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Posted by Proctologically Violated©® on July 6, 2009, 11:48 am
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>> Awl --
>>
>> Yeah, not doing it myself, but I would like to be better prepared, to
>> appear less of my normally rube-ish self, as I start the procuring
>> process.
>>
>> I'll be anodizing 1" x 12" rounds w/ tapped ends, and drilled 1/4" plate,
>> anywhere from 8"x36 to 12"x48, with some drilled holes.
>>
>> Ito of quan, I'd proly be doing any where from 25 rounds/6 plates to
>> mebbe 4 times that, 100 rounds/25 plates or so, at one time.
>>
>> How finished does "finished" have to be, for "good" anodizing results?
>> For example, is typical alum round bar, extruded, and scotchbrited on a
>> lathe a good enough finish?
>>
>> Ito "sandpaper grit" finish on plate, how coarse sandpaper is too coarse?
>> 60? 120? 240?
>>
>> How does their caustic bath act, ito softening sharp edges? Loosening
>> tapped holes? Should these be plugged?
>> I'm assuming these caustic baths will obviate any cleaning/degreasing on
>> my part.
>>
>> Any stories/experiences? Any sample prices?
>
> For big lots the anodizer we use in Baltimore charges $250 per tankload
> when we send up large flat plates (18x33"x.16") 30-150 at a time. Their
> tanks are about 8' long and they can get 8 plates in a load so they charge
> us $31.25 each. That's for type III hardcoat (also called milspec) which
> is much thicker and tougher than normal type II commercial anodizing. We
> negotiated that price based on several hundred plates per year; the type
> II was about $20 per plate. Another big plater in town quoted us 50%
> higher,
Wow, that's a hefty bill, it rivals the cost of the material PLUS the
machining!
Appreciate the reference point, tho, esp. as the geometries are similar.
--
Mr. PV'd
Mae West (yer fav CongressShill) to the Gangster (yer fav Lobbyist):
Hey, Big Boy, is that a wad (of cash) in yer pocket, or are you just
glad to see me??
Experiment on Homo Sapiens -- CEOs, Lawyers, and Politicians, in
particular.
Spare the animals.
Click here every day to feed an animal that needs you today.
www.theanimalrescuesite.com/
> because their tanks were smaller so it would take them more tankloads.
> For smaller pieces and smaller quantities that wouldn't matter so much but
> you will probably see a $75-150 minimum lot charge if you only take up a
> few smaller pieces. The type II has a soft silver color and takes dyes
> well. The type III looks like a muddy brownish silver, even greenish
> sometimes, and doesn't look that good dyed. We don't get it dyed, just
> the natural finish. We used to use type II and have the plates run
> through a grainer with 220 grit (I think), and the etch step took out all
> the scratches and left a very smooth surface to the eye and touch. The
> type III etch is even deeper so we quit graining them, just leave the mill
> finish, and they come out nice and smooth. The Al2O3 layer is less dense
> than the aluminum metal so holes actually shrink in diameter about 0.001"
> or less. We don't have any masking done and the threaded holes come out
> fine. We have three precision through holes and we just had to tweak the
> machined diameter slightly so the final size was as desired. I wouldn't
> leave any big dirt spots on the metal but we just let the coolant drain
> off and air dry and their wash takes care of it.
>
>>
>> So far, my understanding is that regular un-colored anodizing is about
>> 1/3 the cost of colored anodizing. And that the sometimes brilliant
>> finish you see is not anodizing but a kind of clear-coating on top of the
>> anodizing -- extree charge, no doubt. And also extra protection?
>>
>> And a general Q:
>> How does uncolored anodizing differ from regular aluminum oxidation?
>> Rephrased, why does un-colored anodizing look so good, and oxidized
>> aluminum look so crappy? Isn't it all Al2O3?
