Courtney Thomas wrote:

Richard Lamb wrote:

MMC wrote:

Do you have to etch before using this product?
"Richard Lamb" wrote in message
ink.net...

RW Salnick wrote:


If it were me, I'd use a 2-part urethane on it. The finish is superb,
and that stuff is *HARD*. Also, when patch/repairs are needed, it
will
be easier to match the existing finish.

bob

Rusty wrote:


I am having an aluminum dodger built for my sailboat. I want it to be
white when it's finished.

The question is, should I have it powder coated or painted? Either is
possible, and not out of line for cost. I am looking for durability,
long-term looks, and ability to make minor repairs.

Any thoughts either for or against each option?

Thanks,
Rusty



Power coat can chip leaving water access under the film.

My preferred treatment for aluminum is Epi-Bond.

Two-part epoxy primer used in aircraft service.

Paint with two-part urethane after several weeks cure.


Richard





Of course you can etch first. It doesn't hurt anything.
But all it really needs is a good rub with scotchbrite
to clean the surfaces.

Mix epi-bond and catalyst - then add epoxy thinner to thin to
spraying consistency.

SPRAY the epi-bond rather than brush it.
It sets up too fast to flow out smooth and will show brush marks.

The stuff cures hard in less than an hour.
But it will continue to cure for quite a while.

I'd wait a few weeks before final painting.
Dunno if that's necessary or not, but not bad advice.

A quart kit will probably cover your dodger.

Try it, you'll like it...


Richard


Apologies, but I neglected to ask......

Would epi-bond also equally satisfactory for a stainless bimini frame
and would it look the same as on aluminum ?

Thanks again,

Courtney

Probably so, Courtney. We use it on 4130, alumimum, stainless, ???

Ought to look the same baring any surface texture differences in the
metals.

Richard

Richard Lamb wrote:
Courtney Thomas wrote:

Richard Lamb wrote:

MMC wrote:

Do you have to etch before using this product?
"Richard Lamb" wrote in message
ink.net...

RW Salnick wrote:


If it were me, I'd use a 2-part urethane on it. The finish is
superb,
and that stuff is *HARD*. Also, when patch/repairs are needed, it
will
be easier to match the existing finish.

bob

Rusty wrote:


I am having an aluminum dodger built for my sailboat. I want it
to be
white when it's finished.

The question is, should I have it powder coated or painted?
Either is
possible, and not out of line for cost. I am looking for durability,
long-term looks, and ability to make minor repairs.

Any thoughts either for or against each option?

Thanks,
Rusty



Power coat can chip leaving water access under the film.

My preferred treatment for aluminum is Epi-Bond.

Two-part epoxy primer used in aircraft service.

Paint with two-part urethane after several weeks cure.


Richard






Of course you can etch first. It doesn't hurt anything.
But all it really needs is a good rub with scotchbrite
to clean the surfaces.

Mix epi-bond and catalyst - then add epoxy thinner to thin to
spraying consistency.

SPRAY the epi-bond rather than brush it.
It sets up too fast to flow out smooth and will show brush marks.

The stuff cures hard in less than an hour.
But it will continue to cure for quite a while.

I'd wait a few weeks before final painting.
Dunno if that's necessary or not, but not bad advice.

A quart kit will probably cover your dodger.

Try it, you'll like it...


Richard



Apologies, but I neglected to ask......

Would epi-bond also equally satisfactory for a stainless bimini frame
and would it look the same as on aluminum ?

Thanks again,

Courtney


Probably so, Courtney. We use it on 4130, alumimum, stainless, ???

Ought to look the same baring any surface texture differences in the
metals.

Richard

A final question....I don't know how my 50' aluminum mast was previouly
finished, but to obtain durable results, how should it now be prepared,
given that it now has irregular areas of 'peeling' and coating absence
due of abrasion, etc. ?

Should it be taken back to bare metal [whew !] or what, and if yes, what
method would be easiest and which the least expensive, hopefully the
same :-)

Gratefully,
Courtney

Courtney Thomas wrote:


A final question....I don't know how my 50' aluminum mast was previouly
finished, but to obtain durable results, how should it now be prepared,
given that it now has irregular areas of 'peeling' and coating absence
due of abrasion, etc. ?

Should it be taken back to bare metal [whew !] or what, and if yes, what
method would be easiest and which the least expensive, hopefully the
same :-)

Gratefully,
Courtney

That one is a little outside my crystal ball's dynamic range.
I'd have to look at it to make any real recommendations.

If the present finish is flaking or chipping, it would have to be
cleaned up before painting. Or if the surface is painted with something
that will dissolve with lacquer thinner?

For an anodized finish, I'd probably just scotch bite and spray...

Richard

Richard Lamb wrote:
Courtney Thomas wrote:


A final question....I don't know how my 50' aluminum mast was previouly
finished, but to obtain durable results, how should it now be prepared,
given that it now has irregular areas of 'peeling' and coating absence
due of abrasion, etc. ?

Should it be taken back to bare metal [whew !] or what, and if yes, what
method would be easiest and which the least expensive, hopefully the
same :-)

Gratefully,
Courtney

That one is a little outside my crystal ball's dynamic range.
I'd have to look at it to make any real recommendations.

