Frequently Asked Questions:
(Have a question not answered here? Email us.)
How do you use KOBRACAST® ?
KOBRACAST® starts as a pliable bandage that can be cut into strips or shapes as needed. Once heated, the thermoplastic activates: it becomes sticky, and can be stretched and shaped onto any form. Once cool, it is rigid, strong and porous. It can be re-heated endlessly, and glues to itself without needing additional adhesive. KOBRACAST® is heated with hot water, a hairdryer or heat gun.
How do you keep KOBRACAST® from sticking to your fingers?
Keep your hands wet while working with KOBRACAST® . KOBRACAST® does not need mold release when working with a positive or negative mold, as it is flexible when set. Likewise it does not stick to skin when working with body parts (though it can stick to facial hair, and a barrier cream is recommended). However, the adhesive will start to coat fingers and hands as you work with it if they are dry. Keeping your fingers wet helps keep Kobracast smooth and wrinkle free and prevents tears in application.
When is KOBRACAST® best to use?
KOBRACAST® works in many applications where a thermoplastic is useful – props, masks, armor, sets, etc. KOBRACAST® is especially suitable to use as a foundation layer, when things need to be as lightweight as possible, and when breatheability is a bonus or necessity. KOBRACAST® has a lower activation point than most thermoplastics, making it easy to use against skin. KOBRACAST® has an open weave surface, meaning that it must be covered in some way for a smooth finish. For applications where a smooth finish is preferred, Worbla, or a mix of KOBRACAST® and Worbla, may be best.
How to cut KOBRACAST®?
KOBRACAST® can be cut with regular scissors, however it is suggested that you use medical scissors or gypsum board scissors to remove pieces that are wrapped around body parts, to safely remove your KOBRACAST® and avoid cutting your model.
Is KOBRACAST® safe?
Yes. KOBRACAST® is non toxic and used regularly in the medical field in replacement of plaster bandages for casts.
Will it melt in the sun/desert/really hot day/at my LARP/on Mars?
Products made out of KOBRACAST® are heat resistant up to 60 degrees Celsius, water and weather resistant and therefore can be used for outdoor purposes.
However: you must not store your KOBRACAST® in a car, or in a similarly likely to heat space such as a shed or patio, as it will begin to warp completely. (A car can reach an indoor temp of 80C in the sun, and KOBRACAST® activates at 70C.)
How strong is KOBRACAST® ?
We don’t have an actual strength rating for KOBRACAST®. ‘Very strong’ we can say, and ‘intended to support a limb while a bone sets’ is a a good frame of reference.
What is the difference between KOBRACAST® , Worbla and Wonderflex?
Wonderflex is thickest of the three, a plastic with a fabric-style grain to one side, which can take time to finish. Wonderflex is less suited to complex curves, requiring seams to take the shape, but is very durable, and does not tear. Wonderflex activates at 80C and is mildly sticky to the touch with some residue when heated. Wonderflex scraps do not blend well and therefore leaves waste.
Worbla is thin and has no grain allowing it to be given a smooth finish easiest of the three. Worbla can stretch and flex more than Wonderflex, and handles complex curves exceptionally well, but is more brittle when stretched and can tear. Worbla can be layered with itself or foam to give it strength and support while handworking it, and can also be sanded, or sculpted like a clay. Worbla has no waste, as all scraps can be reblended. Worbla activates at 80C and is tacky to the touch when activated, but leaves no residue.
KOBRACAST® is sold by the yard, rather than as a sheet (as Worbla and Wonderflex are) and is an open weave polyester with a thermoplastic backing. It handles complex curves exceptionally well, and remains strong but flexible and very lightweight once cool, weighing almost half of what Worbla or Wonderflex do. KOBRACAST® can be seen and breathed through once cool. KOBRACAST® is very sticky when activated, and needs to be worked with wet hands to prevent tearing. KOBRACAST® has a very rough, open surface that needs to be covered completely to give a smooth finish. KOBRACAST® is activated at 70C, and scraps can be layered to form new sheets with little waste.
All three are self adhesive – they will bond to themselves and one another when heated.
Have a question not answered here? Email us.