Saturday, September 29, 2018

Resin Experiments Follow-Up

My little jar had tiny air bubbles throughout. They aren't hideous - they actually look like little sparkles. You have to look for them, but they're there. So I thought next time I try that, I'd use an actual casting resin, rather than a doming resin. I'm still experimenting and looking for the perfect casting resin for that type of project.


AMAZING 2-Part Epoxy Casting Resin, 8-oz. kit
This two-part clear coating and casting resin is easy to use.
It's great for small items and pieces less than 3/8" thick and excellent for doming bezels or polymer clay pendants and medallions. However, it’s just thick enough that if you use this for cast items thicker or deeper than the recommended 3/8 inch, you are likely to notice tiny air bubbles in your finished product.

You use it like this:
Combine equal parts of Part A and Part B, as measured out in your mixing cups. I find it helpful to mark the increments I want to pour to with a magic marker, like so: (whoops, I forgot to get that picture! Will edit and add that photo tomorrow when the light is better!)

Stir slowly and gently for 2 to 3 minutes, so as to avoid introducing too many air bubbles into your resin. A popsicle stick is perfect for this. I recommend you use the plain wooden popsicle sticks and not the brightly colored dyed ones unless you're okay with some of that color transferring into your resin. 
Plain wooden popsicle sticks

Once combined, you have up to 30 minutes working time, so allow the mixed resin to rest 5 to 10 minutes in order to release air bubbles before pouring onto your piece or into your mold. 

Once you’ve poured your resin, watch for air bubbles to emerge on the surface of your resin. When those appear (and they will!) there are a few ways to deal with them:
  1. You can blow on them gently with your mouth. I've heard it’s the carbon dioxide in your breath that pops the bubbles.
  2. You can blow on them gently with a drinking straw. This concentrates the breath (and CO2), and is a little more effective than simply blowing on them.  
  3. You can use a flame, like from a long-neck lighter or a cooking torch, to EVER SO LIGHTLY AND QUICKLY brush the tip of the flame across the resin surface. There's a link to a video below that shows this technique. You'll want to see how it's done before attempting this method, as it is easy to get carried away with the flame and cause a fire hazard.
Pieces can generally be de-molded in 18 to 24 hours, but will still be what I call "tender" - they may feel firm, but you can accidentally imprint or damage the surface of the resin even though it seems hard - so allow the finished piece to cure a good 48 hours before any sanding, polishing, drilling, or other rough handling.

Use a release agent when using a non-silicone mold for resin casting.

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