View previous topic :: View next topic |
Author |
Message |
SweetChuck
Joined: 01 Jun 2007 Posts: 134 Location: Queensland Australia
|
Link Posted: Sat Dec 04, 2010 12:55 am Post subject: Could all my Marquee Arcing problem be Bad silicon choice ?? |
|
|
My 9500 has be plagued with arcing problems for ages, anyway I just fitted some brand spanking new hv leads and splitter, I've let it cure for a day , and it arcs everywhere , even a load crack , I'm putting this down to the silicon not being cured yet . But i have a horrible thought my silicon is wrong for HV purposes .
Im using Dow Corning 738 (neutral cure)Good dielectric properties(I should think it should be excelent dielectric properties)
Recommended is Dow corning 3145
have I made a huge mistake , The data sheets on the net don't say to much about High Tension applications
|
|
Back to top |
|
|
cmjohnson
Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s
|
Link Posted: Sat Dec 04, 2010 1:27 am Post subject: |
|
|
A day isn't nearly enough.
Give it a week at least.
You may have to totally redo the seal now. The arcing can cause carbon tracking along the arc path through the silicone, and once
that carbon path is formed, it will ALWAYS arc.
Patience, man. Patience. Silicone takes a week to cure properly for high voltage applications.
CJ
|
|
Back to top |
|
|
Nashou66
Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY
|
|
Back to top |
|
|
Nashou66
Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY
|
|
Back to top |
|
|
SweetChuck
Joined: 01 Jun 2007 Posts: 134 Location: Queensland Australia
|
Link Posted: Sat Dec 04, 2010 1:38 am Post subject: |
|
|
cmjohnson wrote: | A day isn't nearly enough.
Give it a week at least.
You may have to totally redo the seal now. The arcing can cause carbon tracking along the arc path through the silicone, and once
that carbon path is formed, it will ALWAYS arc.
Patience, man. Patience. Silicone takes a week to cure properly for high voltage applications.
CJ |
I would have left it for a week but the hv replacement guide here http://www.curtpalme.com/HV_Lead_Removal.shtm in the advanced section says
4) Push down the rubber cap so that the silicone beads out around the rubber cap. Let the silicone dry for at least 4 hours before powering the set up (or however long the instructions on the silicone say that it takes to dry).
4 Hours Didn't think that was right , may need to get that changed
So the Dow Corning I'm using is ok ?
|
|
Back to top |
|
|
dvh99
Joined: 25 Dec 2009 Posts: 2158 Location: nederland
|
Link Posted: Sat Dec 04, 2010 1:46 am Post subject: |
|
|
look at the datasheet, i think yours tells you the properties of the silicone after 7 days.
_________________ 1 answer always poses multiple questions.
marquee 9500ultra HD10L moome hdmi1.3 v3+ some mods.
|
|
Back to top |
|
|
mp20748
Joined: 12 Sep 2006 Posts: 5681 Location: Maryland
TV/Projector: 9500LC Ultra / Super 02 and 03 VIM
|
Link Posted: Sat Dec 04, 2010 4:15 am Post subject: |
|
|
Nashou66 wrote: | I just use the GE silicon II clear stuff.
Athanasios |
Yep. It's the only one I've used that did not require a week to six month cure, with some not working at all and causing the same problem you've having.
For HV, use ONLY GE Silicone II.
I have a NEW set of high voltage wires if you can't clean them up..
|
|
Back to top |
|
|
draganm
Joined: 08 Mar 2006 Posts: 8990 Location: Colorado
|
Link Posted: Sat Dec 04, 2010 6:46 pm Post subject: |
|
|
This keeps coming up. Pure silicone RTV is pure silicone and it's clear. Additives don't significantly change curing time. What changes curing time is temp. and humidity. Full cure is in 24 hours at 70 degrees Farenheit and 50% humidity. If you live in a dry place like I do, average 10% humidity, it can take days. The moisture in the air is what starts the vulcanization process ( RTV = room temp. vulcanization).
To cure it here in 24 to 48 hours I will set the silicone in a warm inside my house place and wrap it with a damp towel. The towel will dry overnight and usually requires re-wetting. Luckily the new stuff is low VOC so it doesn't stink up my living room.
|
|
Back to top |
|
|
Sparky015
Joined: 12 May 2009 Posts: 1185 Location: Cleveland / Akron, OH
|
Link Posted: Sat Dec 04, 2010 7:20 pm Post subject: |
|
|
I just went through this on my red tube. I used the GE Silicone from the hardware store and let it cure for 3 weeks before I attempted to power up the tube. It still arced badly. The reason is because I used way too much silicone and it got too close to the anode wire. My second repair job with a new HV lead, I used a small bead of caulk around the outer edge of the boot. I let it cure 36 hours, and I've been golden ever since. You don't need a long cure time, but how you apply it absolutely matters.
Also, silicone does not like to bond to silicone, so it's very difficult to reuse a HV lead that got silicone way too close to the anode. If you did this, best to replace it. Curt sells them now and at a very reasonable price that I wouldn't even attempt to reuse an old lead again.
_________________ ~Paul
|
|
Back to top |
|
|
|
|