[Fatturtle]

Got a best value vac 0.9 cf 2 months ago and it had a few leaks at different parts of the oven, the worst
one being around the door. There are defects around
the outside of the cage where the gasket sits so it
doesn't hold its vaccuum.

Just bought one from a local guy where I live and
this one too loose a bit of vaccum.
If I put it at 10,000 microns and come back
12 hours later, it will be at 20,000 microns.
I am using a digital vacuum gauge to measure.

So the question is, is it inevitable that an oven will
loose some of it's vacuum over time.

What would be considered an acceptable loss over lets say a 12 hours period starting at 29,5 hg(10,800 microns)?

[Thomas@LRL]

No. My AI Elite 4.4cu ft oven is leak free. I pumped it down and left it for a few weeks when we were still building out the facility and it held there without any notable loss.

[WaterFarmFan]

Try a little vacuum grease on your oven door seals. How are you measuring microns in a sealed oven? It could be your tubing, clamping, digital meter causing the drop. Does the vacuum decrease with all valves closed after being pumped down?

[purplepassion]

Nope

[Fatturtle]

I measure at the vacuum outlet where there is a t
with a valve on each end. One for the pump and one
for the gauge.
I shut all the valves off after vacuming.

I will try the grease around the gasket and tightening
the door.

[Gray Wolf]

Originally Posted by Fatturtle

Got a best value vac 0.9 cf 2 months ago and it had a few leaks at different parts of the oven, the worst
one being around the door. There are defects around
the outside of the cage where the gasket sits so it
doesn't hold its vaccuum.

Just bought one from a local guy where I live and
this one too loose a bit of vaccum.
If I put it at 10,000 microns and come back
12 hours later, it will be at 20,000 microns.
I am using a digital vacuum gauge to measure.

So the question is, is it inevitable that an oven will
loose some of it's vacuum over time.

What would be considered an acceptable loss over lets say a 12 hours period starting at 29,5 hg(10,800 microns)?

All vacuum ovens leak at some level, but all are not created equal. Besides the door seal integrity, some use hose instead of tubing and elastomers are porous. Valves can also leak around the seats or stem seal.

We mostly use Cascade TEK, but have one AI Elite, both of which work well and leakage is negligible, which 10,000 microns in 12 hours would fall under. In process we wouldn't even notice it, since we continue to run our pumps while we are processing material and keep up with the leak rate.

[killa12345]

my first AI oven leaked and they replaced it. They freight picked it up and next day me a new one. I have 2 AI oven and they both hold full vac for as long as i want. I live at sea level just to let you know.