KR> WEST EPOXY

[Larry H.]

I will have to stand corrected on the West System Epoxy being used for 
structure. Jerry Mauhrin said Jim Clements used West to build his wings. He is 
correct ! I am very surprised I will have to admit ! I talked to Jim a couple 
times today by email. Jim said he used West on his first Wittman Tailwind 
starting in 1980 and has only used West for all his Wittmans, he has built 9 of 
them I believe, and they are all beautifull airplanes. I thought I had better 
correct myself on this subject. This does create some history for the West 
system in Wittman wings anyway. That makes at least 26 years since Jim's first 
plane. It is still flying ! I think ?
Larry Howell

KR> WEST EPOXY

[Orma]

I'll have to admit that of all the popular epoxy brands that are out there, 
I have not used T88.  I have for the past 15 years used West System.  I have 
used both fast and slow versions.  I used WS when I instructed at an A 
school on a spar project, where the students scarfed a length of 3/4 spruce 
or pine and following the gluing, they would test the piece to destruction 
by suspending the piece and loading it with weights at the splice.  None of 
the failures occurred at the scarf joint, except where a student failed to 
properly glue or clamp the project.  I keep my WS outside in the cold and 
season after season it still works.  I feel you could debate the glue issue 
long and hard, and WS will still be in the range of good epoxies to use.
Orma
Southfield, MI
KR-2  N110LR  1984
See Tweety at http://www.kr-2.aviation-mechanics.com
See other KR spces at www.kr-2.aviation-mechanics.com/krinfo.htm

KR> WEST EPOXY-WITTMAN

[Larry H.]

OK netters I guess I will step off into it. 
Wittman Tailwinds do have wooden truss ribs. All Wittman Tailwind wings that I 
know of in recent years are glued together with T88. I keep up with the Wittman 
guys closely, I know many of them, I attend their get togethers. The older ones 
used the powder mix for gluing theirs, I don't rember what you call that stuff.
The Wittman has two wooden spars just like a KR. The ribs are actually 1/2" 
wide. The reason is so there is a larger gluing surface for the sheets of 
plywood  that get glued down and covers the wings. Once all the plywood is 
glued, set, sanded smooth the current trend is to cover them with a layer of 
fiberglass cloth mostly for sealing but for some strength. Most builders in the 
last 8 to 10 years are using the West epoxy system for wetting out the 
fiberglass cloth that covers the outside surface of the Wittman wings.
Steve Wittmans plans tell you to cover the wings with doped fabric, as in 
Stits/Poly Fiber, but actually the predecessor to the Poly Fiber system.
Unfortunately what killed Steve Wittman was a mix up in technique . Steve had 
always used the old covering system which allowed you to lay fabric (I am 
talking about fabric covered airplanes type of fabric not fiberglass) on the 
wood and wet it out with the dope just like we do with fiberglass cloth. The 
dope would penetrate through the fabric and then it was stuck down, no problem, 
that is the old way of covering the plywood wings as specified by Mr Wittman.
When he built the O Mr Wittman used the Stits system, but he did it wrong, he 
did it like the old stuff. What he was supposed to do was paint the new stuff 
(Poly Tak) on the plywood first, laying the fabric on top of that while it was 
still wet, covering a little at a time to make sure the Poly Tak stays wet when 
the fabric is applied to it, then use the second step, paint  (Poly Brush) on 
top of the fabric.
The fabric on the O managed to stay on the plane for about 10 years I think 
it was. He had built this plane to carry all of his things to his winter home 
in Ocala Fl from Oshkosh, that is why he named it the O for those of you who 
don't know. The last flight that Steve Wittman made from Ocala headed back to 
Oshkosh for the summer of course was his last, the fabric had delaminated from 
the plywood, set up flutter and tore the wing off of the airplane. I think EAA 
had an article about it, I never read it so I am not sure what they wrote about 
it but this is what happened to it.
Bottom line is know your systems, attempt to know what you are doing and by all 
means pay attention..
I for one would never use West Epoxy for gluing ribs or a wooden airplane 
together. I have never known anyone to have done such. Not saying that there is 
not someone who has but I would never do that.
I know a guy who built his wooden truss ribs with model airplane CA glue, I 
warned against that but a guy has to do what a guy has to do.
I have known guys who use the wrong stuff to build all kinds of airplane parts. 
I will rephrase that and say the wrong stuff as far as I am concerned.
Larry H.

