Casting Coffee...

[Craftdiggity]

...and other loose materials present a problem. Some sink to the bottom of the mold, while others float to the top. Either way creates a bunch up of material at one end and a whole lot of nothing at the other.

For the materials that sink, I guess I could just add more until it fills the mold up, but what about things like coffee beans? They float so adding more doesn't necessarily accomplish anything. What do you guys do to get an even dispersal of your materials?

I have been working with PR if that matters. Alumilite might be different.

 

[bitshird]

Chris, just make sure that you don't use so much filler material that it messes with your amount of MEKP with too much material you have to increase the amount of MEKP. DAMHIKT

 

[PTownSubbie]

I pack my vertical silicone molds full to the top and then pour the PR over top slowly allowing the tube to fill.

Once full, I put a small piece of window screen over the top and secure it with a rubber band. Nothing comes out the top then and the blank is long enough that if some pieces are not in the bottom, it gets cut off anyway...

 

[Craftdiggity]

Thanks, guys. Ken...I found that out on my own.

Fred, good idea about the screen.

 

[atomic ray]

One of the finer points involved with resin casting...suspended materials.

Unfortunately there is no right answer to this one :at-wits-end:

But it greatly depends on the material, you have noted coffee beans...tough because of the potential for floaters. I have dealt with floaters for most of my castings (I deal a lot with desiccated insects, bones, and other organic materials with air pockets) for science centers and museums as well as private collectors.

Floaters are an issue that each caster has a trick to success.

So I offer a few :bananen_smilies035:

Increase weight and decrease surface tension by dipping/soaking your beans a bit before mixing in the MEKP.

Increase the amount of the material and thin your resin a bit with styrene/wax...that way the resin passes by the stable bits.

Cast in successive stages...say in a tube mold...mix the resin without catalyst, separate into 3-4 small batches, cook one batch and pour, drop in beans, wait a minute or two (depending on how fast your resin cooks, I get 8-12 minutes with a 2-3 minute plastic stage), cook next batch and pour, drop in beans, continue...by staging your bean addition with the partial cures you should have enough grip between pours for the beans to find a place rather than bind together and sink.

Cook and pour a batch of resin allowing for a 25-33% volume increase with the bean inclusion...let it set up for a few seconds and drop in some beans, push down some beans using a chop stick (marked in 25% increments of the mold), and see if the remaining floaters sink, if not thne push some more, and continue until you have used the amount of beans (measured in the tube before the pour) desired.

And others.

It greatly depends on how you work, how you cook your resin (hot and fast or cool and slow), the material used, your molds, etc..

To be honest for real floaters I use a shallow mold if possible and let the resin set for a minute or so, paint on hot resin to the floater in question, set in place (held with a waxed SS pin/rod), once it catches then pour the remaining top (or bottom as it normally is) amount of resin.

This is a tough one and is rewarding...a badge of honor among casters...it shows character and creativity with due process.

Best of luck with you efforts :bananen_smilies046: