×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Achieving Vaccuum and passing vibrations!

Achieving Vaccuum and passing vibrations!

Achieving Vaccuum and passing vibrations!

(OP)
Hello all,

Lets see if I can explain this properly. I am trying to improve something that is already working (just want to hear what others do in similar situations). I have a pcb with piezo-electric sensor. On one side we have a machined fitting and on the other side we have a machined cover. The hoses are connected to the fitting during equipment operation to measure speed and altitude. Thus we need all faying faces to be perfectly sealed so that when there is suction or pressure the crystal can measure value properly. At the present we use dow corning grease stuff in between machined steel and pcbs. So far its all good. But the entire process of applying grease and assembling is very nasty and it gets acrylic conformal applied to it after assembly with the the back cover (no conformal on the front side).

That being said, once you assemble it; the grease is squeezed out and it comes in contact with its neighbors (components). Its hard to clean/wipe of the excess and it does not cause any harm to anything. So I am after anything that is easy to be used while having similar properties to vaccuum grease stuff. We also need them to be removed for repairs - so its a no for epoxy or permanent adhesives. Just thought I would ask if anyone out there have better compound/sealant/chemical/technique to achieve proper sealing. I have forgotten to mention this equipment will go through rigorous centrifugal, vibrational and temperature testings.

I am thinking of just having a epdm rubber o-ring that sits inside a groove. But open for other options too!

Cheers,

V.

RE: Achieving Vaccuum and passing vibrations!

Normally, a curing silicone sealant would be used for this rather than a non-curing grease. There are heat cured silicones and RTV(room temperature vulcanizing). RTV's react with moisture in the air and release a small amount of acetic acid (vinegar smell) or methanol during cure. Electronic applications use the methanol kind.

RE: Achieving Vaccuum and passing vibrations!

(OP)
Thanks guys, I was hoping an applications engineer would see this. I have contacted dow corning and they take a long time to get back. So just thought I will put it out there.

Can't do curing stuff as I want them to be removable.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources