Making a cast epoxy paperweight

[David Ragan]

Hi All,

Anyone know how I would turn the little set of floppy lungs below into a clear paperweight?

I have on hand:

a vacuum pump

West system 105/207

I guess I need a mold, release agent, a way to make a vacuum chamber, and a way to smooth out any irregularities which are bound to occur, since I have no idea what Im doing.

Sandy Paperweight.JPG

I will certainly provide a picture(s) of my folly.

Thanks

[Walter Plummer]

West System is not a casting epoxy so I think you will have cracks from the heat. I would try a sample batch before committing your part. I think casting epoxies are a lot slower cure. Maybe an ice bath to slow the reaction. Good luck.

[David Ragan]

I already told wife I was finally going to do this

Cheapest way?

[Frank Pratt]

Polyester resin is quite a bit cheaper than epoxy, is made for casting & is crystal clear. Any reason you couldn't use it?

[John Terefenko]

NO VAC ,pressure is what you want. Casting resins or casting epoxies. Liquid Diamonds (epoxy) Silmar41 resin.

[David Ragan]

I have about $100 to make this happen.

How do pressure do this?

Any tutorials?

[Walter Plummer]

I have not done any casting like you want to do but I have seen kits for it in AC Moore and Michael's. Check their sites or Google casting kits. I'm sure Amazon would have them also. I think they are around the $20. range.

[Grant Wilkinson]

You can look on the Alumilite page for tutorials on how to do this. I've used quite a bit of alumilite and with pressure, it is bubble free. You can make the mold out of anything you like, depending on the final shape you want for the paper weight. I use silicone molds, yogurt containers, plastic cutting board and wood. Release agent if not needed for silicone molds. For the others, I use vaseline.

[David Ragan]

Am looking into this
In particular a silicon mold
And need to watch a few tutorials

[Bill Dufour]

A pressure cooker would allow low pressure and vacuum. Be careful and keep it under 5 psi. My understanding is you do the pour and apply vacuum to float the bubbles up. then add pressure to shrink any remaining bubbles. I suppose you could do the entire process in a vacuum with a glove box set up.
Bil lD.

[Walter Plummer]

Reaction in a vacuum may vary by each epoxy. I'm not sure, but we have degassed several epoxies in the vacuum chamber and all have at least tripled in volume before collapsing. You need a large enough container inside the chamber to not make a mess. Then I guess you would fill your mold and then apply pressure if needed. You Tube has videos of the degassing process. Very fun to watch.

[Bill Dufour]

Reaction in a vacuum may vary by each epoxy. I'm not sure, but we have degassed several epoxies in the vacuum chamber and all have at least tripled in volume before collapsing. You need a large enough container inside the chamber to not make a mess. Then I guess you would fill your mold and then apply pressure if needed. You Tube has videos of the degassing process. Very fun to watch.

I thought the degassing happened after the epoxy was in the mold? Those lungs may have a sealed internal chamber that will not like pressure changes.

[Walter Plummer]

The ones I have used bubble and froth and expand greatly. Then suddenly the air is gone and it collapses back down. Casting epoxy may be different but I don't know. I would not think the kits the hobby and craft stores sell need vacuum or pressure because the average hobbyist won't have that equipment. My guess is the casting mixes are thinner and a lot slower cure time.

[Grant Wilkinson]

I use a lot of alumilite and never use vacuum. I pressurize to about 40 psi and there are no visible bubbles.