Silicone prototypes for market testing

Silicone Prototyping: Clean Fingers Shellfish Eating Glove

Item: LA New Product Development Team
Rating: 5
Author: Megain & Tineaia Comanche

CONCEPT DESIGN
ERGONOMIC DESIGN
MATERIAL SELECTION
3D PRINTING
SILICONE MOLDING
PROTOTYPE TESTING

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Written by Ralph Hill, Mechanical & electrical systems, 3D manufacturing

Prototyping Engineer

Published August 30, 2026

Silicone prototyping is the process of producing working parts in cast elastomer — usually from 3D printed or machined molds — so a soft, stretchy or skin-contact product can be worn, handled and tested before any production tooling is cut. It is how you find out whether a flexible product actually feels right, which a rigid 3D print cannot tell you.

Clean Fingers is a three-finger sleeve that keeps the thumb, index and middle fingers clean while eating crawfish, shrimp and other shellfish. LA NPDT took inventors Megain and Tineaia Comanche from idea to functional cast-silicone prototypes: ergonomic design, material and durometer selection, a single-piece moldable geometry, and wearable units they could test with real users.

Project at a glance

Client: Megain & Tineaia Comanche, inventors of Clean Fingers (Louisiana)
Product: Reusable three-finger sleeve for eating crawfish, shrimp and other shellfish
Starting point: An idea only — no CAD, no prototype
Program focus: Feasibility and proof of concept, prioritized for speed
What we delivered: Ergonomic design and CAD, material and durometer selection, 3D printed form studies, printed molds, cast silicone functional prototypes
Methods: 3D printing, silicone rubber molding, iterative wear testing
Stage reached: Functional prototypes delivered for user testing and market validation
Where it is headed: The inventors are taking the validated prototype toward a consumer launch

What the client said

★★★★★

“My sister and I invented Clean Fingers (soon to hit the consumer market). When we began our journey with our invention we thought we had everything we needed; we quickly found out we needed a GOOD prototype. We are so fortunate to work with LA NPDT's team, specifically Konstantin D.
We had an idea of what we wanted our prototype to look like, however the LA NPDT team and Konstantin have delivered something much more. Konstantin is such a pleasure to work with, his professionalism is A1, more importantly he is very thorough while working with you on your invention, very knowledgable of what it takes to develop your prototype, and communicates 100% via email, text, phone calls and Zoom meetings with regard to improvements, changes or general information.
If you are looking for a company to help bring an idea to life and/or help create a prototype this is the company you should hire, you will not regret it.”

Megain & Tineaia ComancheInventors, Clean FingersGoogle review

A three-finger sleeve taken from a Louisiana inventor's idea to functional silicone prototypes ready for user testing.

The client

Clean Fingers is a soft, reusable sleeve that slips over the thumb, index and middle fingers so you can peel and eat crawfish, shrimp and other shellfish without coating your hands in shell, spice and juice. A strap across the back of the hand holds it in place, and textured fingertips give you grip on a wet shell.

Megain and Tineaia Comanche, sisters and inventors based in Louisiana, brought us the idea and one clear requirement: they wanted to hold a real, working version in their hands as fast as possible. That made this a feasibility and proof-of-concept program rather than a full production build. Our team handled concept design, the ergonomics, material selection and rapid prototyping, and delivered functional silicone units the sisters could put in front of their own potential customers.

The challenge

At a Louisiana crawfish boil the two normal options are both compromises. Bare hands peel well and feel right, but everything you touch afterward — your phone, your drink, someone else's plate — pays for it. Disposable gloves keep you clean and kill the dexterity and the feel that peeling shellfish depends on, and they get thrown away by the handful. The sisters wanted a middle path: cover only the fingers that actually do the work, leave the rest of the hand bare, and make it reusable.

