Thread: Separating pigments problem

OK well, I must finally admit to having a major problem. I've tried all sorts of methods to get a good swirl, but a lot of the time I just can't seem to stop the pigments separating after the pour, as in the attached latest example.

The usual answer given is to pour just before the resin gels, but the time between when it's runny and when it gels is about 5 seconds. I tried this with a different batch yesterday, stirring my main colour constantly till I started to feel it thicken. When it did, I quickly went and started to pour it into the mould with my secondary colour, and the primary stopped pouring out of the cup half way through! It was almost like one of those still life models where the cup was suspended in mid air with the liquid pouring, frozen in time. I quickly glugged the lumps in and tried to pour my secondary around it, and of course ended up with air pockets in the final set.

Any other time when I've poured before this stage, the result is pretty much as you see below. I've had a couple of successes where it has worked, and I think it's down to pigment/resin ratios as to which colour ends up heavier, and therefore sinks. But without some way of measuring the specific gravity of the final mixes, it's rather hard to tell which one will be the heavier colour, although it generally seems the lighter (shade-wise) the colour, the more it sinks, with white being the worst offender.

So, the big question is, how are others handling this problem, or is it something unique to me that I'm doing wrong?

I can get away with it sometimes and the results aren't too bad by the time it's pen-size, but I'm certainly wasting a lot of resin redoing specific requests. The picture shown is supposed to be a Brisbane Broco's colour set of maroon with gold swirls. I'm going to try a Streamline in it and see the result, but I'm doubting it will be what I want it to be.

Thanks. Russell.