Emax ingot size mystery

[subrisi]

Have you ever taken a close look at emax ingots?
A small ingot presses 0.75 g wax
A large ingot presses 2 g wax.
So theoretical if you press two small ingots, you get 1.5 g of wax pressed.
But if you stack two small ingots and set a large one next to it, you see that the large ingot is SMALLER than the two small ingots. You can also weigh it and come to the same result.
I pressed several large ingots, but I never came close to the max wax weight and was OK. Now I pressed a 1.96 g ring and had a short press. The button is non existing. So there is no way to press 2 g wax with a large ingot. If the large ingot would press 2g of wax, the small ingot should press 1 g of wax at least which is not correct either. I could push it up to 0.8 if I use the heaviest ingot out of the tube, but then there is no more button left. What is your explanation about the discrepancy of their wax weight and ingot size/weight? I am puzzled.

 

[user name]

Apparently you are weighing your pattern but not the sprues...? Weigh it after its sprued up and subtract the weight of the base. You can push a large ingot a little over 2grams total weight.

 

[subrisi]

I weigh the base with the hole closed up. Then I attach all the crowns and weigh again. The difference is the wax weight. But this is not the question here. The question is why are 2 small ingots larger than one large one but presses o.5 g less than a large ingot. I already went throught that with ivoclar. They are puzzled too and don't have an answer AGAIN. Forget any human error in the investing and pressing procedure. I just want an explanation on the question above.

 

[subrisi]

Here are the ingots to compare. You can clearly see that the large ingot is smaller than the two small ones. And again: the large ingot suppose to press 2 g wax and the small one 0.75g ( 2ingots= 1,5g). So how do I get 2 g of wax out of the large ingot?
I pressed 3 large ingots in the last two days. One was 1.96g and I had a short press. The other one was 1.92 g and I had a short press again. Today I had 1,78g and that one just had enough to press right. I assume there is no way to go over 1,85 g max. How close to the max wax weight did you get??

 

[GoldRunner]

Here is your answer

You are only calculating the volume (from the density of the wax) of the sprue and pattern. The button left over is the same (hopefully) in both large and small ingots. Thus the large ingot although slightly less volume than 2 small ingots will press more material than individually pressed single ingots (remember 2 buttons). I would suggest no more than 1.75gms to be safe with a large ingot until you see how much button is left over. No more than .60gms for small ingots to be safe.

Of course the probability of a bad pressing is directly related to the urgency of the case and inversely proportional to the number of ingots you have of that shade.

 

[user name]

Ive pressed with successfully over the recommended weight on a large ingot. Is there maybe alot of difference in density/weight of waxes?

 

[subrisi]

I don't know anything about wax density. I use Yety Thowax, Microstar dipping wax and Keystome sprue wax. I didn't even consider differences in wax density. How would you do this with three different materials?