I'm in the process of stripping a set of vending machines down to bare metal to repaint. It will be a rattle can paint job. I'm behind schedule on this install and it's a high-end account, so I want to nail this. I've already screwed up once painting these.

I consider myself a pretty decent DIY'er, but painting of any type has always been a trouble spot for me.

I used 80 grit sandpaper to remove the old paint. Is it necessary to sand the bare metal with a finer grit before priming? If so, what grit should I go down to?

Any other tips on the overall process would be appreciated.

Your using a rattle can? I would find some high build primer and read the can.

Your going to get a finer mist out of a can than with a guy with a 1.8 or 2.2 tip. That finer mist will not cover scratches well.

If it were me I would get some 220grit D/A paper and sand it down with that. Your really not going to see 220 grit scratches and a DA does a good job of making scratches that wont transfer well to the final surface.

When I got my motorcycle frame and tanks painted, I found a Maaco guy who painted on the side. He was excellent and very reasonably priced. I would try to find someone who can do this on the side for you. You do the prep and he sprays. It will look great and make your life easier.

Hey Saigon 71,
A couple of tips I have learned over the years. When spraying aerosol paint there is a window of drying time that is important. Do all your painting and coats with one hour. Do not think that you will do some touch up the next morning, it will bust up and wrinkle on you. Needs to dry a min of 48 hrs. Not many manufactures will tell you this.
Also, feather sand old original paint with 220grit, if you strip bare metalyou can use a aerosol self etching primer. Aerosol is easy, but can be a heart breaker.

Bruce

Also, I find that the problem described above in which a second coat will cause the first one to lift is worse with rustoleum paints. Just my xperience born of frustration

80 grit scratches will show up, now or later. I like no less than 180, and prefer 220 for bare metal.

I like to treat bare metal with a 1:1 solution of Ospho and clean water. 1st I wash it with soap and water with a red scuff pad, then rinse with clean water. After fully rinsed but still wet spray with Ospho mix and go over it with another scuff pad, let it sit for a minute spraying anywhere it's trying to dry. Then rinse off Ospho mix with clean water and dry thoroughly. When you do it right it'll look like it's been blued a little. Your metal will hold paint better and have less a tendency to flash rust.

This is a great idea for one-off paint jobs (and 914 painting in my case)...but I find myself needing to repaint old equipment a couple times a year and want to learn how to lay down a decent paint job.

Thanks for the replies and advice. I am grateful for the wealth of knowledge on this forum.

I went down to 220 grit on the bare metal with the DA sander and blew them off with compressed air. Next was two wipe downs with denatured alcohol, using a fresh microfiber cloth each time.

I applied two coats of primer and HAND SANDED with 220 grit. I hand sanded because my air compressor tends to "spit" when operating in humid weather. I may invest in a good air drying system. I believe this is what has contaminated more than one paint job for me.

After two wipe downs with a damp microfiber cloth I shot two coats of gloss black. The first coat was very light. The second was a full coat. I kept the light on it during the 2nd coat so I could move as soon as it flashed.

Overall, they turned out well. There is one small spot on one side where the paint is rough - but I can hide that. I suspect I didn't shake the can long enough.

Thanks again!

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That's a lot of area for a rattle can. Kudos on getting a good finish!
If you do this a fair amount and would like to learn more about painting, check your local vocational programs.They often have night classes in body and paint...

Echo some of the above statements.
If you do a lot of painting, the HF HVLP guns aren't horrible, and you can get rustoleum in gallon buckets and mix it with xylene (IIRC). Probably cheaper in the long run the rattle cans, and you can get a better coat of paint that way too.

I painted a friends farm truck this way (about 8 coats of paint) and it worked well.


Zach