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From: Richard Riley <>
Newsgroups: rec.aviation.homebuilt
Subject: Re: Dry Layups???
Date: Sun, 24 Oct 1999 18:10:13 -0700

On 24 Oct 1999 21:24:30 GMT, "Redtails" <>

>How can I prevent my resin from flowing out of my cloth before curing ,when
>working on vertical surfaces?  I usually try to move the part to a
>horizontal position, but can't do this in some cases.

Use a resin that's marginally thixotropic.  We use Gougeon's pro-set
125 resin and 233 hardiner for that application, it works nicely.

From: (KernHend)
Newsgroups: rec.aviation.homebuilt
Subject: Re: Epoxy sensitivity
Date: 02 Dec 1999 17:00:26 GMT

Tom Anderson <> wrote:

>There's a difference, my friend. I can work all day long in my garage in
35-50 degree temps., particularly if I've got a little kerosene heater
keeping my buns warm. But, for epoxy to cure properly, it's important to
keep the temp. up around 50 or so (the warmer, the better) throughout
the cure. That means overnight and for the next 48 hours or so.
I can deal with cold tools and fingers...but NOT a delamination at
10,000 feet!<

And, my friend, if you are using a direct fired kerosene heater to keep your
epoxy warm during cure you may have that delamination at 10,000 feet anyway!

Direct fired kerosene and propane to a much lessor exent give off as products
of combustion water, carbon dioxide and unburned hydrocarbons which in
combination can react with curing epoxy to form an unbondable surface.

Better to find another source of heat.

W. Kern Hendricks
System Three Resins, Inc.
P.O. Box 70436
Seattle, WA  98107
Orders Only:  800/333-5514
Technical Support:  206/782-7976

From: Richard Riley <>
Newsgroups: rec.aviation.homebuilt
Subject: Re: Epoxy Work Space Heating
Date: Thu, 23 Dec 1999 15:04:29 -0800

On 23 Dec 1999 22:17:24 GMT, robertr237@aol.compost (RobertR237) did
speak thus :

>In article <Xww84.9894$>, "Dave Detty"
><> writes:
>>Does anyone have any experience with heating their epoxy/fiberglass work
>>space with vent-free natural gas heaters or Kerosun (kerosene) type heaters?
>>I know that vent-free heaters are safe for heating spaces where humans live,
>>but are they safe for heating spaces where I intend laying up epoxy?
>>Inquirying mind wants to know...

Epoxies like to absorb water from the air as they cure - if they do,
they end up weaker and can get an amine blush on the surface.  A kero
or NG heater gives off a lot of water vapor as it burns the fuel, so
take care that the room doesn't become _too_ moist.   Particularly a
problem if the part is cold, and moisture condenses on the surface.

From: (KernHend)
Newsgroups: rec.aviation.homebuilt
Subject: Re: Epoxy Work Space Heating
Date: 29 Dec 1999 00:06:39 GMT

>Greg Piney <>

>With NG there is no residue to end up on your project. <

Except, of course, the products of combustion, carbon dioxide and water vapor,
which in combination form a weak acid.  Since curing epoxy contains alkaline
amines it will react with the carbon dioxide in the presence of moisture to
form amine carbamates and carbonates.  These may affect secondary bonding or
they may not depending upon the particular epoxy formulation.  I'd check to be
sure before giving NG a clean bill of health in this regard.

W. Kern Hendricks
System Three Resins, Inc.
Seattle, WA

From: (KernHend)
Newsgroups: rec.aviation.homebuilt
Subject: Re: Disadvantages of Vinyl Ester?
Date: 1 Jun 1999 22:06:15 GMT

> (Jeff Spitzer)

>When I compare the spec. sheets for vinyl ester resin to epoxy I see
>many advantages.  These include: lower cost, lower viscosity,
>adjustable pot life, higher Tg, etc.  I only see one disadvantage and
>that's shorter shelf life.  Are there any other disadvantages I'm not
>seeing?  Can you bond vinyl ester parts together with epoxy or epoxy
>based adhesives?

The primary advantage for the epoxy is that it is (depending upon the
particular formulation) a lot tougher.  That is, it has better fracture
mechanics.  You see these in terms of better impact, shear and peel strengths
along with fatigue resistance.  In short, this means than an epoxy is a better
adhesive than a vinyl ester.  You can bond sanded vinyl ester parts with an
epoxy adhesive and will get a better bond than if the same sanded parts were
bonded with vinyl ester resin.

Your comparison really applies only to room temperature cured epoxy systems.
The best high temperature cured epoxy systems run rings around a vinyl ester in
the Tg department.  The are a number of good room temperature epoxy
formulations that have lower viscosity than vinyl ester resins, also.

W. Kern Hendricks
System Three Resins, Inc.
P.O. Box 70436
Seattle, WA  98107
Orders Only:  800/333-5514
Technical Support:  206/782-7976

From: Richard Riley <>
Newsgroups: rec.aviation.homebuilt
Subject: Re: composite fueltank questions
Date: Tue, 26 Oct 1999 14:58:13 -0700

On Tue, 26 Oct 1999 21:04:24 GMT, Gary Thomas <> wrote:

>> I have a few questions about construction methods.  Initially I wanted to
>> shape the tank in blue foam, do an epoxy/ glass lay-up and dissolve out the
>> foam with acetone(?).  Has anyone done this?  I would appreciate any tips.
>> I am a little concerned about the surface finish of the tank interior and if
>> any tiny particles of foam will remain to plug filters or if the rough epoxy
>> inside surface will lose small bits of epoxy over time.

