Will a centrifuge get rid of bubbles?

MillenniumFalsehood · Post by **MillenniumFalsehood** » Fri Jun 12, 2015 6:27 am

I was thinking about resin casting, and it occurred to me that pressure casting is potentially dangerous, because I've heard of people having bad experiences with exploding pressure pots. Then I started to think about centrifuges and how they pull all the liquid to the bottom of the container. Would this work well for casting thin resin?

modelnutz · Post by **modelnutz** » Fri Jun 12, 2015 9:39 am

Look in to spin casting.
Works for metal...I'm sure it would work for urethanes.

Of course..if people were in the habit of testing the relief valves on their pressure pots..there wouldn't be so many "horror stories" of exploding pressure pots.

To test safely.... fill the pot nearly full with water...then pressurize the pot to just over the rated release point of the pressure valve ( approx. 85 PSI ? ) till the valve releases.
Why water ?
Water does not compress as highly as air...so, any failure/fracture in the pot will release only the small amount of air pressure...not a full tank at 85 + PSI all at once. ( that would be quite a boom...certainly enough power to send the lid through a floor or roof )

Post by **TER-OR** » Fri Jun 12, 2015 7:22 pm

I think Dream Pod 9 uses their spincasters for both metal and resin. Great resin casting that way, but the molds are BIG.

Kylwell · Post by **Kylwell** » Sun Jun 14, 2015 2:13 pm

Much bigger & less flexible as they have to withstand the heavy gees.

modelnutz · Post by **modelnutz** » Mon Jun 15, 2015 2:09 pm

Another thing to consider..the molds are heat vulcanized.
Lots of heat and pressure.

OdysseySlipways · Post by **OdysseySlipways** » Sun Jun 21, 2015 12:24 pm

if he's doing just resin, that the same rubber material can be used as it doesn't need to be vulcanized and yes, centrifugal force could be your enemy - staying with a pressure pot would be simplere

and i need to find Vulcanize rubber (in it's liquid form)

Kylwell · Post by **Kylwell** » Sun Jun 21, 2015 12:39 pm

OdysseySlipways wrote:if he's doing just resin, that the same rubber material can be used as it doesn't need to be vulcanized and yes, centrifugal force could be your enemy - staying with a pressure pot would be simplere

and i need to find Vulcanize rubber (in it's liquid form)

The process involves a touch of sulfur iirc...

modelnutz · Post by **modelnutz** » Sun Jun 21, 2015 5:45 pm

The rubber typically used in spin casting is a sheet material.
Much firmer than the silicone most guys use.

I'm sure that you can find "RTV" rubber in a liquid form ... that's "Room Temperature Vulcanizing" silicone...AKA Mold-Max, GI-1000,etc.

I would say standard silicone would work fine..provided you design your molds with the pressures and forces taken in to consideration
i.e...large "keys" for no mold slip
heavier exterior walls along parting lines ( the spinning mold/resin pushes outward with a fair amount of force.)

Go Flight · Post by **Go Flight** » Mon Jun 22, 2015 10:32 am

IMHO I would see where these bad experiences are coming from. Are they guys building their own pots and not knowing what they are doing?
There are far to many guys in the GK hobby pressure casting for it to be truly dangerous.

Just my 2¢

Wug · Post by **Wug** » Wed Jun 24, 2015 9:55 am

You could try a slower setting resin. Spin it to get rid of bubbles then stop the spinning before the resin sets to avoid distortion. Of course this will lower your throughput and might be tougher on your molds.

SCI-FI · Post by **SCI-FI** » Wed Jun 24, 2015 2:32 pm

MillenniumFalsehood wrote:I was thinking about resin casting, and it occurred to me that pressure casting is potentially dangerous, because I've heard of people having bad experiences with exploding pressure pots. Then I started to think about centrifuges and how they pull all the liquid to the bottom of the container. Would this work well for casting thin resin?

A centrifuge wouldn't be more dangerous than a pressure pot?

Seems like trading one set of troubles for another, though I'd love to hear a comparison from someone who has done both...

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Will a centrifuge get rid of bubbles?

Will a centrifuge get rid of bubbles?

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