Silicon attenuates too much (
http://scitation.aip.org/getabs/serv...cvips&gifs=yes )
, epoxy is much better. Mineral oil is very good, but it can be
messy/complicated. Ideally you want to match the speed of sound in the
materials to water to avoid high power reflections at the
transducer-epoxy-hull-water interfaces.

To bleed air bubbles from the epoxy, take an orbital sander put on a felt
pad and place it on the other side of the hull opposite the epoxy. The
vibration will bleed out the bubbles, do this before applying the transducer
and the epoxy must still be unhardened. Epoxy does sheer off in one nice big
chunk when removing. Also be sure to fill in the air bubbles in the
fiberglass mat of the hull if there are any.

Make sure you get a license before doing this!



wrote in message
...
On Fri, 29 Feb 2008 10:28:20 -0800, "Capt. JG"
wrote:

wrote in message
. ..
On Fri, 29 Feb 2008 09:39:45 -0800, "Capt. JG"
wrote:

"Phil Abuster" wrote in message
...
Transducers will work throught the hull from the inside if properly
mounted in a bed of epoxy.

Here's one example:

http://www.starmarinedepot.com/Rayma...ransducer.html

I've mounted a thru-hull inside the hull bedding in epoxy (make sure
no
air bubbles in epoxy) and it works great.


They don't need to be mounted in epoxy (those not going through the
hull)
to
work properly. They do need to not shoot through air. If you mount them
in
epoxy, you'll find it difficult to remove them if they fail.

Not difficult at all.

Well, it's not impossible, but it certainly easier if you don't have to do
it at all.


Actually, it's easier to remove one that is epoxied than it is to
remove all traces of silicone from one that is set in Silicone. I
removed one for a friend using a hammetr and a chisel. Took a lot less
time than when I had to deal with silicone residue n my own boat to
replace the install using epoxy. For that matter, if I was to do it
again, I wouldn't even worry about the existing puck, and would just
mount the new one in a different spot, like an inch away from the old
one. No removal is really needed.

In the method I
mentioned elsewhere, you don't have to be concerned with bubbles in the
epoxy because the transducer sits in mineral oil in a stable container
(one
that is epoxied to the hull in the appropriate spot).

The epoxy may not have bubbles in it to begin with, and if it does, it
is a very simple matter to remedy.

I'd really like to know how...

a sewing needle works very well.

how can you be sure one doesn't develop after
it hardens? I thought you said that it happened to you? Maybe I mis-read
that... a friend is contemplating the exact same type of installation.

No. The problem I had was after a few years, my silicone installation
apparently started to separate from the hull slightly (clear silicone
is NOT a good adhesive) and formed a gap that caused intermitant loss
of readings. I redid the install with epoxy and everything is fine.
The "possibility" of air bubbles is slight if you pour carefully, and
as I said, easy to remedy if there is a bubble or two.

I've done the old "tube full of oil" method, but its a lot more work,
and requires a spot with more space. It's also more vulnerable to
something knocking into it and causing it to leak. BTDT. That's why I
stopped doing them that way.



The main issue is
finding a spot via testing (as another suggested) before placing the
transducer holder.

"Phil Abuster" wrote in message
...
Silicon attenuates too much (
http://scitation.aip.org/getabs/serv...cvips&gifs=yes )
, epoxy is much better. Mineral oil is very good, but it can be
messy/complicated. Ideally you want to match the speed of sound in the
materials to water to avoid high power reflections at the
transducer-epoxy-hull-water interfaces.

To bleed air bubbles from the epoxy, take an orbital sander put on a felt
pad and place it on the other side of the hull opposite the epoxy. The
vibration will bleed out the bubbles, do this before applying the
transducer and the epoxy must still be unhardened. Epoxy does sheer off in
one nice big chunk when removing. Also be sure to fill in the air bubbles
in the fiberglass mat of the hull if there are any.

Make sure you get a license before doing this!


Huh? How do you do that with the boat in the water... without electrocuting
yourself or the nearby diver? And, how do you do it after the epoxy has
hardened?

License??

--
"j" ganz @@
www.sailnow.com

"Capt. JG" wrote in message
...
"Phil Abuster" wrote in message
...
Silicon attenuates too much (
http://scitation.aip.org/getabs/serv...cvips&gifs=yes )
, epoxy is much better. Mineral oil is very good, but it can be
messy/complicated. Ideally you want to match the speed of sound in the
materials to water to avoid high power reflections at the
transducer-epoxy-hull-water interfaces.

To bleed air bubbles from the epoxy, take an orbital sander put on a felt
pad and place it on the other side of the hull opposite the epoxy. The
vibration will bleed out the bubbles, do this before applying the
transducer and the epoxy must still be unhardened. Epoxy does sheer off
in one nice big chunk when removing. Also be sure to fill in the air
bubbles in the fiberglass mat of the hull if there are any.

