I hope some one in the vast assembly of Orchid members can explain
what happened to my casting today.
But first a little history.
I have cast only on Thursday and Friday for the last 20 or so years.
My wife says I am too much a creature of habit. So today I decided to
break the mold and cast on Wednesday and Thursday. Was the problem I
had today a sign from the casting guardians telling me that I should
remain a creature of habit and cast only on Thursday and Friday?
Were the casting guardians not happy with the designs on the things
I wanted to cast today so they caused this weird problem hoping the
items would never be cast?
I planned on investing 18 2 1/2 inch flasks. I vacuum on a table
similar to Rio"s vacuum table. It is a flat inch aluminum plate
mounted on springs to a base with a vacuum gage and a valve. Early
this morning I check to insure my mixer and vacuum pump work. So far
so good. Being a creature of habit I mix 5 pounds of investment. That
should be enough to pour around 7 or 8 flasks
The mixing goes well. I put my rubber mixing bowl on the rubber pad
on the vacuum plate, put my bell jar over the bowl and shut the
valve. No vacuum in the bell jar. Remove the bell jar and put a
finger over the vacuum tube that leads from the bell jar to the
vacuum pump. A vacuum. Back on with the bell jar. No vacuum. Remove
that bell jar and go to the backup bell jar I have. No vacuum. By
this time the mixed investment is starting to set so I dump it and
I Live in Phoenix and cast outside. Today the temperature of 112
degrees is not conducive for one to keep his cool.
Now I have time to figure what the problem is. The pump is pulling a
vacuum of around 26 inches without the bell jar but not in the bell
jar. What the heck is the problem?
I changed rubber pads. Still no vacuum.
I wet the bottom edge of the bell jar and place it on the rubber
pad. I notice the vacuum is pulling bubbles from underneath one side
of the bell jar. Rotate the bell jar and the same area is bubbling.
Could it be the inch aluminum plate is no longer flat? Sure enough
the plate has a dip of about 1/32 inch on one side.
How did the plate become warped. Have any of your ever had that
problem? The plate is about 10 years old. I do cast 6" flasks that
have 5 pounds of investment in a flask the weigh several pounds. Is
it possible the heat and weigh of such a large flask has caused the
plate to bend down?
You may ask what happened to the investing. Thank goodness I am a
pack rat. I had an old aluminum vacuum plate I saved from an old
vacuum system I had. And who says it is not good to be a pack rat?
The investment went well with the new plate.
Tomorrow I will determine if the design guardians dislike my design.
If they don"t like the designs today will be for naught.