My outboard, 20hp Honda, jumped off my transom yesterday and hit the
pavement at 20-25mph. No critical damage but knocked a gapping hole,
the size of a golf ball, in the cast aluminum lower pan, the one below
the power head, next to the tiller handle. Fortunately, I have the
knocked out piece and it fits back in the hole perfectly. My first
thought was to have it tig welded. But it's in a really tight place
and I doubt I'd get a good weld without removing the pan which means
taking the whole power head off. I could tack weld it but that'd leave
a crack that could leak splashing water, not to mention look kinda bad
(as if it doesn't look bad enough).
So now I'm thinking about just using epoxy to glue it in. Mind you,
it doesn't need to be terribly strong. On the other hand, I don't want
it to fall out by just jostling either.
Anybody ever tried epoxy to glue cast aluminum parts back together?
How well will it hold? And for how long?
Thanks in advance,
Phantman

lid wrote:
My outboard, 20hp Honda, jumped off my transom yesterday and hit the
pavement at 20-25mph. No critical damage but knocked a gapping hole,
the size of a golf ball, in the cast aluminum lower pan, the one below
the power head, next to the tiller handle. Fortunately, I have the
knocked out piece and it fits back in the hole perfectly. My first
thought was to have it tig welded. But it's in a really tight place
and I doubt I'd get a good weld without removing the pan which means
taking the whole power head off. I could tack weld it but that'd leave
a crack that could leak splashing water, not to mention look kinda bad
(as if it doesn't look bad enough).
So now I'm thinking about just using epoxy to glue it in. Mind you,
it doesn't need to be terribly strong. On the other hand, I don't want
it to fall out by just jostling either.
Anybody ever tried epoxy to glue cast aluminum parts back together?
How well will it hold? And for how long?
Thanks in advance,
Phantman

Epoxy won't do it very well, but there are several urethanes and
acrylates which will.

Try www.loctite.com for more. Look at u50fl for a urethane. They have a
50 ml tube and mixing nozzle that might be the right size for what you need.

They have several acrylate type adhesives that work well also, but I
can't come up with any suggestions off the top of my head.


--
“No battle plan survives first contact with the enemy”
Sun Tzu

PhantMan wrote:
Anybody ever tried epoxy to glue cast aluminum parts back together?

dazed and confuzzed wrote:
Try www.loctite.com for more. Look at u50fl for a urethane.

Thanks. Is that a transposition? I found u05fl. Says it can be used on
metal, wood, etc.

They have several acrylate type adhesives that work well also

I went through their selection process (nice website that) and it
pointed me to Depend 330, a no mix adhesive. The tech sheet says
"Technology = Acrylic" and under that it says "Chemical Type =
Urethane methacrylate ester". Soooo.... I guess it's an Acrylate,
huh? (obviously, the tech sheet is beyond me).
Also says it's good to bond metal, wood, ferrite, etc. then goes on to
talk about bond strength of grit blasted mild steel. Didn't mention
cast aluminum but I assume it'll work on that as well.

Anyhow, thanks for pointing me there.

PhantMan

lid wrote:
PhantMan wrote:

Anybody ever tried epoxy to glue cast aluminum parts back together?


dazed and confuzzed wrote:

Try www.loctite.com for more. Look at u50fl for a urethane.


Thanks. Is that a transposition? I found u05fl. Says it can be used on
metal, wood, etc.
Yes, it was a trasposition.


They have several acrylate type adhesives that work well also


I went through their selection process (nice website that) and it
pointed me to Depend 330, a no mix adhesive. The tech sheet says
"Technology = Acrylic" and under that it says "Chemical Type =
Urethane methacrylate ester". Soooo.... I guess it's an Acrylate,
huh?
Yep

(obviously, the tech sheet is beyond me).
Also says it's good to bond metal, wood, ferrite, etc. then goes on to
talk about bond strength of grit blasted mild steel. Didn't mention
cast aluminum but I assume it'll work on that as well.

Keep looking. You'll find some that are excellent on aluminum.

Anyhow, thanks for pointing me there.

