PR Question

[jkeithrussell]

I tried my first 3 casts last night. Using Silmar 41 and US Composites' liquid coloring agents. Overall, went better than I expected, but I couldn't figure out how to get swirls. On the first one, I waited too long and the PR had gelled. I ended up with a pile of goo on top when it grabbed the toothpick. On the second one, I put the second color in too soon, and it was absorbed by the primary color. I did a little better on the third one, but still put it in too soon. Once it starts to gel, it goes pretty fast. Any tips?

 

[NewLondon88]

Just out of curiosity, which colors are you swirling? And how?

Yes, it sets up quick. You might try mixing your first color in a container that you
can pour from .. and mix the second color in a second container. When you are ready,
drizzle the second color into the first container over the primary resin color and then
pour. I find that putting a popsicle stick or a chopstick across the pouring container
helps to keep the 'lines' and cuts down on the amount of air introduced by the
action of pouring. The resin flows down the stick and into your mold.
Obviously, you do this before it gels.

You also get better swirl in a larger mold. Trying to get a swirl in a single blank mold
will give you more or less straight lines. If you pour into a block mold or pour over
tubes, anything that gets in the way canl cause a swirl. You can also use the
chopsticks to swirl the color.

 

[jkeithrussell]

It was burnt orange (1 part red, 1 part yellow, 1/2 part brown) and cream (off-white). I mixed 7 ounces of the burnt orange in one cup, 2 ounces of the cream in a second cup. Added catalyst, stirred for a bit, then poured all of the burnt orange into the 3x6x1 mold, stirred a few minutes more, then poured the cream into the mold. I tried to swirl it in with a toothpick, but it mostly sank and/or disappeared into the burnt orange. I popped out the brick over my lunch break and it looks good from the outside -- but I can't see inside to know what became of the cream color.

Just out of curiosity, which colors are you swirling? And how?

Yes, it sets up quick. You might try mixing your first color in a container that you
can pour from .. and mix the second color in a second container. When you are ready,
drizzle the second color into the first container over the primary resin color and then
pour. I find that putting a popsicle stick or a chopstick across the pouring container
helps to keep the 'lines' and cuts down on the amount of air introduced by the
action of pouring. The resin flows down the stick and into your mold.
Obviously, you do this before it gels.

You also get better swirl in a larger mold. Trying to get a swirl in a single blank mold
will give you more or less straight lines. If you pour into a block mold or pour over
tubes, anything that gets in the way canl cause a swirl. You can also use the
chopsticks to swirl the color.

 

[ngeb528]

I usually use a timer when I'm using more than one color. I set it at 15 minutes once I put the catalyst in. I occassionally stir the different containers during the 15 minutes to see if either is setting up faster than another.

When they start feeling thicker I typically drizzle the container with the smaller amount onto the PR in the other container while I'm slowly pouring it into the mold.

You get a good mix that way and don't have to do any mixing once they are in the mold. I will occassionally swirl a toothpick once the PR is in the mold to make sure any pearlex gives a good reflection once it's set but it's just one or two swirls so the colors don't totally combine.

 

[RAdams]

I use the little silicone muffin cups that i also use as molds for my pendant blanks. I mix each color individually. I add the hardener, and stir for a few minutes. Then i pour most of the base color in the mold (a 3 single pen blank blank mold). then i add the colors, and finish off with the rest of the base color.

I dont have to use any sticks or anything to swirl. If i pour the colors together while they are really wet, then they kinda blend into each other, giving this weird space dust look while still staying seperated for the most part (see my first fountain pen sale in the gallery). If i wait till they are about to gel, then i get really strong seperation ( see my personal fountain pen in the gallery)

I use the mica from coastal scents. It doesn't seem to bleed the colors together too much even if you mix the catalyst and pour immediately. I think if you use the pigments made for PR, they will want to blend together by nature. I have never used said pigments, so i am just guessing, but anything developed specifically to be saturated by PR won't hold seperation like something that was not designed for PR... make sense?

 

[NewLondon88]

I use the mica from coastal scents. It doesn't seem to bleed the colors together too much even if you mix the catalyst and pour immediately. I think if you use the pigments made for PR, they will want to blend together by nature. I have never used said pigments, so i am just guessing, but anything developed specifically to be saturated by PR won't hold seperation like something that was not designed for PR... make sense?

That seems to depend on the color. Some colors hold separation well and
some separate completely. When I mix black and red it swirls fine.
If I overmix, it comes out a dull muddy red.

When I do the exact same thing with black and green, the black sinks to
the bottom by the time it gels. I'm wondering if it has something to do with
the specific gravity of the material they use as a pigment.

Also, different rules seem to apply for PR or Alumilite..

 

[PR_Princess]

When I do the exact same thing with black and green, the black sinks to
the bottom by the time it gels. I'm wondering if it has something to do with
the specific gravity of the material they use as a pigment.

Also, different rules seem to apply for PR or Alumilite..

Exactly Charlie!! Different dyes and other additives (such as mica) will have different effects on the PR. Some micas and powdered dyes can make the PR more "heavy", while liquid dyes (especially the transparent dyes) can dilute the resin and therefore make it "lighter".

In addition, the chemical make up of each the additives can have an effect on the gelling time. For me, black sets up in two shakes of a rats' tail (go ahead Skippy :biggrin:), while the transparent reds seem to take foreveeeerrrrr...

The best advise I can give...experiment, practice and watch over your resin like a hawk. Over time, you will find out what works best for you, with the materials you use and in your specific geographic location. We can all try to give out general guidelines and rules of thumb, but on the scale that we use....well, this is just not an exact science. Besides if it were, would it still be fun???:biggrin:

 

[NewLondon88]

I was thinking that I haven't really had any problem with mica powders, but then
I remembered that I've really only done solid colored blanks with them.. so it
wouldn't matter.