Frequently Asked Questions

How do I get the resin off my clothes or examining table?

The water curable polyurethane resin is very difficult to remove from clothing. Every effort should be made to avoid any contact of the casting socks with skin or clothing. Industrial solvent such as Orange Sol (Home Depot) or adhesive remover such as UNI-SOLVE (Smith& Nephew) sometimes are useful in removing the product from a vinyl exam table. We recommend using a paper or plastic cover to protect your examining table.

How do you get the resin off your skin?

Latex examining gloves and the plastic baggies that are provided should always be used. If a small amount of the cured resin gets on your skin it will eventually (a few days) wear off. Sometimes using nail polish remover and/or soap will enhance the process.

Do I have to use the plastic baggie that is supplied?

Yes. The polyurethane resin that is impregnated onto each of the casting socks will stick to the skin and therefore all exposed areas of the skin must be protected. Always use the plastic baggie that is supplied to protect the skin of the patient/client.

Do I need special blue gloves when I apply the sock?

No. Any type of examining glove may be used. You do not need to use specially treated blue or green examining gloves. You do however need to wear gloves.

Why is the resin sometimes sticky and why does it cling to the examining gloves?

The polyurethane resin that is used has unique characteristics. The more water that is applied to the sock the more slippery it becomes. Therefore, if you want to achieve a glass smooth finish, make certain that your gloves are very wet or add additional cool water. Having a spray water bottle available (with fine mist setting) while applying the sock makes it convenient to apply additional water during the molding phase.

Why does the casting sock sometimes feel hard?

The polyurethane resin that is used on the casting socks is water curable meaning that it will harden or set up once it comes in contact with water or even moisture from the environment. Very infrequently a seal on the aluminum pouch is breached by a pin hole or a faulty seal. If this occurs, we will replace the product for you without question. Merely send the hardened sock to us with the aluminum pouch, with your name and address and we will replace the faulty sock immediately.

What is the shelf life of the casting socks?

All STS products have a printed Lot # on the label representing the date of manufacturing. Slipper Socks are guaranteed for 12 months and all other products are guaranteed for 18 months from the date of manufacturing.

What is the difference between the Tubular Socks (17″ and 30″) and the Fitted Socks?

Both the 17″ and 30″ Tubular Socks are made from polyester/spandex yarn that are knit in a “tube sock” shape and then impregnated with a water curable polyurethane resin. The “fitted” casting socks (Ankle, Mid-Leg, Bermuda) are also made of polyester material but are knitted with a defined heel and toe area (much like a regular sock) and then impregnated with the same water curable resin.

Is water needed to cure each sock?

Absolutely. Each casting sock should be thoroughly submerged in water and the sock squeezed several times under water for about 5 seconds to activate the resin on both inner and outer surfaces of the sock.

Will the temperature of the water make any difference?

Yes. The resin will cure faster with warm water. When first using our products, cool or room temperature water should be used to allow longer application time. Once familiar with the application process, warmer water can be used to speed up the cure time.

What should I do if the sock is too long or if I have a portion of the tubular sock that is unrolled?

You should always immediately remove excess material or any portion of a tubular fiberglass sock that is not unrolled.  This can be done with scissors. Removal will prevent excess exotherm or heat to prevent burning the patient in the unrolled portion of the sock.

What is the difference in the set up or cure time of each of the resins?

Using room temperature water, the resin that is impregnated into the slipper socks is formulated to set up in 2-3 minutes. The resin impregnated in all other products is formulated to set up set up in 4-5 minutes.

Do I need to use the Slipper Clip that is supplied with the Slipper sock?

We strongly advise you to use the Slipper Clip that comes with the slipper socks. The Slipper Clip is designed to cinch up the arch area of the slipper sock (just like a “Mary Jane” shoe strap).  This prevents “bridging” of the sock across the arch and helps ensure excellent conformity of the sock to the foot which will provide a very accurate mold.

How can I assure that the Slipper Clip will be secured to the slipper socks?

