03-17-2010, 06:43 AM
Trekker...what you are describing is a ticking time bomb.
First, I have an industrial pressure pot ( 7.5 gallon chamber ) and the lid for that is a piece of 1 inch thick acrylic.
No holes.
Even at that thickness, I get a deflection of nearly 1/8 inch in the center of the lid during use.
By drilling a hole in the center of your acrylic lid, you have introduces a stress point in the plastic. I may not have failed yet...but, trust me...when it does...you do NOT want to be anywhere near that thing.
Let me elaborate... I once purchased at an auction, a large bell jar type of vacume chamber.
Worked great...for a while...then, the sub-standard base that the previous owner made decided to give out while under 29 inches of vacume ( a LOT of vacume)....when the base cracked..it caused the bell jar to shatter ( implode actually...think...submarine diving too deep)
Now, keep in mind...this bell jar was 1/2 inch thick TEMPERED glass....damn near indestructable.....
Well, when it went off, the jar sucked inward and then rebound outward with enough force to sink a big piece of that heavy glass about 1/2 inch into the ceiling over my head. Took a pair of pliers to dislodge it.
Please....always use only the proper equipment to do this casting stuff...and never forget that we're working with BOMBS !
First, I have an industrial pressure pot ( 7.5 gallon chamber ) and the lid for that is a piece of 1 inch thick acrylic.
No holes.
Even at that thickness, I get a deflection of nearly 1/8 inch in the center of the lid during use.
By drilling a hole in the center of your acrylic lid, you have introduces a stress point in the plastic. I may not have failed yet...but, trust me...when it does...you do NOT want to be anywhere near that thing.
Let me elaborate... I once purchased at an auction, a large bell jar type of vacume chamber.
Worked great...for a while...then, the sub-standard base that the previous owner made decided to give out while under 29 inches of vacume ( a LOT of vacume)....when the base cracked..it caused the bell jar to shatter ( implode actually...think...submarine diving too deep)
Now, keep in mind...this bell jar was 1/2 inch thick TEMPERED glass....damn near indestructable.....
Well, when it went off, the jar sucked inward and then rebound outward with enough force to sink a big piece of that heavy glass about 1/2 inch into the ceiling over my head. Took a pair of pliers to dislodge it.
Please....always use only the proper equipment to do this casting stuff...and never forget that we're working with BOMBS !