What type of paints can I use on Smooth-On plastic resins and what is the best method for painting my casting?

A. Acrylic paints generally work best.

First, apply a high quality auto body primer (available at your local auto supply stores). Apply 1 or 2 coats evenly over casting as needed, and allow to dry.

Customers contact us regularly asking which primer works best as a foundation for painting their Smooth-On plastic castings. To settle the question once and for all, we tested over 30 aerosol primers and found that most did not work, or worked poorly at best.

The low-quality primer would "bead up" on the surface of the casting.

Whether applied to the rubber mold surface or applied to cured castings (no release agent used), two primers did stand out, providing excellent adhesion and the best for painting.

Plasti-KoteTM Sandable Primer - can be found at auto supply stores in the U.S. Contact: Plasti-Kote in Medina, OH Tel. 800 431 5928 or http://www.plastikote.com/products/Primer/Sandable-Primer.html

BulldogTM Adhesion Promoter - Contact: W.M. Barr Co. in Memphis, TN Tel. 800 398 3892 or www.wmbarr.com. Or order online at www.levineautoparts.com

After primer has completely dried, the casting may be painted with acrylic paint or similar paint products. Model train paints (available at many hobby stores) work well. Some testing for paint compatibility may be necessary.

Disclaimer
This FAQ article is offered as a guideline and offers possible solutions to problems encountered during mold making and casting. No warranty is implied and it is up to the end user to determine suitability for any specific application. Always refer to the provided Technical Bulletins (TB) & Safety Data Sheets (SDS) before using any material. A small scale test is suggested to determine suitability of any recommendation before trying on a larger scale for any application.