Another DIY Paint Job Question

Scott Gordo said:

Skimmed older posts but after a few discussions with shop guys and
hearing all kinds of debris I figured I'd go to the Oracle. That's you
guys.

I garbage picked a half-stripped Specialized Sirrus, probably no more
than a couple years old. Looks like it had been a delivery bike and
treated downright sadistically: maybe 40% of the dark red paint has
been chipped up by a carelessly swung Kryptonite chain and the entire
downtube is now exposed aluminum. There isn't a tube on the bike that
didn't suffer this kind of ritualized beating. What little wasn't
chain-flogged was protected by a thick coat black brake, grease, and
road mung.

Cleaned it up a bit and upon inspection I didn't find any cracks or
dents. Put some wheels on it and took a slow spin (vbrakes had been
removed) around the block and didn't feel anything that suggested
impending catastrophic failure. I've also got some parts lying around
I think would make a happy home on it (and would make my home happier
with less bits strewn about.)

I know we're not exactly talking about a vintage Masi here, but if it
doesn't mean a ludicrous amount of labor I'd be interested in
stripping the frame down and trying a decent rattlecan job. More than
anything this would be a trial run as within a few years I don't think
I'll be able to find a nail polish brush wide enough for some of my
steel frames.

I've heard everything from stripping with nasty oven cleaning spray
and a hose to professional bead blasting being the only solution as
there's some kind of factory surface treatment that, if harmed, will
do bad things to the frame. I also read an archived post of Mr. Muzi's
that suggested simply roughing up the clearcoat's surface layer with
sandpaper, priming, and painting, but I think it's likely that the
small craters left where there once was paint will stand out without
some kind of filler, which seems potentially more time consuming than
stripping. I could, however, be coerced otherwise....

Also, naturally, I'm trying to keep the price on this project as close
to nil as possible. Lets say under $30.

For under $30, wash the bare frame (detergent and hot water) thoroughly
to remove any oil, wax, crud, silicon, etc. Wetsand the finish with 400
paper such that there are no shiny spots in the old paint.

I'd chance a good scrubbed and sanded aluminum and old paint substrate
with grey aerosol primer at this level. If you find poor adhesion after
a year or two, you can use real metal etch next time. (I don't think,
given the budget and your educational component here, that's worth
anguishing over)

Wetsand with 600 between coats of primer and before color if desired.
You'll get a much improved finish with a small time investment at that
point. Multiple primer coats are OK to fill uneven 'lock peened' areas.

Note that you can't get a decent finish working below about 65 degrees
and you'll need ventilation, so, depending on your location, January may
be a problem.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

"A Muzi" wrote: (clip) Note that you can't get a decent finish working
below about 65 degrees (clip)
^^^^^^^^^^^^^^^^^^^
When I want my rattle-can paint to spray really well, especially in cold
weather, I shake the can while holding it under a hot water tap. Adjust the
water temp 'til it's ALMOST uncomfortable. This raises the propellant
pressure and lowers the paint viscosity, both of which help produce a very
fine spray.

DON'T do what my friend did, and heat it on the stove, while chatting
outside with a friend. The can exploded, shot up like a rocket, broke the
stove grate and sprayed red paint all over his kitchen, and embedded itself
in the ceiling.

Leo Lichtman said:

When I want my rattle-can paint to spray really well, especially in cold
weather, I shake the can while holding it under a hot water tap. Adjust the
water temp 'til it's ALMOST uncomfortable. This raises the propellant
pressure and lowers the paint viscosity, both of which help produce a very
fine spray.

You still won't get a proper finish below 65 degrees without mixing
the paint with a proper low temp additive (difficult with a rattle
can).

Leo Lichtman said:

DON'T do what my friend did, and heat it on the stove, while chatting
outside with a friend. The can exploded, shot up like a rocket, broke the
stove grate and sprayed red paint all over his kitchen, and embedded itself
in the ceiling.

GIF! GIF!

Leo Lichtman said:

...
DON'T do what my friend did, and heat it on the stove, while chatting
outside with a friend. The can exploded, shot up like a rocket, broke the
stove grate and sprayed red paint all over his kitchen, and embedded itself
in the ceiling.

We want video!

--
Tom Sherman - Holstein-Friesland Bovinia
POST FREE OR DIE!