I wouldn't do it - blue foam/acetone (or lacquer thinner) form a goo
that you'll have a real hard time getting out.

Better to make it out of urethane or (preferably) PVC.  You can make
flat stock and assemble it out of sheets, or make a deep dish and
close it out with a piece of flat stock.  Or 2 deep dishes, and glue
their flanges together.

>> Another problem is I called Aircraft Spruce and Specialty and they do not
>> recommend the use of any of the epoxies they supply for use where the epoxy
>> will contact fuel.  Any recommendations?

WEST epoxy from Gougeon has 20 years of fuel immersion data from
boats, it will stand up just fine, especially to avgas (fewer new
additives than autogas)

>> ASS recommends polyester or vinylester resins for this application.  The
>> problem is I pretty sure they both dissolve blue foam.


From: (KernHend)
Newsgroups: rec.aviation.homebuilt
Subject: Re: Gorilla Glue?
Date: 30 May 2000 13:53:42 GMT (Beaux Graham) wrote:

>Any opinions / pireps on using Gorilla Glue in sticking spruce
>together in structural applications?

We don't recommend using any polyurethane adhesive for a structural
application.  When urethane adhesives cure they react with moisture in the wood
forming millions of tiny bubbles of carbon dioxide.  In effect you are bonding
wood with "microfoam".  Structural applications should be glued with a two-part
epoxy like T-88 (ours).  Leave the urethanes to the woodworkers.

W. Kern Hendricks
System Three Resins, Inc.
Seattle, WA
Technical Support:  206/782-7976
Orders Only:  800/333-5514

PS:  We also make a urethane adhesive like Gorilla Glue so we really have no
axe to grind in this matter.

From: Richard Riley <>
Newsgroups: rec.aviation.homebuilt
Subject: Re: Best bond of Aluminum to Composite
Date: Thu, 07 Sep 2000 18:15:57 GMT

On 7 Sep 2000 15:57:09 GMT, in rec.aviation.homebuilt (Charles K. Scott) wrote:

>In article <>
>richard riley <> writes:
>> On Thu, 07 Sep 2000 10:33:28 -0400, John Mireley <>
>> wrote:
>> >To get the best bond of an Aluminum fuel fitting
>> >flange to a composite fuel tank, should resin or
>> >resin and flox mixture be used?
>> The flox doesn't change the bond quality particularly, it just changes
>> the viscosity of the resin so it will stay and not ooze away before it
>> cures.  We'd use flox/resin for that.  We'd also sand the aluminum
>> immediately before coating with wet resin, and use WESTepoxy - it
>> bonds nicely to aluminum and stands up to fuel..
>When I fabricated fiberglass tanks and wanted to bond the filler neck I
>took the additional step of drilling the collar around the rim to make
>sure the fiberglass and flox had something to grip too.  Probably
>wasn't necessary.

But not a bad idea at all.  Unless you do a lot of prep corrosion will
eat its way under the epoxy and the bond will become very, very weak
over time.  We don't ever depend on the strength of a
composite-aluminum bond, we always have some form of mechanical
attachment as well.  MIL-C-5541E gives the spec for prepping aluminum
for a bond.

Drilling the flange and filling the holes with flox creates "flox
rivets" that mechanically hold the flange even if there's no bond at
all.  It's a technique we use often.

From: (KernHend)
Newsgroups: rec.aviation.homebuilt
Date: 25 Nov 2000 01:09:52 GMT
Subject: Re: Shelf Life Question (Don & Pam Thornton) wrote:

>I have two gallon of DOW DER 330 Epoxy with Hardener that I purchased from
Wicks Aircraft Supply.  The catalog states this material has a shelf life of
one year.  They are now almost four years old.<

Generally, epoxy resin and hardeners do not degrade over time so long as they
are kept dry.  To satisfy yourself that your's is still "good" mix some and
glue a couple of pieces of wood together.  Allow to cure a couple of days and
break the piece.  If the material is hard and the failure does not cleanly
occur on the glue line it is fine.

W. Kern Hendricks
System Three Resins, Inc.
3500 West Valley Highway, N   Suite 105
Auburn, WA  98001
Technical Support:  253/333-8118
Orders Only:  800/333-5514

From: (KernHend)
Newsgroups: rec.aviation.homebuilt
Date: 25 Nov 2000 17:35:32 GMT
Subject: Re: Shelf Life Question

Richard Lamb <> wrote:

>Well, sure, you could do that, but this is a laminating resin...

So what?  If it fails as a wood adhesive it will also fail as a laminating
resin.  Based upon over 25 years of epoxy formulating experience if it "passes"
as a wood adhesive it will "pass" as a laminating resin. This does not mean
that it is necessarily a good wood adhesive but only that wood bonding is a
quick test for viability which, after all, was the original question.  With the
information given by the original poster we don't know if it is even a good
laminating resin.   DER 330 is nothing more than an uncut epoxy resin. The
ultimate properties (which determine its efficacy as a laminating resin) will
depend upon the curing agent used.  Perhaps you have more information and know
something I don't know.  If so, I am all ears.


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