Make sure you get a license before doing this!


Huh? How do you do that with the boat in the water... without
electrocuting yourself or the nearby diver? And, how do you do it after
the epoxy has hardened?

License??

--
"j" ganz @@
www.sailnow.com




You wouldn't install a thru hull with the boat in the water would you?

The most interesting use I've found for the display type depth finder is to
press it against your belly or head and use it as an ultrasound scanner.
It's really neat to see body parts moving (such as your heart, lungs) or
check bladder fullness with it. Much cheaper than a doctor!

The license is so you don't electrocute yourself.

Salty has the whole process down pat. He must have a license.

"Phil Abuster" wrote in message
...

"Capt. JG" wrote in message
...
"Phil Abuster" wrote in message
...
Silicon attenuates too much (
http://scitation.aip.org/getabs/serv...cvips&gifs=yes )
, epoxy is much better. Mineral oil is very good, but it can be
messy/complicated. Ideally you want to match the speed of sound in the
materials to water to avoid high power reflections at the
transducer-epoxy-hull-water interfaces.

To bleed air bubbles from the epoxy, take an orbital sander put on a
felt pad and place it on the other side of the hull opposite the epoxy.
The vibration will bleed out the bubbles, do this before applying the
transducer and the epoxy must still be unhardened. Epoxy does sheer off
in one nice big chunk when removing. Also be sure to fill in the air
bubbles in the fiberglass mat of the hull if there are any.

Make sure you get a license before doing this!


Huh? How do you do that with the boat in the water... without
electrocuting yourself or the nearby diver? And, how do you do it after
the epoxy has hardened?

License??

--
"j" ganz @@
www.sailnow.com




You wouldn't install a thru hull with the boat in the water would you?

No, but it sounds like you would. We were talking about sounders that shoot
through the hulls.

The most interesting use I've found for the display type depth finder is
to press it against your belly or head and use it as an ultrasound
scanner. It's really neat to see body parts moving (such as your heart,
lungs) or check bladder fullness with it. Much cheaper than a doctor!

Sounds like you wouldn't find much if you point it at your head! LOL

The license is so I don't electrocute myself.

I agree!

Salty has the whole process down pat. He must have a brain.




--
"j" ganz @@
www.sailnow.com

On Fri, 29 Feb 2008 19:07:31 -0500, WaIIy wrote:

It's a fantastic adhesive.

You just need to know how to apply it.

Please do tell us.

Wally stated:
Final cleaning with isopropyl (rubbing) alcohol works well.

Isopropyl alcohol leaves quite a lot of residue unless rubbed dry with a
clean cloth.

You can dip your finger in IPA to work it if you want to smooth a seam,
wipe a drip, etc. Also good for cleanup before initial set.

Why on earth would you want to waste a good India Pale Ale that way???

Red

"Capt. JG" wrote in message
...

Sounds like you wouldn't find much if you point it at your head! LOL


If it were pointed toward your rectum we would find an assortment of
interesting objects, including your head! LOL

"Jakob Krutzfeld" wrote in message
...

"Capt. JG" wrote in message
...

Sounds like you wouldn't find much if you point it at your head! LOL


If it were pointed toward your rectum we would find an assortment of
interesting objects, including your head! LOL


It sure doesn't take long for people to realize Jon Boy is gay. Har har har!

WaIIy wrote:
On Fri, 29 Feb 2008 14:01:20 -0500, wrote:

clear silicone
is NOT a good adhesive)

It's a fantastic adhesive.

You just need to know how to apply it.

Ps - Silicone is not gas and oil friendly.


NASA spent a bazillion bucks trying to find a suitable adhesive for the
heat shield tiles on the shuttle, ended up using good ol' silicone, (RTV
if you want to sound tech savvy).

Cheers
Marty

wrote:

NASA spent a bazillion bucks trying to find a suitable adhesive for the
heat shield tiles on the shuttle, ended up using good ol' silicone, (RTV
if you want to sound tech savvy).

Cheers
Marty

Adhesive Bond Used on Columbia Space Shuttle Known to be Less Heat
Resistant, Says UB Materials Engineer

[snip PHD's pontificating]


Some days I wonder if they hand out PHDs with cornflakes. Typical
adhesives only good to 250F? What a crock. Just look at the use of high
temp silicones to gasket any modern internal combustion engine. Look
even further at the products manufactured by Loctite and used to both
fix an seal numerous fasteners and surfaces in relatively high
temperature places in motors manufactured by Rotax.

From a personal empirical point of view; I had bonded cement tiles to
drywall to act as a heatshield behind a wood fired cook stove in my
house, following a house fire, within two feet of the nearest tiles, the
tiles still could not be pulled of the wall by hand. A wrecking bar had
to be employed and the drywall was pulled apart. BTW, the fire had
nothing to do with the cook stove, but it did lead to about $200k in
repairs.

Cheers
Marty