>
> It's all Al2O3 but the anodized film is thicker, more uniform, and the
> sealing step makes it denser and adhere better so it is much more scratch
> resistant (doesn't flake off). I've cleaned grungy spills with a red
> scotchbrite pad and didn't leave any scratches.
>
>>
>> And another general Q:
>>
>> What alternatives are there to anodizing? Paint/laquer? Powder metal
>> coatings? Any "stains" for alum?
>> Any opinions on the relative merits of these, cost or otherwise?
>>
>> --
>>
>> Mr. PV'd
>>
>> Mae West (yer fav CongressShill) to the Gangster (yer fav Lobbyist):
>> Hey, Big Boy, is that a wad (of cash) in yer pocket, or are you just
>> glad to see me??
>>
>> Experiment on Homo Sapiens -- CEOs, Lawyers, and Politicians, in
>> particular.
>> Spare the animals.
>>
>> Click here every day to feed an animal that needs you today.
>> www.theanimalrescuesite.com/
>>
>>
>>
>>
>
> Verizon cut the alt groups so this probably won't get to alt.machines.cnc,
> sorry.
>
> -----
> Regards,
> Carl Ijames
>
>
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Posted by on July 5, 2009, 6:30 pm
Please log in for more thread options On Jul 5, 11:33=A0am, "Proctologically Violated=A9=AE"
> Awl --
>
> Yeah, not doing it myself, but I would like to be better prepared, to app=
ear
> less of my normally rube-ish self, =A0as I start the procuring process.
>
> I'll be anodizing 1" x 12" rounds w/ tapped ends, and drilled 1/4" plate,
> anywhere from 8"x36 to 12"x48, with some drilled holes.
>
> Ito of quan, I'd proly be doing any where from 25 rounds/6 plates to mebb=
e 4
> times that, 100 rounds/25 plates or so, at one time.
>
> How finished does "finished" have to be, for "good" anodizing results?
> For example, is typical alum round bar, extruded, and scotchbrited on a
> lathe a good enough finish?
>
> Ito "sandpaper grit" finish on plate, how coarse sandpaper is too coarse?
> 60? =A0120? =A0240?
>
> How does their caustic bath act, ito softening sharp edges? =A0Loosening
> tapped holes? =A0Should these be plugged?
> I'm assuming these caustic baths will obviate any cleaning/degreasing on =
my
> part.
>
> Any stories/experiences? =A0Any sample prices?
>
> So far, my understanding is that regular un-colored anodizing is about 1/=
3
> the cost of colored anodizing. =A0And that the sometimes brilliant finish=
you
> see is not anodizing but a kind of clear-coating on top of the anodizing =
-- =A0
> extree charge, no doubt. =A0And also extra protection?
>
> And a general Q:
> =A0 =A0How does uncolored anodizing differ from regular aluminum oxidatio=
n?
> Rephrased, why does un-colored anodizing look so good, and oxidized alumi=
num
> look so crappy? =A0Isn't it all Al2O3?
>
> And another general Q:
>
> What alternatives are there to anodizing? =A0Paint/laquer? =A0Powder meta=
l
> coatings? =A0Any "stains" for alum?
> Any opinions on the relative merits of these, cost or otherwise?
>
> --
>
> Mr. PV'd
>
For a time, I worked Q. C. in a motor home anodizing plant. First
tank in was a hot saturated caustic etch solution, any semblance of a
polish disappeared rapidly after that. It removed any residual oxide
film, plus got rid of bending lube, finger prints and general plant
crud. So don't expect a mirror polish to last under your anodizing,
not going to happen. There's hundreds of different formulas for
anodizing processes, we were using one Alcoa developed for decorative
anodizing, which could be dyed. It used sulphuric acid for the
electrolyte. Had humongous chillers to keep the solution temp down,
too. You can have decorative anodizing, or you can go with the hard
stuff, which can't be dyed. Pick your poison. The hard stuff uses
chromic acid, EPA hates it. So probably will be limited availability
on that. The decorative sort leaves an oxide surface of hexagonal
pores, which can be filled with a dye solution and sealed off with a
hot nickel acetate solution. The color only lasts as long as the dye,
red fades fast, black fades to either blue or brown. The oxide
surface is kind of like glass, any extreme bends and the stuff
cracks. The decorative sort isn't that abrasion resistant, either, I
remember one fellow's Walther PPK was worn down to the metal with just
a couple of years of carrying.