KR> WEST EPOXY-WITTMAN

[Jerry Mahurin]

Not to say that either system is superior, 'cause I have used  probably
gallons of T88 but I think that you would have a hard time telling Jim
Clement, who has built at least 10 Tailwinds,  that he is using T88 instead
of West Go to the Tailwind Groups on Yahoo and Matronics and you
will see what is being used and how.

Just my long nose and nickles worth.

On 1/27/06, Larry H.  wrote:
>
> OK netters I guess I will step off into it.
> Wittman Tailwinds do have wooden truss ribs. All Wittman Tailwind wings
> that I know of in recent years are glued together with T88. I keep up with
> the Wittman guys closely, I know many of them, I attend their get togethers.
> The older ones used the powder mix for gluing theirs, I don't rember what
> you call that stuff.
> The Wittman has two wooden spars just like a KR. The ribs are actually
> 1/2" wide. The reason is so there is a larger gluing surface for the sheets
> of plywood  that get glued down and covers the wings. Once all the plywood
> is glued, set, sanded smooth the current trend is to cover them with a layer
> of fiberglass cloth mostly for sealing but for some strength. Most builders
> in the last 8 to 10 years are using the West epoxy system for wetting out
> the fiberglass cloth that covers the outside surface of the Wittman wings.
> Steve Wittmans plans tell you to cover the wings with doped fabric, as in
> Stits/Poly Fiber, but actually the predecessor to the Poly Fiber system.
> Unfortunately what killed Steve Wittman was a mix up in technique . Steve
> had always used the old covering system which allowed you to lay fabric (I
> am talking about fabric covered airplanes type of fabric not fiberglass) on
> the wood and wet it out with the dope just like we do with fiberglass cloth.
> The dope would penetrate through the fabric and then it was stuck down, no
> problem, that is the old way of covering the plywood wings as specified by
> Mr Wittman.
> When he built the O Mr Wittman used the Stits system, but he did it
> wrong, he did it like the old stuff. What he was supposed to do was paint
> the new stuff (Poly Tak) on the plywood first, laying the fabric on top of
> that while it was still wet, covering a little at a time to make sure the
> Poly Tak stays wet when the fabric is applied to it, then use the second
> step, paint  (Poly Brush) on top of the fabric.
> The fabric on the O managed to stay on the plane for about 10 years I
> think it was. He had built this plane to carry all of his things to his
> winter home in Ocala Fl from Oshkosh, that is why he named it the O for
> those of you who don't know. The last flight that Steve Wittman made from
> Ocala headed back to Oshkosh for the summer of course was his last, the
> fabric had delaminated from the plywood, set up flutter and tore the wing
> off of the airplane. I think EAA had an article about it, I never read it so
> I am not sure what they wrote about it but this is what happened to it.
> Bottom line is know your systems, attempt to know what you are doing and
> by all means pay attention..
> I for one would never use West Epoxy for gluing ribs or a wooden airplane
> together. I have never known anyone to have done such. Not saying that there
> is not someone who has but I would never do that.
> I know a guy who built his wooden truss ribs with model airplane CA glue,
> I warned against that but a guy has to do what a guy has to do.
> I have known guys who use the wrong stuff to build all kinds of airplane
> parts. I will rephrase that and say the wrong stuff as far as I am
> concerned.
> Larry H.
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--
Jerry Mahurin - aka - KRJerry
EAA#  0034283
Lugoff, SC 29078