Touching up black anodized alu heat sinks

[oparr@hotmail.com]

You're bound to get scratches and scrapes when you buy these in bulk.
Even handling/installing them can result in occasional scratches. What
are some good marker/paint brands for touching them up?

I suspect the particular black dye or concentration used for coloring
after anodizing may play a part in this so a perfect match would be
next to impossible in all cases. Nevertheless, something like a black
Sharpie marker would be way off in most cases since it has too much
purple in it. IOW, some blacks will be more suitable than others.
Thanks!

 

[Lostgallifreyan]

"oparr@hotmail.com" <oparr@hotmail.com> wrote in news:1838bd41-e2b3-4f37-
8320-780131843ff0@o27g2000vbd.googlegroups.com:

You're bound to get scratches and scrapes when you buy these in bulk.
Even handling/installing them can result in occasional scratches. What
are some good marker/paint brands for touching them up?

I suspect the particular black dye or concentration used for coloring
after anodizing may play a part in this so a perfect match would be
next to impossible in all cases. Nevertheless, something like a black
Sharpie marker would be way off in most cases since it has too much
purple in it. IOW, some blacks will be more suitable than others.
Thanks!

Staedtler permanent lumocolor black might be good. Experiment with rubbing or
scratching with a fingernail right after applying to minimise it to only the
scratch to be filled. If it fails you can remove it with isopropanol to
retry or use something else. Those things are good for lots of stuff, filling
tiny flaws in etch resist before etching (red resists ferric chloride better
than black though), and for CD marking, drawing very fine tamper-revealing
markings on fixings, etc.. I've tried several types but those beat all else
so far. They're extremely good for darkening fine scorings on aluminium and
stainless steel when marking out for machining.

 

[Eeyore]

"oparr@hotmail.com" wrote:

You're bound to get scratches and scrapes when you buy these in bulk.
Even handling/installing them can result in occasional scratches. What
are some good marker/paint brands for touching them up?

I suspect the particular black dye or concentration used for coloring
after anodizing may play a part in this so a perfect match would be
next to impossible in all cases. Nevertheless, something like a black
Sharpie marker would be way off in most cases since it has too much
purple in it. IOW, some blacks will be more suitable than others.

Well I was going to suggest a Sharpie but you can also get permanent ink
markers for 'artwork' type use that have smaller tips and a denser dye.
Staedler comes to mind.

Graham

 

[Smitty Two]

In article
<1838bd41-e2b3-4f37-8320-780131843ff0@o27g2000vbd.googlegroups.com>,
"oparr@hotmail.com" <oparr@hotmail.com> wrote:

You're bound to get scratches and scrapes when you buy these in bulk.
Even handling/installing them can result in occasional scratches. What
are some good marker/paint brands for touching them up?

I suspect the particular black dye or concentration used for coloring
after anodizing may play a part in this so a perfect match would be
next to impossible in all cases. Nevertheless, something like a black
Sharpie marker would be way off in most cases since it has too much
purple in it. IOW, some blacks will be more suitable than others.
Thanks!

Aluminum oxide is as hard as diamond, fer christ's sake. It's not all
that easy to scratch if you're moderately careful. And the color isn't
something that's put on after anodizing, it's built in. There's some
great colors available these days besides black, BTW.

You're right about one thing - a Sharpie doesn't match. But there is a
marker out there somewhere that comes pretty close; it's advertised to
match. Sorry I don't remember the name of it, though.

It might be careless design, but I've seen anodizing used as the sole
electrical insulator in some applications. Touching up a scratch with a
marker is obviously inappropriate for those situations.

 

[Archimedes' Lever]

On Sun, 10 May 2009 17:37:06 -0700, Smitty Two <prestwhich@earthlink.net>
wrote:

In article
1838bd41-e2b3-4f37-8320-780131843ff0@o27g2000vbd.googlegroups.com>,
"oparr@hotmail.com" <oparr@hotmail.com> wrote:

You're bound to get scratches and scrapes when you buy these in bulk.
Even handling/installing them can result in occasional scratches. What
are some good marker/paint brands for touching them up?

I suspect the particular black dye or concentration used for coloring
after anodizing may play a part in this so a perfect match would be
next to impossible in all cases. Nevertheless, something like a black
Sharpie marker would be way off in most cases since it has too much
purple in it. IOW, some blacks will be more suitable than others.
Thanks!

Aluminum oxide is as hard as diamond, fer christ's sake. It's not all
that easy to scratch if you're moderately careful. And the color isn't
something that's put on after anodizing, it's built in. There's some
great colors available these days besides black, BTW.

You're right about one thing - a Sharpie doesn't match. But there is a
marker out there somewhere that comes pretty close; it's advertised to
match. Sorry I don't remember the name of it, though.

It might be careless design, but I've seen anodizing used as the sole
electrical insulator in some applications. Touching up a scratch with a
marker is obviously inappropriate for those situations.

"black anodized" is surely able to be scratched. "Hard anodized" is
the one that is unlikely to get scratched, unless it was not properly
applied.

 

[Archimedes' Lever]

On Sun, 10 May 2009 17:37:06 -0700, Smitty Two <prestwhich@earthlink.net>
wrote:

It might be careless design, but I've seen anodizing used as the sole
electrical insulator in some applications. Touching up a scratch with a
marker is obviously inappropriate for those situations.

That is HARD anodized. A simple black anodized heat sink is NOT
insulated at all. If it is insulated, then it is hard anodized.

Either way, your remark about touch up resulting in a non-insulative
"repair" is true.

 

[Archimedes' Lever]

On Sun, 10 May 2009 17:37:06 -0700, Smitty Two <prestwhich@earthlink.net>
wrote:

Aluminum oxide is as hard as diamond,

That is HARD anodizing.

fer christ's sake. It's not all
that easy to scratch if you're moderately careful.

Hard anodized Al has a surface that is harder than steel.

And the color isn't
something that's put on after anodizing, it's built in. There's some
great colors available these days besides black, BTW.

That is NOT hard anodizing. Those surfaces CAN be easily scratched,
and are NOT electrically insulative.

 

[Smitty Two]

In article <6n2f055f2cf7o909h9m9e7gfgm99cq8cvd@4ax.com>,
Archimedes' Lever <OneBigLever@InfiniteSeries.Org> wrote:

"black anodized" is surely able to be scratched. "Hard anodized" is
the one that is unlikely to get scratched, unless it was not properly
applied.

The only difference between standard anodizing, and hard anodizing, is
the depth. Standard anodizing is on the order of 0.0003" thick, while
"hard" anodizing is on the order of 0.001" thick. They're both aluminum
oxide, therefore same hardness.

 

[Archimedes' Lever]

On Sun, 10 May 2009 23:21:45 -0700, Smitty Two <prestwhich@earthlink.net>
wrote:

In article <6n2f055f2cf7o909h9m9e7gfgm99cq8cvd@4ax.com>,
Archimedes' Lever <OneBigLever@InfiniteSeries.Org> wrote:

"black anodized" is surely able to be scratched. "Hard anodized" is
the one that is unlikely to get scratched, unless it was not properly
applied.

The only difference between standard anodizing, and hard anodizing, is
the depth. Standard anodizing is on the order of 0.0003" thick, while
"hard" anodizing is on the order of 0.001" thick. They're both aluminum
oxide, therefore same hardness.

"Hard anodizing came in three flavors at one time, and all three were
depth related, and though the normal method is the same process, the fact
that it is not done to a substantial depth, and the fact that that means
it will have sparse surface coverage as well, means that one gets not
insulative property, and next to no hardness gain. At least not enough to
resist scratches as well as the mil spec methods do.