A Question on Casting Resins

[Tom Collins]

I am in the research phase of using casting resins to fill voids in bowls and hollow form shapes. A lot of the pieces I have seen have a swirl effect made up of a couple different colors. My question is, how is the swirl produced? Do the two colors not mix to make a third color? For example, why doesn't a blue and red swirl pattern just turn the whole batch of resin purple?

I have not done any casting yet and once I do many of my questions will be answered but at the price of the resins I don't want too many failures.

Thanks,
TomC

[Jim Burr]

The swirl is caused by mixing the 2 resin colors as they "gel" This time of year is ideal for casting due to high temps. If you live were it's cold...I'll be there in a minute! Due to the density of the colors and the depth at which the mix occurs, the colors can morph, two colors look like four. Once they start to gel, you have about 30 seconds to get it right. Even if it's not right...it still looks cool! Good luck!

[James Combs]

Something else that contributes to the swirl pattern. Swirl will be evident in even one color castings if you are NOT using dyes as your colorant. If you are using pearlescent powders such as Pearl-Ex there will be swirly pearlescent effect in the resin. You can get some of the effect with a combination of dye and powder if the dye is used sparingly. But, as Jim B. says, two different colors(preferably pearlescent colors but solid colors will work) mixed at the jell stage gives the best definition of two or more colors in the same resin batch. Keep in mind for best results you don't mix the colors external to the casting. Both colors are poured into the casting at the same time and mix as they are going in. Hope this is helpful.

[Jim Burr]

But, as Jim B. says, two different colors(preferably pearlescent colors but solid colors will work) mixed at the jell stage gives the best definition of two or more colors in the same resin batch. Keep in mind for best results you don't mix the colors external to the casting. Both colors are poured into the casting at the same time and mix as they are going in. Hope this is helpful.

Oops...Thanks JD, I was operating on assumption. He did a great job of articulating what I was trying to say Tim.
Those pearlescents are found from Pearl-ex, Costal scents mica powders and so on. Costal scents is really inexpensive for what you get, but does lack some of the "Pow!" of Pearl-ex. Jacquard, the company that makes Pearl-ex does sell in bulk and those prices aren't bad!

[Tom Collins]

Thanks, Jim and James, just the information I was looking for.

TomC

[Quinn McCarthy]

What brand of casting resin does everyone like and where do they get them from?

Q

[Jim Burr]

What brand of casting resin does everyone like and where do they get them from?

Q

There are several choices Quinn; Cast-n-Craft from Michaels...not a bad price if you use the weekly 50% coupons, catalyst is extra. Silmar 41 is good, but since is is shipped Hazmat, you pay through the wazoo for shipping!
Alumilite is cool stuff, but it does require pressure and no moisture anywhere near it!!
Since I'm small time, pen casting and stuff, CnC works fine for me. It is however really touchy on catalyst/resin ratio.

[James Combs]

Tom we have given you some good general information. If you would like some great detail on the howtos, the differences in resins, molds etc. check out the IAP(International Association of Pen-Turners) located at "penturners dot org". Their "Library-Casting" has a tremendous amount of casting info in downloadable PDFs.

Edit: You will want to check out their "Casting and Stabilization" forum as well.