aluminum hull protection
 

I have an aluminum hull which I have sandblasted and would like to know the best approach to sealing the keel/hull seam for added protection against any pin hole leaks that might exist prior to primer. I've heard of many primers and would like to know which one works the best, zinc chromate which will eventually be phased (inorganic I believe) or organic or other primers like Dupont's Variprime. The methods of barrier coating seem overwhleming! I want to do it right before I proceed,.

My two cents in this scenario would be tar epoxy after the selected primer then finish up fairing the area. Honestly, I am new to this being my first boat and have time to get it right the first time. Anyone that would like to weigh in on this that has good credentials like Steve, is welcomed.

John

aluminum hull protection
 

On Sat, 12 Sep 2009 17:52:03 +0100, EASI54
wrote:


I have an aluminum hull which I have sandblasted and would like to know
the best approach to sealing the keel/hull seam for added protection
against any pin hole leaks that might exist prior to primer. I've heard
of many primers and would like to know which one works the best, zinc
chromate which will eventually be phased (inorganic I believe) or
organic or other primers like Dupont's Variprime. The methods of
barrier coating seem overwhleming! I want to do it right before I
proceed,.

My two cents in this scenario would be tar epoxy after the selected
primer then finish up fairing the area. Honestly, I am new to this
being my first boat and have time to get it right the first time.
Anyone that would like to weigh in on this that has good credentials
like Steve, is welcomed.

John

Normally some sort of etching primer is used as a first coat as
aluminum corrodes almost immediately after being cleaned. However, two
part paints frequently cannot be applied over etching primer.
I would suggest that you contact a marine paint maker for suggestions
for a paint schedule.

By the way, what makes you believe that you have "pin hole leaks"?
Usually leaks are patched or welded up before painting.

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

aluminum hull protection
 

EASI54 wrote:
/snip/
Anyone that would like to weigh in on this that has good credentials
like Steve, is welcomed.

John

*~*

That's the drawback of asking advice on newsgroups.
You are never sure of the value of responses - the biggest poseurs will
tell you they have background. So, there is no substitute for judgment
and cross-checking.

Brian W

Thank you Bruce for replying.

You never can be too sure with a twenty year old hull and evidence of patch work with epoxy delamination in few areas. Just some reassurance.

John

aluminum hull protection
 

EASI54 wrote:
I have an aluminum hull which I have sandblasted and would like to know
the best approach to sealing the keel/hull seam for added protection
against any pin hole leaks that might exist prior to primer. I've heard
of many primers and would like to know which one works the best, zinc
chromate which will eventually be phased (inorganic I believe) or
organic or other primers like Dupont's Variprime. The methods of
barrier coating seem overwhleming! I want to do it right before I
proceed,.

My two cents in this scenario would be tar epoxy after the selected
primer then finish up fairing the area. Honestly, I am new to this
being my first boat and have time to get it right the first time.
Anyone that would like to weigh in on this that has good credentials
like Steve, is welcomed.

John





An aluminum filled moisture cured urethane (MCU coatings) - several
coats. Then an epoxy but NOT a coal tar epoxy.

email me privately for more specifics - --- this
is a non-commercial news group!


paul oman
progressive epoxy polymers, inc.
www.epoxyproducts.com/marine.html

see www.epoxyproducts.com/aluthane.html for more on MCU coatings.

aluminum hull protection
 

On Sun, 13 Sep 2009 13:40:22 +0100, EASI54
wrote:


Bruce In Bangkok;743651 Wrote:
On Sat, 12 Sep 2009 17:52:03 +0100, EASI54
wrote:
-

I have an aluminum hull which I have sandblasted and would like to
know
the best approach to sealing the keel/hull seam for added protection
against any pin hole leaks that might exist prior to primer. I've
heard
of many primers and would like to know which one works the best, zinc
chromate which will eventually be phased (inorganic I believe) or
organic or other primers like Dupont's Variprime. The methods of
barrier coating seem overwhleming! I want to do it right before I
proceed,.

My two cents in this scenario would be tar epoxy after the selected
primer then finish up fairing the area. Honestly, I am new to this
being my first boat and have time to get it right the first time.
Anyone that would like to weigh in on this that has good credentials
like Steve, is welcomed.

John-

Normally some sort of etching primer is used as a first coat as
aluminum corrodes almost immediately after being cleaned. However, two
part paints frequently cannot be applied over etching primer.
I would suggest that you contact a marine paint maker for suggestions
for a paint schedule.

By the way, what makes you believe that you have "pin hole leaks"?
Usually leaks are patched or welded up before painting.

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

Thank you Bruce for replying.

You never can be too sure with a twenty year old hull and evidence of
patch work with epoxy delamination in few areas. Just some
reassurance.

John

If you are saying that you have an aluminum boat that developed a leak
and that leak was repaired by "gluing" a patch over the hole with
epoxy and you are doing a refit then I really would suggest that you
fix it right. Take off the epoxy patch and weld up the hole.

Of course, if this is an aluminum "fishing boat", open, old and not
worth much, then the epoxy "scab patching" makes sense and I would
suggest that just grind off any patches that are coming loose and re
do them.

What is this thing anyway?

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)