Bubbles In Molds?

Decorating By elliebuff Updated 7 Jan 2010 , 10:38pm by DianeLM

elliebuff Posted 1 Jan 2010 , 2:31am
post #1 of 7

What is the best way to reduce the number of bubbles in molds? I realize it's probably best to use the liquid silicone on 3D objects, but is there any technique that can be used to minimize bubbles in the putty-consistency silicone?

Thanks!

6 replies
MYOM-Dominic Posted 1 Jan 2010 , 6:11pm
post #2 of 7

Great Question! The answer is Yes, there is a way of insuring no air entrapment went making a mold with non-liquid silicones. You can achieve this by using Silicone Spread in conjunction with Silicone Plastique. Because Silicone Spread is a paste, you can apply it first with a natural bristle artist brush making sure that everything is covered and no air has been trapped. Because you can see through Silicone Spread, you can inspect for bubbles and eliminate them. Now here is the important part. You must let Silicone Spread half cure - this usually takes about an hour at 70 degrees. If you can touch it and it is sticky but does not come off on your finger, it is ready. The second application is done with Silicone Plastique right on top of the Silicone Spread. Because you have taken care of details and air bubbles with Silicone Spread, you can apply the Silicone Plastique with less attention to detail and just add a layer that will give you a proper thickness and durability. The two silicone materials will bond together and you should let the whole project cure for about two hours at least at 70 degrees. What you end up with is what I call a compound mold where two different silicones are used to great one great mold.

Hope This Helps,

Dominic icon_smile.gif

DianeLM Posted 1 Jan 2010 , 6:21pm
post #3 of 7

I'm very excited to learn this! It never would have occurred to me to use two different products together. I will probably use this technique often. I even get air pockets on smooth surfaces.

I imagine this technique would also eliminate the need for a plaster cast on certain projects.

Hi Dominic! It's me, Diane! (yeah, right... I'm sure you recognize me by my font. LOL) I regret we didn't get a chance to visit longer than 'hello' in the vendor area at convention. My mom took ill so we had to leave early. Hope to see you in San Diego!

MYOM-Dominic Posted 1 Jan 2010 , 6:54pm
post #4 of 7

Hi Diane - Yes I remember seeing you at convention - sorry I couldn't spend more time but I was 10 people deep teaching mold making and answering questions from sugar artists on a mission. Hope your Mom is okay.

About your question, yes this method is great and you will not need support shells with small items. But when you have a larger project, I always recommend the use of support shells so that you can keep your silicone mold thin and very flexible. The thicker you make a rubber mold, the less flexible it is.

This method is especially helpful when making molds of smooth objects. Believe it or not, smooth objects are harder to coat than detailed objects. Painting first with Silicone Spread is great with glass bottles, large gems, and smooth ceramics.

By the way, your cakes are fabulous - I remember when you were first starting out at the Washington ICES convention.

Dominic icon_smile.gif

elliebuff Posted 4 Jan 2010 , 1:46pm
post #5 of 7

Great information, Dominic--thanks so much for the information!

MYOM-Dominic Posted 4 Jan 2010 , 3:22pm
post #6 of 7

my pleasure!

I also responded to your post in the sugar forum about white/cloudy isomalt. Did you cook the Isomalt with water or without water?

Dominic icon_smile.gif

DianeLM Posted 7 Jan 2010 , 10:38pm
post #7 of 7
Quote:
Originally Posted by MYOM-Dominic

Hi Diane - Yes I remember seeing you at convention - sorry I couldn't spend more time but I was 10 people deep teaching mold making and answering questions from sugar artists on a mission. Hope your Mom is okay.

About your question, yes this method is great and you will not need support shells with small items. But when you have a larger project, I always recommend the use of support shells so that you can keep your silicone mold thin and very flexible. The thicker you make a rubber mold, the less flexible it is.

This method is especially helpful when making molds of smooth objects. Believe it or not, smooth objects are harder to coat than detailed objects. Painting first with Silicone Spread is great with glass bottles, large gems, and smooth ceramics.

By the way, your cakes are fabulous - I remember when you were first starting out at the Washington ICES convention.

Dominic icon_smile.gif




I apologize for the late reply. Thank you for your kind compliment!

I'm so glad to know that I'm not the only one who has trouble with smooth objects. I was thrilled to learn at one of your later demos that I could fill in air holes in completed molds with more silicone. That piece of advice has saved me an untold amount of time trimming and buffing!

I am in complete agreement that certain projects rely on the flexibility of the mold. That was the case with my 3-D bowling pin mold (cake is on page 1 of my pics). I didn't have the time or patience to divide the pin exactly in half. Knowing that one half would inevitably be larger than the other, I counted on the flexibility of the silicone spread to facilitate unmolding the larger side. Worked like a charm! Although now that I have the time, I really should make the mold correctly. icon_smile.gif

And my mom is doing fine, thank you. icon_smile.gif

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