wrote:

On Fri, 12 Oct 2007 20:39:24 -0700, "Lew Hodgett"
wrote:


"Alex" wrote:


At the risk of (1) being exposed as a boatbuilding dunce or (2) even
worse, starting a thread as hotly contested as the hypotheteical 40'
vertical sal****er still, the comment about Dow Corning 795 leads me to
ask a (naive) question.

Could this high-strength, high-grab, somewhat flexible adhesive, or one
somewhat similar, be used to build a boat from aluminum panels, somewhat
the way epoxy is used for stitch-and-glue with plywood?

I realize there would have to be a lot of modifications to the
construction process. But is the concept reasonable with today's
adhesives? Certainly DC 795 seems to have no trouble bonding to aluminum.

(Dow says 795 is not for use on surfaces continuously under water, so that
would be a problem for anything except trailered boats or dinghy-type
uses. But again, I'm just raising the question, not proposing it as a real
option. And there may be other adhesives that would be OK for underwater
applications.)


You might want to contact SikaFlex tech service (Metro Detroit) and ask some
of these questions.

Lew



Years ago I read an article about a British engineering student who
built a race car as his "Theses". He wanted the body to fail
progressively and ended up gluing the aluminum body panels together
using an adhesive made by locktite. You might have a look at their
literature.


Bruce in Bangkok
(brucepaigeATgmailDOTcom)


Loctite (now owned by another company)U-05FL 2 part urethane.. Great
bond to aluminum (with proper prep).

There is another guy I know of using methacrylate for the same concept.

You have to use rivets to hold the large panels in place until it cures
and to provide shear strength.

At the rate I am building mine, I'll be done in another year or so and
let you know how it works then. So far, it works well. The only issue is
the pot time, but that can be overcome with a bit of planning and some
help from friends.



--
“TANSTAAFL”

__________________________________________________ __________________________

But - there is a point where criticism, even offered in the guise of
love, moves past the point of correction and to the point of
destruction. It's a subtle line, but it exists.

On Sat, 13 Oct 2007 01:03:29 GMT, "Alex"
wrote:


Could this high-strength, high-grab, somewhat flexible adhesive, or one
somewhat similar, be used to build a boat from aluminum panels, somewhat the
way epoxy is used for stitch-and-glue with plywood?

Alex



There was a light airplane built with glued wing panels - they were
aluminum as I recall which is still flying in some numbers.
So it can be done

Brian W

On Sat, 13 Oct 2007 01:03:29 GMT, "Alex"
wrote:


"Bob" wrote in message
ups.com...

Dow COrning 795 aint your grandpa's silicone seal........... think
"structural" silicone. Really heavy duty industrial hold twin tower
windows in w/o fastners really thick kinda silicone.

get their spec sheet and check the lap strength for diffrent materials
and strech numbers. I used it when I fabricated my 7"x15"x 3/8"
polycarb dead lights. Min DC 795 thickness :1/8". Of course fastned
with ten 316L 1/4"x20 PH MS.

At the risk of (1) being exposed as a boatbuilding dunce or (2) even worse,
starting a thread as hotly contested as the hypotheteical 40' vertical
sal****er still, the comment about Dow Corning 795 leads me to ask a (naive)
question.

Could this high-strength, high-grab, somewhat flexible adhesive, or one
somewhat similar, be used to build a boat from aluminum panels, somewhat the
way epoxy is used for stitch-and-glue with plywood?

I realize there would have to be a lot of modifications to the construction
process. But is the concept reasonable with today's adhesives? Certainly DC
795 seems to have no trouble bonding to aluminum.

(Dow says 795 is not for use on surfaces continuously under water, so that
would be a problem for anything except trailered boats or dinghy-type uses.
But again, I'm just raising the question, not proposing it as a real option.
And there may be other adhesives that would be OK for underwater
applications.)

Alex


That is how I built my airplane floats. Stiched together with blind
rivets and seams sealed with sikaflex 1A construction adhesive.

On Oct 12, 6:03 pm, "Alex"
wrote:
"Bob" wrote in message


At the risk of (1) being exposed as a boatbuilding dunce or (2) even worse,
starting a thread as hotly contested as the hypotheteical 40' vertical
sal****er still, the comment about Dow Corning 795 leads me to ask a (naive)
question.

Could this high-strength, high-grab, somewhat flexible adhesive, or one
somewhat similar, be used to build a boat from aluminum panels, somewhat the
way epoxy is used for stitch-and-glue with plywood?
Alex


Good idea..... Years ago I worked at a research oyster hatchery. They
used silicone seal to bond 200 gallon glass tanks. The tanks were set
into a 2"x4" wood frame. But the glass panes were all bonded with
clear silicone seal...... never a failure

I would think 5200 might work for a quick boat. I used it to patch all
the lose rivits and holes in an 18' Grumman canoe that a bunch of
drunk cowboys abused for 10 years.

Bob