help my sanity-- spray paint troubles

I have 2 flat metal parts made out of steel. I want to paint them flat black. I was recommended Rust-o-Leum 7777 as a perfect match for the
paint color and finish.
I first stripped the old paint with a spray-on stripper and than spray painted. Looked great, but I wasn't pleased with how hard the finish was. It scratched with my finger-nail.
I re-read the directions and realized I did *not* use primer. Of course I was pissed off, but I decided to redo everything.
I stripped the paint again using the same, nasty spray-on stuff. I then rinsed with water, and used a wire-brush attached to my electric drill to get most of the old stuff off. I then wiped it down with a wet rag and let dry.
This time I used Rust-o-leum primer first, then applied the same spray paint. But it seems the finish is even softer than before.
What am I doing wrong? I'm about to give up on this seemingly simple project. The cast-iron parts that I painted are just fine.
--Mike
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Mike wrote:

Rustoleum dries particularly slowly. If you have a "hot box" or oven you could bake the painted pieces in for a couple of days, you will go from "soft finish" to "hard as it'll get".
It still won't be as hard as powder coat etc.

There are a lot of different primers available. Generally there's more paint to dry with two coats and it'll be softer for longer.
Tim.
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Mike wrote:

You can try baking them at 300F for 45 minutes or so to make sure they are fully dry. Other than that, you can start thinking about topcoats, or redoing with a tougher paint. Perhaps an epoxy paint would have worked better for you, or powdercoating.
GWE
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Nothin'... Alkyd enamels take quite a bit of time (often weeks) to reach full hardness. Cyanic hardeners will speed that up, but you can't add them to spray paint already in the can.
LLoyd
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Yes... weeks upon weeks sometimes before Rustoleum fully "cures out". You shouldn't use their "Rusty Metal Primer" on clean metal either, because there's too much fish oil in it, so it dries even slower and the paint won't adhere very well. David

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I quit using the hardware store Rustoleum paints years ago because they dry too slowly. However, their industrial paint line has a much larger variety. One of which is:
http://www.rust-oleum.com/Product.asp?frm_product_id 6&SBL=2&ddis Randy

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If it's for outside use, there's other choices than Rustoleum. My last go-around with that brand has put me off it indefinitely. Stuff would lift off with naptha after two weeks drying time in the summer heat. Naptha normally doesn't affect most dry and cured finishes. You could try the oven for drying, if the parts are small enough or use heat lamps to see if you can get a better cure.
Last time I needed a flat black finish, I went with urethane in a spray can. That brand disappeared overnight off the paint store shelves when CA went with their revised VOC regs. The stuff I've sprayed with it has stood up well, though, still have some full cans of it. There's some flat epoxy sprays that work pretty good, not as durable as the urethane, though.
You have a much wider paint selection if you can get even a small spray gun setup, auto finishes are extremely durable and you can get just about any color you want. Downside is cost for the paint, though. Small touchup guns like I started with run $15-20 on sale at HF, work great for the odd small paint job and usually don't need a huge compressor.
Stan
If it's for outside use, there's other choices than Rustoleum. My last go-around with that brand has put me off it indefinitely. Stuff would lift off with naptha after two weeks drying time in the summer heat. Naptha normally doesn't affect most dry and cured finishes. You could try the oven for drying, if the parts are small enough or use heat lamps to see if you can get a better cure.
Last time I needed a flat black finish, I went with urethane in a spray can. That brand disappeared overnight off the paint store shelves when CA went with their revised VOC regs. The stuff I've sprayed with it has stood up well, though, still have some full cans of it. There's some flat epoxy sprays that work pretty good, not as durable as the urethane, though.
You have a much wider paint selection if you can get even a small spray gun setup, auto finishes are extremely durable and you can get just about any color you want. Downside is cost for the paint, though. Small touchup guns like I started with run $15-20 on sale at HF, work great for the odd small paint job and usually don't need a huge compressor.
Stan
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One comment on the cost of paint...There are paint shops that will sell or even give away mistints and body shops will sometimes let older partial cans of paint go so they don't have to dispose of it. A spray gun is the way to go for job you need a durable finish on. Steve
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I often get lots of already mixed paints form body shops...I get all kinds of colors and types, with the exceptions of primer sealers. They have to pay to have it hauled away, and most are happy to let someone have it for free.
On Wed, 12 Apr 2006 16:23:32 -0500, "Steve Peterson"

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RustOleum is more decorative than durable. Urethanes and epoxies are much more durable. If you can't find the color you want as a stock item, you can buy paint in cans, mix to get the color you want, thin with appropriate thinner and spray. If you don't have a compressor, you can buy little Pre-Val oneshot sprayers that work with a can of propellent.
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Balderdash and poppycock. When I refinished the headlight buckets for my Roadster, I sandblasted them, applied 2 coats of Rustoleum red primer, then 2 coats of Rustoleum Copper Enamel. Once *dry*, the finish is beautiful, and plenty hard. I test the finish as I type: Dragging the thumbnail at right angles across the finish as hard as practical, the finish is absolutely unmarked. I agree, however, Rustoleum is not as hard as a good cured epoxy or urethane. JR Dweller in the cellar
Don Foreman wrote:

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wrote:
Response bottom-posted

Perhaps "durable" is a subjective term. If Rustoleum results are acceptable, it is definitely more cost-effective. I use it on some projects. There is no way I'd paint a car or any part of a car with it, YMMV. Even acrylic enamel (e.g. Delstar) delivers considerably better gloss (distinction of image) and durability than Rustoleum.
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JR North wrote:

Agreed.
the only thing I've found better than Rusty Metal Primer is Epi-Bond, but for the price difference!
Richard
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Thanks for all the replies. Sounds like I just need to exercise a little more patience before taking my fingernail to the finish! I'll also try using some heat in the form of high-wattage light bulbs.
On Wed, 12 Apr 2006 10:41:20 -0500, Mike wrote:

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If you can stand a little bit of a satin finish try using bar-b-cue black and then baking it. Pretty nice finish on bike parts for the anti chrome set.
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I just kit what ever I intend to paint with KRYLON paint, and the hell with primers and all the fuss of prep etc, and the paint sticks just fine and is there years down the road..........pitch the rustoleum, just clean off the old paint, use krylon spray on primer and top coat with krylon paint. Flat black is afterall flat black....Krylon is not fussy, and odds are skipping the primer won;t hurt much of anything either. Primer in no way makes a surface finish harder.

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