Tuesday, October 27, 2015

Using Resin in our Best Flexible Molds

"Can I use resin in your molds?" This is a question we are so often asked. The answer is "Yes, But".

After a lot of research, below is the info about using resin in our molds. 

Because Best Flexible Molds are made of Urethane Rubber a highly  flexible, tough, long lasting rubber, they are often confused with Silicone rubber. Urethane molds have a long library life, are tough, and flexible.

Our molds are designed to be push molds for polymer clay. Other materials that can be used easily in our molds are: Plaster of Paris, Melt and Pour soap, Paper Clay, UTEE, Eraser Clay and Metal Clays.

Mold Cleaning: If clay builds up in the openings of our molds, they can be washed by hand in warm, soapy dish water or even in the dishwasher if the dry cycle is set “Heat Off”.
When dry, the molds can be refreshed with a light mist of Armor-All.

 After speaking with a tech at the company where our rubber is manufactured, he told me that -- 

Yes, our molds can be used with resin with the following requirements. They MUST be properly released.

The openings in the mold must be released with paste wax (flat

yellow can in photo, bottom left) and it needs to be the kind of paste wax that is used for floors, NOT the kind that is used for cars. The reason for this is that car wax has water in it.

The brand of release agent recommended by the manufacturer of our rubber is Johnson's Paste Floor wax. There is no water in this wax.

Always remember --- When it comes to resin and urethane molds, water is not your friend!!

The reason? If there is water in the wax, the water will cause the resin to bond to the rubber mold and destroy the opening in the mold.

Here is a link to the product that they recommend.

More info: Using Johnson’s paste wax as a release we tested a two part 50/50 resin epoxy and polyester resin (a liquid resin where a larger amount is sold with a small bottle of activator.) See first photo, upper left of 50/50 resin epoxy.

At this time three kinds of resin have been tested. The molds were released using the paste wax listed above.

Magic Gloss, made by Lisa Pavelka.

This material comes in one bottle and is hardened by exposure to a UV lamp, black light or sunlight and does not require a release in our molds. Judi W. tested the Magic Gloss on a mold earlier this year. The resulting hummingbird looked like a jewel. No release was needed but continued use might cause problems if un-released.

Regular Polyester Resin: 

Available at many hobby stores like Hobby Lobby. This type resin is activated with a few drops of liquid catalyst. It normally comes in a large container with a small bottle attached. The small bottle is the activator. This type resin must have a release agent. The rubber manufacturer only recommends SC Johnson’s paste floor wax as a release agent.

Epoxy resins.
Salad oil release worked OK, but was messy

This kind of resin is a 50/50 mix of two materials and usually comes in a package of two equal sized bottles.

Urethanes and Resins MUST have a release agent. Always read the label and never use a wax with water in it as water will cause the resin and bond to and destroy the mold.

I hope this helps to clarify the use of resin in Urethane Molds like ours.
Thanks so much for stopping by.

Penni Jo Couch
Designer/ Sculptor 
White Pearl Resin Roses.


Bonnie Kreger at B-LEE KREATIONS said...

This is a great article. I have used your molds with Magic Glos many times and they turn out beautiful. Never had a problem with the mold after it was finished.

The one thing I did discover, is you have to make your molds in layers if the molds are deep or they don't harden. I've made quite a few molds of your crosses with Magic Glos and put glitter or other inclusions in before the second layer.

I love your molds, I'm sure I'm your biggest fan.

Bonnie Kreger at B-LEE KREATIONS said...

My comma after the "is" disappeared. Anyway, it's all great with your molds. Thank you so much for sharing all the information you do.

Penni Jo AKA Claylady43 said...


Thank you so much for your very valuable input, especially about the layers in the deep molds.
Thank you so much for your continuing support and, we love that you are our biggest fan. :-)
Blessings Always,
Penni Jo