Cast alum. (maybe magnesium) brake caliper. Original paint is chipped off in
places, and metal looks oxidized.
How to best prepare this metal? A good scrubbing and rinsing, of course.
Light sanding, too. Then a good primer, thorough dry, and one or more top
coats (complete dry between).
How important is it to sand *every* crevice? Am I compromising the entire
paint job if I can't get these tiny corners?
And regarding product: is just enamel OK? The calipers are basically sand-
(and gravel-) blasted all day long. Is there a better spray product (powder
coating not an option) than hardware store enamel? Which primer to use?
Maybe not critical, but close. consider wire brush.
Wherever you don't clean is where the paint will fail.
I doubt it, but I don't have a can here.
I would bet it wants to be sprayed directly on the base metal.
* Aluminum (Limited Adhesion).
That's it, no more suggestions
there are a lot of break caliper paints out there in many colors so you
find one that fits your taste (i would say follow directions as to what
primer/prep). as to prep if you cant sand blast i would clean as best you
and lightly sand then put them in a bucket with a lid and fine sand and
shake, roll down a hill a few times, or put in the back of another vehicle
drive is stop and go traffic for a few days
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On Tue, 1 Sep 2009 20:51:13 -0700, Steve Lusardi wrote
(in article ):
Thanks very much, Steve, for sharing that experience. Very helpful. I get to
learn from your experimentation. Which likely means success the first time
This can be an issue because most of the time you do not know the cause of the
corrosion and that cause, whatever it is, will be
in the pits. Here is an example I had a cast aluminum base from a pedestal that
was badly corroded. I faced this base leaving just
a few remaining pits. I then placed the base on a new, never exposed to weather
aluminum plate for 24 hrs. After returning and
lifting the base, the new plate was corroding in the same location of the
remaining pits on the base.. This base had been exposed
to salt water very briefly and was the cause of this corrosion. I then washed
the base with white vinegar and replaced the base
again on another fresh plate. One day later, no corrosion. Salt reacts with
aluminum very rapidly if not well anodized. So the
lesson is that if the cause of this corrosion is not neutralized before
painting, the corrosion will continue and the paint
system, whatever it is, will fail. I think it is safe to assume that your
observed corrosion could be caused by road salt. Please
consider treating the casting with vinegar after thorough cleaning. Wash again,
dry the casting and use an etching primer before
This tip was the result of a discussion I had with a professional powder coater
who stated that very often corroded aluminum
parts, even after thorough bead blasting had been done, the fresh powder coating
failed. I believe I have discovered why. Now the
powdercoater routinely washes corroded aluminum pieces after beadblasting with
vinegar as insurance and has not had a failure
"Steve Lusardi" wrote: I assumed that salt is a base and to neutralize it,
the application of an acid would be in order. As vinegar is a mild form of
Salt is not a base. Salts are the reaction products of acids and bases, and
are neutral. If vinegaqr worked, it ios probably becaquse it is a solvent
for the corrosion that was on the metal. (Table salt, NaCl, is the reaction
product of HCl and NaOH.)
Caustic soda (drain cleaner )is a good paint stripper , but it will
attack aluminium and completely dissolve it if left in the solution too
I have used it to strip paint from parts for my power hacksaw
restoration it removed 40 years of layered repaints from the parts very
Some of the parts were aluminium and I had to watch them very closely ,
as soon as the paint has been removed you need to wash them with clean
water , the paint will just wash off.
I would plug any holes and galleries that you don't want the solution to
I would bead blast, mask, prime with an etching primer (check with
FinshMaster, I think I've been payint $16 per spray can) and then use the
industrial Imron in the color of your choice. the urethane will hold up
better to the blasting by road dust than an enamel or lacquer
i recently recoated my kitchen cabinet knobs. sand blasted them with AlO2
first, down to bare metal, then 2 coats of rustoleum appliance epoxy paint
in a high gloss black (rattlecan). it filled the blasted surface completely
(to where you can't tell it was blasted) and after curing at 200F for 4
hours, is very hard to scratch off.
follow can directions for recoating and cure times correctly.