Oxidized aluminum just happens, anodizing makes sure that the job is
done evenly.
A much more resistant sort of finish is powder coat, we had polyester
and epoxy(different colors). Either would outlast anodizing 10 to one
in the 1000 hour salt spray test. By the end, the anodized test
coupons had vanished, the powder-coated stuff was just a little chewed
around the edges.
As far as production cost is concerned, the running cost for powder
coating on a production basis is a whole lot less, a lot fewer toxics
involved. If done properly, you can recover what little powder
escapes the transfer process. We had to have folks spend a lot of
time racking and unracking parts on the anodizing side, had to use
titanium racks and hardware. Everything had to be bolted up to make
electrical contact, lots of hands involved in that. Powder-coating
parts were just hung on conveyor hooks that ran through the washer and
drying oven, a continuous process.
Stan
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Posted by Proctologically Violated©® on July 6, 2009, 12:01 pm
Please log in for more thread options
On Jul 5, 11:33 am, "Proctologically Violated©®"
> Awl --
>
> Yeah, not doing it myself, but I would like to be better prepared, to
> appear
> less of my normally rube-ish self, as I start the procuring process.
>
> I'll be anodizing 1" x 12" rounds w/ tapped ends, and drilled 1/4" plate,
> anywhere from 8"x36 to 12"x48, with some drilled holes.
>
> Ito of quan, I'd proly be doing any where from 25 rounds/6 plates to mebbe
> 4
> times that, 100 rounds/25 plates or so, at one time.
>
> How finished does "finished" have to be, for "good" anodizing results?
> For example, is typical alum round bar, extruded, and scotchbrited on a
> lathe a good enough finish?
>
> Ito "sandpaper grit" finish on plate, how coarse sandpaper is too coarse?
> 60? 120? 240?
>
> How does their caustic bath act, ito softening sharp edges? Loosening
> tapped holes? Should these be plugged?
> I'm assuming these caustic baths will obviate any cleaning/degreasing on
> my
> part.
>
> Any stories/experiences? Any sample prices?
>
> So far, my understanding is that regular un-colored anodizing is about 1/3
> the cost of colored anodizing. And that the sometimes brilliant finish you
> see is not anodizing but a kind of clear-coating on top of the
> anodizing --
> extree charge, no doubt. And also extra protection?
>
> And a general Q:
> How does uncolored anodizing differ from regular aluminum oxidation?
> Rephrased, why does un-colored anodizing look so good, and oxidized
> aluminum
> look so crappy? Isn't it all Al2O3?
>
> And another general Q:
>
> What alternatives are there to anodizing? Paint/laquer? Powder metal
> coatings? Any "stains" for alum?
> Any opinions on the relative merits of these, cost or otherwise?
>
> --
>
> Mr. PV'd
>
For a time, I worked Q. C. in a motor home anodizing plant. First
tank in was a hot saturated caustic etch solution, any semblance of a
polish disappeared rapidly after that. It removed any residual oxide
film, plus got rid of bending lube, finger prints and general plant
crud. So don't expect a mirror polish to last under your anodizing,
not going to happen. There's hundreds of different formulas for
anodizing processes, we were using one Alcoa developed for decorative
anodizing, which could be dyed. It used sulphuric acid for the
electrolyte. Had humongous chillers to keep the solution temp down,
too. You can have decorative anodizing, or you can go with the hard
stuff, which can't be dyed. Pick your poison. The hard stuff uses
chromic acid, EPA hates it. So probably will be limited availability
on that. The decorative sort leaves an oxide surface of hexagonal
pores, which can be filled with a dye solution and sealed off with a
hot nickel acetate solution. The color only lasts as long as the dye,
red fades fast, black fades to either blue or brown. The oxide
surface is kind of like glass, any extreme bends and the stuff
cracks. The decorative sort isn't that abrasion resistant, either, I
remember one fellow's Walther PPK was worn down to the metal with just
a couple of years of carrying.