Only three fingers. The thumb, index and middle fingers do the peeling; covering the other two adds bulk and heat for nothing.
Dexterity has to survive. The wearer still needs to feel the shell and find the seam, so the wall had to be thin and the material soft.
Grip on a wet shell. Shellfish are slick, so the fingertips needed texture rather than a smooth molded surface.
One size has to fit most hands. A consumer product sold at retail cannot ship in six sizes on day one.
Reusable and washable. The whole point is that it is not another box of disposables.
Cheap to make. The retail price this product can carry is small, so the part had to be manufacturable in one piece.

Our solution

Designing for Hands Is Harder Than It Looks

Anything worn on the body pushes product design into ergonomics, and hands are one of the least forgiving places to start. Finger length, finger diameter, web spacing and knuckle position vary enormously from person to person, and the same hand changes shape completely between an open palm and a pinch. A shape that fits snugly on one hand can be tight enough to cut off circulation on the next or loose enough to slide off mid-peel.

We resolved that with three decisions taken together. The geometry was designed around the closed, pinching hand rather than the flat hand, because that is the position the product is used in. The material was chosen to stretch and recover so a single size could absorb a wide range of finger sizes instead of matching one. And the fit was made adjustable at the wrist and back of the hand with a perforated strap, so the wearer sets the tension themselves rather than relying on the sleeve gripping the fingers.

Clean Fingers prototype shown flat on an open hand with the perforated adjustable strap across the back of the hand — The perforated strap sets fit per user — the reason one molded size can cover a wide range of hands.

Close view of the Clean Fingers silicone prototype fingertips showing the molded grip texture for holding wet shellfish — The perforated strap sets fit per user — the reason one molded size can cover a wide range of hands.

Material and Process Selection

Silicone prototyping was the right answer here because the properties that make the product work — softness, stretch, recovery, washability and food contact — are the properties a rigid 3D print cannot demonstrate. A printed part tells you whether the shape is right; only a cast elastomer tells you whether the product is right. We used both, in that order, moving from printed form studies to silicone rubber molding in printed tooling.

3D printed form studies. Fast, cheap checks on finger length, web geometry and strap placement before committing to a mold.
Printed molds, cast silicone. Molds were printed and finished in-house, then filled with platinum-cure silicone to produce functional units in days rather than weeks.
Durometer selection. Several hardnesses were evaluated against the tension-versus-comfort trade-off; too soft tears at the web, too firm fights the hand. Hardness is measured on the ASTM D2240 Shore A scale, and a few points either way changes how the part feels on the hand.
Food-contact material. Because the product touches food, the material path was chosen from silicones that can meet FDA food-contact substance requirements at production.
Single-piece geometry. The sleeve, the fingertip texture and the strap features were designed to come out of one mold, with no assembly and no secondary operations — the single biggest lever on unit cost at volume.

Iterating to Functional Prototypes

The program ran in short loops. Each round produced a wearable part, went onto several different hands, and came back with a specific correction: a finger shortened, a web opened up, a wall thinned, a strap moved. After a couple of design iterations and a few rounds of prototypes, we delivered functional units the Comanche sisters could wear at an actual boil and hand to other people for feedback — which is exactly what a proof-of-concept prototype exists to do.

Because design, engineering and prototyping all run under one roof in Ruston, Louisiana, those loops were measured in days. Nothing waited in a queue between an outside design firm and an outside model shop, and the engineer who changed the CAD was the one who pulled the next part out of the mold.

The result

Ergonomic industrial design and production-intent CAD for the three-finger sleeve
Material and durometer selection, including a food-contact-capable path to production
Single-piece, moldable geometry with integrated fingertip texture and strap features
3D printed form studies across several iterations
Printed molds and cast silicone functional prototypes in multiple rounds
Wearable units delivered for the inventors' own user testing and market validation

If you need custom silicone parts, a wearable, or any soft hand-held product idea proven out before you spend money on tooling, our Ruston, Louisiana team can take it from sketch to a part you can wear. Crawfish season peaks across Louisiana each spring, and this product had to be ready for it — tell us about your product and we will map the fastest honest route to a testable prototype.

