, e.g. the Welch Model 1397, are:

• McGrath, Inc., 35 Osborne Street, Salem, MA 01970; (978) 744-3546.
• Mass-Vac, Inc., 247 Rangeway Road, P.O. Box 359, North Billerica, MA 01862-0359; (978) 667-2393.
• Advanced Technical Services, 8401 White Oak Avenue, Suite 110, Rancho Cucamonga, CA 91730; (800) 577-3477.

     We suggest reading page 20 of the Manual & Catalog before you buy a vacuum system, as pressure casting is in some cases a cheaper and easier method of eliminating bubbles.

Now, No Hazard Fees
Poly-Optic^® and 81 Series No Longer DOT "Toxic" Liquids

Close Window