Check out what happened on Thrusday

[desertfox384]

Just a regular casting you might say?

As I was casting I opened the oven, metal was ready to go, grabbed the ring and just felt something was off.. after I let it go i realized the oven was sitting at 150 degrees C ! I let it burn out too long and my oven went into idle mode... I couldn't believe it cast out this good, Im guessing if I had more than one unit it wouldn't have.

 

[corona]

twliight zone stuff . nice balancing act with the button .

 

[DMC]

Many Jewlers let a ring bench set after burn-out for quite a while and then cold-cast.

Works fine for precious and semi-precious. Completly normal.

 

[charles007]

desertfox, spruing tip I use, sprue mesial or distal corners on anterior singles and mesial or distal marginal ridge where your wings are on posterior singles, on fully layered pfms. I've used this technique for 30 years and it saves a lot of finishing time. Wax thin and no worries about grinding holes on the facial or buccal where you were grinding off the sprue. If the crown is really thick, sprue in that area as usual.

 

[the_prez3]

I let my rings cool down out of the oven for a minute or two before casting. Especially for heavy crowns. Reduces porosity but I've never cast one that cool. Gives me more confidence with my technique.


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[desertfox384]

Wow, I never knew jewlers did that, pretty cool. This by the way is NP (talladium).. I don't normally cast such a big button but this metal is sold in big ingots only.
Charles, good tip, I think I will do that from now on.. although I'm so used to my own waxing I just zip the stump off and finish with a barrel stone, no other reducing needed.. I know exactly what 3 tenths looks like in my wax, but I like your idea.

 

[Flipperlady]

I have a degree in jewelry technology and i've never heard of cold casting.

 

[rlhhds]

I have a degree in jewelry technology and i've never heard of cold casting.

Just curious since we all blame short castings as a cold cast, what would cause a casting to come up short. Assuming proper sprueing and placement of pattering on the base former.

 

[doug]

Metal too cold...

 

[bullit]

To bad you used your "good luck" quota on thursday...........could have bought a lottery ticket!!!!

 

[Flipperlady]

Just curious since we all blame short castings as a cold cast, what would cause a casting to come up short. Assuming proper sprueing and placement of pattering on the base former.

Temp (don't let the casting ring cool too much) and maybe not enough winds on the machine. Wind the casting machine one more turn.

 

[kimba]

I once had a casting machine abort the cast just as the metal reached temp. The platform dropping down was enough to perfectly cast a gold unilateral removeable framework !!

sometimes he smiles on you , but not often enough