From: freenet.edmonton.ab.ca!pjwylie@imagelan.com
Date: Thu, 25 Apr 1996 18:44:10 -0600 (MDT)
To: "donald l. owens" <CompuServe.COM!76250.453@imagelan.com>
Subject: Re: Copy of: Pin-holes
In-Reply-To: <960425181034_76250.453_CHK68-1@CompuServe.COM>
Message-Id: <Pine.A32.3.91.960425174420.14321A-100000@fn1.freenet.edmonton.ab.ca>
Don, I'm no expert but I am working on coating probelems of my own and
through testing have learned from my own mistakes and advice from some
really good people. This information I submit should offer additional clarity
for Hyplon or other compounds:
Many technologies cure progressively and slowly from their surfaces
inward, like paint. To achieve the build-up of any MEANINGFUL
THICKNESS, several of these thin layers must be applied, always allowing
sufficient time between the layers for each to thoroughly cure from
moisture they take from the air before another thin layer can be applied.
If a too-thick a coating (too-viscous) should be attempted (been there done
that), its air-exposed surface would SKIN OVER first, leaving the
still-wet interior without the air-moisture contact needed for its curing.
As curing slowly progressed from what moisture could penetrate that skin,
the product of cure, carbon dioxide, would accumulate in small bubbles
between the membrane and its Nylon substrate, being unable to rise and
release through the skin. This "GASSING" as it's commonly called, can
accumulate its small bubbles to cause blisters and even complete
delamination of the membrane from its substrate. Someone pointed out that
ambient temperature is important and helps cause an even cure throughout
any thickness.I believe this to be excellent advice given to perform our
coating at a lower (or cooler room temp)I have discovered too that it is
imperative that the substrate be severly penetrated. The base membrane
mixture must be fluid enough to allow easy spreading, sufficient
self-leveling to eliminate any marks caused by spreading and the easy
rise-and-release of any bubbles of whipped in air. To reiterate... Air
that has been trapped by too viscous a base membrane mixture, or for any
other reason, may cause a surface blister IF A RISE IN TEMPERATURE causes
it to expand while the base membrane is still fluid. I have also learned
that not all solvents used to mitigate the thickness of your coating
compound are ideal. For instance I attempted using alcolhol as a carrier
which I soon discovered inhibited the curing process and was a source of
gassing within the compound. Naturally I desired a more environmentally
friendly application but NO DICE! Xylene is for me the solvent of
choice(not because of it's toxic effect on the liver , kidneys and
brain)USE A GOOD INDUSTRIAL CARTRIDGE MASK by all means while using such
a powerful carrier to penetrate the nylon substrate for that all
important initial base coat.
Of course use only what the manufacture recommends. There is old technology and there is new
technology and at present I'm testing the new which looks promising.In
any event I am working hard to prove to myself new potentials. It sure is
easier to relate to someone elses concerns when you have experienced theirs for
yourself.
I wonder if George ever produced a coating manual other than his
commentary in his book "BAIDARKA"? I hope this information is of some
help to you but I would certainly defer to George's experience.
Regards,
Philip Wylie
"The location of all creativity is in pure awareness...
The eye refuses to see what the mind does not know!" ( Deepak Chopra )
email: pjwylie@freenet.edmonton.ab.ca