too tight crowns for PFMs

[pit-stain]

yeah so...

 

[charles007]

yeah so...

Sorry Pit-Stain..... over looked your problem with HS. I've used HS for almost 3 years and love the investment.... Are you following directions to the letter, or very close? I use it will all my pfms -Nobel alloy, type 3 gold, and emax with great results. I use no debubblizer with emax and use with metal alloys. Apparently your getting investment breakdown from doing something wrong.
Basic question, what have you changed beyond following directions. Are you cutting your mixing time short? I turn on my mixer with vac, let stand for 15 sec. then mix for 50 seconds. '60 seconds cuts my working time to much.' Vibrate for 15 seconds on vibrator, paint on investment on patterns and pour in plastic rings. Bench set for 15 minutes, 20 minutes with 200gr. Place in oven at 1560 and cast 50 minutes later if only one ring.. add 10 minutes per extra ring.
Using debubblizer, I spray on and lighly blow off, then spray with water, blow off and still is little wet looking, but not puddled at all ! Use 4 turns on my kerr casting machine.
My best guest without seeing your casting, your mixing time is cut short or your over heating you alloy by a mile. Check you gauges on your oxy and propane. I say that since you said that debubblizer is not used all the time... Also assuming your burnout temp is correct for your alloy.

Charles

 

[Cjen]

Use Peel-Away die spacer from J. Morita.
It will allow you to get looser fit if investment maximum expansion is not enough.

 

[CatamountRob]

Use Peel-Away die spacer from J. Morita.
It will allow you to get looser fit if investment maximum expansion is not enough.

Thanks for the timely answer!!
We've been wondering what to do since 2008...,

 

[CoolHandLuke]

well he only registered in 2011 and figured he's keep us in suspense!