I am back! Thanks again to all of you who made suggestions
when I had difficulties with my LX-201. It turned out that it was
indeed the transducer itself!
Although I considered many solution alternatives (with your
help) I finally settled on trying an Airmar P79 in-hull transducer
because they told me it would be compatible with the LX-201.
Also, I preferred not to mess with the old thru-hull as it needed to
be pulled from the bottom and appeared to be epoxyed in place.
Initial tests have shown that the Airmar will work well as it
will be used on a non-cored Grady White with a solid hull thickness
of less than one inch.
The problem has been the mounting of the transducer. Airmar
uses a bottomless base with a flange that is secured to the
inside of the hull with adhesive. The base is then filled with either
mineral oil or propylene glycol (their instructions), and the
transducer snaps on over that such that its bottom face "floats" on
the liquid. Obviously whatever adhesive is used must make a permanent
seal between the hull and the base flange as the base itself has no
bottom.
Here is the problem. Airmar specifically states that epoxy,
or the previously recommended Boatlife LIfe Seal or 3M 4200
are *not* to be used. Only GE Silicone II is allowed! With an area
perfectly cleaned with 409 (the area has a gloss), I have tried to
mount the base three times, each with many hours of cure time.
Each time when I have added the glycol, it leaks out after a few
seconds as if it were reacting with the silicone. When the base is
removed, the silicone on the flange is a sticky mess.
It really doesn't make sense to me that silicone would work at
all in this application. So why not use epoxy? Is it just that it
would be permanent and if the transducer base had to be
moved or removed you couldnt get it off? Surely Airmar sells
replacement bases. (I will check tomorrow.)
Your counsel is much appreciated. Am I just doing something
wrong in applying the Silicone II? (Otherwise known as "Kitchen
and Bath.") Or am I correct that this is a bad idea for a permanent
installation and epoxy should be used?
Thank you.
Frank







On 2 Apr 2006 21:53:32 -0700, "DPFresh"
wrote:

Hello all, so as oppossed to drilling a hole in my hull for a depth
finder sensor, I should be able to set it up inside the hull as long as
the sensor is in some type of liquid right? IT will be able to tell
depths through the fiberglass hull right?

Thanks,
David

frank1492 wrote in
:

Am I just doing something
wrong in applying the Silicone II?

I find their recommendations quite strange. I made a blob of 2-part Epoxy
mix in the bilge of the Sea Ray and pushed the little Garmin in-hull
transducer face directly into the epoxy blob. I know it's permanent but
you can always put the next transducer right next to it 5 years from
now......well, the new owner probably could...(c;

Not sure why Silicone II. Seems too soft for good sound transfer to the
hull, to me.

Before you commit to any location, what you should do is flood the hull
with a couple of inches of fresh water and go for a ride. While someone
else is driving in 50' of water or so, move the transducer around under the
water inside the bilge until you get the best picture and find the best
"hotspot" for both best picture and best mounting position. Many places
work better than others at transmitting sound through the hull.

Mineral oil is:

A - Inert
B - clear so if it oozes noone will know.

I'd also be tempted to use what the Navy uses on their transducer coupling
fluid....K-Y Jelly....the industrial strength equivalent, which is lots
thicker. It, too, is inert and clear.

On Fri, 28 Jul 2006 11:49:57 GMT, frank1492
wrote:
snip
With an area
perfectly cleaned with 409 (the area has a gloss), I have tried to
mount the base three times, each with many hours of cure time.
Each time when I have added the glycol, it leaks out after a few
seconds as if it were reacting with the silicone. When the base is
removed, the silicone on the flange is a sticky mess.

It takes Silicone a good 24 hours to firm up, and several days to
fully cure. Your just not wating long enough for the thick silicone
to cure..

We use Silicone to hold telescope mirrors in place, I learned the hard
way that 24hrs isn't enough time for the silicone to cure.
Take Care,
James Lerch
http://lerch.no-ip.com/atm (My telescope construction, Testing, and Coating site)
http://lerch.no-ip.com/ChangFa_Gen (My 11.2Kw generator project)
Press on: nothing in the world can take the place of perseverance.
Talent will not; nothing is more common than unsuccessful men with talent.
Genius will not; unrewarded genius is almost a proverb.
Education will not; the world is full of educated derelicts.
Persistence and determination alone are omnipotent.
Calvin Coolidge

"frank1492" wrote
Here is the problem. Airmar specifically states that epoxy,
or the previously recommended Boatlife LIfe Seal or 3M 4200
are *not* to be used. Only GE Silicone II is allowed!

Frank,

Some plastics are affected by the solvents that are used in various
adhesives and sealants. They can cause rapid cracking - Not sure which
plastic they are using, but it sounds like they have had problems with
several types of adhesive (Just read their installation instructions which
are very good):

http://www.airmartechnology.com/uplo.../17-217-01.pdf

I would heed their advice (unless they offer alternatives - try phoning
them). Make sure you use a marine grade silicone such as:

http://makeashorterlink.com/?O40D32A7D

When you install the unit, put a healthy bead on the bottom edge as they
suggest and let it cure for 24hrs. Then, add a fillet of same product about
1/2" x 1/2" or larger all round for support. Make sure you get all oil
removed from surface - If it is in the bilge area, oil may be absorbed into
the surface - a light sanding with fine paper may help after first
thoroughly degreasing.

