Thread: Casting Seed Pods / Banksia Nuts

Are you casting vertically or horizontally ? with vertical molds you need clearance all round so the resin can flow freely around the product to be cast in the case of banksias ( the small coastal ones at least ) I drill a 1/4" hole the full length before casting ,this allows the acrylic to fill any small holes that go to the centre of the pod, usually I pour some of the mix into the mold first about an inch or so deep, then put the blank in and push it down into the mix this forces the poly to rise and fill the holes,top up as needed ,the banksias will float up a bit ,so keep on pushing them down till it gells ,this action does like a pump or syphon and fills any nooks and crannies If you want to use pressure it does shrink a bit so I use a paddle pop stick that just reaches to the top of the mold ,and a bit of gaffer tape to hold it in place ,making sure not to block the hole where you want pressure to penetrate . Same sort of process with most things with horizontal molds ,I pour from one end and let the poly flow along by itself till the mold is about half full , I then tip the mold in all directions to remove any trapped air from underneath where you normally can't see, do this a few times then complete the pour , with this type my molds have a well at the top to allow for shrinkage ,a few more tipping of the mold to move the resin about and into the pressure pot if needed I make an assesment each time I cast whether I think pressure is needed or not Hope that helps a bit ,sounds more complecated than it is hehe ! cheers ~ John

I forgot to mention ,before putting in pressure pot ,a few minutes vibration on my bandsaw table to help any small bubbles to surface as well

Well this is the result.

P1010131.JPG

Not to flash but maybe just maybe...

So I put one into the lathe (l/h one) and this is what I found P1010136.JPG P1010137.JPG P1010138.JPG

I had one section catch whilst turning and pop out
I also see a couple of spots where it doesnt appear to be mixed well.

I have learned a lot with this and hopefully will do better next time.

Any suggestions/advice will be appreciated.

Cheers

Shawn

Originally Posted by gawdelpus

Are you casting vertically or horizontally ? with vertical molds you need clearance all round so the resin can flow freely around the product to be cast in the case of banksias ( the small coastal ones at least ) I drill a 1/4" hole the full length before casting ,this allows the acrylic to fill any small holes that go to the centre of the pod, usually I pour some of the mix into the mold first about an inch or so deep, then put the blank in and push it down into the mix this forces the poly to rise and fill the holes,top up as needed ,the banksias will float up a bit ,so keep on pushing them down till it gells ,this action does like a pump or syphon and fills any nooks and crannies If you want to use pressure it does shrink a bit so I use a paddle pop stick that just reaches to the top of the mold ,and a bit of gaffer tape to hold it in place ,making sure not to block the hole where you want pressure to penetrate . Same sort of process with most things with horizontal molds ,I pour from one end and let the poly flow along by itself till the mold is about half full , I then tip the mold in all directions to remove any trapped air from underneath where you normally can't see, do this a few times then complete the pour , with this type my molds have a well at the top to allow for shrinkage ,a few more tipping of the mold to move the resin about and into the pressure pot if needed I make an assesment each time I cast whether I think pressure is needed or not Hope that helps a bit ,sounds more complecated than it is hehe ! cheers ~ John

I forgot to mention ,before putting in pressure pot ,a few minutes vibration on my bandsaw table to help any small bubbles to surface as well

Gawdelpus,

I did these using a resin saver mould done horizontally. I did put it on a belt/disc sander combo I have to help reduce the bubbles. This time I only had a couple bubbles.

Shawn go to you tube and look up neil (dai sensie) casting & moulding video you will find it most valuable.

Originally Posted by tdrumnut

Shawn go to you tube and look up neil (dai sensie) casting & moulding video you will find it most valuable.

i have watched this...once....must re-watch and take more notes this time.

Thanks.