PhantMan



--
“No battle plan survives first contact with the enemy”
Sun Tzu

Your simplest solution would be to grind a moderate bevel on the loose
piece, get it welded to the extent possible, and then caulk the whole seam
with 5200. Don't go hi tech. - Bill
wrote in message
...
My outboard, 20hp Honda, jumped off my transom yesterday and hit the
pavement at 20-25mph. No critical damage but knocked a gapping hole,
the size of a golf ball, in the cast aluminum lower pan, the one below
the power head, next to the tiller handle. Fortunately, I have the
knocked out piece and it fits back in the hole perfectly. My first
thought was to have it tig welded. But it's in a really tight place
and I doubt I'd get a good weld without removing the pan which means
taking the whole power head off. I could tack weld it but that'd leave
a crack that could leak splashing water, not to mention look kinda bad
(as if it doesn't look bad enough).
So now I'm thinking about just using epoxy to glue it in. Mind you,
it doesn't need to be terribly strong. On the other hand, I don't want
it to fall out by just jostling either.
Anybody ever tried epoxy to glue cast aluminum parts back together?
How well will it hold? And for how long?
Thanks in advance,
Phantman

"Bill Kreamer" wrote:
Your simplest solution would be to grind a moderate bevel on the loose
piece

Actually, all the jagged edges match up perfectly and the piece fits
back together like a jig saw puzzle. Held in place, you can barely see
the seam where it fits together. I was thinking it'd be better to glue
it back just the way it is. Am I wrong for a reason I'm unaware?

get it welded to the extent possible, and then caulk the whole seam
with 5200.

In fact, I'd received that very advice at the coffee shop this
morning. Except in reverse order. Stick it together with 5200 (I was
told it's a Urethane based product) to bond and seal it, then
tack/spot weld it where possible for added strength.

Don't go hi tech

..... uh.... I dunno Bill, around here, 3M 5200 IS high tech lol!

Thanks :-)

PhantMan

dazed and confuzzed wrote:
Try www.loctite.com for more. Look at u50fl for a urethane.


D&C,
What's your opinion of 3M's 5200 for this? (I already have a tube of
it).

PhantMan

On Wed, 12 Oct 2005 20:04:34 -0500, lid wrote:

My outboard, 20hp Honda, jumped off my transom yesterday and hit the
pavement at 20-25mph. No critical damage but knocked a gapping hole,
the size of a golf ball, in the cast aluminum lower pan, the one below
the power head, next to the tiller handle. Fortunately, I have the
knocked out piece and it fits back in the hole perfectly. My first
thought was to have it tig welded. But it's in a really tight place
and I doubt I'd get a good weld without removing the pan which means
taking the whole power head off. I could tack weld it but that'd leave
a crack that could leak splashing water, not to mention look kinda bad
(as if it doesn't look bad enough).
So now I'm thinking about just using epoxy to glue it in.

Check out JB Weld. The stuff is absolutely phenominal. I've heard of
people bonding pieces of engine block back on with it and running the
engine for years.

Corky Scott

lid wrote:
dazed and confuzzed wrote:

Try www.loctite.com for more. Look at u50fl for a urethane.



D&C,
What's your opinion of 3M's 5200 for this? (I already have a tube of
it).

PhantMan

never tried it with aluminum. HOWEVER:

THe issue with aluminum is that the bond is usually to the oxide layer
that forms rather than to the aluminum itself. Some folks have had good
luck with epoxy and some form of "brillo" type pad or sandpaper to break
this layer so that the epoxy can bond to the aluminum. With a cast part,
you might get enough"tooth" to make 5200 work.

I dunno, never having tried to bond aluminum with 5200.

Just because it is a urethane doesn't mean it will bond well to aluminum.

I'd stay away from welding after bonding though.

I think that the advice to TIG the parts is probably the best for a long
term solution. You can sand or grind the seam flat, and with a little
paint, no one will know.

--
“No battle plan survives first contact with the enemy”
Sun Tzu

THe issue with aluminum is that the bond is usually to the oxide layer
that forms rather than to the aluminum itself. Some folks have had good
luck with epoxy and some form of "brillo" type pad or sandpaper to break
this layer so that the epoxy can bond to the aluminum. With a cast part,
you might get enough"tooth" to make 5200 work.

If it breaks and he puts it back a few days later there won't be
an oxide layer yet.


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