Shop OBEX P1 Docs P2 Docs Learn Events
Silicone sealant and PCB's — Parallax Forums

Silicone sealant and PCB's

mojorizingmojorizing Posts: 249
edited 2010-01-24 07:58 in General Discussion
I'm knee deep in mud in the middle of the Great NW working on a Komatsu excavator that has hydraulic control problems. In taking apart the pump computer board, I find that all the leads for all components (processor, resistors, caps, etc.) are sealed with clear silicone sealant. I thought it was common knowledge and an industry standard to avoid using silicone sealant on circuits due the acetic acid corrosion. This excavator is circa 1985. What are your thoughts on this? The mud here is unbelievable, we've had a lot of rain in the last few days!

Kevin

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Bad spellers of the world untie!

Comments

  • Peter KG6LSEPeter KG6LSE Posts: 1,383
    edited 2010-01-24 01:57
    Actually they do make a non corrosive RTV for potting .. " MG Chem" makes it ..

    I used it for a UW comms system with great results ..

    www.mgchemicals.com/products/silicones/index.html

    RTV160...
    " The pourable consistency of this product makes it ideal for thin section PCB coating. It is non-corrosive and safe for electronics and metal application. Cures at room temperature."

    Peter KG6LSE

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    "Carpe Ducktum" "seize the tape!!"
    peterthethinker.com/tesla/Venom/Venom.html
    Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway. —Tanenbaum, Andrew S.
    LOL
  • ForrestForrest Posts: 1,341
    edited 2010-01-24 02:38
    There are many types of conformal coating, including silicone conformal coating that are safe to use on electronics. Silicone conformal coating typically doesn't have good resistance to many solvents. If solvent resistance is important, I'd use a polyurethane based conformal coating.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2010-01-24 02:40
    I believe BoatLife silicone sealant is also acetic acid-free.

    -Phil
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2010-01-24 06:30
    Yes, RTV has that sharp odor, that makes your head go back a tick like.·

    How's the acetic-free variety that way then?
  • mikestefoymikestefoy Posts: 84
    edited 2010-01-24 07:58
    I use this RTV sealant all the time, wonderful stuff, but expensive.

    dont use normal bathroom sealant, as it is corrosive ( gives off the vinegar smell)

    http://uk.farnell.com/dow-corning/2768003/rtv-silicone-3145-clear-90ml/dp/537007

    its dow corning 3145, there is a lower viscosity version 3140 which "runs" over the components until it sets.

    Mike
Sign In or Register to comment.