Casting Materials

[Kretzky]

Having seen some of the wonderful blanks produced by members, I'm thinking of having a go at casting. What are the advantages & disadvantages of the various systems? Note, I'm asking about casting materials used & not casting methods.
Why do you use, PR, Silmar or Alumilite (there may well be others). What are the relative merits & demerits of each? I appreciate for many it will come down to nothing more than a personal preference, but I'm hoping for input on ease of use, open time, colouring & mixing, & eventual suitability for ease of turning.
Thanks in advance for your help & advice

 

[robutacion]

Having seen some of the wonderful blanks produced by members, I'm thinking of having a go at casting. What are the advantages & disadvantages of the various systems? Note, I'm asking about casting materials used & not casting methods.
Why do you use, PR, Silmar or Alumilite (there may well be others). What are the relative merits & demerits of each? I appreciate for many it will come down to nothing more than a personal preference, but I'm hoping for input on ease of use, open time, colouring & mixing, & eventual suitability for ease of turning.
Thanks in advance for your help & advice

Well, there is nothing to it really, if you have the right bits of wood to cast, unless you want to go acrylic only then, things are even easier.

Yes there are many ways to go about mine is, a pressure pot, molds made with white kitchen chopping boards, some de-molding/releasing agent, and PR (Polyester resin) as any other option for me here in Australia, are out of question.

There are 2 main types of resin, the PR (polyester) and the Polyurethane 2 part mix, known is the US and Canada as Alumilite.

The best colours to use are the Pearlex powders and Alumilite is a little more fiddly to work with but a little easier to work with and certainly with much better adhesion to wood when necessary but doesn't produce the shine the PR can...!

The PR, is easier to work, better working times and if you don't abuse of the catalyst/hardener (no more than 2%) the blanks don't come up too brittle so, they cut quite nice and polish to a great finish.

In simplistic terms, that's it, in technical terms we may be here until Christmas nest year...!!!

Good luck,

Cheers
George

 

[Vince_Hoffmann]

I find that clear epoxy resin works just as well (and smells a LOT better) than polyester resin. I also find that the polyurethane resin does not cure hard enough for my liking.
As far as dyes, liquid colorants will give you a more saturated color, powdered pigments will give you tints, and depending on the material in the powder, metallic or sparkly effects.

 

[Jim Burr]

My only add to Georges' excellent example would be with coloring. Pearl-ex is $$! Coastal Scents mica powder doesn't quite have the bang factor that Pearl-ex has, but you get 10x the amount for about the same price.
It really is easy, buy some mold from the amazing vendors here, make your own...it's a wide open craft. Check out Youtube, Grub has the best vid's on casting.

 

[Kenny Durrant]

I think all the products you listed are good products. The main difference is which one works best for you. The alumilite gave me to many problems with bubbles. I had to stir rather quickly because it jelled too fast therefore I had bubbles. On the other hand I turned alumilite others cast and it turned really well. The pr resin set time can be controled by the amount of hardener so it gives me time to play with it. It also effects the brittleness of the cast. The difference between pr at local hobbie stores and silmar41 is the fressness of the resin. the fressness can make a huge difference. Good luck.