Casting help

[McTeeth]

Hey guys,

I'm a rookie in the casting department, so I'm not sure the problem here. We have the Neo Castcom unit and I assumed it was idiot proof

Thanks,
Sean

 

[2thm8kr]

Old school broken arm caster here.

Sprue to the thickest part of the pattern.
Sprue reservoir needs to be in the heat center of the ring. Pattern needs to be outside the heat center of the ring.
Sprue reservoir needs to be the same mass as the pattern.

Get this book: Metal Ceramic Technology, by Patrick Naylor. ISBN 0-86715-237-0
Chapter 5 has just about everything you need to know about the fundamentals of casting.

 

[McTeeth]

Excellent, Thank you

So what happened? Just a spruing issue?

 

[2thm8kr]

Excellent, Thank you

So what happened? Just a spruing issue?

I'm thinking it's a spruing issue. The metal looks like it may have been too hot as well. Hopefully one of the Castcom users will chime in, but it's just about happy hour so you may have to wait 'til tomorrow for a response from them.

 

[Big Guy]

Don't burry your units deep in the ring make your sprues longer and don't cover your units with too much investment and all of the above

 

[user name]

Old school broken arm caster here.

Sprue to the thickest part of the pattern.
Sprue reservoir needs to be in the heat center of the ring. Pattern needs to be outside the heat center of the ring.
Sprue reservoir needs to be the same mass as the pattern.

Get this book: Metal Ceramic Technology, by Patrick Naylor. ISBN 0-86715-237-0
Chapter 5 has just about everything you need to know about the fundamentals of casting.

Yup. Everything was done wrong here. Reservoir is too small; the button is so big that its mass was drawing the alloy that should have gone to the crown. Vent should be attached to the side of the crown opposite of the sprue and kept close to the side of the ring so it cools first, and your main sprue should attach at an angle , not flat to a side.

 

[Al.]

Sprue reservoir needs to be the same mass as the pattern..

Agree. 100% and #1 reason for porosity.
Stock spruces too small for most FGCs.
I make my own. Roll balls of rope wax to the same size as the crown so each crown has a different sized reservoir. That means some will be huge.
I have the super neo cascom and you still need to use correct casting principles.

 

[ztech]

Best way to look at casting is that the last thing to cool will have porosity, no way around it.

 

[Al.]

Heres mine. Get porous free casting with this way. Week after week year after year.
10 ga sprue on crown, wax ball then 8 ga sprue from ball to former.
Funny you can see my finger prints in the reservoir's from rolling the wax into balls
This is with the Neo super cascom

 

[ztech]

Great Photo's Al, you can see in the bottom half of the reservoirs the porosity. Exactly where it needs to be.