The Science of Nails

The Gel Menagerie

With the new technology being applied to gels there is a good range of options for techs looking to create pink-and- whites, correct damaged or misshapen nails, add shine and protection to natural nails or acrylic enhancements, or give a client durable and long-wearing nail color. The main thing to keep in mind when dealing with various forms of gel is that the primary difference between them is the viscosity.

One-step Systems

One-step systems consist of a single gel that is applied to the nail in two to three coats. The gels used in these systems tend to be of a medium viscosity. Some single-step gels are available in both transparent and blush formulas. After two to three layers of gel are applied to the nail, the final cured layer of gel is cleansed, revealing a shiny surface.

Multiple-step Systems

Multiple-step systems consist of two to three gels of varying viscosities. These systems generally have a bonder or base gel which forms a very thin layer on the natural nail, a builder or sculpture gel to give the nail shape and thickness, and a sealer gel which adds a final, ultra-thin, high-gloss protective coat. More specifically, builder gels are used for natural nail overlays or tip-with-overlay services, while sculpture gels tend to be a bit thicker and are used for pink-and-white sculpture services.

High-, Low-Watt Gels

Gels cure at a specific bandwidth of UV light. Lamps are graded according to the predominant bandwidth that they produce. The UV lamps used in curing gel products range from 4-, 6-, 8-, to 9-watts.

High-watt gels cure with 9-watt lamps. These gels work with the strength of the bulb and therefore need less photo-initiator in order to cure properly, says Wetzel.

Low-watt gels are those that cure with 4-, 6-, and 8-watt lamps. These gels tend to have more photo-initiator in the formula in order to make up for the lower wattage. Both high-and low-watt gels can be found in all of the different viscosities from thin base coat gels to builder or sculpture gels as well as in both single- step and multiple-step systems.

Colored Gel

Colored gel has the consistency of a traditional builder gel, but is infused with pigment. The nail techs we spoke to agreed that while colored gel is thick enough to form a complete gel nail, it is advisable to use it only as the final layer of a gel nail. “Color affects adhesion because it acts as a contaminant,” says Wetzel. “The very bottom layer at least must be clear in order to get the best adhesion. Also, you always want to be able to see the nail bed clearly.” It is also more practical to use color in a thin layer in order to reduce the amount of potential work during a fill service as all color must be removed at each fill.

Gel Polish

Gel polish is a relatively new form of gel. Inspired by colored gel, gel polish is a heavily pigmented yet extremely thin gel designed to be worn over a fully formed nail instead of nail polish. This gel is not designed to be used to build or shape the actual nail, but merely to finish it. Highly durable, gel polish is becoming a favorite because it is applied in a single layer and once it is cured, it cannot be smudged or damaged like traditional nail polish. If a client tires of the color she may apply traditional polish over it or have it filed off by her nail technician.


  • self-levelling
  • less filing
  • less prone to lifting due to better adhesion to the natural nail
  • odorless — good for spas, natural appeal
  • lighter than acrylics
  • natural-looking
  • easier to apply than before due to better consistency
  • impervious to chemicals
  • no mixing
  • application time is similar to acrylics — some techs can do a full set or fill in less time than with traditional acrylics
  • crystal clear
  • flexible
  • cures in about 10 minutes


  • may not be suitable for clients with sensitive or very thin natural nails
  • techniques can be difficult to master for acrylic techs
  • initial start-up cost can be pricey due to lamp purchases
  • some clients and nail techs can develop allergies to gels
  • because gels are meant to be a permanent enhancement (think hair color or highlights) most are not easily removed and cannot be soaked off.

What Is That Tacky Layer?

Oxygen prevents gel from curing, so the uppermost layer of gel will remain uncured regardless of how long it is exposed to UV light. This layer is important when creating a gel enhancement in that it gives subsequent layers something to adhere to and is crucial in creating one solid mass of gel on the nail. As gel does not stick to shiny surfaces, removing the gummy layer after each curing will result in poor adhesion and pronounced flaking and chipping of the layers.

Be very careful to remove this layer thoroughly after the final curing as skin exposed to uncured gel is likely to become irritated and may develop an allergy to gel products. Nail techs who are just getting the hang of gels may want to invest in barrier creams that are designed to protect the skin during nail procedures.


Understanding the science behind gels allows nail techs to better understand the nature of the beast and gives them the tools to make complete use of the various forms of gel at their disposal. Here we play professor and break down the basics of gel technology in terms of its relationship to acrylic technology.

  • All gels are members of the acrylate family — a cousin of the methacry- late family, which acrylics are members of, as well as of the cyanoacrylate family, which includes nail glues.
  • Acrylic systems consist of monomer, polymer, and a chemical catalyst to begin the hardening process once the monomer and polymer are mixed. There is a narrow range of mix ratio for monomers and polymers, which varies from product to product. Acrylics harden in about two to three minutes and cure in 24-72 hours (They actually continue to cure at a very slow pace until the product is removed.)
  • In most cases, gels have identical ingredients as acrylics — monomer and polymer — but they are a different chemical composition than acrylic and to not require mixing. The gel oligorner is made up of larger molecules that are pre-joined or “partially polymerized” even before the curing process begins. Gel uses a photo-initiator to tell itself to harden in UV light. Inhibitors are used to keep the gel (or monomer in acrylic systems) from hardening in the container Most UV gels harden in about one minute and reach maximum strength in about an hour. (Like acrylics, gels continue to cure for the duration they are on the nails.)


Gels are extremely flexible in their uses and can be incorporated into many services.

  • Wraps. Gel systems work beautifully with fiberglass or silk wraps to give natural nails added strength and beauty. Another option is to embed patterned fabric in gel on the toes or fingers.
  • Nail Art. Gel polish and colored gel may be used to create unique and long-lasting nails.
  • Pedicures. Gel polish or colored gel may be used instead of nail polish on the toes after a pedicure. Gel will resist chipping or fading on even the most hardworking of feet.
  • Gel sealant (the thin high-gloss formula) may be used to protect nail polish or nail art of any kind, from handpainted to airbrushed art.
  • Missing or chipped nails. Gel may be used to fix a chipped or broken natural nail instead of nail glue or acrylic. Missing nails may be replaced with one or two very thin layers of gel applied directly to the skin. Make sure that gel is thoroughly cured in order to avoid allergic reactions or irritated skin.

As an overlay for acrylics. Clients that prefer acrylics can still take advantage of the glassy, durable protection that gels offer

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