CurtPalme.com Home Theater Forum

lostmandan · Posted: Sat Nov 29, 2008 9:01 pm Post subject: NEC PG Glycol Chamber Bleeding

Hi,

I bled the tubes of my PG9 about a year ago figuring that it would do for quite a while. Today I look and I notice that the 1/2-1" air bubbles I left in each of the glycol chambers are gone.

I assume that this means that the tubes should be bled again? I do not want to end up with cracked glass...

I have not been using the home theatre that much (once every 2 weeks or so since last Christmas). The room is in the basement, but there is a dehumidifier running in there and the room measures around 40-45% humidity year-round.

Is there a key to making sure a tube bleeding job lasts longer than a year?

Just a thought - given that moisture comes through the silicone/RTV at the edges of the glass, has anyone experimented with a coating of waterproofing? I cannot think of anything off the top of my head, but it seems to me that there must be something that could be applied to the outer surface of the bead to prevent moisture passing through.

Anyways, I would appreciate knowing if this is typical or if I should be doing something differently to avoid this issue.

Thanks,
Dan

kschmit2 · Posted: Sun Nov 30, 2008 9:25 am Post subject:

If you don't run the set it will only last for maybe 1 year until you have to bleed it again.

If you run it you shouldn't have that problem.

Silicone is already waterproof (water as in liquid water). That's why it's used for any type of aquarium glass e.g.

lostmandan · Posted: Sun Nov 30, 2008 4:35 pm Post subject:

Thanks Kai! I definitely need to run the set more. I bled the tubes yesterday afternoon. The glycol didn't well up out of the access hole so there wasn't any internal pressure, but I decided to leave a 30-40mm bubble.

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

I just did mine yesterday, i made the bubble about 17/32 - 9/16ths big, this rig wont get much use before my new house is built, and i have a mate that just bought a 9PG as well, so ill be the PG tube bleeding master in the next couple years.... Sad

Its funny how my Sony VPH-1001QM sat under a music stage for 7 years, on its back, and yet it still has perfect bubbles, and none of this fungus i hear about. It had alot of use in its life before it was decomissioned, it ran at least 15 hrs every day for many years, the blue tube is about a high 3 to maybe a mid 4 depending on how fussy you are, and the green is about a 6. Red is at least 8.

Why do the NEC tubes like to suck in the moisture?

lostmandan · Posted: Mon Dec 01, 2008 3:08 pm Post subject:

kschmit2 · Posted: Mon Dec 01, 2008 3:58 pm Post subject:

at least they are not prone to grow fungus.

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

Well maybe not, but if they keep diluting with more water all the time, eventually the glycol wont be glycol anymore, and itll need to be pumped out and replaced.

Mark_A_W · Posted: Tue Dec 02, 2008 7:23 am Post subject:

That won't happen.

And water would work fine anyway Wink

kschmit2 · Posted: Tue Dec 02, 2008 9:03 am Post subject:

if you use the PJ, and even just sporadically so, it should never be a problem.