If the present finish is flaking or chipping, it would have to be
cleaned up before painting. Or if the surface is painted with something
that will dissolve with lacquer thinner?

For an anodized finish, I'd probably just scotch bite and spray...

Richard

Richard,

The only thing you have to look out for with powder coating is if the
metal is heat treated. If the metal was heat treated the baking part of
the powder coating process can cause big problems with the integrity of
the metal. This happened on several occasions to people who had scuba
tanks powder coated, they blew up. If their's no heat treating involved
it's probably not a problem.

Got some numbers (temperatures) for this one? Without digging out the data,
my impression is that baking the paint happens at a few hundred degrees F
and heat treating at much higher temperatures.

Were the tanks pressurized when baked, or did they blow up later?

Roger

http://home.insightbb.com/~derbyrm

"Capt John" wrote in message
oups.com...

The only thing you have to look out for with powder coating is if the
metal is heat treated. If the metal was heat treated the baking part of
the powder coating process can cause big problems with the integrity of
the metal. This happened on several occasions to people who had scuba
tanks powder coated, they blew up. If their's no heat treating involved
it's probably not a problem.

'High Temperatures'? You must be thinking of iron, copper, etc.

Not aluminum. In fact there are many alloys which are room-temperature
heat treated.

bob
(refugee of both ALCOA and Kaiser Aluminum)


derbyrm wrote:
Got some numbers (temperatures) for this one? Without digging out the data,
my impression is that baking the paint happens at a few hundred degrees F
and heat treating at much higher temperatures.

Were the tanks pressurized when baked, or did they blow up later?

Roger

http://home.insightbb.com/~derbyrm

"Capt John" wrote in message
oups.com...

The only thing you have to look out for with powder coating is if the
metal is heat treated. If the metal was heat treated the baking part of
the powder coating process can cause big problems with the integrity of
the metal. This happened on several occasions to people who had scuba
tanks powder coated, they blew up. If their's no heat treating involved
it's probably not a problem.

Sure, I know about "ice box rivets," but do dive tanks come in that kind of
aluminum?

Roger (who does associate heat treatment with iron and copper)

http://home.insightbb.com/~derbyrm

"RW Salnick" wrote in message
...
'High Temperatures'? You must be thinking of iron, copper, etc.

Not aluminum. In fact there are many alloys which are room-temperature
heat treated.

bob
(refugee of both ALCOA and Kaiser Aluminum)


derbyrm wrote:
Got some numbers (temperatures) for this one? Without digging out the
data, my impression is that baking the paint happens at a few hundred
degrees F and heat treating at much higher temperatures.

Were the tanks pressurized when baked, or did they blow up later?

Roger

http://home.insightbb.com/~derbyrm

"Capt John" wrote in message
oups.com...

The only thing you have to look out for with powder coating is if the
metal is heat treated. If the metal was heat treated the baking part of
the powder coating process can cause big problems with the integrity of
the metal. This happened on several occasions to people who had scuba
tanks powder coated, they blew up. If their's no heat treating involved
it's probably not a problem.

From what I remember reading of it the combination of temperature and
baking time weakened the tanks. They were not pressurized at the time,
the valves were removed. They ruptured during their first refill after
coating, SCUBA tanks are placed in water during filling, so if they go
their not like a bomb. Supposedly makes a hell of a noise and lots of
water thrown all over the place. But the energy is disapated in the
water.

Capt John wrote:

From what I remember reading of it the combination of temperature and
baking time weakened the tanks. They were not pressurized at the time,
the valves were removed. They ruptured during their first refill after
coating, SCUBA tanks are placed in water during filling, so if they go
their not like a bomb. Supposedly makes a hell of a noise and lots of
water thrown all over the place. But the energy is disapated in the
water.


Not necessarily. The water helps contain any fragments but is actually
there to cool the tank during filling.

There is a LOT of energy in a tank that has 3000 psi in it.

One example:

http://www.napsd.com/cscuba.htm

Note the bottom photo of the water tank that the scuba cylinder was in
at the time.

--

The Universe is utterly indifferent to the fact that you do not realize
the consequences of your actions
__________________________________________________ ______________________________
"A prudent man foresees the difficulties ahead and prepares for them;
the simpleton goes blindly on and suffers the consequences." - Proverbs 22:3

Most scuba tanks are 6061 aluminum and is precipitation hardened at around
200F for several days. Most powder coat needs 250 to 300F for about 20
minutes. Powder coating will weaken a tank some but a reasonable safety
margin for high pressure tanks is at least 3 to 1 so if it exploded the
powder coat may have contributed but there was another fault that was the
primary reason.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"derbyrm" wrote in message
news:1ytDf.521748$084.451397@attbi_s22...
Got some numbers (temperatures) for this one? Without digging out the
data, my impression is that baking the paint happens at a few hundred
degrees F and heat treating at much higher temperatures.

Were the tanks pressurized when baked, or did they blow up later?

Roger

http://home.insightbb.com/~derbyrm

"Capt John" wrote in message
oups.com...

The only thing you have to look out for with powder coating is if the
metal is heat treated. If the metal was heat treated the baking part of
the powder coating process can cause big problems with the integrity of
the metal. This happened on several occasions to people who had scuba
tanks powder coated, they blew up. If their's no heat treating involved
it's probably not a problem.