Resin Coloring Disappeared!

[mikepet]

I am a newbie using the Hobby Lobby 32 oz polyester resin. It sticks to high heaven, but no need for a pressure pot, so that is what I went with.

I'd rather have a lot of colors to experiment with rather than a single expensive bottle or two of whatever.

I used acrylic paint, an 8 set of flourescent and glitter colors. I used Blue and Orange. Mixing each into its own cup, adding the catalyst and stir like crazy.

Then, pour into the mold. The blue/orange swirled nicely and it seemed like things were going to work great.

As it started curing, I noticed that the orange started to get smaller and smaller area wise. By the time it was semi-cured it was blue and green. Ok, green makes sense.. the orange combined with the blue to make greenish.
Next time I would just let it sit a bit longer so its thicker before pouring.

But then once it was completely cured, the green was also gone! The entire thing is blue... but cloudy looking. I actually really like it... a semi-opaque blue cloudy look with blue/white swirls.

The question is: What happened? The orange die was fine when in the cup, even after adding catalyst and stirring. And when pouring it was fine.

Id appreciate any pro tips.

Also, how to get more resin for cheaper. Right now its 25 bucks, minus 40% coupon for 32 oz.

 

[JohnU]

I'm not experienced with using acrylic paint. I like to use the polyresin dyes and have good luck with them. I would guess that the blue just overtook the orange. The problem with all polyresin is they cure slowly and kind of churn around in the mold as they cure. This is where the new blending of colors usually come from. I started with Hobby Lobby Casting resin and later switched to Silmar 41 from online vendors. The problem with the "on the shelf" resin is that you never know how long its been there and that can make a difference. Silmar is only about $36 a gallon and you get fresh stuff. They also sell the proper dyes that work with it. When it comes to color casting, nothing works (IMHO) as well as alumilite because it cures so quickly. If you want success with polyresin color casting you will have to get good with watching the clock. It needs to cure and thicken before pouring. You will have to experiment a little to see what works for you but take notes each time you pour so you know how long you waited between adding the catalyst and pouring. Air and resin temp can alter these results. Warm your resin in the sun or under a lightbulb before you mix. It will help the airbubble move up before you pour, since your not using pressure. Also remember some dyes or colorants are heavier than others so you may get color separation because of that. Casting is a hole different monster with lots of variables. Keep at it and you'll find what works for you. Just remember cheap prices are not always cheaper if your getting failures and have to keep buying more.

 

[Sylvanite]

One of two things happened. Either:

1. The colorant you used is not compatible with polyester resin and as it cured, the color shifted. I've had this happen using dyes for Alumilite in PR. Or,
2. You combined the colors before they gelled and they blended. One color then overwhelmed the other. To get good color separation, you need to wait until the resin starts to kick off before you combine the colors. Then the resin thickens and the colors don't get much of an opportunity to mix before setting up. Timing the pour can be tricky, especially if you use any pigments that retard gelling.

I hope that helps,
Eric

 

[mikepet]

Thanks guys. I will have to do further testing to see. I'd expect to see a little bit of green at least if the blue overtook the orange.

Next time I will let it sit up a bit and thicken before pouring.

 

[chartle]

I've tried all the alternative colorants for PR and the only thing that really works of those types is powder coat paint. I've had some success with Adirondack Alcohol inks but the colors are not very deep.

I've since bought the small sample packs of pearlex from Micheal's. They have 2 sets of 12 small bottles that I'm not close to using up. Best thing is Michael's has a 50% off any item that runs through the end of the week so I got those 12 bottles for about $12. I have both sets and of course used either another 50% or the 40% they usually have.

But as a tip you should wait until it thickens up a bit before you pour. The issue is I have had it go from snots, to jelly, to bottle stopper blank in less than a minute.

I wait until it gets to maple syrup before I pour.

 

[chartle]

Also I've found that until it gells, PR sort of looks like its "boiling". After I add the pearlex and then the MEK I think it starts to heat up and it really moves around.