Gorilla Glue?

I agree on the first part, but my preference is to have it welded.

gyrobob wrote:

How about crafting the pieces so they fit very precisely, etching the
aluminum immediately prior to applying T-88 epoxy, using lots of
rivets, and then as a final step -- sealing it all with gas tank
sealer that coats the inside of the tank?

Richard Lamb wrote One fellow told me about the
way he built a gas tank. Formed endplates and a wrapper - all about
.040 5052-H32. Then etched and assembled with PL-1 (polyurethane
construction adhesive) and a few pop rivets. Flanges faced out, btw.
He said it worked well, had so many hours on it. But I never had the
guts to try it.

Gyro,

althogh T-88 is waterproof. It is not water vaopor proof. Therfore water
being 2 parts oxygen to 1 part hyrdrogen will allow oxide to form and
weaken the joint. as a matter of fact the low tech test that boeing uses
is called the wedge test, which consists of the test coupon being
etched, primed and bonded as a lap joint, A wedge is then driven between
the lap and the end of the split marked, then it is set in a high
humidity environment with I believe and incandesent light on it. if the
debond line progresses any further in x amount of time then the bond fails.

I will research more over the weekend and post more on monday as ya
got me wondering about it it now.

Drat.



"Ron Natalie" wrote
How rapidly does the oxide form on aluminum? Seconds? Minutes? Hours?
Almost instantaneous.

If you had your parts all ready to go, then hit them with some
scotchbrite to get them oxide-less and satiny-shiny, and slathered on
the T-88 within a few seconds, would that allow the glue to bond to
the aluminum and not to an oxide layer?
Nope.

How rapidly does the oxide form on aluminum? Seconds? Minutes?
Hours?

I don't have it handy but Boeings BAC 5555 spec for anodizing specifies
something like less than 30 seconds between tanks. The oxide layer forms very
quickly. Aluminum is a very reactive metal.

If all you want to do is make a fuel tank just pop-rivet the thing together
with enough rivets to hold the thing together and seal the joint as you rivet
with Pro-Seal. It stands up to the fuel just fine. The BD-5 wet wings are
made this way and don't leak if built with a bit of care.

For structural bonding of aluminum there is no substitute for the proper
anodizing process. If properly anodized, per BAC 5555 or similar, the parts
can sit on the shelf for a long time before they are bonded. For us "poor
boys" that just want a beter bond on non structural parts look up the FPL
(Forest Products Labrotories) etch. The only problem with this is how to
dispose of the left over Chromic acid.......

This is some good stuff - the aluminum will fail before the joint...

http://www.hernonmfg.com/categories/charts/react.htm

http://www.hernonmfg.com/tds/td-761.pdf

--
Dan D.



..
"seantrost" wrote in message m...
Gyro,
I have read about aluminum bonding as told by I believe jack lambe
(spelling?) and the consensus is that unless you are able to etch, prime and
then bond with a high quality control then bonding aluminum to aluminum is
not recomended. The cause for failure of the bond is that the bond line is
to the aluminum oxide that forms rather quickly on the surface of the
aluminum and not the base metal. therefore a weak bond and one that most
likely will fail.

As to wood to aluminum I have not a clue, I have seen aluminum plates bonded
to wood as a bearing plate and as such would really not be adversely
effected by a failure of the bond line as the bolt would hold in place at
any rate.

Fiberboard I can reasonable say will fail before t-88.

as to the flexibility the flexural modulus of t-88 is 375,000 and that would
compare with nylon at 380,000 or abs plastic at 405,000, stiff but not
really brittle.

all the best
Sean "dusting off the sawdust" Trost
"gyrobob" wrote in message
om...
Does T-88 cure to a flexible state or a brittle state?

How much flexing can it take when cured?

I know it is poor craftsmanship to glue different materials together,
but how well would it handle gluing two layers of different material
together, with the materials having different rates of expansion. For
example, plastic glued to aluminum, two different thicknesses of
aluminum glued together, fiberboard and spruce, etc.

Thanks for any info.

That looks like some *really* good stuff.

Not recommended for plastics and keep it away from motor oil and brake fluid
(or at least don't immerse for 30 days at almost 200 degrees F like they
did).
Strangely enough, immersing in unleaded gasoline gives it 110% strength!

Eric

"Blueskies" wrote in message
gy.com...
This is some good stuff - the aluminum will fail before the joint...

http://www.hernonmfg.com/categories/charts/react.htm

http://www.hernonmfg.com/tds/td-761.pdf

--
Dan D.

It may be good stuff, but at $190 per liter, I think I'll pass.


"Blueskies" wrote in message news This is some good stuff - the aluminum will fail before the joint...
http://www.hernonmfg.com/categories/charts/react.htm
http://www.hernonmfg.com/tds/td-761.pdf --
Dan D.