Cheap potting alternative

 

Is it possible to use epoxy or polyester surfboard resin for potting
audio fequency PCB's?

How about the crystal epoxy used for encapsulating insects, etc?

Any other low cost alternatives, aside from flexible rubber/silicone?

Many thanks,

Larry Kent

 

says...

I tried a solvent based 2 part epoxy mistint sold for cheap at a paint
store.
It only dries in thin film as it's supposed to.
I tried potting and it was still gooey after 1 week.
The gooeyness could be from solvent getting trapped by the skin that
forms. iows.. The epoxy paint self-seals extending the cure time.
That or the paint was overtinted. Was blue.
So don't try that.
Solvent based epoxy paint is different than 100% solids epoxy or the
type used for glue.

Maybe try 100% solids epoxy for floors??


--
D from BC
British Columbia

 



epoxy cures by a thermal reaction;it can get pretty hot,especially in thick
applications.
Some folks discovered this when the plastic tub of epoxy they mixed up
melted from the heat of the reaction.

--
Jim Yanik
jyanik
at
localnet
dot com

 

 larrykent@raglands.com (Larry Kent) wrote:


Don't use general purpose epoxy or polyester!  Some formulas will sweat
compounds that are corrosive and conductive.  Formulas meant for fiber
composites can get so hot in large volumes that they'll incinerate
themselves.

You can buy electronics potting compounds at online electronics stores.

Conformal coatings can provide water and dirt resistance without making
the circuit impossible to repair.  Aerosol cans of pure urethane from a
hardware store seem to work well too.  I haven't seen urethane attack
anything yet and adhesion is pretty good.


Avoid 3M Scotch Weld Epoxy Potting Compound because it has extremely
poor adhesion.  It forms beads in thin films and it cracks away in thick
films.  Either way your project is ruined.
--
I won't see Google Groups replies because I must filter them as spam

 

Hi Larry,

Larry Kent wrote:

What are your *goals* in potting the circuit ("protect" IP, prevent
tampering, environmental extremes, etc.)?

Also, what other criteria affect your choice of compounds (e.g.,
thermal properties, weight, etc.)