By the way, oil or gel is better than glycol especially on a power boat
because they do not form bubbles when agitated.

Good Luck!

GBM

Thanks to Larry and (again) to GBM. I guess I will try again
with the Silicone, one more time before calling. I gather
people have had some success using this as a permanent
adhesive, but I just can't imagine it. I do like the idea of
being able to move the transducer easily in the event that
the originally chosen location turns out to be N.G.
At the present time the transducer is sitting face down
in the bilge. At mooring the readings seem approximately
correct +/- about a foot. I won't be able to do much with a
retry of mounting over the weekend as I'm having guests. As
I am on Cape Cod with mostly sandy bottom, I use the depth finder
mostly to tell me when it's time to put the stern drive up as
I come into the beach, so nothing critical.
I'll be interested to see the readings I get when I get
under way. (Too windy to go out today.)
Will report back on everything.
Thank you again.
Frank
P.S. Will mount the base *exactly* to manu specs to
make sure I get the right angle. The Grady has a deadrise
near the stern of about 20 degrees.




On Fri, 28 Jul 2006 11:49:57 GMT, frank1492
wrote:

I am back! Thanks again to all of you who made suggestions
when I had difficulties with my LX-201. It turned out that it was
indeed the transducer itself!
Although I considered many solution alternatives (with your
help) I finally settled on trying an Airmar P79 in-hull transducer
because they told me it would be compatible with the LX-201.
Also, I preferred not to mess with the old thru-hull as it needed to
be pulled from the bottom and appeared to be epoxyed in place.
Initial tests have shown that the Airmar will work well as it
will be used on a non-cored Grady White with a solid hull thickness
of less than one inch.
The problem has been the mounting of the transducer. Airmar
uses a bottomless base with a flange that is secured to the
inside of the hull with adhesive. The base is then filled with either
mineral oil or propylene glycol (their instructions), and the
transducer snaps on over that such that its bottom face "floats" on
the liquid. Obviously whatever adhesive is used must make a permanent
seal between the hull and the base flange as the base itself has no
bottom.
Here is the problem. Airmar specifically states that epoxy,
or the previously recommended Boatlife LIfe Seal or 3M 4200
are *not* to be used. Only GE Silicone II is allowed! With an area
perfectly cleaned with 409 (the area has a gloss), I have tried to
mount the base three times, each with many hours of cure time.
Each time when I have added the glycol, it leaks out after a few
seconds as if it were reacting with the silicone. When the base is
removed, the silicone on the flange is a sticky mess.
It really doesn't make sense to me that silicone would work at
all in this application. So why not use epoxy? Is it just that it
would be permanent and if the transducer base had to be
moved or removed you couldnt get it off? Surely Airmar sells
replacement bases. (I will check tomorrow.)
Your counsel is much appreciated. Am I just doing something
wrong in applying the Silicone II? (Otherwise known as "Kitchen
and Bath.") Or am I correct that this is a bad idea for a permanent
installation and epoxy should be used?
Thank you.
Frank







On 2 Apr 2006 21:53:32 -0700, "DPFresh"
wrote:

Hello all, so as oppossed to drilling a hole in my hull for a depth
finder sensor, I should be able to set it up inside the hull as long as
the sensor is in some type of liquid right? IT will be able to tell
depths through the fiberglass hull right?

Thanks,
David

"frank1492" wrote in message
...
Thanks to Larry and (again) to GBM. I guess I will try again
with the Silicone, one more time before calling.

I'm always puzzled by this. Is it the same thing as refusing to stop and
ask for directions when driving? I always pickup the phone and call the
VENDOR when dealing with something problematic. Now, they're not always
speedy in their replies (teleflex calls me back A MONTH after I leave a
voicemail and send e-mail) so asking online also helps.

But really, in the case of something not working as per the vendor's own
instructions I'd never bother trying it again without calling them poste
haste. Especially not when it's something as important as a depth
transducer.

-Bill

Hi Bill-
I did call the vendor and they did give me a few tips. This
time I roughed up both the hull surface and the transducer base
with a little fine sandpaper and tried the silicone again, this time
with a longer cure. Got a good bond this time.
Getting to good tech people when you call doesn't always
happen. The responses on newsgroups can sometimes be
more thoughtful and useful.
BTW, I never stop to ask for directions LOL.
Frank



On Fri, 28 Jul 2006 13:04:55 -0400, "Bill Kearney"
wrote:


"frank1492" wrote in message
.. .
Thanks to Larry and (again) to GBM. I guess I will try again
with the Silicone, one more time before calling.

I'm always puzzled by this. Is it the same thing as refusing to stop and
ask for directions when driving? I always pickup the phone and call the
VENDOR when dealing with something problematic. Now, they're not always
speedy in their replies (teleflex calls me back A MONTH after I leave a
voicemail and send e-mail) so asking online also helps.

But really, in the case of something not working as per the vendor's own
instructions I'd never bother trying it again without calling them poste
haste. Especially not when it's something as important as a depth
transducer.

-Bill