Phenolic Copper Clad Board

[Jdansti]

You could always coat the entire board with Envirotex epoxy after you've built and tested it. It's really overkill, but it's easy to apply-just pour it on. Envirotex should be free of off gassing once it's cured, after all, it's used to coat bars and tables in restaurants.

[amptramp]

what's that conformal coating stuff made from?

MG Chemicals has a bunch made from several chemicals : http://www.mgchemicals.com/products/protective-coatings/conformal/

For the record, NASA uses a 2 part epoxy. They did in the 80's anyway.
Applied with a brush, to about 1/8 - 1/4 inch thick. That was a PITA.

This was not entirely the case.  NASA usually purchased many subsystem units such as momentum wheels, thrusters, earth sensors, star sensors and processors as complete items from outside vendors, so they did not do all the processing but they passed judgement on anything that was used and various things have been used.  Parylene (made from paraxylene) was considered a good conformal coating material and a good process.  Paraxylene was sublimated onto the boards from a gaseous state and formed a conformal coat that was 0.0005" thick (half a thousandth).  There are versions of silicone that do not generate acetic acid during cure that can also be used.  NASA maintained a PPSL (program parts selection list) that identified all the components and processes that could be used without separate qualification testing.  Everything on the PPSL was trailing edge technology with a proven track record and established reliability.  If you wanted to used something not on the list i.e. something modern, you had the expense of running testing.  We had a soft urethane material, Solithane 113, that we used for holding components on the board and a hard epoxy, Epiphen 825A, for rigid mounting.  They were already on the PPSL.

[CodeMonk]

what's that conformal coating stuff made from?

MG Chemicals has a bunch made from several chemicals : http://www.mgchemicals.com/products/protective-coatings/conformal/

For the record, NASA uses a 2 part epoxy. They did in the 80's anyway.
Applied with a brush, to about 1/8 - 1/4 inch thick. That was a PITA.

This was not entirely the case.  NASA usually purchased many subsystem units such as momentum wheels, thrusters, earth sensors, star sensors and processors as complete items from outside vendors, so they did not do all the processing but they passed judgement on anything that was used and various things have been used.  Parylene (made from paraxylene) was considered a good conformal coating material and a good process.  Paraxylene was sublimated onto the boards from a gaseous state and formed a conformal coat that was 0.0005" thick (half a thousandth).  There are versions of silicone that do not generate acetic acid during cure that can also be used.  NASA maintained a PPSL (program parts selection list) that identified all the components and processes that could be used without separate qualification testing.  Everything on the PPSL was trailing edge technology with a proven track record and established reliability.  If you wanted to used something not on the list i.e. something modern, you had the expense of running testing.  We had a soft urethane material, Solithane 113, that we used for holding components on the board and a hard epoxy, Epiphen 825A, for rigid mounting.  They were already on the PPSL.

In addition to soldering endless PCB's (Mostly for Galileo), I also worked in the Polymerics lab at JPL in the late 80's.
All the conformal coating I applied to PCB's was a 2 part eopxy, although it was soft, kind of like silicon soft.
We brushed it on then put the PCB in a small vacuum chamber (About as big as an oversized keg).
The majority of that was for one of the early mars rovers.
This was in 1987 - 1989.
I can't speak for what they did there after or before that or what they did at other facilities.
Sorry to make it sound like that was done that way at every facility.

Once I also had to replace a chip on a radar module for one of the space shuttles.
It had the same type of coating on it.

[armdnrdy]

I also worked in the Polymerics lab at JPL in the late 80's.

Are you still in So Cal?

[CodeMonk]

I also worked in the Polymerics lab at JPL in the late 80's.

Are you still in So Cal?

Nah, except for a 4 year period (2008 - 2012), I've been living in Nevada (Carson City, Reno, Sparks, other nearby areas) since 1989.
JPL was a fun job though.
I tried to get back in there when I was in L.A. during my time down there, but no luck
Although the first 2+ years of that was taking care of my dad, so job hunting was not an option then.

But during my JPL, Litton, ITT, etc. days, I lived in the SFV.

[armdnrdy]

Just wondering if you were still "local"

Born and raised here. Used to pass JPL going to an ex-girlfriends house in La Crescenta.

I've actually been to Sparks some time ago on my way to Pyramid Lake to fish for Lahontans.

Sorry guys.....I feel like I turned this thread into a chat room. 

[PRR]

It's not clear to me that phenolic is horribly poisonous.

I've handled it all my life, which may be good or bad. I'm far more worried about other things I've been exposed to.

Note: there is phenol, a liquid/vapor; and phenolic, a hard brittle solid.

Most of the tox data I can find relates to phenol; you are far less likely to eat circuit board stuff.

"Listerine" was originally phenol (carbolic acid). It IS an effective germ killer, so no surprise it also irritates higher organisms. It's still around as a minor ingredient in many personal products. Also in a whiskey.

You would *never* touch pure phenol except in a few industrial situations.

If I am reading this US Government study correctly, significant exposure is FAR more than handling a circuit board; more like re-converting a board back to phenol and drinking a "board" a month.

www.atsdr.cdc.gov/toxprofiles/tp115.pdf

"It {phenol} is found in various consumer products including throat lozenges, mouthwashes, and antiseptic lotions."

I suppose the way they turn phenol liquid to solid phenolic involves formaldhyde? Some variant of the BakeLite process? I collected samples from the industrial area around the former BakeLite factory to Bound Brook NJ. Real dead-zone, though several other nasty factories were also in the area (Johns-Manville, GAF). Uck.

Ah... phenolic IS the generic for BakeLite. And BakeLite itself has never been seen as a health issue for consumer handling. BakeLite info  "...saxophone mouthpieces, whistles, cameras, solid-body electric guitars, telephone housings and handsets, early machine guns, pistol grips, and appliance casings. ...pipe stems, buttons, etc."

Don't eat phenolic board. (And don't let your dog eat it!) Wash your hands after handling more active metals (copper, lead, tin, solder), which also washes any phenol/phenolic.

Many building materials use phenolic binders. Less than they used to, but kitchen countertops used to be mainly filled phenolic, and particle board used to have some phenolic binder. Some people are highly sensitive to something in that stuff. The "no added formaldehyde!" trend has reduced this exposure. But unless you have got all that stuff out of your house, there's far more in the house than in all your pedals.