Porosity in bulky 60% gold implant, help.

JMN

JMN

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Some people are comforted by portable wealth.
 
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Yuugen

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Opps sorry bout that JMN was a little busy did'nt really reviewed it but i was saying. When your casting some thick crown or implant or bridge you can see the thickest part and that is were I attached a piece of same metal to chill it. this is how i will sprue if this is metal bridge thumbnail.jpg
Sorry but I get a solid "HUH?" out of that.
can you please try saying that differently?
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You need a thicker sprue attached to the pontic. Its the most mass, so it will cool last and needs he molten metal access.
Theres 6 problems with that sprue job that I see.
 
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Yuugen

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I was told to spue it this way since 1990 and still works up to now with no problem using the broken arm casting machine. Im still open for improvement if theres another way of spruing
 
CatamountRob

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I see at least 8 problems with that.
 
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Yuugen

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:) sorry i tried, But will difinitely look for a better way
 
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charles007

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So many spruing rules broken... wow
 
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@Yuugen
If its working, great.
I cringe because Ive had issues even when it seemed I was doing everything correct.
Ill let the others be more specific if they choose. I quit doing any metal work, so Ill bow out.

Ill be the first to admit, i dont know what I dont know.
 
CatamountRob

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I’ll list a few, beginning with the top of the former, it should be rounded like a button or funnel shaped, not flat.
The runner leading to the bar is too small and there probably should be two.
I suspect the bar diameter is smaller than the pontic in cross section, it should be larger.
The sprue leading to the Pontic is too small and I’d likely use two.
I can’t tell if the sprues are connected to the thickest parts of the patterns but they need to be.
Most people would add vents, I might or might not, I’ve never really been sold on them.
Your connections should all be smoother, sharp angles lead to broken bits of investment included in the casting, usually near the margins.
I’d cast it cool, 900 F or so after burning it out at 1300 F.
Attaching the dwt at the top is new to me, but interesting.
That’s all I’ve got, I just said 8 to keep User up all night wondering what the other two were
 
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perkmark

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fill in porosity by sweating solder for quick fix
 
JMN

JMN

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i agree with Rob but i would also put two 10 ga sprues on that molar .. https://www.google.com/search?client=firefox-b-d&q=reservoir
the dwt of metal on top is what.....for luck? better tv reception?
get the Ney C&B Manual and use it
Greetings Earthling! Welcome!
The dwt is to help the thickest part cool faster.

I took the searchkey out of your link so we didn't all share your search history. Some of us look up odd stuff you don't want to be associated with. Like doilies from 1770's with secret codes in the edging. Really wild stuff.
 
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corybaby

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Also it wouldnt hurt to clean ALL the old investment out of the ring before you invest it,(the corner of the ring wont be clean but flakey and bits can fall in when you cast it) res should be touching the crown not separated from it and yes the vent is on the wrong end....ive never had a button draw metal before a reservour, use more metal....

my advice
Still casting everything everyday for 35 years
 
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If you guys have the time I would love to see pics of your ideal setups for larger castings, big singles and bridges/frames. I've learned all of the bad habits from my predecessors and it's glaringly obvious on my platnium plus castings. Photos being worth a thousand words such.
 
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