Hold both clips between the thumb and index finger of each hand with the “hooks” oriented downward. You do not have to touch the sock with your fingers to use this clip. Hook the medial clip just under the elastic band at the apex of the medial arch. Pull the sock upward. When the sock is about an inch away from the foot, aggressively “jam” the hook into the fabric of the sock (just under the elastic band) to anchor it securely. Do the same on the lateral side.

Do I need a cast cutter to remove the sock?

No.  In most instances, the slipper sock is easily removed by hand. At times, particularly with a pes cavus type foot, it may be necessary to cut the sock at the anterior portion of the opening directed towards the colored stitch line to assist in removal. For the other STS socks, small specially designed STS scissors (Item #1006) are best used to cut the hardened sock.  A letter opener (envelope slitter) can also be used to carefully cut the material after it is hard directly above the cutting strip. Make sure the cutting strip is in place to the skin.

Do orthotic labs accept casts made of the STS Slipper Sock ?

Yes. Virtually all of the major orthotic laboratories willingly accept casts take with the Slipper Sock as long as it is applied correctly.

Do I need to read the entire instruction booklet?

Yes.  Especially for first time users. The instruction pamphlet has useful hints that will assist you in obtaining excellent negative casts. It is recommended that you read the instruction pamphlet before you begin casting.

Can the impressions obtained with one of the STS Casting socks be scanned?

Absolutely. The STS casting socks are ideal for CAD/CAM scanning because of the glass smooth uniformity of material thickness and excellent light reflection characteristics. There is no overlapping of material as one would find in either plaster wrap or fiberglass rolls.  The negative impressions are extremely accurate.

Can I see the skin lines on the negative cast?

No. Because you need to use a plastic baggie on the foot you will not be able to see skin lines as you would on plaster.

How do I mark lesions on the cast? Will marks on the skin transfer?


Do custom shoe companies accept casts taken with the STS Sock?

Yes. Most custom shoemakers prefer casts taken with the STS Ankle Sock. The shoe manufacturer often finds that casts taken with the STS Ankle Sock are more accurate and more durable than those made from either plaster of Paris or fiberglass wrap. The STS Ankle Sock is ideal for CAD/CAM which many shoemakers 1. 1use to create lasts to make their products.

Which is the correct casting sock to use for an AFO?

Generally speaking, the STS Ankle Casting sock is used for supra malleolar AFO’s such as the  “Richie Brace”.  The Midleg and Bermuda sock are used for traditional AFO’s and custom gauntlets depending on the height of the device.  The Bermuda sock is typically used for CROW boot casting or those patients/clients with long lower extremities. The 17″  Tubular Sock can also be used for custom gauntlets and the 30″ AFO tubular sock for posterior leaf spring and CROW walkers. Because of its increased  stretch capability, the 17” sock is recommended for the edematous foot/ankle. If in doubt as to which product to use, contact the lab that will fabricate the orthosis for their recommendation.

What sock do I use for a BK socket design?

The Trans-tibial sock is designed to be used to cast BK residual limbs for socket fabrication.  The Trans-femoral sock is used to cast AK residual limbs for socket fabrication.

What sock do I use for a rigid post amputation dressing?

The Rigid dressing sock is designed to be used over dressing gauze of a recently amputated lower limb.

Will a cast change shape after it is cured?

We advise waiting 8 hours before placing the negative cast(s) into a box if mailing to a central fabrication orthotic laboratory. It is also a good practice to stuff the cured cast with paper or bubble wrap before shipping, particularly in warm climate zones. It usually takes 4-5 hours before a cast is fully cured and hardened. We also advise not to keep the cast in the trunk of a car or outside in hot weather as excessive heat may soften the mold.

What is the shelf life of the product?

Shelf life of the slipper sock is one year from the date of manufacture. Shelf life of all other products is 18 months from the date of manufacture. Date of manufacture is indicated as the first six numbers of the lot # on the packaging label. Most products are shipped within a week or two from the date of manufacture.