micron gauge

[va-sawyer]

Yes, it was the supplied battery and that is why I just noted to low hours rather than harping about it. I also figured the battery could have arrived with partial charge. I haven't done a re-cal on it yet, and haven't seen it go into sleep mode either. If it is on, I'm running the pump or looking for leaks.

Put some Nylog on the port today trying to get a better seal with the VCRT. Still getting 1.1 micron/second rise with valve shut. Rate is constant from about 175 microns up to 1000 where I stopped the test. If I leave the ball closed and turn the pump back on, it doesn't change the rate, so I'm thinking the VCRT valve is good. There is a small amount of 'play' between the male port and guage body. Moving it doesn't seem to affect the rate either. Is it even possible to get a fairly steady reading around 500 microns with the BluVac directly on the end of the VCRT ? Note: side tap was sealed with Nylog and cap. Removing cap did not change leak rate either.

Rick

[joeyd]

...Is it even possible to get a fairly steady reading around 500 microns with the BluVac directly on the end of the VCRT ? Note: side tap was sealed with Nylog and cap. Removing cap did not change leak rate either.

I just realized that you are trying to hold a stable vacuum on an incredibly small volume. The results you are getting are *spectacular*. You've probably got as leak tight an assembly as humanly possible without going to "scientific" level hardware and hermetic seals! Even the smallest molecular leak is going to show that slow rise you are seeing...so I say everything looks fantastic. Once you apply it to an actual system with a real volume, and things are dry and tight, the vacuum rise should settle out to zero nicely.

Good job!

[va-sawyer]

JoeyD,

I have had it on a real system and couldn't get the rate to 'zero out' there either. I'm working with a small space on purpose to eliminate as many variables as possible. My goal is less than .3 micron/sec leak rate or better.
I need to prove my setup is tight before telling someone else that theirs is leaking. ( Sorry, but almost 30 years in Aviation means I don't trust anything till I see it myself.) I'll keep working on it and let you know what I find.

Rick

PS The dog in your avitar looks just like my Shepherd Samson, except Sam is now a bit older.

[itsiceman]

When I tested a capped off core remover and BluVac only it settled out in the 1500-2000 micron range but also at that small volume any change in temp would also change the reading up and down.

[va-sawyer]

itsiceman,

Yes, I noted in post 58 that in a steady state situation, I could affect the reading just by putting the guage fitting between my fingers. I figured it was responding to body heat. That is SENSITIVE !

I took both O-rings out of the end of my VCRT , cleaned them and coated with Nylog. Being careful to avoid dog hairs, I put them back in and tried another test. I managed an average rate of .28 microns per second from 300 to 500 microns.

Worked the side of the flare cone on the guage with 1000 grit paper and now have it almost holding steady at 400 microns. I think that I'm going to call that close enough. Now onto my next stage of testing.......

Rick

[cy]

hmmm blue vac?

how much better than say Robinair 14830A thermistor micron gauge or Supco VG64?

[Legacy80]

I have this unit, it's a piece of ****. compared to the analog, this jb is very inconsistent.

I have the JB supernova, works well however you need to get Tee for it to work. the supco micron gauge doesn't require one but i've heard many complaints about it from other tech's in my company.

[valdelocc]

I have this unit, it's a piece of ****. compared to the analog, this jb is very inconsistent.

I have compared the supernova with my thermal and they are almost identical in performance, the biggest disparity is the way they react to a loss of vacuum, the thermal is way faster than the supernova, I got used to it and it does no bother me at all.

[Legacy80]

Attempted to use my HB supernova this morning. The vac pump had been running over night, the supernova said I was at 2500 microns, I was 100% sure there were no leaks. Thought it might have been my pump, so I connected the supernova to just the pump, still only dropped to 2100. Got the trusty but bulky thermal vac guage out. Connected it to system.... 400 microns. This only the 4-5 time I tried to use the supernova. It might have worked properly the first time or two.