Oxidized aluminum just happens, anodizing makes sure that the job is
done evenly.
A much more resistant sort of finish is powder coat, we had polyester
and epoxy(different colors). Either would outlast anodizing 10 to one
in the 1000 hour salt spray test. By the end, the anodized test
coupons had vanished, the powder-coated stuff was just a little chewed
around the edges.
As far as production cost is concerned, the running cost for powder
coating on a production basis is a whole lot less, a lot fewer toxics
involved. If done properly, you can recover what little powder
escapes the transfer process. We had to have folks spend a lot of
time racking and unracking parts on the anodizing side, had to use
titanium racks and hardware. Everything had to be bolted up to make
electrical contact, lots of hands involved in that. Powder-coating
parts were just hung on conveyor hooks that ran through the washer and
drying oven, a continuous process.
================================
=================================
I thought anodized alum was Da Bomb ito of finishing and durability, but
you're saying not so.
So why do people go through the extra expense of anodizing?
What is your opinion on the aesthetic/architectural value of anodized vs.
PMC?
I can see the trial and error/decision making on the finishing phase of this
part is going to be a long haul.
Also, the little I've read indicates that diy PMC is a lot more practical
than diy anodizing. And proly a lot more legal, as well.
--
Mr. PV'd
Mae West (yer fav CongressShill) to the Gangster (yer fav Lobbyist):
Hey, Big Boy, is that a wad (of cash) in yer pocket, or are you just
glad to see me??
Experiment on Homo Sapiens -- CEOs, Lawyers, and Politicians, in
particular.
Spare the animals.
Click here every day to feed an animal that needs you today.
www.theanimalrescuesite.com/
Stan
|
|
Posted by Richard J Kinch on July 6, 2009, 5:23 pm
Please log in for more thread options Proctologically Violated©® writes:
> So why do people go through the extra expense of anodizing?
Powder coating is just paint, a plastic polymer such as polyester, stuck on
the surface. Anodizing is hard and durable metal oxide which is chemically
bonded to the elemental metal. Maybe powder coating lasts longer in a salt
spray test for a chemically corrosive environment, but it won't stand up to
UV exposure outdoors as well as anodizing.
My anodized aluminum screen enclosure has spent 30 years in the Florida sun
and rain. The oxide itself is worn but intact. The anodizing dye has
started to fade in the more exposed areas. I can't believe paint or
powder-coating would have lasted more than 5 or 10 years.
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>>
>> Yeah, not doing it myself, but I would like to be better prepared, to
>> appear less of my normally rube-ish self, as I start the procuring
>> process.
>>
>> I'll be anodizing 1" x 12" rounds w/ tapped ends, and drilled 1/4" plate,
>> anywhere from 8"x36 to 12"x48, with some drilled holes.
>>
>> Ito of quan, I'd proly be doing any where from 25 rounds/6 plates to
>> mebbe 4 times that, 100 rounds/25 plates or so, at one time.
>>
>> How finished does "finished" have to be, for "good" anodizing results?
>> For example, is typical alum round bar, extruded, and scotchbrited on a
>> lathe a good enough finish?
>>
>> Ito "sandpaper grit" finish on plate, how coarse sandpaper is too coarse?
>> 60? 120? 240?
>>
>> How does their caustic bath act, ito softening sharp edges? Loosening
>> tapped holes? Should these be plugged?
>> I'm assuming these caustic baths will obviate any cleaning/degreasing on
>> my part.
>>
>> Any stories/experiences? Any sample prices?