Polyester resin coloring agents

Polyester resin coloring agents

or this post could be alternatively titled

Five things not to do when casting resin

One of the things I love to do for Resin Obsession fans is take experiment requests.  I totally get this.  I wouldn’t want to waste resin either on something without knowing whether or not is was going to work.  I have been conducting a series of resin experiments over the last 18 months or so and am always looking for more to do.  I have received a few emails asking whether or not the Resin Obsession color pigments would work in polyester casting resin.  I added the idea to my resin studio schedule for the week of January 16.

This is where it all started to go wrong.  

I admit it.  I didn’t follow my own advice and made several mistakes.  While I was able to get the answer I was looking for, the finished castings are nothing short of a big hot mess.

Let me go a little off-topic for a moment.

In case you missed it, I spent several days in Phoenix, Arizona, last week and this week for the Creativation show organized by the Craft and Hobby Association.  I was determined to get these castings done before I left so I could write about them when I got back.  On the day scheduled to do this experiment, I had another urgent matter to tend to, so I didn’t start casting these until late in the day.

Mistake #1:  Try to cast resin when you don’t give yourself enough time.

polyester resin colors

Since I was working with polyester resin, I wanted to do this outside because the smell is so bad.  (By the way, if you have never worked with polyester casting resin, here are five things you need to know first.)  It was about 4 PM and I knew I would only have about another 60 to 90 minutes of daylight (and warmth) to work the resin.  I prepped my individual 1 ounce mixing cups with a toothpick of color from each of the twenty-five Resin Obsession color pigments.

polyester casting resin

I wanted to have enough polyester resin to put in 25 cups, so I poured as much of the resin as I could into one of my 10 ounce mixing cups.

Mistake #2:  Mix more resin than you can possibly use in the pot time.

adding catalyst to resin

While it was in the upper 70’s temperature when I started this, I knew it was not going to last as the sun went down.  I figured I would pour approximately 1/3 inch of resin into each cup.  Note:  Polyester resin is different from many other resins in that the amount of catalyst you add is dependent on the thickness of the casting.  According to the directions, I should have added 6 to 8 drops of hardener to this resin.  I wanted this stuff to get warm quickly to start curing quickly, before the ambient temperature cooled off.

Mistake #3:  Add more hardener to get things to cure quickly and think there won’t be consequences.

casting polyester resin

I quickly poured resin in all of my cups.  This took probably two to three minutes.

mixing resin color

I stirred with the toothpicks already in the cup instead of getting stir stix.  The stir stix would have been a better choice here as it would have blended the color into the resin faster and with fewer bubbles.

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Mistake #4:  Be too lazy or unorganized to get the right tools for the project.

bubbles in colored resin

So I didn’t get too far into this to realize that my resin was starting to gel.  By the end, I was mixing this like I was making scrambled eggs.  I was introducing sooo many bubbles.  I hoped I could get them out once I finished mixing.

Mistake #5:  Use poor resin techniques and think you can fix it later.

At this point, I had to get my assistant who was taking pictures to get gloves and help mix the colors.  Even with that, we couldn’t get to the end before I was dealing with a goopy mess.

polyester resin coloring agents

The good news in all this is that the resin did cure.  I can now advise customers that regardless of how well you mix it in, it will cure.  *insert a Homer Simpson DOH here*

polyester resin starting to gel

This was one of the final cups of resin that I got to mix before it started to gel.  (I was only about halfway through mixing the twenty-five cups at this point.)  Mixing the color into the polyester resin was like trying to mix the color into Jell-O.

By the way, the cup of resin shown here is fully cured.  Yes, it is lumpy and those bubbles are forever trapped in the mess I made.

opaque colors polyester resin

I was happy to see the colors cast as I expected they would.

These were some of the first cups of resin and color I was able to get mixed well.  You can see holes the bubbles left behind on the tops of the resin.  While the bubbles were able to rise to the top, the resin was start ed to thicken and couldn’t level out after they popped.

neon colors polyester casting resin

So while they only managed to get to be swirls in the polyester resin before they cured, I think the Resin Obsession bright neon pigments are my favorite.  I think these have potential to make great polyester resin coloring agents.

So how about you?  What are some of your big resin fails?  

One Comment

Kathy

I am on the floor laughing here because I know each and every of these mistakes. Not with polyester resin but it really doesn’t matter. It happens with epoxy too. Pouring with not enough time planned will be a disaster. Oh and how many times have I mixed too much resin, poured some pieces, got a new idea and raced around half an hour in my apartment to look for the sea shells or glitter or whatever that of course have dissappeared? Just to find the resin with the stir stick in the cup gooey and just ready for the bin. And each time I swear it won’ happen to me again….

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