THI-VEX Thixotropic Agent for Thickening Smooth-On Silicone Rubbers

In this review of THI-VEX the bottom line is simple: it is a focused tool for makers who need to turn pourable Smooth-On silicones into brushable, vertical-surface mixes. The product is intended for artists, model makers, and mold makers who want to build brush-on molds without sagging or waste. THI-VEX thickens by volume-percentage of Part A, mixes into Parts A and B, and delivers reliable increases in viscosity when used correctly, making it the go-to accessory when a little thickener prevents a lot of mess.

Key Features

• Thickening Liquid: Specifically formulated to turn Smooth-On silicone rubbers into a brushable consistency for vertical surfaces and detail work.
• Variable Viscosity: Different thicknesses are achieved simply by varying the percentage added to Part A, allowing control over the application.
• Brush-On Mold Use: Enables building up layers on molds and models without significant sagging, which is essential for layered brush techniques.
• Small Amount Required: Only a small percentage of THI-VEX is needed to alter viscosity, so a pint stretches across multiple projects.
• Mixes with Parts A and B: When thoroughly blended with both components it maintains silicone cure behavior while increasing body for vertical application.

Who It's For

THI-VEX is best for hobbyists and professional mold makers working with Smooth-On silicones who need a predictable way to make brushable, non-sagging coats. If you frequently build brush-on molds for prototypes, sculpture, or tooling, it streamlines work by preventing waste and enabling controlled layering.

Those who should look elsewhere are users of Mold Max 40 or Mold Max 60, because THI-VEX does not work with those specific silicone formulations. Also, if you only pour molds or never brush silicone on vertical surfaces, a thixotropic agent may be unnecessary.

Pros & Cons

Pros

• Effective at increasing viscosity so brush coats stay in place and reduce sagging.
• Easy to use when added as a percentage of Part A and thoroughly mixed into Parts A and B.
• High material quality noted by users, helping to avoid wasted silicone during application.

Cons

• Not compatible with Mold Max 40 or Mold Max 60, limiting use with those silicone lines.

Specifications

Product name	THI-VEX Thixotropic Agent
Intended use	Thickening Smooth-On silicone rubbers for brush-on molds
Formulation role	Added as percentage of Part A; mixes with Parts A and B
Compatibility note	Does not work with Mold Max 40 or Mold Max 60
Container size	Pint bottle
Typical benefit	Enables vertical surface application and reduced waste

Our Verdict

THI-VEX is a pragmatic, cost-effective thixotropic agent for anyone who needs to convert Smooth-On silicones into a brushable form. It delivers reliable thickness control with minimal material required, making it a good value for artists and mold makers who work on vertical or detailed surfaces. Avoid it only if you use Mold Max 40 or Mold Max 60 or never brush silicone.

Frequently Asked Questions

Can I use THI-VEX with any Smooth-On silicone?
It works with most Smooth-On silicones when added as a percentage of Part A, but it will not work with Mold Max 40 or Mold Max 60.

How much THI-VEX should I add?
Different viscosities are attained by varying the amount added to Part A; only a small percentage is typically required, and thorough mixing with Parts A and B is essential.

Is THI-VEX suitable for brush-on molds?
Yes, it is designed specifically for vertical surface application and building brush-on molds by preventing sag and waste.