Learn more to decide if you should purchase a fiberglass female mold (four different types available), or opt for the convenient (and also cost effective) Permanent Hats or Reusable Hats instead of a female mold:

FFF 175 125
Floating Fiberglass
Female Mold
FFL 175 125
Full Fiberglass
Female Molds (3 types)
PermHat175 125
Permanent Hats
(used per casting)
ReuseHat175 125
Reusable Hats
(up to a point!)

For many types of open mold casting, both a male and female mold are required. Examples are vanity bowls, bathtubs and some accessory products. Female molds are the mold shape that forms the underside or backside of a cast cultured marble or solid surface product. When properly positioned with the male mold, the female mold creates the cavity that is filled by matrix to form the cast part. There are four kinds of traditional female molds:

  • Floating Fiberglass Female (FFF)
  • Full Fiberglass Female-Flange Out (FFO)
  • Lightweight Fiberglass Female (FFL)
  • Ultralight Fiberglass Female (ULFF) 

In addition to female molds, alternatives have been developed to satisfy the diverse needs of our customers. However, because there is such a diversity of needs and production methods, one type of female hat may work better than another, for different customers, including:

  • Permanent Hats - this is an "expendable" type of female, in that it is a lightweight, low-cost plastic "hat" that is used in place of a true female mold and cast into place, and cannot be removed nor reused.

  • Reusable Hats - reused many times like a female mold, but not nearly as durable as a female mold.

Below, we'll differentiate these options:

Traditional Fiberglass Female Molds

  • Two types - floating fiberglass female, and full fiberglass females
  • Higher initial cost than hats, but no ongoing per unit costs
  • The most durable female option - best for demanding workloads.

Floating Fiberglass Female (FFF)

Full Fiberglass Female-Flange Out (FFO) female mold type
Like the male mold, Floating Fiberglass Female molds are made entirely of fiberglass, providing the ultimate in strength, durability, and reusability. Simply apply a coat of mold-release wax to the clean, inside surface of the hat before each casting to assure easy release. The FFF will produce a smooth surface on the underside of the bowl. "FFF" molds are dimensionally stable and result in a uniform wall thickness and smooth surface to the underside of the bowl or other casting, and are durable and excellent reusability. In addition, these female molds include a generous fiberglass flange around the hat to enable it to rest solidly on the first pour matrix. The fiberglass female must be clamped to the male mold prior to casting the product.To order a Floating Fiberglass Female, place the letters "FFF" in front of the series designation of the bowl with which the hat will be used. For example: If ordering a Floating Fiberglass Female for a series "N" bowl, the order would read "FFF-N."

Full Fiberglass Females (3 types):

A Full Cover Fiberglass Female mold offers all the advantages of strength, durability and reusability as the Floating Fiberglass Female (FFF) above, but with two additional advantages:
  1. The overall size of the female matches the overall size of the modular vanity mold with which it is used
  2. It has a heavy steel frame that provides not only rigid support to the female but also a firm surface for clamping the female to the male mold.

The full-cover flange length permits complete coverage of the male mold and is the basis of the "single pour" production system used in many high volume marble plants. All Full Cover Fiberglass Females are adaptable for use with our G-Clamp clamping system, an optional feature available on many Marshall-Gruber modular vanity molds.

Full Fiberglass Female-Flange Out (FFO) female mold type

Full Fiberglass Female-Flange Out (FFO)

The FFO yields a finished part with a nominal 3/4" (l.9 cm) thickness both in the deck and bowl sides. Available for most standard modular mold lengths up to 49" (124.5 cm).
Lightweight Fiberglass Female (FFL) female mold type

Lightweight Fiberglass Female (FFL)

The FFL yields a part with a 1/2" (1.3 cm) thickness over most of the deck area and a 3/4" (1.9 cm) thick bowl. Available for most standard modular mold lengths up to 49" (124.5 cm).

Lightweight Fiberglass Female (FFL) female mold type

Ultralight Fiberglass Female (ULFF)

The ULFF yields a part that is not only 1/2" (1.3 cm) thick over most of the deck area, but also creates a 1/2" (1.3 cm) thick bowl. Available in standard lengths up to 37" (94 cm) for many, but not all, modular molds.

Note: Both the FFL and ULFF create lighter-weight parts that reduce material costs and maximize cost efficiency in production.

Note: Most females must be ordered separately in addition to the male mold. Refer to the Mold product section, and the various female mold and hat options will be listed with each mold.

Female Mold Alternatives:

Marshall-Gruber also offers two kinds of female "hats" - permanent hats, and reusable hats. These are popular and can be more economical than purchasing a female mold in some sitations - particularly where your frequency of use is relatively low.

• With or without Overflow
• Trimmed or Untrimmed styles
• Reusable Funnel accessory available - don't spill matrix!
• Choice of types and styles

Permanent Hats

White Permanent Hat, with Overflow
White, with Overflow
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White, No Overflow
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Clear, with Overflow
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Clear, No Overflow

Permanent Hats become a permanent part of the marble product, providing a finished underside which requires very little, if any, additional finishing. The hat is set in place on the un-gelled first cast immediately following vibration. Gently depress the step-down part of the flange into the matrix just enough too barely cover it. Because they conceal the underside of the bowl, any color of matrix can be used for the backpour. When the first cast of matrix has gelled and cooled, the second cast (backpour) can be made. The permanent hats are available in a white or clear plastic, and with a choice of including an overflow, or no overflow. Part numbers beginning with PH are permanent hats.

Reusable Hats

White Reusable Hat, with Overflow
White, with Overflow
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White, No Overflow
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Clear, with Overflow
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Clear, No Overflow

Fabricated of high-density polyethylene, a reusable hat will provide many trouble free castings if reasonable care is exercised in its use and storage. A reusable hat is applied to the mold after the initial pour of the matrix has been vibrated. It is placed over the bowl and the rim of the hat is gently pressed into the un-gelled matrix. A generous 2” flange is provided around the perimeter of the hat to allow for maximum adhesion of the hat to the matrix. Reusable hats are also available with an “untrimmed” flange around the perimeter.

Reusable Funnels are a convenient add-on to your Permanent or Reusable Hat. They provide easier pouring, particularly from large mixing pots into the bowl hole. Available for Round, oval and square pour holes.

Which type of female mold or mold alternative (hat) is best for you?

  • Fiberglass Female Molds are the most dimensionally stable, and result in a uniform wall thickness.

  • Permanent Hats are a one-use product that is embedded in the finished cast product, but eliminates the requirement to use and demold a traditional female mold after casting. Permanent Female Hats are very popular because of their ease of use.

  • Reusable Hats are as they imply, lower cost substitutes for a traditional female mold, and are demolded and reused after casting. They are not as durable or long-lasting as a traditional female mold however, but they are less expensive, so for limited casting requirements on a particular mold, a reusable hat may be the best option. Reusable Polyethylene Female Hats are still preferred by some customers, even though they are more difficult to work with and produce a less uniform part.