Capabilities used on this project

Rapid prototyping services
3D printing, CNC machining, urethane casting and functional prototype builds with published materials, tolerances and lead times.
Concept design
Sketch exploration, form studies and CAD concepts that turn an idea into a buildable direction.

How a wearable silicone product gets prototyped

The path from a soft-product idea to a part someone can actually wear, in the order the decisions have to be made.

1. Define the product around the hand in use
Wearables are designed in the position they are used in, not the position they are easiest to draw in. Clean Fingers was modelled around a closed, pinching hand — the posture of peeling a crawfish — so the sleeve stays taut where it does work and slack where the hand needs to flex.
2. Solve fit before you solve form
Finger length, diameter, web spacing and knuckle position vary enormously between people. One size fits most is achieved with a stretch-and-recover material plus an adjustable strap that lets the wearer set tension, not by averaging dimensions across a size chart.
3. Print the shape, cast the product
3D printed studies answer geometry questions in hours and cost almost nothing. Only a cast elastomer answers the questions that decide whether the product works: softness, stretch, grip, recovery and comfort over a whole meal.
4. Choose durometer against the comfort trade-off
Too soft and the part tears at the finger webs; too firm and it fights the hand and gets taken off. Several silicone hardnesses were made up and worn before one was selected, which is only affordable because printed molds are cheap.
5. Design for one-piece molding from day one
Consumer products at this price point cannot absorb assembly. The sleeve, the fingertip grip texture and the strap features were all designed to come out of a single mold with no secondary operations — the largest single lever on unit cost at volume.
6. Put wearable units in real users' hands
The deliverable of a proof of concept is evidence, not a part. The Comanche sisters received functional prototypes they could wear at an actual crawfish boil and hand to potential customers for feedback before committing to tooling.

Ways to keep your hands clean while eating shellfish

Option	Dexterity & feel	Cleanliness	Reusable	Cost per use
Bare hands	Best	None	n/a	Free
Disposable gloves	Poor — bulky and slippery	Full hand	No	Low but recurring
Full reusable glove	Fair — warm, covers everything	Full hand	Yes	Moderate
Three-finger silicone sleeve	Good — thin wall, textured tips	The three fingers that do the work	Yes, washable	Lowest over time

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Questions about this project

Straight answers from the engineers who ran the build. Have a different question? Ask us directly.

Talk to an engineer

How is a silicone prototype actually made?

The part is designed in CAD, a mold is 3D printed or machined from that CAD, and platinum-cure silicone is poured or injected into the mold and demolded once cured. Because the mold itself is printed, a new revision can be in hand in days instead of the weeks production tooling takes.

What does silicone prototyping cost?

For a small consumer part like this, expect roughly $2,000 to $8,000 across several iterations, depending on part size, how many hardnesses you evaluate and how many rounds it takes to get the fit right. That is a fraction of the cost of cutting a production mold and discovering the fit is wrong.

How do you make a wearable product fit everyone?

You do not size it, you make it adapt. A material that stretches and recovers absorbs a wide band of finger and hand sizes, and an adjustable strap lets each wearer set their own tension. Sizing only becomes worthwhile once sales volume justifies multiple molds.

Can a silicone prototype be used with food?

Yes, if the material is chosen for it. We specify silicones with a path to FDA food-contact compliance so the prototype behaves like the production part and the production material is not a surprise later.

How long does a proof-of-concept prototype take?

For a product of this complexity, a first wearable part typically lands within a few weeks of kickoff, with each following iteration measured in days — because design, engineering and prototyping all happen in our Ruston, Louisiana shop rather than across three vendors.

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Project at a glance

Designing for Hands Is Harder Than It Looks

Material and Process Selection

Iterating to Functional Prototypes

Capabilities used on this project

Rapid prototyping services

Concept design

How a wearable silicone product gets prototyped

1. Define the product around the hand in use

2. Solve fit before you solve form

3. Print the shape, cast the product

4. Choose durometer against the comfort trade-off

5. Design for one-piece molding from day one

6. Put wearable units in real users' hands

Questions about this project

Industries this project belongs to

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