Myst or smoke in vac chamber

[gumby420]

So I just got a new pump recently and as im pulling a vac it looks like smoke is coming into my chamber for about 10 seconds, then disappears.
@Graywolf i saw you posted this on IC for someone else who had a similar problem,

"it could be the moisture attached to the inside of the chamber walls boiling off under vacuum.

You also decompressed the remaining moisture laden air in the chamber, which cooled it down, thus lowering the dew point, which might form clouds. "


but he said his humidity was super high, im in So Cal so i woulndt think that would be the issue. anyone else have this happen? any idea what it is? thanks

 

[Myco]

I've also noticed this before... But much quicker than 10 seconds. More like 2-3.

I also wrote it off to be water vapor from residual moisture in the chamber.

However, I also live in an with mid to mid-high humidity at times, though.

 

[gumby420]

ya it probably wasnt 10 seconds, just a little freaked after i saw it happen. i did check the weather report yesterday and we had 88% humidity at the time i was using my vac......hopefully that was it...

 

[toquer]

I can pull vac in the morning at the shop. It's mid 80% in the mornings there outside early due to the dew point. Will let you know if I see anything. Heat from below as well? I too am in socal.

 

[gumby420]

I can pull vac in the morning at the shop. It's mid 80% in the mornings there outside early due to the dew point. Will let you know if I see anything. Heat from below as well? I too am in socal.

ya inside the chamber is around 90-95* from a griddle below. thanks man much appreciated

 

[Myco]

Well, I evacuated my camber, got down to 29.9", broke the vacuum, then immediately evacuated again. Both evacuations I saw the "cloud"... first time was maybe 50% thicker of a "cloud" than the second.

We've had pretty high humidity as of late...

So my conclusion is that it is indeed moisture that is on the chamber walls. The first evacuation pulled out the majority of the moisture in the form of this 'cloud'... once I broke vacuum and the chamber sucked in a bunch of RH 70%+ atmosphere, the second evacuation created about half as much of a cloud because not as much moisture had enough time to re-accumulate in the chamber.

*shrug*

 

[gumby420]

Well, I evacuated my camber, got down to 29.9", broke the vacuum, then immediately evacuated again. Both evacuations I saw the "cloud"... first time was maybe 50% thicker of a "cloud" than the second.

We've had pretty high humidity as of late...

So my conclusion is that it is indeed moisture that is on the chamber walls. The first evacuation pulled out the majority of the moisture in the form of this 'cloud'... once I broke vacuum and the chamber sucked in a bunch of RH 70%+ atmosphere, the second evacuation created about half as much of a cloud because not as much moisture had enough time to re-accumulate in the chamber.

*shrug*

thanks so much, ive been tripping out on this and not wanting to do any more runs, this puts me at ease a lot more. And both time i saw this was Late night/ early morning when the RH is highest.

 

[welder]

Are you positive that its coming from the inside of the chamber and not the vegetable lube oil that the pump uses? My pump always puts out a mist the first 10 seconds or so until it hits about 15hg. I put a hand towel over my pump exhaust to keep it out of the air.

 

[LittleDabbie]

Yeah i got a feeling its just the vac pump back feeding vapor from when the pump first starts up...Mine does it too so i just run the pump a few mins before i connect it to the chamber.. No more cloudy gas in my chamber.. and its been humid as fuck here..

Been doing ALOT of vacs lately on other shit to dry and haven't noticed the issue when i run the pump first then connect the hoses..