Re: Coating Secondary with Epoxy

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

Here's another idea for a "bandaid" fix..

Wrap the entire secondary in that wide stretch film used for palletizing
stuff.
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Sunday, January 05, 2003 3:50 PM
Subject: Re: Coating Secondary with Epoxy


 > Original poster: "Scott Hanson by way of Terry Fritz
<teslalist-at-qwest-dot-net>" <huil888-at-surfside-dot-net>
 >
 > Dave -
 >
 > According to the rather limited data available from TAP Plastics, the
 > Ultra-Glo "polymer coating" is a finish resin and not a laminating resin,
 > which means that it should not have any residual tackiness after curing.
 >
 > I have used epoxy resins for many years for coating, insulating, and
potting
 > purpose. In my experience, the most likely cause of tacky "patches" is
 > inadequate mixing of the resin and hardener, leaving hardener "starved"
 > areas. If there was a fundamental problem with the ratio of resin to
 > hardener, or if the hardener was "old", the entire surface would be tacky.
 > Thorough mixing of the resin and hardener is especially critical with
 > transparent epoxy systems, where it is visually very difficult to
determine
 > when the two components are properly mixed. To get adequate mixing, you
will
 > usually end up with a large amount of entrained air bubbles. To minimize
 > bubbles in the coating will require that the mixed resin be vacuum
degassed,
 > which can be done even with a small automotive hand vacuum pump.
 >
 > A less likely cause is contamination of the resin with oil, grease or
other
 > material from the mixing vessel or from the secondary itself.
 >
 > Trying to sand the tacky spots is usually futile as any abrasive paper
will
 > clog instantly. I'd set the secondary outdoors in the bright sun for
several
 > days, and see if the ultraviolet in the sunlight, plus the warmth, will
help
 > finish the cure cycle. If this doesn't work, you can try adding a third
 > coat, but there's no guarantee that whatever's inhibiting full cure of the
 > second coat won't propagate through and affect the third coats also.
 >
 > Scott Hanson
 > ----- Original Message -----
 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > To: <tesla-at-pupman-dot-com>
 > Sent: Sunday, January 05, 2003 12:48 PM
 > Subject: Coating Secondary with Epoxy
 >
 >
 >  > Original poster: "Dave Leddon by way of Terry Fritz
<teslalist-at-qwest-dot-net>"
 > <leddon-at-attbi-dot-com>
 >  >
 >  > Hi Folks,
 >  >
 >  > Last Thursday I coated a 10-inch secondary with Ultra Glo, an epoxy
sold
 > by
 >  > Tap Plastics, and Friday I applied a complete second coat to cover
several
 >  > areas that came out a little thin.  Now, 48 hours later, I've still
have
 >  > several small areas which are tacky to the touch.  The product
literature
 >  > claims a complete cure after 24 hours at room temperature so I suspect
 > that
 >  > this stuff has cured as much as it's going to cure.  Any ideas on
causes
 >  > and treatment?
 >  >
 >  > Thanks,
 >  > Dave
 >  >
 >  >
 >  >
 >
 >