Before you fill the holes and lay up with the cloth I would drill several
little 1/16" or smaller holes around the circumference of the damage.
Then I would mix a very wet micro mix and syringe it into the holes to
see if you can drive the "mix" from 1 hole to the others. If you have
fuel getting into the foam it will tell you how much foam is missing and
give you confidence (or not) about using this canard. The micro mix is a
good accepted repair for delaminations on wings as the foam and glass
need to be bonded to have the shear web needed in composite construction.
Oh, if the micro mix doesn't run from 1 hole to another you might try
drill 2 small holes in the middle of the "indentation" to see if the
"mix" will run from 1 to the other. If you can't get the micro to run
underneath the glass then forget it and fill the holes and glass over.

Bruce Crain


On Fri, 12 Jan 2001 08:28:36 -0500 "Dave Richardson"
<dave@...> writes:

Hi Folks.

I'm in the process of getting things ready for the first Q-Talk of
2001 and
I received article part of which is shown below from one of the guys
subscribing. When I see a 'question' type of a note from people
sending in
articles, I'm going to submit it to the Q-List on their behalf to give
them
some access to this wealth of knowledge. If there questions that need
to be
asked, I'll collect them and get in touch with the individual and post
the
answers to the questions on the Q-List. Believe it or not, there are
still
plenty of QBA folks who are not on the internet but still have
questions. I
intend on putting their full article in the Q-Talk along
a synopsis of the answers or directions suggested by the Q-List.

Here it is.

Thanks.
Dave


In storage, a peculiar problem again has surfaced and I do not know
how to
remedy it. On the leading edge of the canard I've noticed many
indentations. It's as though a sharp edged tool was hammered down the
surface. These indentations are about 6" - 8" apart, 1"-2" long and
about
1/8" deep. The layered expoxied fiberglass seems to have been sucked
down.
Don't know how this is possible! The foam beneath this could have
shrunk,
making these indentations. I wrote to Ron Alexander about this. He
suggested I fill the indentations with an epoxy slurry mix, sand to
the
adjoining surface and then place another fiberglass layer over all of
this.
A lot of work, but worth doing.




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Finley is on target with this. If the Q1 driver built it then he knows what
is underneath. I have not heard of this kind of damage of a PLANS built
canard in 20 years of looking. But then, it would be helpful to actually see
what the builder describes. If the Q1 driver HAS to know the cause he will
have to open it up. I can't imagine how you would get spontaneously appearing
dents from static storage. We have seen corrugations on top of the canard
from lack of post curing however.

Hi Folks.

I'm in the process of getting things ready for the first Q-Talk of 2001 and
I received article part of which is shown below from one of the guys
subscribing. When I see a 'question' type of a note from people sending in
articles, I'm going to submit it to the Q-List on their behalf to give them
some access to this wealth of knowledge. If there questions that need to be
asked, I'll collect them and get in touch with the individual and post the
answers to the questions on the Q-List. Believe it or not, there are still
plenty of QBA folks who are not on the internet but still have questions. I
intend on putting their full article in the Q-Talk along
a synopsis of the answers or directions suggested by the Q-List.

Here it is.

Thanks.
Dave


In storage, a peculiar problem again has surfaced and I do not know how to
remedy it. On the leading edge of the canard I've noticed many
indentations. It's as though a sharp edged tool was hammered down the
surface. These indentations are about 6" - 8" apart, 1"-2" long and about
1/8" deep. The layered expoxied fiberglass seems to have been sucked down.
Don't know how this is possible! The foam beneath this could have shrunk,
making these indentations. I wrote to Ron Alexander about this. He
suggested I fill the indentations with an epoxy slurry mix, sand to the
adjoining surface and then place another fiberglass layer over all of this.
A lot of work, but worth doing.

Gosh Dave! Anybody that answers this question is likely to get hammered by
someone else. So, since I won't be getting email for the next week - I'll
do it!! :-)

I believe the leading edge of the canard provides a fair amount of
structural strength so I believe this area is important (compared to the
slot cores, for example). If there is no damage to the foam (or very
surfacy) and depending on the number of these "indentations", I would
probably follow Ron's advice using BID overlapping onto the bottom. The
problem with a non-engineer, back yard mechanic type like me saying this is
that you now have a canard with load characteristics, twist characteristics,
and stress points unlike what was intended/designed. How big a deal is
this, I don't know. Fix it as suggested, roll it over, and load test it (I
know, that only answers the static strength question leaving many others
answered but it is about the best us homebuilders can do (as far as I
know)). The bottom line is the pilots comfort. If, even after a load test,
the pilot will not be comfortable with a repaired canard, then build a new
one.

Jon Finley
N54JF - Quickie - 1835CC VW
N90MG - Q2 - EA81 Turbo Subaru
Apple Valley, MN

JMasal@... wrote:

<snip>

I can't imagine how you would get spontaneously appearing
dents from static storage.

Perhaps it was damaged in an earlier life?... maybe by colliding
with a fence???... which produced the repeating pattern in the
leading edge, which was filled with bondo and then painted,
and the bondo is shrinking?

my $.0000000002

Pat

Can a photo be supplied of the damage? Barring physical damage such as hangar
rash, I suspect that a non-standard epoxy filler may have been used, such as a
polyester resin.. Uncured material can and will seep into the pinholes in the
glass, caviting the foam underneath. This is probably not dangerous.

I would drill two small holes into each dimple and inject micro-slurry. This
will strengthen the area. The builder might be able to get away with sanding
off the paint in the damaged area, filling the dimple with dry micro, then
paint.

Sam

Dave Richardson wrote:

Dave,

before this can be repaired it would be prudent to find out what caused the problem.

If the canard has been the subject of mechanical damage then the extent and nature
of the damage is likely to be fairly obvious. Judging by the description is sounds as
though either something has been dropped or driven into the leading edge or the aircraft
has been driven into something.

The LE skin is important for torsional reasons and such damage will compromise the
canard strength.

Can I suggest that before doing anything further, you obtain a copy of the plans and
carefully establish the layup schedule of the glass in the areas of damage. There are
a couple of ways of tackling the repair but they all involve sanding back to bare glass
around the damaged areas and looking for hidden damage. The rule of thumb is
to sand back an inch on either side of the damage for each layer of glass plus one for the
bid which goes on last. i.e. if the skin is two of uni then the sanded area will be 6 inches
wide if the damage is in a line ( 2" + 2" + 2") . the sanded surface is white so it is very hard to
see through, but if you wet it with a damp cloth transparency is restored ( while it is wet).

Other contributors have described the process of injecting any voids with micro and the
only comments I would add are to be sure that the holes you drill are a tight fit around
your syringe and that you do a tap test to ensure that you have fully defined any delamination/
void. Use a small syringe, the big ones are too hard to push. With big delaminations you have
to watch for exotherms, because the heat cannot escape. One solution is to do several injections.
The temptation is heat up the micro prior to injecting. Avoid the tempation, make the micro
wetter.

The next step is to either cut out the damaged glass ( in which case you do not have to inject
with micro before cutting!) or to re contour the dent back to the original surface, then lay up your
patches in the original order and sequence followed by the final bid. Peel ply the whole area
and the finishing process will be a whole lot easier. Micro, sand and paint and you are done.

If you are cutting out the damaged glass, the standard practice is to taper the surface glass by
one thickness per inch. This is not easy to do properly but is best performed with a small right
angle air powered sander ( disc about 30 mm in diam) and done gently.

Then cut the patches to the size of the sanded rings and making sure the glass orientation is
correct, lay it up. finish it up as above.

Hope this helps

John